# =========================================================
# EGARCH(1,1)-X + Mean–VaR Optimization with DEoptim
# Extended: Simulasi Max Risk
# =========================================================

library(readxl)
library(dplyr)
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library(stringr)
library(lubridate)
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## Attaching package: 'lubridate'
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library(PerformanceAnalytics)
## Loading required package: xts
## Loading required package: zoo
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## # work, which breaks lag(my_xts). Calls to lag(my_xts) that you type or       #
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library(forecast)
## Registered S3 method overwritten by 'quantmod':
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library(tseries)
library(car)
## Loading required package: carData
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library(lmtest)
library(PortfolioAnalytics)
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library(DEoptim)
## Loading required package: parallel
## 
## DEoptim package
## Differential Evolution algorithm in R
## Authors: D. Ardia, K. Mullen, B. Peterson and J. Ulrich
library(reshape2)
library(ggplot2)
library(quadprog)
library(quantmod)
## Loading required package: TTR
library(rugarch) # Untuk GARCH-X
library(gridExtra)
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library(tidyr)
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library(tibble)
# 1. Data
# Import BI Rate data
birate <- read_excel("Database/bi_rate.xlsx")
colnames(birate) <- c("date","bi_rate")
head(birate); tail(birate)
## # A tibble: 6 × 2
##   date              bi_rate
##   <chr>             <chr>  
## 1 18 Desember 2024  6.00   
## 2 20 November 2024  6.00   
## 3 16 Oktober 2024   6.00   
## 4 18 September 2024 6.00   
## 5 21 Agustus 2024   6.25   
## 6 17 Juli 2024      6.25
## # A tibble: 6 × 2
##   date              bi_rate
##   <chr>             <chr>  
## 1 22 September 2016 5.00   
## 2 19 Agustus 2016   5.25   
## 3 21 Juli 2016      5.25   
## 4 16 Juni 2016      5.25   
## 5 19 Mei 2016       5.50   
## 6 21 April 2016     5.50
Sys.setlocale("LC_TIME", "id_ID.UTF-8") 
## [1] "id_ID.UTF-8"
birate <- birate %>%
  mutate(date = dmy(date))
birate$bi_rate <- as.numeric(birate$bi_rate)
birate <- birate[order(birate$date), ]
head(birate)
## # A tibble: 6 × 2
##   date       bi_rate
##   <date>       <dbl>
## 1 2016-04-21    5.5 
## 2 2016-05-19    5.5 
## 3 2016-06-16    5.25
## 4 2016-07-21    5.25
## 5 2016-08-19    5.25
## 6 2016-09-22    5
# Import 10-year bond data
bond10 <- read.csv("Database/bond10 new.csv")
bond10 <- bond10[, c("Date", "Price")]
colnames(bond10) <- c("date", "bond10")
bond10$date <- ymd(as.Date(bond10$date))
str(bond10)
## 'data.frame':    234 obs. of  2 variables:
##  $ date  : Date, format: "2025-04-30" "2025-03-27" ...
##  $ bond10: num  99.1 97.4 98.7 98.4 97.3 ...
# Filter data antara 2014-01-01 dan 2024-12-31
bond10 <- bond10 %>%
  filter(date >= as.Date("2014-01-01") & date <= as.Date("2024-12-31"))
bond10 <- bond10[order(bond10$date), ]
head(bond10)
##           date  bond10
## 132 2014-01-30  96.883
## 131 2014-02-28  99.809
## 130 2014-03-28 102.600
## 129 2014-04-30 102.700
## 128 2014-05-30 102.150
## 127 2014-06-30 100.800
# Import Bitcoin data
btc_usd <- read.csv("Database/btc_usd.csv")
btc_usd <- btc_usd[, c("Tanggal", "Terakhir")]
colnames(btc_usd) <- c("date", "btc")
btc_usd <- btc_usd %>%
  mutate(date = dmy(date))
btc_usd <- btc_usd[order(btc_usd$date), ]
btc_usd <- btc_usd %>%
  mutate(btc = as.numeric(gsub(",", "", btc)))
head(btc_usd)
##            date  btc
## 4015 2014-01-01 7403
## 4014 2014-01-02 7750
## 4013 2014-01-03 8121
## 4012 2014-01-04 8018
## 4011 2014-01-05 9040
## 4010 2014-01-06 9345
# Import CPI data
cpi <- read_excel("Database/inflation.xlsx")
colnames(cpi) <- c("date", "cpi")
bulan_id <- c("Januari","Februari","Maret","April","Mei","Juni",
              "Juli","Agustus","September","Oktober","November","Desember")
bulan_en <- c("January","February","March","April","May","June",
              "July","August","September","October","November","December")

cpi <- cpi %>%
  mutate(date = str_replace_all(date, setNames(bulan_en, bulan_id)),
         date = parse_date_time(date, orders = "my"),
         date = as.Date(date))
cpi <- cpi[order(cpi$date), ]
cpi$cpi <- as.numeric(cpi$cpi)
head(cpi)
## # A tibble: 6 × 2
##   date         cpi
##   <date>     <dbl>
## 1 2014-01-01  8.22
## 2 2014-02-01  7.75
## 3 2014-03-01  7.32
## 4 2014-04-01  7.25
## 5 2014-05-01  7.32
## 6 2014-06-01  6.7
# Import JKSE data
jkse <- read.csv("Database/jkse.csv")
jkse <- jkse[, c("Tanggal", "Terakhir")]
colnames(jkse) <- c("date", "jkse")
jkse <- jkse %>%
  mutate(date = dmy(date))
jkse <- jkse[order(jkse$date), ]
jkse <- jkse %>%
  mutate(
    jkse = str_replace_all(jkse, "\\.", ""),  # hapus titik (pemisah ribuan)
    jkse = str_replace_all(jkse, ",", "."),   # ubah koma jadi titik (desimal)
    jkse = as.numeric(jkse)                   # ubah jadi numeric
  )
head(jkse)
##            date    jkse
## 2681 2014-01-01 4274.18
## 2680 2014-01-02 4327.27
## 2679 2014-01-03 4257.66
## 2678 2014-01-06 4202.81
## 2677 2014-01-07 4175.81
## 2676 2014-01-08 4200.59
# Import IDR exchange rate data
kurs_idr <- read.csv("Database/idr_kurs.csv")
kurs_idr <- kurs_idr[, c("Tanggal", "Terakhir")]
colnames(kurs_idr) <- c("date", "kurs_idr")
kurs_idr <- kurs_idr %>%
  mutate(date = dmy(date))
kurs_idr <- kurs_idr[order(kurs_idr$date), ]
kurs_idr <- kurs_idr %>%
  mutate(
    kurs_idr = str_replace_all(kurs_idr, "\\.", ""),  # hapus titik (pemisah ribuan)
    kurs_idr = str_replace_all(kurs_idr, ",", "."),   # ubah koma jadi titik (desimal)
    kurs_idr = as.numeric(kurs_idr)                   # ubah jadi numeric
  )
head(kurs_idr)
##            date kurs_idr
## 2815 2014-01-01  12170.0
## 2814 2014-01-02  12160.0
## 2813 2014-01-03  12170.0
## 2812 2014-01-06  12180.0
## 2811 2014-01-07  12237.5
## 2810 2014-01-08  12235.0
# Gold data
gold <- read.csv("Database/gold.csv")
gold <- gold[, c("Tanggal", "Terakhir")]
colnames(gold) <- c("date", "gold")
gold <- gold %>%
  mutate(date = dmy(date))
gold <- gold[order(gold$date), ]
gold <- gold %>%
  mutate(
    gold = str_replace_all(gold, "\\.", ""),  # hapus titik (pemisah ribuan)
    gold = str_replace_all(gold, ",", "."),   # ubah koma jadi titik (desimal)
    gold = as.numeric(gold)                   # ubah jadi numeric
  )
head(gold)
##            date   gold
## 2816 2014-01-02 1225.2
## 2815 2014-01-03 1238.6
## 2814 2014-01-06 1238.0
## 2813 2014-01-07 1229.6
## 2812 2014-01-08 1225.5
## 2811 2014-01-09 1229.4
## Monthly Data Aggregation and Preprocessing
# Convert data to monthly format (for those that aren't already monthly)

birate_monthly <- birate %>%
  mutate(year_month = floor_date(date, "month")) %>%
  group_by(year_month) %>%
  summarise(bi_rate = mean(bi_rate, na.rm = TRUE)) %>%
  rename(date = year_month)

bond10_monthly <- bond10 %>%
  mutate(date = floor_date(date, "month"))

btc_monthly <- btc_usd %>%
  mutate(year_month = floor_date(date, "month")) %>%
  group_by(year_month) %>%
  summarise(btc = mean(btc, na.rm = TRUE)) %>%
  rename(date = year_month)

jkse_monthly <- jkse %>%
  mutate(year_month = floor_date(date, "month")) %>%
  group_by(year_month) %>%
  summarise(jkse = mean(jkse, na.rm = TRUE)) %>%
  rename(date = year_month)

kurs_idr_monthly <- kurs_idr %>%
  mutate(year_month = floor_date(date, "month")) %>%
  group_by(year_month) %>%
  summarise(kurs_idr = mean(kurs_idr, na.rm = TRUE)) %>%
  rename(date = year_month)

gold_monthly <- gold %>%
  mutate(year_month = floor_date(date, "month")) %>%
  group_by(year_month) %>%
  summarise(gold = mean(gold, na.rm = TRUE)) %>%
  rename(date = year_month)

cpi_monthly <- cpi %>%
  mutate(year_month = floor_date(date, "month")) %>%
  group_by(year_month) %>%
  summarise(cpi = mean(cpi, na.rm = TRUE)) %>%
  rename(date = year_month)

# Merge all datasets
merged_data <- birate_monthly %>%
  full_join(bond10_monthly, by = "date") %>%
  full_join(btc_monthly, by = "date") %>%
  full_join(cpi_monthly, by = "date") %>%
  full_join(jkse_monthly, by = "date") %>%
  full_join(kurs_idr_monthly, by = "date") %>%
  full_join(gold_monthly, by = "date")

# Sort by date
merged_data <- merged_data %>% arrange(date)

# Check the result
head(merged_data)
## # A tibble: 6 × 8
##   date       bi_rate bond10   btc   cpi  jkse kurs_idr  gold
##   <date>       <dbl>  <dbl> <dbl> <dbl> <dbl>    <dbl> <dbl>
## 1 2014-01-01      NA   96.9 8194.  8.22 4350.   12158. 1244.
## 2 2014-02-01      NA   99.8 6605.  7.75 4515.   11918. 1301.
## 3 2014-03-01      NA  103.  5929.  7.32 4720.   11416. 1337.
## 4 2014-04-01      NA  103.  4620.  7.25 4871.   11431. 1299.
## 5 2014-05-01      NA  102.  4829.  7.32 4925.   11536. 1288.
## 6 2014-06-01      NA  101.  6179.  6.7  4898.   11892. 1283.
tail(merged_data)
## # A tibble: 6 × 8
##   date       bi_rate bond10   btc   cpi  jkse kurs_idr  gold
##   <date>       <dbl>  <dbl> <dbl> <dbl> <dbl>    <dbl> <dbl>
## 1 2024-07-01    6.25   97.9  62.9  2.13 7258.   16238. 2398.
## 2 2024-08-01    6.25  100.   60.0  2.12 7417.   15735. 2474.
## 3 2024-09-01    6     101.   60.5  1.84 7740.   15318. 2579.
## 4 2024-10-01    6      98.6  65.7  1.71 7621.   15558. 2695.
## 5 2024-11-01    6      98.1  86.5  1.55 7269.   15813. 2656.
## 6 2024-12-01    6      97.3  98.3  1.57 7216.   16036. 2650.
# Check for missing values
colSums(is.na(merged_data))
##     date  bi_rate   bond10      btc      cpi     jkse kurs_idr     gold 
##        0       27        0        0        0        0        0        0
# Data with non NA values
non_na_data <- merged_data %>%
  filter(complete.cases(.))
# Check the non NA data
head(non_na_data)
## # A tibble: 6 × 8
##   date       bi_rate bond10   btc   cpi  jkse kurs_idr  gold
##   <date>       <dbl>  <dbl> <dbl> <dbl> <dbl>    <dbl> <dbl>
## 1 2016-04-01    5.5    105. 4352.  3.6  4853.   13172. 1244.
## 2 2016-05-01    5.5    104. 4617.  3.33 4770.   13417. 1261.
## 3 2016-06-01    5.25   106. 6445.  3.45 4871.   13338. 1279.
## 4 2016-07-01    5.25   110. 6616.  3.21 5166.   13114. 1339.
## 5 2016-08-01    5.25   109. 5858.  2.79 5401.   13160. 1344.
## 6 2016-09-01    5      110. 6083.  3.07 5337.   13110. 1330.
tail(non_na_data)
## # A tibble: 6 × 8
##   date       bi_rate bond10   btc   cpi  jkse kurs_idr  gold
##   <date>       <dbl>  <dbl> <dbl> <dbl> <dbl>    <dbl> <dbl>
## 1 2024-07-01    6.25   97.9  62.9  2.13 7258.   16238. 2398.
## 2 2024-08-01    6.25  100.   60.0  2.12 7417.   15735. 2474.
## 3 2024-09-01    6     101.   60.5  1.84 7740.   15318. 2579.
## 4 2024-10-01    6      98.6  65.7  1.71 7621.   15558. 2695.
## 5 2024-11-01    6      98.1  86.5  1.55 7269.   15813. 2656.
## 6 2024-12-01    6      97.3  98.3  1.57 7216.   16036. 2650.
nrow(non_na_data)
## [1] 105
# Convert BTC to IDR
btc_idr <- non_na_data %>%
  mutate(btc_idr = btc * kurs_idr) %>%
  dplyr::select(date, btc_idr)

# Convert Gold to IDR
gold_idr <- non_na_data %>%
  mutate(gold_idr = gold * kurs_idr) %>%
  dplyr::select(date, gold_idr)

# Add BTC_IDR and Gold_IDR to the dataset
non_na_data <- non_na_data %>%
  left_join(btc_idr, by = "date")
non_na_data <- non_na_data %>%
  left_join(gold_idr, by = "date")

# Select final set of variables
non_na_data <- non_na_data %>%
  dplyr::select(date, bi_rate, bond10, btc_idr, cpi, jkse, kurs_idr, gold_idr)

# Display the final dataset
head(non_na_data); tail(non_na_data)
## # A tibble: 6 × 8
##   date       bi_rate bond10   btc_idr   cpi  jkse kurs_idr  gold_idr
##   <date>       <dbl>  <dbl>     <dbl> <dbl> <dbl>    <dbl>     <dbl>
## 1 2016-04-01    5.5    105. 57318032.  3.6  4853.   13172. 16383543.
## 2 2016-05-01    5.5    104. 61939403.  3.33 4770.   13417. 16912360.
## 3 2016-06-01    5.25   106. 85965931.  3.45 4871.   13338. 17061819.
## 4 2016-07-01    5.25   110. 86769238.  3.21 5166.   13114. 17561010.
## 5 2016-08-01    5.25   109. 77097435.  2.79 5401.   13160. 17693830.
## 6 2016-09-01    5      110. 79744103.  3.07 5337.   13110. 17430969.
## # A tibble: 6 × 8
##   date       bi_rate bond10  btc_idr   cpi  jkse kurs_idr  gold_idr
##   <date>       <dbl>  <dbl>    <dbl> <dbl> <dbl>    <dbl>     <dbl>
## 1 2024-07-01    6.25   97.9 1021903.  2.13 7258.   16238. 38941212.
## 2 2024-08-01    6.25  100.   944448.  2.12 7417.   15735. 38926254.
## 3 2024-09-01    6     101.   926531.  1.84 7740.   15318. 39502303.
## 4 2024-10-01    6      98.6 1021507.  1.71 7621.   15558. 41930732.
## 5 2024-11-01    6      98.1 1368402.  1.55 7269.   15813. 42000372.
## 6 2024-12-01    6      97.3 1576530.  1.57 7216.   16036. 42502040.
# Calculate returns and changes for each variable
non_na_data$bi_rate <- as.numeric(non_na_data$bi_rate)
apt_data <- non_na_data %>%
  arrange(date) %>%
  mutate(
    jkse_return = c(NA, diff(log(jkse))),
    bond_return = c(NA, diff(log(bond10))),
    btc_return = c(NA, diff(log(btc_idr))),
    gold_return = c(NA, diff(log(gold_idr))),  # Add gold returns calculation
    birate_change = c(NA, diff(bi_rate)),
    cpi_change = c(NA, diff(cpi) / cpi[-length(cpi)]),
    kurs_change = c(NA, diff(kurs_idr) / kurs_idr[-length(kurs_idr)])
  ) %>%
  na.omit()

# Create risk-free rate variable from BI Rate
apt_data$rf_rate <- apt_data$bi_rate / 12 / 100  # Convert annual BI Rate to monthly

# Calculate excess returns
apt_data$excess_jkse <- apt_data$jkse_return - apt_data$rf_rate
apt_data$excess_bond <- apt_data$bond_return - apt_data$rf_rate
apt_data$excess_btc <- apt_data$btc_return - apt_data$rf_rate
apt_data$excess_gold <- apt_data$gold_return - apt_data$rf_rate  # Add excess returns for gold

# Check the data
head(apt_data)
## # A tibble: 6 × 20
##   date       bi_rate bond10   btc_idr   cpi  jkse kurs_idr  gold_idr jkse_return
##   <date>       <dbl>  <dbl>     <dbl> <dbl> <dbl>    <dbl>     <dbl>       <dbl>
## 1 2016-05-01    5.5    104. 61939403.  3.33 4770.   13417. 16912360.     -0.0173
## 2 2016-06-01    5.25   106. 85965931.  3.45 4871.   13338. 17061819.      0.0210
## 3 2016-07-01    5.25   110. 86769238.  3.21 5166.   13114. 17561010.      0.0589
## 4 2016-08-01    5.25   109. 77097435.  2.79 5401.   13160. 17693830.      0.0445
## 5 2016-09-01    5      110. 79744103.  3.07 5337.   13110. 17430969.     -0.0120
## 6 2016-10-01    4.75   109. 83963283.  3.31 5406.   13018. 16481679.      0.0128
## # ℹ 11 more variables: bond_return <dbl>, btc_return <dbl>, gold_return <dbl>,
## #   birate_change <dbl>, cpi_change <dbl>, kurs_change <dbl>, rf_rate <dbl>,
## #   excess_jkse <dbl>, excess_bond <dbl>, excess_btc <dbl>, excess_gold <dbl>
summary(apt_data)
##       date               bi_rate          bond10          btc_idr         
##  Min.   :2016-05-01   Min.   :3.500   Min.   : 83.80   Min.   :    16779  
##  1st Qu.:2018-06-23   1st Qu.:4.188   1st Qu.: 97.23   1st Qu.:   118135  
##  Median :2020-08-16   Median :4.750   Median :100.53   Median :   342069  
##  Mean   :2020-08-15   Mean   :4.886   Mean   : 99.82   Mean   :  8297702  
##  3rd Qu.:2022-10-08   3rd Qu.:5.750   3rd Qu.:102.90   3rd Qu.:   724748  
##  Max.   :2024-12-01   Max.   :6.250   Max.   :110.16   Max.   :110728567  
##       cpi             jkse         kurs_idr        gold_idr       
##  Min.   :1.320   Min.   :4599   Min.   :13018   Min.   :15468115  
##  1st Qu.:2.167   1st Qu.:5853   1st Qu.:13954   1st Qu.:18062115  
##  Median :3.060   Median :6237   Median :14345   Median :25328121  
##  Mean   :2.997   Mean   :6248   Mean   :14459   Mean   :24420591  
##  3rd Qu.:3.490   3rd Qu.:6843   3rd Qu.:15057   3rd Qu.:28087431  
##  Max.   :5.950   Max.   :7740   Max.   :16335   Max.   :42502040  
##   jkse_return         bond_return           btc_return      
##  Min.   :-0.201493   Min.   :-0.0828848   Min.   :-6.89749  
##  1st Qu.:-0.012833   1st Qu.:-0.0143272   1st Qu.:-0.06265  
##  Median : 0.008020   Median :-0.0021093   Median : 0.02405  
##  Mean   : 0.003815   Mean   :-0.0007608   Mean   :-0.03455  
##  3rd Qu.: 0.020662   3rd Qu.: 0.0113273   3rd Qu.: 0.14451  
##  Max.   : 0.086305   Max.   : 0.1371552   Max.   : 0.65514  
##   gold_return        birate_change         cpi_change       
##  Min.   :-0.062174   Min.   :-0.250000   Min.   :-0.302752  
##  1st Qu.:-0.009984   1st Qu.: 0.000000   1st Qu.:-0.077589  
##  Median : 0.007048   Median : 0.000000   Median :-0.013377  
##  Mean   : 0.009166   Mean   : 0.004808   Mean   :-0.002132  
##  3rd Qu.: 0.026680   3rd Qu.: 0.000000   3rd Qu.: 0.068724  
##  Max.   : 0.100150   Max.   : 0.625000   Max.   : 0.314394  
##   kurs_change           rf_rate          excess_jkse        
##  Min.   :-0.054480   Min.   :0.002917   Min.   :-0.2052429  
##  1st Qu.:-0.006061   1st Qu.:0.003490   1st Qu.:-0.0176251  
##  Median : 0.001096   Median :0.003958   Median : 0.0038237  
##  Mean   : 0.002065   Mean   :0.004072   Mean   :-0.0002566  
##  3rd Qu.: 0.011865   3rd Qu.:0.004792   3rd Qu.: 0.0164970  
##  Max.   : 0.102563   Max.   :0.005208   Max.   : 0.0831804  
##   excess_bond          excess_btc        excess_gold       
##  Min.   :-0.086635   Min.   :-6.90145   Min.   :-0.066132  
##  1st Qu.:-0.017855   1st Qu.:-0.06723   1st Qu.:-0.013795  
##  Median :-0.005789   Median : 0.01946   Median : 0.001944  
##  Mean   :-0.004832   Mean   :-0.03862   Mean   : 0.005095  
##  3rd Qu.: 0.008181   3rd Qu.: 0.14029   3rd Qu.: 0.022617  
##  Max.   : 0.132155   Max.   : 0.65159   Max.   : 0.094941
min(apt_data$date)
## [1] "2016-05-01"
max(apt_data$date)
## [1] "2024-12-01"
#Figure 1. Monthly Closing Price of Assets 
# Prepare data for plotting
price_data <- non_na_data %>%
  dplyr::select(date, jkse, bond10, btc_idr, gold_idr) %>%
  mutate(
    log_jkse = log(jkse),
    log_bond10 = log(bond10),
    log_btc_idr = log(btc_idr),
    log_gold = log(gold_idr)
  ) %>%
  dplyr::select(date, log_jkse, log_bond10, log_btc_idr, log_gold)

# Reshape for ggplot
price_long <- melt(price_data, id.vars = "date", variable.name = "Asset", value.name = "LogPrice")
asset_labels <- c(
  log_jkse = "JKSE",
  log_bond10 = "Bond 10Y",
  log_btc_idr = "Bitcoin (IDR)",
  log_gold = "Gold"
)
price_long$Asset <- factor(price_long$Asset, levels = names(asset_labels), labels = asset_labels)

# Plot
ggplot(price_long, aes(x = date, y = LogPrice, color = Asset)) +
  geom_line(linewidth = 1) +
  labs(title = "Monthly Log Closing Price of Assets",
       x = "Date", y = "Log Price",
       color = "Asset") +
  theme_minimal() +
  theme(legend.position = "bottom")

# 2. Hitung Surprise Faktor (kurs, cpi, birate)
compute_surprise_ses <- function(series, series_name = NULL) {
  m <- forecast::ses(series, h = 1)
  res_raw <- as.numeric(residuals(m))
  fit_val <- as.numeric(fitted(m))
  
  if (!is.null(series_name) && tolower(series_name) %in% c("cpi", "kurs_idr")) {
    res_adj <- res_raw / as.numeric(series)
  } else {
    res_adj <- res_raw
  }
  
  list(
    res = res_adj,
    fit = fit_val
  )
}

apt_data <- apt_data %>%
  mutate(
    surprise_kurs = compute_surprise_ses(kurs_idr)$res,
    surprise_cpi  = compute_surprise_ses(cpi)$res,
    surprise_birate = compute_surprise_ses(bi_rate)$res,
    birate_forecast = compute_surprise_ses(bi_rate)$fit,
    cpi_forecast = compute_surprise_ses(cpi)$fit,
    kurs_forecast= compute_surprise_ses(kurs_idr)$fit
  ) %>%
  drop_na()

apt_data <- na.omit(apt_data)

# Rate plot
p1 <- ggplot(apt_data, aes(x = 1:nrow(apt_data))) +
  geom_line(aes(y = bi_rate, color = "Actual"), linewidth = 1) +
  geom_line(aes(y = birate_forecast, color = "Forecast"), size = 1) +
  labs(title = "BI Rate: Actual vs Forecast", x = "Time", y = "Rate") +
  scale_color_manual(values = c("blue", "red")) +
  theme_minimal()
## Warning: Using `size` aesthetic for lines was deprecated in ggplot2 3.4.0.
## ℹ Please use `linewidth` instead.
## This warning is displayed once every 8 hours.
## Call `lifecycle::last_lifecycle_warnings()` to see where this warning was
## generated.
# CPI plot
p2 <- ggplot(apt_data, aes(x = 1:nrow(apt_data))) +
  geom_line(aes(y = cpi, color = "Actual"), size = 1) +
  geom_line(aes(y = cpi_forecast, color = "Forecast"), size = 1) +
  labs(title = "CPI: Actual vs Forecast", x = "Time", y = "Rate") +
  scale_color_manual(values = c("blue", "red")) +
  theme_minimal()

# Exchange Rate plot
p3 <- ggplot(apt_data, aes(x = 1:nrow(apt_data))) +
  geom_line(aes(y = kurs_idr, color = "Actual"), size = 1) +
  geom_line(aes(y = kurs_forecast, color = "Forecast"), size = 1) +
  labs(title = "Exchange Rate: Actual vs Forecast", x = "Time", y = "IDR/USD") +
  scale_color_manual(values = c("blue", "red")) +
  theme_minimal()

# Show plots
library(gridExtra)
grid.arrange(p1, p2, p3, ncol = 1)

# desctiptive table exxess for macroeconomic variables
library(psych)
## 
## Attaching package: 'psych'
## The following objects are masked from 'package:ggplot2':
## 
##     %+%, alpha
## The following object is masked from 'package:car':
## 
##     logit
macro_vars <- apt_data %>%
  dplyr::select(surprise_birate, surprise_cpi, surprise_kurs
  )
describe(macro_vars)
##                 vars   n  mean     sd median trimmed    mad     min     max
## surprise_birate    1 104  0.00   0.16   0.00   -0.01   0.00   -0.25    0.63
## surprise_cpi       2 104 -0.02   0.33  -0.03   -0.03   0.31   -0.99    1.26
## surprise_kurs      3 104 26.51 272.41  15.68   32.73 190.96 -855.85 1412.00
##                   range skew kurtosis    se
## surprise_birate    0.88 1.10     2.86  0.02
## surprise_cpi       2.25 0.59     1.81  0.03
## surprise_kurs   2267.85 0.61     6.23 26.71
summary(macro_vars)
##  surprise_birate      surprise_cpi      surprise_kurs    
##  Min.   :-0.250025   Min.   :-0.98998   Min.   :-855.85  
##  1st Qu.: 0.000000   1st Qu.:-0.24248   1st Qu.: -92.02  
##  Median : 0.000000   Median :-0.02996   Median :  15.68  
##  Mean   : 0.004815   Mean   :-0.01692   Mean   :  26.51  
##  3rd Qu.: 0.000000   3rd Qu.: 0.17250   3rd Qu.: 159.20  
##  Max.   : 0.625038   Max.   : 1.25997   Max.   :1412.00
# Uji Stasioneritas
# Daftar variabel yang akan diuji stasioneritasnya
variables_to_test <- c(
  "excess_jkse", "excess_bond", "excess_btc", "excess_gold",
  "surprise_birate", "surprise_cpi", "surprise_kurs"
)

# Lakukan PP test untuk setiap variabel
stationarity_results <- lapply(variables_to_test, function(var_name) {
  if (var_name %in% colnames(apt_data)) {
    x <- apt_data[[var_name]]

    x <- as.numeric(x)
    x <- na.omit(x)
    
    # Jalankan pp.test dengan tryCatch untuk hindari error
    test_result <- tryCatch(
      pp.test(x, alternative = "stationary"),
      error = function(e) NULL
    )
    
    if (!is.null(test_result)) {
      data.frame(
        Variable = var_name,
        PP_Statistic = test_result$statistic,
        P_Value = test_result$p.value,
        Stationary = ifelse(test_result$p.value < 0.05, "Yes", "No")
      )
    } else {
      data.frame(
        Variable = var_name,
        PP_Statistic = NA,
        P_Value = NA,
        Stationary = "Error or non-numeric data"
      )
    }
    
  } else {
    data.frame(
      Variable = var_name,
      PP_Statistic = NA,
      P_Value = NA,
      Stationary = "Variable not found"
    )
  }
})
## Warning in pp.test(x, alternative = "stationary"): p-value smaller than printed
## p-value
## Warning in pp.test(x, alternative = "stationary"): p-value smaller than printed
## p-value
## Warning in pp.test(x, alternative = "stationary"): p-value smaller than printed
## p-value
## Warning in pp.test(x, alternative = "stationary"): p-value smaller than printed
## p-value
## Warning in pp.test(x, alternative = "stationary"): p-value smaller than printed
## p-value
## Warning in pp.test(x, alternative = "stationary"): p-value smaller than printed
## p-value
## Warning in pp.test(x, alternative = "stationary"): p-value smaller than printed
## p-value
# Gabungkan hasil
stationarity_summary <- do.call(rbind, stationarity_results)
print(stationarity_summary)
##                                Variable PP_Statistic P_Value Stationary
## Dickey-Fuller Z(alpha)      excess_jkse    -65.85094    0.01        Yes
## Dickey-Fuller Z(alpha)1     excess_bond   -102.95927    0.01        Yes
## Dickey-Fuller Z(alpha)2      excess_btc   -106.53823    0.01        Yes
## Dickey-Fuller Z(alpha)3     excess_gold    -72.91623    0.01        Yes
## Dickey-Fuller Z(alpha)4 surprise_birate    -48.99106    0.01        Yes
## Dickey-Fuller Z(alpha)5    surprise_cpi   -111.55318    0.01        Yes
## Dickey-Fuller Z(alpha)6   surprise_kurs    -61.99687    0.01        Yes
# Interpretasi:
# P-value < 0.05 menunjukkan bahwa kita menolak hipotesis nol (data tidak stasioner)
# dan menyimpulkan bahwa data stasioner.
# 3. Fungsi fit EGARCH(1,1)-X dengan aturan distribusi
fit_egarchx <- function(returns, exog_matrix = NULL, asset_name = NULL) {
  dist_model <- ifelse(tolower(asset_name) == "gold_return", "norm", "sstd")
  
  # Spesifikasi model EGARCH
  spec <- ugarchspec(
    variance.model = list(
      model = "eGARCH",
      garchOrder = c(1, 1),
      external.regressors = exog_matrix
    ),
    mean.model = list(
      armaOrder = c(1, 0),
      include.mean = TRUE,
      external.regressors = exog_matrix
    ),
    distribution.model = dist_model
  )
  
  # Estimasi model
  tryCatch(
    ugarchfit(
      spec,
      data = returns,
      solver = "hybrid",
      fit.control = list(scale = TRUE)
    ),
    error = function(e) {
      message("ugarchfit error on ", asset_name, ": ", conditionMessage(e))
      return(NULL)
    }
  )
}
# 4. Fit tiap aset
assets <- c("gold_return", "btc_return", "jkse_return", "bond_return")

# Di sini: mxreg1 = surprise_birate, mxreg2 = surprise_kurs, mxreg3 = surprise_cpi
exog_mat <- as.matrix(
  apt_data %>% dplyr::select(surprise_birate, surprise_kurs, surprise_cpi)
)

# Fit model untuk tiap aset
fits <- lapply(assets, function(a) {
  fit_egarchx(apt_data[[a]], exog_mat, asset_name = a)
})

names(fits) <- assets
print(fits)
## $gold_return
## 
## *---------------------------------*
## *          GARCH Model Fit        *
## *---------------------------------*
## 
## Conditional Variance Dynamics    
## -----------------------------------
## GARCH Model  : eGARCH(1,1)
## Mean Model   : ARFIMA(1,0,0)
## Distribution : norm 
## 
## Optimal Parameters
## ------------------------------------
##         Estimate  Std. Error  t value Pr(>|t|)
## mu      0.006399    0.000000  27716.6        0
## ar1     0.331473    0.000141   2358.0        0
## mxreg1  0.039969    0.000016   2560.1        0
## mxreg2  0.000044    0.000000   4255.6        0
## mxreg3 -0.006859    0.000001  -7865.3        0
## omega  -1.453529    0.000167  -8723.4        0
## alpha1  0.178093    0.000141   1266.7        0
## beta1   0.795904    0.000013  59212.5        0
## gamma1 -0.634272    0.000095  -6650.2        0
## vxreg1 -0.375513    0.000064  -5868.3        0
## vxreg2  0.000234    0.000000  22535.0        0
## vxreg3  0.394621    0.000237   1667.2        0
## 
## Robust Standard Errors:
##         Estimate  Std. Error  t value Pr(>|t|)
## mu      0.006399    0.000015   427.80        0
## ar1     0.331473    0.000491   675.53        0
## mxreg1  0.039969    0.000051   788.33        0
## mxreg2  0.000044    0.000000   436.36        0
## mxreg3 -0.006859    0.000009  -791.87        0
## omega  -1.453529    0.002182  -666.28        0
## alpha1  0.178093    0.000158  1124.64        0
## beta1   0.795904    0.000270  2951.85        0
## gamma1 -0.634272    0.001158  -547.66        0
## vxreg1 -0.375513    0.000351 -1068.90        0
## vxreg2  0.000234    0.000000   816.43        0
## vxreg3  0.394621    0.000589   669.86        0
## 
## LogLikelihood : 232.0345 
## 
## Information Criteria
## ------------------------------------
##                     
## Akaike       -4.2314
## Bayes        -3.9263
## Shibata      -4.2546
## Hannan-Quinn -4.1078
## 
## Weighted Ljung-Box Test on Standardized Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                     0.0491  0.8246
## Lag[2*(p+q)+(p+q)-1][2]    1.1100  0.6725
## Lag[4*(p+q)+(p+q)-1][5]    2.2759  0.6311
## d.o.f=1
## H0 : No serial correlation
## 
## Weighted Ljung-Box Test on Standardized Squared Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                   0.006987  0.9334
## Lag[2*(p+q)+(p+q)-1][5]  1.213559  0.8097
## Lag[4*(p+q)+(p+q)-1][9]  2.706393  0.8063
## d.o.f=2
## 
## Weighted ARCH LM Tests
## ------------------------------------
##             Statistic Shape Scale P-Value
## ARCH Lag[3]    0.6988 0.500 2.000  0.4032
## ARCH Lag[5]    1.8983 1.440 1.667  0.4942
## ARCH Lag[7]    2.9880 2.315 1.543  0.5158
## 
## Nyblom stability test
## ------------------------------------
## Joint Statistic:  4.8219
## Individual Statistics:              
## mu     0.02004
## ar1    0.02119
## mxreg1 0.02111
## mxreg2 0.02031
## mxreg3 0.01990
## omega  0.01946
## alpha1 0.02151
## beta1  0.26484
## gamma1 0.02178
## vxreg1 0.01983
## vxreg2 0.02036
## vxreg3 0.01849
## 
## Asymptotic Critical Values (10% 5% 1%)
## Joint Statistic:          2.69 2.96 3.51
## Individual Statistic:     0.35 0.47 0.75
## 
## Sign Bias Test
## ------------------------------------
##                    t-value   prob sig
## Sign Bias          0.24097 0.8101    
## Negative Sign Bias 0.21700 0.8287    
## Positive Sign Bias 0.20758 0.8360    
## Joint Effect       0.09025 0.9930    
## 
## 
## Adjusted Pearson Goodness-of-Fit Test:
## ------------------------------------
##   group statistic p-value(g-1)
## 1    20     15.62       0.6828
## 2    30     35.04       0.2033
## 3    40     41.38       0.3670
## 4    50     53.69       0.2993
## 
## 
## Elapsed time : 0.4381549 
## 
## 
## $btc_return
## 
## *---------------------------------*
## *          GARCH Model Fit        *
## *---------------------------------*
## 
## Conditional Variance Dynamics    
## -----------------------------------
## GARCH Model  : eGARCH(1,1)
## Mean Model   : ARFIMA(1,0,0)
## Distribution : sstd 
## 
## Optimal Parameters
## ------------------------------------
##         Estimate  Std. Error   t value Pr(>|t|)
## mu     -0.055685    0.000021 -2687.307        0
## ar1     0.387728    0.000207  1872.133        0
## mxreg1 -0.049824    0.002489   -20.022        0
## mxreg2 -0.000053    0.000000  -140.217        0
## mxreg3 -0.048510    0.002947   -16.459        0
## omega  -0.124739    0.000053 -2367.664        0
## alpha1 -1.376329    0.001017 -1353.303        0
## beta1   0.903576    0.000430  2102.230        0
## gamma1 -1.046768    0.000162 -6453.323        0
## vxreg1 -0.299846    0.001880  -159.516        0
## vxreg2 -0.000408    0.000000 -5328.537        0
## vxreg3 -0.388068    0.000193 -2012.231        0
## skew    0.664115    0.000236  2816.547        0
## shape   2.159145    0.002131  1013.358        0
## 
## Robust Standard Errors:
##         Estimate  Std. Error     t value Pr(>|t|)
## mu     -0.055685    0.000155  -358.87677  0.00000
## ar1     0.387728    0.000021 18233.86133  0.00000
## mxreg1 -0.049824    0.065295    -0.76306  0.44543
## mxreg2 -0.000053    0.000001   -41.01746  0.00000
## mxreg3 -0.048510    0.069130    -0.70171  0.48286
## omega  -0.124739    0.000177  -706.52252  0.00000
## alpha1 -1.376329    0.030077   -45.75985  0.00000
## beta1   0.903576    0.003126   289.07837  0.00000
## gamma1 -1.046768    0.002406  -435.11283  0.00000
## vxreg1 -0.299846    0.007840   -38.24497  0.00000
## vxreg2 -0.000408    0.000003  -157.07293  0.00000
## vxreg3 -0.388068    0.002742  -141.55075  0.00000
## skew    0.664115    0.002082   318.99749  0.00000
## shape   2.159145    0.064727    33.35748  0.00000
## 
## LogLikelihood : 25.28327 
## 
## Information Criteria
## ------------------------------------
##                      
## Akaike       -0.21699
## Bayes         0.13899
## Shibata      -0.24781
## Hannan-Quinn -0.07277
## 
## Weighted Ljung-Box Test on Standardized Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                      1.355  0.2445
## Lag[2*(p+q)+(p+q)-1][2]     2.749  0.0573
## Lag[4*(p+q)+(p+q)-1][5]     3.801  0.2589
## d.o.f=1
## H0 : No serial correlation
## 
## Weighted Ljung-Box Test on Standardized Squared Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                  0.0009317  0.9756
## Lag[2*(p+q)+(p+q)-1][5] 0.3377119  0.9796
## Lag[4*(p+q)+(p+q)-1][9] 0.4248927  0.9991
## d.o.f=2
## 
## Weighted ARCH LM Tests
## ------------------------------------
##             Statistic Shape Scale P-Value
## ARCH Lag[3]   0.02562 0.500 2.000  0.8728
## ARCH Lag[5]   0.05894 1.440 1.667  0.9938
## ARCH Lag[7]   0.08832 2.315 1.543  0.9995
## 
## Nyblom stability test
## ------------------------------------
## Joint Statistic:  3.0314
## Individual Statistics:              
## mu     0.01597
## ar1    0.01634
## mxreg1 0.01554
## mxreg2 0.01624
## mxreg3 0.01709
## omega  0.01595
## alpha1 0.01601
## beta1  0.01603
## gamma1 0.01602
## vxreg1 0.01616
## vxreg2 0.01602
## vxreg3 0.01588
## skew   0.01591
## shape  0.01595
## 
## Asymptotic Critical Values (10% 5% 1%)
## Joint Statistic:          3.08 3.34 3.9
## Individual Statistic:     0.35 0.47 0.75
## 
## Sign Bias Test
## ------------------------------------
##                    t-value   prob sig
## Sign Bias           0.5775 0.5649    
## Negative Sign Bias  0.1306 0.8963    
## Positive Sign Bias  0.1892 0.8503    
## Joint Effect        0.4683 0.9258    
## 
## 
## Adjusted Pearson Goodness-of-Fit Test:
## ------------------------------------
##   group statistic p-value(g-1)
## 1    20     14.46       0.7562
## 2    30     33.31       0.2655
## 3    40     34.46       0.6769
## 4    50     56.58       0.2131
## 
## 
## Elapsed time : 1.635065 
## 
## 
## $jkse_return
## 
## *---------------------------------*
## *          GARCH Model Fit        *
## *---------------------------------*
## 
## Conditional Variance Dynamics    
## -----------------------------------
## GARCH Model  : eGARCH(1,1)
## Mean Model   : ARFIMA(1,0,0)
## Distribution : sstd 
## 
## Optimal Parameters
## ------------------------------------
##         Estimate  Std. Error   t value Pr(>|t|)
## mu      0.000410    0.000000  5804.068        0
## ar1     0.245304    0.000082  2988.312        0
## mxreg1  0.007651    0.000045   170.836        0
## mxreg2 -0.000071    0.000000 -1474.595        0
## mxreg3 -0.015171    0.000008 -1927.433        0
## omega  -0.263280    0.000108 -2446.027        0
## alpha1 -0.277770    0.000068 -4088.559        0
## beta1   0.962923    0.000381  2527.223        0
## gamma1 -0.286556    0.000101 -2833.834        0
## vxreg1 -0.450730    0.000142 -3171.449        0
## vxreg2  0.000380    0.000003   135.308        0
## vxreg3  0.222168    0.001988   111.732        0
## skew    0.553738    0.006930    79.903        0
## shape  50.730228    0.453655   111.826        0
## 
## Robust Standard Errors:
##         Estimate  Std. Error   t value Pr(>|t|)
## mu      0.000410    0.000002  258.7109        0
## ar1     0.245304    0.004700   52.1924        0
## mxreg1  0.007651    0.000311   24.5957        0
## mxreg2 -0.000071    0.000008   -8.7675        0
## mxreg3 -0.015171    0.000026 -577.1976        0
## omega  -0.263280    0.014879  -17.6942        0
## alpha1 -0.277770    0.028138   -9.8717        0
## beta1   0.962923    0.056291   17.1061        0
## gamma1 -0.286556    0.007482  -38.3007        0
## vxreg1 -0.450730    0.051458   -8.7592        0
## vxreg2  0.000380    0.000028   13.5475        0
## vxreg3  0.222168    0.013402   16.5774        0
## skew    0.553738    0.070485    7.8561        0
## shape  50.730228    7.266975    6.9809        0
## 
## LogLikelihood : 249.2664 
## 
## Information Criteria
## ------------------------------------
##                     
## Akaike       -4.5244
## Bayes        -4.1684
## Shibata      -4.5552
## Hannan-Quinn -4.3801
## 
## Weighted Ljung-Box Test on Standardized Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                     0.3711  0.5424
## Lag[2*(p+q)+(p+q)-1][2]    0.5874  0.9398
## Lag[4*(p+q)+(p+q)-1][5]    1.3199  0.8881
## d.o.f=1
## H0 : No serial correlation
## 
## Weighted Ljung-Box Test on Standardized Squared Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                      2.069  0.1503
## Lag[2*(p+q)+(p+q)-1][5]     2.703  0.4641
## Lag[4*(p+q)+(p+q)-1][9]     3.636  0.6510
## d.o.f=2
## 
## Weighted ARCH LM Tests
## ------------------------------------
##             Statistic Shape Scale P-Value
## ARCH Lag[3]    0.5574 0.500 2.000  0.4553
## ARCH Lag[5]    1.1995 1.440 1.667  0.6748
## ARCH Lag[7]    1.7317 2.315 1.543  0.7739
## 
## Nyblom stability test
## ------------------------------------
## Joint Statistic:  NaN
## Individual Statistics:              
## mu     0.03691
## ar1    0.03696
## mxreg1 0.03711
## mxreg2 0.03743
## mxreg3 0.03742
## omega  0.03690
## alpha1 0.03707
## beta1      NaN
## gamma1 0.03635
## vxreg1 0.03697
## vxreg2 0.03765
## vxreg3 0.03608
## skew   0.03200
## shape  0.03635
## 
## Asymptotic Critical Values (10% 5% 1%)
## Joint Statistic:          3.08 3.34 3.9
## Individual Statistic:     0.35 0.47 0.75
## 
## Sign Bias Test
## ------------------------------------
##                    t-value    prob sig
## Sign Bias           1.8030 0.07442   *
## Negative Sign Bias  0.0121 0.99037    
## Positive Sign Bias  1.7395 0.08505   *
## Joint Effect        4.4766 0.21439    
## 
## 
## Adjusted Pearson Goodness-of-Fit Test:
## ------------------------------------
##   group statistic p-value(g-1)
## 1    20     19.46       0.4276
## 2    30     35.62       0.1850
## 3    40     37.54       0.5366
## 4    50     57.54       0.1885
## 
## 
## Elapsed time : 1.331631 
## 
## 
## $bond_return
## 
## *---------------------------------*
## *          GARCH Model Fit        *
## *---------------------------------*
## 
## Conditional Variance Dynamics    
## -----------------------------------
## GARCH Model  : eGARCH(1,1)
## Mean Model   : ARFIMA(1,0,0)
## Distribution : sstd 
## 
## Optimal Parameters
## ------------------------------------
##         Estimate  Std. Error    t value Pr(>|t|)
## mu      0.001902    0.000001   3573.024        0
## ar1    -0.020583    0.000005  -4467.015        0
## mxreg1 -0.000399    0.000014    -28.983        0
## mxreg2 -0.000059    0.000000  -3861.484        0
## mxreg3 -0.005680    0.000003  -1984.392        0
## omega  -1.854290    0.000271  -6837.150        0
## alpha1 -0.755627    0.000011 -66264.271        0
## beta1   0.748407    0.000101   7396.339        0
## gamma1 -1.049795    0.000354  -2962.330        0
## vxreg1  0.812749    0.000391   2080.245        0
## vxreg2 -0.002736    0.000001  -4116.540        0
## vxreg3 -0.221540    0.002107   -105.133        0
## skew    1.025567    0.002573    398.595        0
## shape   3.039306    0.000554   5481.277        0
## 
## Robust Standard Errors:
##         Estimate  Std. Error    t value Pr(>|t|)
## mu      0.001902    0.000003    709.595        0
## ar1    -0.020583    0.000001 -14677.695        0
## mxreg1 -0.000399    0.000004    -88.772        0
## mxreg2 -0.000059    0.000000   -596.198        0
## mxreg3 -0.005680    0.000009   -625.531        0
## omega  -1.854290    0.001305  -1421.307        0
## alpha1 -0.755627    0.000168  -4497.847        0
## beta1   0.748407    0.002048    365.452        0
## gamma1 -1.049795    0.001522   -689.578        0
## vxreg1  0.812749    0.001321    615.309        0
## vxreg2 -0.002736    0.000003   -938.133        0
## vxreg3 -0.221540    0.001971   -112.419        0
## skew    1.025567    0.006601    155.372        0
## shape   3.039306    0.001132   2686.048        0
## 
## LogLikelihood : 263.3789 
## 
## Information Criteria
## ------------------------------------
##                     
## Akaike       -4.7957
## Bayes        -4.4398
## Shibata      -4.8266
## Hannan-Quinn -4.6515
## 
## Weighted Ljung-Box Test on Standardized Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                      2.602 0.10670
## Lag[2*(p+q)+(p+q)-1][2]     2.927 0.04058
## Lag[4*(p+q)+(p+q)-1][5]     3.299 0.35987
## d.o.f=1
## H0 : No serial correlation
## 
## Weighted Ljung-Box Test on Standardized Squared Residuals
## ------------------------------------
##                         statistic p-value
## Lag[1]                     0.5281  0.4674
## Lag[2*(p+q)+(p+q)-1][5]    2.1658  0.5798
## Lag[4*(p+q)+(p+q)-1][9]    3.1202  0.7390
## d.o.f=2
## 
## Weighted ARCH LM Tests
## ------------------------------------
##             Statistic Shape Scale P-Value
## ARCH Lag[3]   0.06794 0.500 2.000  0.7944
## ARCH Lag[5]   0.81490 1.440 1.667  0.7886
## ARCH Lag[7]   1.19566 2.315 1.543  0.8798
## 
## Nyblom stability test
## ------------------------------------
## Joint Statistic:  4.4131
## Individual Statistics:              
## mu     0.09466
## ar1    0.09307
## mxreg1 0.06152
## mxreg2 0.09954
## mxreg3 0.09548
## omega  0.23234
## alpha1 0.09315
## beta1  0.14217
## gamma1 0.07518
## vxreg1 0.08963
## vxreg2 0.09587
## vxreg3 0.05216
## skew   0.13174
## shape  0.09455
## 
## Asymptotic Critical Values (10% 5% 1%)
## Joint Statistic:          3.08 3.34 3.9
## Individual Statistic:     0.35 0.47 0.75
## 
## Sign Bias Test
## ------------------------------------
##                    t-value   prob sig
## Sign Bias           0.1381 0.8904    
## Negative Sign Bias  1.0098 0.3151    
## Positive Sign Bias  0.2797 0.7803    
## Joint Effect        1.4832 0.6862    
## 
## 
## Adjusted Pearson Goodness-of-Fit Test:
## ------------------------------------
##   group statistic p-value(g-1)
## 1    20     20.62       0.3584
## 2    30     36.19       0.1680
## 3    40     36.77       0.5721
## 4    50     50.81       0.4022
## 
## 
## Elapsed time : 0.565541
extract_egarchx_stats <- function(model, asset_name) {
  if (is.null(model)) {
    return(data.frame(
      Asset = asset_name, Convergence = "Failed",
      Mean_Intercept = NA, Mean_Intercept_SE = NA, Mean_Intercept_p = NA,
      Beta_BIRate = NA, Beta_BIRate_SE = NA, Beta_BIRate_p = NA,
      Beta_Exchange = NA, Beta_Exchange_SE = NA, Beta_Exchange_p = NA,
      Beta_Inflation = NA, Beta_Inflation_SE = NA, Beta_Inflation_p = NA,
      AR1 = NA, AR1_SE = NA, AR1_p = NA,
      GARCH_Alpha1 = NA, GARCH_Alpha1_SE = NA, GARCH_Alpha1_p = NA,
      GARCH_Beta1 = NA, GARCH_Beta1_SE = NA, GARCH_Beta1_p = NA,
      Persistence = NA, Log_Likelihood = NA,
      stringsAsFactors = FALSE
    ))
  }
  
  # convergence slot
  conv_code <- tryCatch(model@fit$convergence, error = function(e) NA)
  conv <- ifelse(!is.na(conv_code) && conv_code == 0, "Success", "Failed")
  
  coefs <- tryCatch(coef(model), error = function(e) NULL)
  ll    <- tryCatch(model@fit$LLH, error = function(e) NA)
  matc  <- tryCatch(model@fit$matcoef, error = function(e) NULL)
  
  if (conv == "Failed" || is.null(coefs) || is.null(matc)) {
    return(data.frame(
      Asset = asset_name, Convergence = conv,
      Mean_Intercept = NA, Mean_Intercept_SE = NA, Mean_Intercept_p = NA,
      Beta_BIRate = NA, Beta_BIRate_SE = NA, Beta_BIRate_p = NA,
      Beta_Exchange = NA, Beta_Exchange_SE = NA, Beta_Exchange_p = NA,
      Beta_Inflation = NA, Beta_Inflation_SE = NA, Beta_Inflation_p = NA,
      AR1 = NA, AR1_SE = NA, AR1_p = NA,
      GARCH_Alpha1 = NA, GARCH_Alpha1_SE = NA, GARCH_Alpha1_p = NA,
      GARCH_Beta1 = NA, GARCH_Beta1_SE = NA, GARCH_Beta1_p = NA,
      Persistence = NA, Log_Likelihood = ll,
      stringsAsFactors = FALSE
    ))
  }
  
  # helper untuk ambil nilai aman
  safe_extract <- function(name, col) {
    if (!is.null(matc) && name %in% rownames(matc)) {
      return(matc[name, col])
    } else {
      return(NA_real_)
    }
  }
  
  data.frame(
    Asset = asset_name,
    Convergence = conv,
    
    # Mean equation
    Mean_Intercept     = safe_extract("mu", 1),
    Mean_Intercept_SE  = safe_extract("mu", 2),
    Mean_Intercept_p   = safe_extract("mu", 4),
    
    Beta_BIRate        = safe_extract("mxreg1", 1),
    Beta_BIRate_SE     = safe_extract("mxreg1", 2),
    Beta_BIRate_p      = safe_extract("mxreg1", 4),
    
    Beta_Exchange      = safe_extract("mxreg2", 1),
    Beta_Exchange_SE   = safe_extract("mxreg2", 2),
    Beta_Exchange_p    = safe_extract("mxreg2", 4),
    
    Beta_Inflation     = safe_extract("mxreg3", 1),
    Beta_Inflation_SE  = safe_extract("mxreg3", 2),
    Beta_Inflation_p   = safe_extract("mxreg3", 4),
    
    # AR term
    AR1                = safe_extract("ar1", 1),
    AR1_SE             = safe_extract("ar1", 2),
    AR1_p              = safe_extract("ar1", 4),
    
    # Variance model parameters
    GARCH_Alpha1       = safe_extract("alpha1", 1),
    GARCH_Alpha1_SE    = safe_extract("alpha1", 2),
    GARCH_Alpha1_p     = safe_extract("alpha1", 4),
    
    GARCH_Beta1        = safe_extract("beta1", 1),
    GARCH_Beta1_SE     = safe_extract("beta1", 2),
    GARCH_Beta1_p      = safe_extract("beta1", 4),
    
    # Derived stats
    Persistence        = sum(c(safe_extract("alpha1", 1), safe_extract("beta1", 1)), na.rm = TRUE),
    Log_Likelihood     = ll,
    stringsAsFactors = FALSE
  )
}

egarchx_stats <- do.call(rbind, lapply(names(fits), function(asset) {
  extract_egarchx_stats(fits[[asset]], asset)
}))

print(egarchx_stats)
##         Asset Convergence Mean_Intercept Mean_Intercept_SE Mean_Intercept_p
## 1 gold_return     Success   0.0063988406      2.308665e-07                0
## 2  btc_return     Success  -0.0556845360      2.072131e-05                0
## 3 jkse_return     Success   0.0004103234      7.069582e-08                0
## 4 bond_return     Success   0.0019020401      5.323334e-07                0
##     Beta_BIRate Beta_BIRate_SE Beta_BIRate_p Beta_Exchange Beta_Exchange_SE
## 1  0.0399691524   1.561209e-05             0  4.380247e-05     1.029287e-08
## 2 -0.0498240619   2.488526e-03             0 -5.338921e-05     3.807621e-07
## 3  0.0076509014   4.478519e-05             0 -7.099364e-05     4.814451e-08
## 4 -0.0003987212   1.375705e-05             0 -5.948425e-05     1.540451e-08
##   Beta_Exchange_p Beta_Inflation Beta_Inflation_SE Beta_Inflation_p         AR1
## 1               0   -0.006859032      8.720677e-07                0  0.33147318
## 2               0   -0.048509767      2.947300e-03                0  0.38772783
## 3               0   -0.015170548      7.870858e-06                0  0.24530363
## 4               0   -0.005680366      2.862523e-06                0 -0.02058317
##         AR1_SE AR1_p GARCH_Alpha1 GARCH_Alpha1_SE GARCH_Alpha1_p GARCH_Beta1
## 1 1.405742e-04     0    0.1780932    1.405920e-04              0   0.7959045
## 2 2.071048e-04     0   -1.3763285    1.017014e-03              0   0.9035757
## 3 8.208769e-05     0   -0.2777696    6.793828e-05              0   0.9629232
## 4 4.607812e-06     0   -0.7556268    1.140323e-05              0   0.7484068
##   GARCH_Beta1_SE GARCH_Beta1_p  Persistence Log_Likelihood
## 1   1.344149e-05             0  0.973997722      232.03455
## 2   4.298176e-04             0 -0.472752820       25.28327
## 3   3.810202e-04             0  0.685153527      249.26635
## 4   1.011861e-04             0 -0.007219951      263.37887
# 5. Forecast mu dan sigma (1-step ahead)
last_exog <- matrix(tail(exog_mat, 1), nrow = 1) # 1 x n_mxreg

get_forecast <- function(fit, exog) {
  if (is.null(fit)) return(list(mu = NA_real_, sigma = NA_real_))
  f <- tryCatch(
    ugarchforecast(fit, n.ahead = 1,
                   external.forecasts = list(mregfor = exog, vregfor = exog)),
    error = function(e) {
      message("ugarchforecast error: ", conditionMessage(e))
      return(NULL)
    }
  )
  if (is.null(f)) return(list(mu = NA_real_, sigma = NA_real_))
  
  # forecast slots: f@forecast$seriesFor, f@forecast$sigmaFor
  list(
    mu = as.numeric(f@forecast$seriesFor[1, ]),
    sigma = as.numeric(f@forecast$sigmaFor[1, ])
  )
}

forecasts <- lapply(fits, get_forecast, exog = last_exog)

# Ambil mu dan sigma, fallback ke mean/sd historis dari apt_data jika forecast gagal
mu_vec <- sapply(seq_along(assets), function(i) {
  fmu <- forecasts[[i]]$mu
  if (is.na(fmu)) mean(apt_data[[assets[i]]], na.rm = TRUE) else fmu
})
sigma_vec <- sapply(seq_along(assets), function(i) {
  fs <- forecasts[[i]]$sigma
  if (is.na(fs)) sd(apt_data[[assets[i]]], na.rm = TRUE) else fs
})
names(mu_vec) <- assets
names(sigma_vec) <- assets
# 6. Setup Parameter Mean–VaR Optimization
alpha <- 0.05
lambda <- 10
n_sim <- 20000
# 7. Fungsi Objective (dengan target_return)
objective_mean_var <- function(w_raw, max_risk = NA, target_return = NA) {
  w <- pmax(0, w_raw)
  if (sum(w) == 0) w <- rep(1 / length(w), length(w))
  w <- w / sum(w)
  
  # Simulasi returns (asumsi normal independen)
  sims <- matrix(
    rnorm(n_sim * length(assets),
          mean = rep(mu_vec, each = n_sim),
          sd = rep(sigma_vec, each = n_sim)),
    ncol = length(assets)
  )
  port_rets <- sims %*% w
  
  mean_p <- mean(port_rets)
  sd_p <- sd(port_rets)
  var_p <- quantile(port_rets, probs = alpha, type = 7)
  
  penalty_risk <- 0
  if (!is.na(max_risk) && sd_p > max_risk) {
    penalty_risk <- 1e4 * (sd_p - max_risk)^2
  }
  
  penalty_return <- 0
  if (!is.na(target_return)) {
    penalty_return <- 1e4 * (mean_p - target_return)^2
  }
  
  obj <- -mean_p + lambda * abs(var_p) + penalty_risk + penalty_return
  return(obj)
}
# 8. Fungsi Optimasi DEoptim (dengan target_return)
optimize_portfolio <- function(max_risk = NA, target_return = NA) {
  lower <- rep(0, length(assets))
  upper <- rep(1, length(assets))
  
  res <- DEoptim(
    fn = function(w) objective_mean_var(w, max_risk, target_return),
    lower = lower, upper = upper,
    control = DEoptim.control(NP = 60, itermax = 150, trace = FALSE)
  )
  
  best_w <- pmax(0, res$optim$bestmem)
  best_w <- best_w / sum(best_w)
  
  # Hitung ulang metrik hasil terbaik
  sims <- matrix(
    rnorm(n_sim * length(assets),
          mean = rep(mu_vec, each = n_sim),
          sd = rep(sigma_vec, each = n_sim)),
    ncol = length(assets)
  )
  port_rets <- sims %*% best_w
  mean_p <- mean(port_rets)
  sd_p <- sd(port_rets)
  var_p <- quantile(port_rets, probs = alpha, type = 7)
  
  tibble(
    max_risk = ifelse(is.na(max_risk), "No Limit", sprintf("%.2f", max_risk)),
    target_return = ifelse(is.na(target_return), "None", round(target_return, 6)),
    Mean = mean_p,
    SD = sd_p,
    VaR = var_p,
    t(best_w)
  )
}
# 9. Hitung target_return dari equal-weighted portfolio
equal_w <- rep(1 / length(assets), length(assets))
target_return_eq <- sum(equal_w * mu_vec)
cat("Target Return (Equal-Weighted):", round(target_return_eq, 6), "\n")
## Target Return (Equal-Weighted): 0.000602
# 10. Simulasi Max Risk + Target Return
max_risk_values <- c(NA, 0.02, 0.04, 0.06, 0.08)
results <- lapply(max_risk_values, function(r) optimize_portfolio(r, target_return_eq))

# Ambil best solution dari scenario tanpa batas risiko (pertama)
w_opt <- as.numeric(results[[1]]$`t(best_w)`)
# fallback jika tidak tersedia
if (is.null(w_opt) || any(is.na(w_opt))) {
  w_opt <- equal_w
}

# Simpan equal weight vector
w_eq <- equal_w
# 11. Evaluasi kinerja kedua portofolio
return_matrix <- do.call(cbind, lapply(assets, function(a) apt_data[[a]]))
colnames(return_matrix) <- assets

# helper functions
calculate_portfolio_return <- function(w, ret_matrix) {
  sum(w * colMeans(ret_matrix, na.rm = TRUE))
}
calculate_portfolio_var <- function(w, ret_matrix) {
  covm <- cov(ret_matrix, use = "pairwise.complete.obs")
  sqrt(as.numeric(t(w) %*% covm %*% w))
}

eval_portfolio <- function(w, mu, cov_matrix, alpha = 0.05) {
  mu_p <- sum(w * mu)
  sigma_p <- sqrt(as.numeric(t(w) %*% cov_matrix %*% w))
  VaR_p <- mu_p + qnorm(alpha) * sigma_p
  ES_p <- mu_p + (dnorm(qnorm(alpha)) / alpha) * sigma_p
  return(c(mu_p, sigma_p, VaR_p, ES_p))
}

mu_hist <- colMeans(return_matrix, na.rm = TRUE)
cov_matrix <- cov(return_matrix, use = "pairwise.complete.obs")

perf_opt <- eval_portfolio(w_opt, mu_hist, cov_matrix)
perf_eq  <- eval_portfolio(w_eq,  mu_hist, cov_matrix)

comparison <- data.frame(
  Portfolio = c("Mean–VaR (EGARCH(1,1)-X+DEOptim)", "Equal-Weighted"),
  Mean_Return = c(perf_opt[1], perf_eq[1]),
  Volatility = c(perf_opt[2], perf_eq[2]),
  VaR_5pct = c(perf_opt[3], perf_eq[3]),
  ES_5pct = c(perf_opt[4], perf_eq[4])
)

print(comparison)
##                          Portfolio  Mean_Return Volatility    VaR_5pct
## 1 Mean–VaR (EGARCH(1,1)-X+DEOptim)  0.004882497 0.01766997 -0.02418202
## 2                   Equal-Weighted -0.005582913 0.17948072 -0.30080243
##      ES_5pct
## 1 0.04133057
## 2 0.36463427
weights_df <- data.frame(
  Asset = assets,
  EGARCHX_MeanVaR = w_opt,
  Equal_Weighted = w_eq,
  stringsAsFactors = FALSE
)

melted_weights <- reshape2::melt(weights_df, id.vars = "Asset")

ggplot(melted_weights, aes(x = Asset, y = value, fill = variable)) +
  geom_bar(stat = "identity", position = "dodge") +
  geom_text(aes(label = round(value, 3)), 
            vjust = -0.5, size = 3.5, position = position_dodge(0.9)) +
  labs(
    title = "Perbandingan Bobot Portofolio: Mean–VaR (EGARCH(1,1)-X+DEOptim) vs Equal-Weighted",
    x = "Aset",
    y = "Bobot",
    fill = "Metode"
  ) +
  theme_minimal()

# 12. Backtesting
# Utility untuk conditional mean/vol
extract_conditional_mean <- function(egarchx_model) {
  if (is.null(egarchx_model)) return(NULL)
  if (egarchx_model@fit$convergence != 0) return(NULL)
  fitted(egarchx_model)
}
extract_conditional_volatility <- function(egarchx_model) {
  if (is.null(egarchx_model)) return(NULL)
  if (egarchx_model@fit$convergence != 0) return(NULL)
  sigma(egarchx_model)
}

# calculate_egarchx_var returns time series of VaR estimates (negative numbers)
calculate_egarchx_var <- function(egarchx_model, confidence_level = 0.95) {
  if (is.null(egarchx_model)) return(NULL)
  if (egarchx_model@fit$convergence != 0) return(NULL)
  cond_mean <- fitted(egarchx_model)
  cond_vol <- sigma(egarchx_model)
  df <- tryCatch(coef(egarchx_model)["shape"], error = function(e) NA)
  if (is.na(df) || df <= 2) df <- 5
  t_critical <- qt(1 - confidence_level, df = df)
  # VaR per time: negative sign so exceedances measured as actual_loss > VaR
  vaR_ts <- -(cond_mean + t_critical * cond_vol)
  return(vaR_ts)
}

perform_egarchx_var_backtesting <- function(returns_vec, egarchx_model, confidence_level = 0.95) {
  if (is.null(egarchx_model) || egarchx_model@fit$convergence != 0) {
    return(list(exceedances = NA, dates = NA, var_estimates = NA, n = NA))
  }
  var_estimates <- calculate_egarchx_var(egarchx_model, confidence_level)
  # align lengths - tail to match returns length (if needed)
  n <- min(length(var_estimates), length(returns_vec))
  var_estimates <- tail(var_estimates, n)
  returns_vec <- tail(returns_vec, n)
  exceedances <- ifelse(-returns_vec > var_estimates, 1, 0)
  list(var_estimates = var_estimates, exceedances = exceedances, dates = NULL, n = n)
}

kupiec_test <- function(exceedances, total_obs, confidence_level) {
  alpha <- 1 - confidence_level
  x <- sum(exceedances, na.rm = TRUE)
  p_hat <- x / total_obs
  
  if (x == 0) {
    lr_stat <- -2 * log((1 - alpha)^total_obs)
  } else if (x == total_obs) {
    lr_stat <- -2 * log(alpha^total_obs)
  } else {
    lr_stat <- -2 * (log((1 - alpha)^(total_obs - x) * alpha^x) -
                       log((1 - p_hat)^(total_obs - x) * p_hat^x))
  }
  
  p_value <- 1 - pchisq(lr_stat, df = 1)
  list(
    exceptions = x,
    total_obs = total_obs,
    expected_rate = alpha,
    actual_rate = p_hat,
    lr_stat = lr_stat,
    p_value = p_value,
    result = ifelse(p_value > 0.05, "Accept H0", "Reject H0")
  )
}

# Map returns ke nama fits (harus tersedia kolom excess_* di apt_data)
returns_list <- list(
  gold_return = apt_data$excess_gold,
  btc_return  = apt_data$excess_btc,
  jkse_return = apt_data$excess_jkse,
  bond_return = apt_data$excess_bond
)

egarchx_backtest_results <- list()
egarchx_kupiec_results <- list()

for (asset_name in names(returns_list)) {
  model <- fits[[asset_name]]
  backtest <- perform_egarchx_var_backtesting(returns_list[[asset_name]], model, confidence_level = 0.95)
  egarchx_backtest_results[[asset_name]] <- backtest
  
  if (!is.na(backtest$n)) {
    kupiec <- kupiec_test(backtest$exceedances, backtest$n, confidence_level = 0.95)
    egarchx_kupiec_results[[asset_name]] <- kupiec
  }
}

egarchx_kupiec_summary <- do.call(rbind, lapply(names(egarchx_kupiec_results), function(asset) {
  result <- egarchx_kupiec_results[[asset]]
  if (is.null(result)) return(NULL)
  data.frame(
    Asset = asset,
    Observations = result$total_obs,
    Exceptions = result$exceptions,
    Expected_Rate = result$expected_rate,
    Actual_Rate = result$actual_rate,
    LR_Statistic = result$lr_stat,
    P_Value = result$p_value,
    Result = result$result,
    stringsAsFactors = FALSE
  )
}))

print(egarchx_kupiec_summary)
##         Asset Observations Exceptions Expected_Rate Actual_Rate LR_Statistic
## 1 gold_return          104          1          0.05 0.009615385    5.2787477
## 2  btc_return          104          1          0.05 0.009615385    5.2787477
## 3 jkse_return          104          7          0.05 0.067307692    0.5945158
## 4 bond_return          104          6          0.05 0.057692308    0.1237054
##      P_Value    Result
## 1 0.02158727 Reject H0
## 2 0.02158727 Reject H0
## 3 0.44067817 Accept H0
## 4 0.72504991 Accept H0
# 13. Compare Mean–VaR and Equal-weighted Portfolio Performance
dates <- as.Date(apt_data$date)

# Hitung return portofolio berdasarkan bobot optimal dan equal-weight
apt_data$portfolio_return_egarchx <- as.numeric(return_matrix %*% w_opt)
apt_data$portfolio_return_equal <- as.numeric(return_matrix %*% w_eq)

# Hitung cumulative returns (mulai dari 1)
egarchx_cumulative <- cumprod(1 + apt_data$portfolio_return_egarchx)
equal_cumulative <- cumprod(1 + apt_data$portfolio_return_equal)
jkse_cumulative  <- cumprod(1 + apt_data$jkse_return)
bond_cumulative  <- cumprod(1 + apt_data$bond_return)
btc_cumulative   <- cumprod(1 + apt_data$btc_return)
gold_cumulative  <- cumprod(1 + apt_data$gold_return)

plot(
  dates, egarchx_cumulative, type = "l", col = "red", lwd = 2,
  xlab = "Date", ylab = "Cumulative Return (Start = 1)",
  main = "Cumulative Performance Comparison",
  ylim = c(
    min(0.5, min(egarchx_cumulative, equal_cumulative, na.rm = TRUE) * 0.9),
    max(egarchx_cumulative, equal_cumulative, btc_cumulative, na.rm = TRUE) * 1.1
  )
)

lines(dates, equal_cumulative, col = "blue", lwd = 2, lty = 2)
lines(dates, jkse_cumulative, col = "darkgreen", lwd = 1)
lines(dates, bond_cumulative, col = "purple", lwd = 1)
lines(dates, btc_cumulative, col = "black", lwd = 1)
lines(dates, gold_cumulative, col = "goldenrod1", lwd = 1)

legend(
  "topleft",
  legend = c("Mean–VaR+EGARCH(1,1)-X", "Equal-Weight", "JKSE", "Bond", "BTC", "Gold"),
  col = c("red", "blue", "darkgreen", "purple", "black", "goldenrod1"),
  lwd = c(2, 2, 1, 1, 1, 1),
  lty = c(1, 2, 1, 1, 1, 1),
  cex = 0.8
)

# Rolling Metrics (24-month window)
window <- 24
assets_returns <- cbind(
  apt_data$portfolio_return_egarchx,
  apt_data$portfolio_return_equal,
  apt_data$jkse_return,
  apt_data$bond_return,
  apt_data$btc_return,
  apt_data$gold_return
)

colnames(assets_returns) <- c("MeanVar_EGARCHX", "Equal", "JKSE", "Bond", "BTC", "Gold")

rolling_returns    <- rolling_volatility <- rolling_sharpe <- rolling_var <- 
  matrix(NA, nrow = nrow(assets_returns) - window, ncol = ncol(assets_returns))

for (i in 1:(nrow(assets_returns) - window)) {
  window_data <- assets_returns[i:(i + window - 1), , drop = FALSE]
  rolling_returns[i, ]    <- colMeans(window_data, na.rm = TRUE)
  rolling_volatility[i, ] <- apply(window_data, 2, sd, na.rm = TRUE)
  rolling_sharpe[i, ]     <- rolling_returns[i, ] / rolling_volatility[i, ]
  rolling_var[i, ]        <- apply(window_data, 2, function(x) -quantile(x, 0.05, na.rm = TRUE))
}

# Plot Rolling Sharpe Ratio
par(mfrow = c(2, 1))

plot(
  dates[(window + 1):length(dates)], rolling_sharpe[, 1],
  type = "l", col = "red", lwd = 2,
  xlab = "Date", ylab = "Sharpe Ratio",
  main = "Rolling 24-Month Sharpe Ratio",
  ylim = range(rolling_sharpe[, 1:2], na.rm = TRUE) * c(0.9, 1.1)
)
lines(dates[(window + 1):length(dates)], rolling_sharpe[, 2], col = "blue", lwd = 2, lty = 2)
abline(h = 0, lty = 2, col = "gray")

legend(
  "bottomright",
  legend = c("Mean–VaR+EGARCHX", "Equal-Weight"),
  col = c("red", "blue"),
  lwd = 2, lty = c(1, 2), cex = 0.8
)

# Plot Rolling VaR
plot(
  dates[(window + 1):length(dates)], rolling_var[, 1],
  type = "l", col = "red", lwd = 2,
  xlab = "Date", ylab = "Value-at-Risk (95%)",
  main = "Rolling 24-Month VaR (95%)",
  ylim = range(rolling_var[, 1:2], na.rm = TRUE) * c(0.9, 1.1)
)
lines(dates[(window + 1):length(dates)], rolling_var[, 2], col = "blue", lwd = 2, lty = 2)
legend(
  "topright",
  legend = c("Mean–VaR+EGARCHX", "Equal-Weight"),
  col = c("red", "blue"),
  lwd = 2, lty = c(1, 2), cex = 0.8
)

par(mfrow = c(1, 1))

# Summary Statistics
return_stats <- data.frame(
  Mean_Return = colMeans(assets_returns, na.rm = TRUE) * 100,
  Volatility  = apply(assets_returns, 2, sd, na.rm = TRUE) * 100,
  Sharpe      = colMeans(assets_returns, na.rm = TRUE) /
    apply(assets_returns, 2, sd, na.rm = TRUE),
  VaR_95      = apply(assets_returns, 2, function(x) -quantile(x, 0.05, na.rm = TRUE)) * 100,
  Max_Drawdown = apply(assets_returns, 2, function(x) {
    cumu <- cumprod(1 + x)
    peak <- cumu[1]
    maxDD <- 0
    for (i in 2:length(cumu)) {
      if (cumu[i] > peak) peak <- cumu[i]
      DD <- (peak - cumu[i]) / peak
      if (DD > maxDD) maxDD <- DD
    }
    return(maxDD * 100)
  })
)

return_stats$Portfolio <- rownames(return_stats)
return_stats <- return_stats[order(-return_stats$Sharpe), ]

print(return_stats)
##                 Mean_Return Volatility      Sharpe    VaR_95 Max_Drawdown
## Gold             0.91661033   3.194470  0.28693662  3.901653    14.468387
## MeanVar_EGARCHX  0.48824973   1.766997  0.27631610  2.384892     8.507039
## JKSE             0.38148754   3.514663  0.10854170  4.619607    32.465213
## Bond            -0.07608112   2.835834 -0.02682848  4.497432    24.838468
## Equal           -0.55829126  17.948072 -0.03110592  7.463672   251.233083
## BTC             -3.45518180  71.955272 -0.04801847 25.803555   145.022780
##                       Portfolio
## Gold                       Gold
## MeanVar_EGARCHX MeanVar_EGARCHX
## JKSE                       JKSE
## Bond                       Bond
## Equal                     Equal
## BTC                         BTC
# Visualisasi VaR backtesting GARCH-X untuk semua aset (termasuk gold)
par(mfrow=c(2,2))
confidence_level <- 0.95
for (asset_name in names(egarchx_backtest_results)) {
  backtest <- egarchx_backtest_results[[asset_name]]
  asset_returns <- returns_list[[asset_name]]
  if (is.na(backtest$n)) next
  plot_data <- data.frame(
    Index = 1:length(asset_returns),
    Return = asset_returns,
    VaR = backtest$var_estimates,
    Exceed = backtest$exceedances
  )
  plot_data$NegReturn <- -plot_data$Return
  plot(plot_data$Index, plot_data$NegReturn, type = "l", 
       col = "black", xlab = "Observation", ylab = "Return/VaR", 
       main = paste0(asset_name, " EGARCHX-VaR (", confidence_level*100, "%)"),
       ylim = c(min(c(plot_data$NegReturn, plot_data$VaR), na.rm=TRUE),
                max(c(plot_data$NegReturn, plot_data$VaR), na.rm=TRUE) * 1.2))
  lines(plot_data$Index, plot_data$VaR, col = "blue", lty = 2)
  exceed_idx <- which(plot_data$Exceed == 1)
  points(exceed_idx, plot_data$NegReturn[exceed_idx], 
         col = "red", pch = 19, cex = 0.8)
  if (asset_name %in% names(egarchx_kupiec_results)) {
    result <- egarchx_kupiec_results[[asset_name]]
    legend_text <- paste0(
      "Exceptions: ", result$exceptions, "/", result$total_obs, " (", 
      round(result$actual_rate * 100, 2), "%)\n",
      "Expected: ", round(result$expected_rate * 100, 2), "%\n",
      "p-value: ", round(result$p_value, 4), "\n",
      "Result: ", result$result
    )
  } else {
    legend_text <- "No Kupiec test results"
  }
  legend("topright", legend = legend_text, bty = "n", cex = 0.7)
}

# Basel traffic light test
basel_traffic_light <- function(exceptions, observations, confidence_level) {
  if (confidence_level == 0.99) {
    if (exceptions <= 4) return("Green Zone")
    else if (exceptions <= 9) return("Yellow Zone")
    else return("Red Zone")
  } else if (confidence_level == 0.95) {
    expected_exceptions <- observations * 0.05
    if (exceptions <= expected_exceptions * 1.2) return("Green Zone")
    else if (exceptions <= expected_exceptions * 1.6) return("Yellow Zone")
    else return("Red Zone")
  }
}

basel_results_egarchx <- lapply(egarchx_kupiec_results, function(result) {
  if (is.null(result)) return(NULL)
  zone <- basel_traffic_light(result$exceptions, result$total_obs, confidence_level)
  data.frame(
    Exceptions = result$exceptions,
    Observations = result$total_obs,
    Expected_Rate = result$expected_rate,
    Actual_Rate = result$actual_rate,
    Zone = zone
  )
})

basel_egarchx_summary <- do.call(rbind, lapply(names(basel_results_egarchx), function(asset) {
  result <- basel_results_egarchx[[asset]]
  if (is.null(result)) return(NULL)
  result$Asset <- asset
  return(result)
}))

if (!is.null(basel_egarchx_summary) && nrow(basel_egarchx_summary) > 0) {
  basel_egarchx_summary <- basel_egarchx_summary[, c("Asset", "Exceptions", "Observations", 
                                                   "Expected_Rate", "Actual_Rate", "Zone")]
  print(basel_egarchx_summary)
  ggplot(basel_egarchx_summary, aes(x = Asset, y = Actual_Rate * 100, fill = Zone)) +
    geom_bar(stat = "identity") +
    geom_hline(yintercept = 5, linetype = "dashed", color = "black") +
    scale_fill_manual(values = c("Green Zone" = "darkgreen", 
                                 "Yellow Zone" = "gold",
                                 "Red Zone" = "darkred")) +
    theme_minimal() +
    labs(title = "EGARCHX-VaR Exceedance Rates by Asset with Basel Zones",
         subtitle = paste0(confidence_level * 100, "% VaR"),
         y = "Exceedance Rate (%)",
         x = "Asset") +
    theme(axis.text.x = element_text(angle = 45, hjust = 1))
}
##         Asset Exceptions Observations Expected_Rate Actual_Rate        Zone
## 1 gold_return          1          104          0.05 0.009615385  Green Zone
## 2  btc_return          1          104          0.05 0.009615385  Green Zone
## 3 jkse_return          7          104          0.05 0.067307692 Yellow Zone
## 4 bond_return          6          104          0.05 0.057692308  Green Zone

# Optional: Export Summary
if (!requireNamespace("writexl", quietly = TRUE)) install.packages("writexl")
writexl::write_xlsx(return_stats, "Portfolio_Performance_Comparison EGARCHX.xlsx")

result_df <- bind_rows(results)
result_df <- result_df[,-5]
assets_weight <- bind_rows(data.frame(results[[1]]$`t(best_w)`),data.frame(results[[2]]$`t(best_w)`),
                           data.frame(results[[3]]$`t(best_w)`),data.frame(results[[4]]$`t(best_w)`),
                           data.frame(results[[5]]$`t(best_w)`))
colnames(assets_weight) <- assets
result_df <- cbind(result_df,assets_weight)
writexl::write_xlsx(data.frame(result_df),"Comparison Data Frame EGARCHX.xlsx")
# 14. Tampilkan Seluruh Hasil Simulasi
cat("\n=== Hasil Simulasi Mean–VaR dengan Batas Risiko ===\n")
## 
## === Hasil Simulasi Mean–VaR dengan Batas Risiko ===
print(result_df)
##   max_risk target_return         Mean         SD t(best_w).1 t(best_w).2
## 1 No Limit      0.000602 0.0004431166 0.01605084 0.476353587 0.005286068
## 2     0.02      0.000602 0.0006385414 0.01603827 0.483998422 0.005827608
## 3     0.04      0.000602 0.0003340957 0.01567232 0.467903139 0.002392165
## 4     0.06      0.000602 0.0003003612 0.01601335 0.473673824 0.004028096
## 5     0.08      0.000602 0.0008059399 0.01608408 0.486802382 0.003529337
##   t(best_w).3 t(best_w).4 gold_return  btc_return jkse_return bond_return
## 1 0.238916868 0.279443477   0.4763536 0.005286068   0.2389169   0.2794435
## 2 0.264319187 0.245854783   0.4839984 0.005827608   0.2643192   0.2458548
## 3 0.254689608 0.275015087   0.4679031 0.002392165   0.2546896   0.2750151
## 4 0.263832358 0.258465721   0.4736738 0.004028096   0.2638324   0.2584657
## 5 0.267681877 0.241986404   0.4868024 0.003529337   0.2676819   0.2419864
# 15. Visualisasi Perubahan Bobot
library(reshape2)
melted <- melt(result_df[, c("max_risk", assets)], id.vars = "max_risk")

ggplot(melted, aes(x = max_risk, y = value, fill = variable)) +
  geom_bar(stat = "identity", position = "dodge") +
  labs(
    title = "Perubahan Bobot Portofolio terhadap Batas Risiko",
    x = "Batas Risiko (SD Maksimum)",
    y = "Bobot Aset",
    fill = "Aset"
  ) +
  theme_minimal() +
  theme(
    plot.title = element_text(size = 14, face = "bold"),
    axis.text.x = element_text(size = 12)
  )+
  geom_text(
    aes(label = round(value, 4)),                # menampilkan nilai bobot
    position = position_dodge(width = 0.9),     # sejajar dengan batang
    vjust = -0.3,                               # posisi sedikit di atas batang
    size = 3.5                                  # ukuran teks
  )

plot_pie <- function(risk_label, data) {
  data_subset <- data %>% filter(max_risk == risk_label)
  
  ggplot(data_subset, aes(x = "", y = value, fill = variable)) +
    geom_col(width = 1, color = "white") +
    coord_polar(theta = "y") +
    labs(
      title = paste("Distribusi Bobot Portofolio\nBatas Risiko:", risk_label),
      fill = "Aset"
    ) +
    geom_text(
      aes(label = paste0(round(value * 100, 2), "%")),
      position = position_stack(vjust = 0.5),
      color = "white",
      size = 4
    ) +
    theme_void() +
    theme(
      plot.title = element_text(hjust = 0.5, size = 13, face = "bold"),
      legend.title = element_text(size = 10),
      legend.text = element_text(size = 9)
    )
}

# Buat pie chart untuk tiap kondisi risiko
plots <- lapply(unique(melted$max_risk), function(risk) plot_pie(risk, melted))

# Tampilkan semua dalam grid (3 kolom)
do.call(grid.arrange, c(plots, ncol = 3))