#!/bin/sh

HNAME=$(uci get system.@system[0].hostname)
DATE=$(date +%Y-%m-%d_%H-%M)

S_MOUNT="/tmp/share"
S_ADDR="nfs.lan:/mnt/media1/backup"

C_LIST="
/etc/config/
/etc/xray/
/etc/unbound/
/root/.ssh/
/opt/xray-config/
/opt/backup-manager/
"

H_REPLACE="wpad dnsmasq"

DIR="/opt/backup-manager"
SCR_BACKUP="$DIR/backup-configs.sh"
SCR_OPKG="$DIR/backup-opkg.sh"

check_dependencies() {
    echo "--- Checking NFS dependencies ---"
    local missing=""
    local pkgs="kmod-fs-nfs kmod-fs-nfs-v3 kmod-fs-nfs-v4 nfs-utils"
    
    for pkg in $pkgs; do
        if ! opkg list-installed | grep -q "^$pkg "; then
            missing="$missing $pkg"
        fi
    done

    if [ -n "$missing" ]; then
        echo " [!] Missing packages:$missing"
        printf "Would you like to install them now? (y/n): "
        read ans
        if [ "$ans" = "y" ] || [ "$ans" = "Y" ]; then
            echo "Updating package lists..."
            opkg update >/dev/null 2>&1
            for m in $missing; do
                printf " [+] Installing $m... "
                if opkg install "$m" >/dev/null 2>&1; then
                    echo "OK"
                else
                    echo "FAILED"
                    return 1
                fi
            done
            /sbin/depmod >/dev/null 2>&1
        else
            echo "Error: Cannot proceed without NFS dependencies."
            return 1
        fi
    fi
    echo " [+] All dependencies are satisfied."
    return 0
}

mount_share() {
    mkdir -p "$S_MOUNT"
    mount -t nfs "$S_ADDR" "$S_MOUNT" -o nolock,tcp >/dev/null 2>&1
    if ! grep -qs "$S_MOUNT" /proc/mounts; then
        echo "Error: Failed to mount NFS share ($S_ADDR)"
        return 1
    fi
    return 0
}

check_nfs_write() {
    echo "--- Testing NFS Write/Read access ---"
    mount_share || return 1
    
    local test_file="$S_MOUNT/.nfs_test_$(date +%s)"
    
    if ! touch "$test_file" >/dev/null 2>&1; then
        echo " Error: Cannot write to NFS share (Read-only?)"
        umount "$S_MOUNT"
        return 1
    fi
    
    if ! cat "$test_file" >/dev/null 2>&1; then
        echo " Error: Cannot read from NFS share"
        rm -f "$test_file"
        umount "$S_MOUNT"
        return 1
    fi
    
    rm -f "$test_file"
    echo " [+] NFS Write/Read test passed."
    umount "$S_MOUNT"
    return 0
}

clean_old_backups() {
    mount_share || return 1
    echo "--- Cleaning up backups older than 30 days ---"
    
    find "$S_MOUNT" -maxdepth 1 -type f \( -name "*.tar.gz" -o -name "*.lst" \) -mtime +30 -exec rm -f {} \;
    
    echo "Cleanup complete."
    umount "$S_MOUNT"
}

select_remote_file() {
    local ext="$1"

    check_dependencies || exit 1
    check_nfs_write || exit 1
    mount_share || return 1

    echo "--- Select $ext file from NFS ---" >&2
    FILES=$(find "$S_MOUNT" -maxdepth 1 -name "*$ext" | sort -r)
    
    if [ -z "$FILES" ]; then
        echo "No $ext files found." >&2
        umount "$S_MOUNT"
        return 1
    fi

    i=1
    for f in $FILES; do
        size=$(du -sh "$f" | awk '{print $1}')
        echo " [$i] $(basename "$f") ($size)" >&2
        i=$((i+1))
    done

    printf "Selection (0 to cancel): " >&2
    read choice
    
    if [ -z "$choice" ] || [ "$choice" -eq 0 ] || [ "$choice" -ge "$i" ]; then
        echo "Cancelled." >&2
        umount "$S_MOUNT"
        return 1
    fi

    SELECTED=$(echo "$FILES" | sed -n "${choice}p")
    
    RET_PATH="/tmp/restore_target$ext"
    cp "$SELECTED" "$RET_PATH"
    
    umount "$S_MOUNT"
    SELECTED_PATH="$RET_PATH"
}

case "$1" in
    backup)
        echo "--- Remote Backup Starting ---"

        check_dependencies || exit 1
        check_nfs_write || exit 1
        mount_share || exit 1
        
        REMOTE_BACKUP="$S_MOUNT/backup_${HNAME}_${DATE}.tar.gz"
        REMOTE_LIST="$S_MOUNT/packages_${HNAME}_${DATE}.lst"
        
        $SCR_BACKUP "$REMOTE_BACKUP" "$REMOTE_LIST" "$SCR_OPKG" "$C_LIST" "$H_REPLACE"
        
        sync
        umount "$S_MOUNT"
        echo "--- Backup Successfully Saved to NFS ---"

        clean_old_backups
        ;;

    restore-pkgs)
        SELECTED_PATH=""
        select_remote_file ".lst"
        if [ -n "$SELECTED_PATH" ] && [ -f "$SELECTED_PATH" ]; then
            echo "Restoring packages from $SELECTED_PATH..."
            $SCR_OPKG restore "$SELECTED_PATH" "$H_REPLACE"
            rm "$SELECTED_PATH"
        fi
        ;;

    restore-sys)
        SELECTED_PATH=""
        select_remote_file ".tar.gz"
        if [ -n "$SELECTED_PATH" ] && [ -f "$SELECTED_PATH" ]; then
            echo "Restoring system from $SELECTED_PATH..."
            sysupgrade -r "$SELECTED_PATH"
            echo "Restore complete. Reboot is recommended."
        fi
        ;;
    *)
        echo "Usage: $0 {backup|restore-pkgs|restore-sys}"
        exit 1
        ;;
esac