#!/bin/sh

CMD="$1"
PKG_FILE="$2"
HOT_REPLACE="$3"

[ -z "$CMD" ] || [ -z "$PKG_FILE" ] || [ -z "$HOT_REPLACE" ] && echo "Missing params!" && exit 1

TMP_DIR="/tmp/opkg_restore"

fix_dns() {
    local dns1="1.1.1.1"
    local dns2="1.0.0.1"

    if ! grep -q "$dns1" /etc/resolv.conf; then
        echo " [+] Patching DNS for restore..."
        sed -i "1i nameserver $dns1" /etc/resolv.conf
        sed -i "2i nameserver $dns2" /etc/resolv.conf
    fi
}

list_user_packages() {
    awk -f - << 'EOF'
BEGIN {
    status_file = "/usr/lib/opkg/status"
    cmd="opkg info busybox | grep '^Installed-Time: '"
    if ((cmd | getline line) > 0) {
        FLASH_TIME = substr(line, 17)
    }
    close(cmd)
    
    while ((getline < status_file) > 0) {
        if ($1 == "Package:") { pkg = $2 }
        if ($1 == "Installed-Time:") {
            installed_time = $2
            if (installed_time > FLASH_TIME) {
                check_cmd = "opkg whatdepends " pkg " | wc -l"
                check_cmd | getline whatdepends
                close(check_cmd)
                if (whatdepends == 3) print pkg
            }
        }
    }
}
EOF
}

case "$CMD" in
    write)
        mkdir -p "$(dirname "$PKG_FILE")"
        echo "Scanning for user-installed packages..."
        
        > "$PKG_FILE"
        
        for pkg in $(list_user_packages); do
            echo "$pkg" >> "$PKG_FILE"
            echo " [+] $pkg"
        done
        
        echo "Total $(wc -l < "$PKG_FILE") packages saved to $PKG_FILE"
        ;;
    restore)
        [ ! -f "$PKG_FILE" ] && echo "File not found!" && exit 1

        [ ! -f /etc/resolv.conf-backup ] && cp /etc/resolv.conf /etc/resolv.conf-backup
        fix_dns

        echo "Updating package lists..."
        opkg update >/dev/null 2>&1

        echo "Phase 1: Removing conflicts ($HOT_REPLACE)..."
        if [ -n "$HOT_REPLACE" ]; then
            REMOVABLE=$(opkg list-installed | grep -E $(echo "$HOT_REPLACE" | tr ' ' '|') | awk '{print $1}')
            for p in $REMOVABLE; do 
                opkg remove "$p" --force-depends >/dev/null 2>&1
            done
        fi

        echo "Phase 2: Installing packages from list..."
        for pkg in $(cat "$PKG_FILE"); do
            if opkg list-installed | grep -q "^$pkg "; then
                echo " [s] $pkg is already installed"
            else
                fix_dns
                printf " [+] Installing $pkg... "
                if opkg install "$pkg" >/dev/null 2>&1; then
                    echo "OK"
                else
                    echo "FAILED"
                fi
            fi
        done

        [ -f /etc/resolv.conf-backup ] && mv /etc/resolv.conf-backup /etc/resolv.conf
        echo "Restore complete. Reboot is recommended."
        ;;
esac