#!/bin/bash

# Global variables for restore directory
restoreDir="/etc/restore"
backupDir="${restoreDir}/data"

# Internal Variables used globally
declare -a exclude_opts
declare -A rename_map
declare restore_uuid=true

# Function to create backup directory
create_backup_dir() {
    echo "Creating backup directory at ${backupDir}..."
    mkdir -p "$backupDir"
    echo "Backup directory created."
}

# Function to backup a partition table
backup_partition() {
    local device="$1"

    echo "Backing up partition table for $device..."
    sfdisk --dump "$device" > "${backupDir}/partition_table_$(basename "$device").backup"
    echo "Partition table backed up to ${backupDir}/partition_table_$(basename "$device").backup"
}

# Function to backup filesystem UUID
backup_uuid() {
    local partition="$1"

    echo "Backing up UUID for $partition..."
    blkid "$partition" | awk '{print $2}' > "${backupDir}/uuid_$(basename "$partition").backup"
    echo "UUID backed up to ${backupDir}/uuid_$(basename "$partition").backup"
}

# Function to backup Btrfs subvolumes, excluding snapshots and nested subvolumes
backup_btrfs_subvolumes() {
    local mount_point="$1"
    local subvol_path
    local subvol_name

    echo "Backing up Btrfs subvolumes from $mount_point to ${backupDir}..."
    mkdir -p "${backupDir}/btrfs_subvolumes"
    btrfs subvolume list -p "$mount_point" | while read -r line; do
        subvol_path=$(echo "$line" | awk '{print $NF}')
        subvol_name=$(basename "$subvol_path")

        # Skip snapshots and subvolumes under .snapshots
        if [[ "$subvol_path" == *.snapshots/* || "$subvol_path" == ".snapshots" ]]; then
            continue
        fi

        echo "Backing up subvolume $subvol_name"
        btrfs subvolume snapshot "$mount_point/$subvol_path" "${backupDir}/btrfs_subvolumes/$subvol_name"
    done
    echo "Btrfs subvolumes backed up to ${backupDir}/btrfs_subvolumes"
}

# Function to backup current mount points and options
backup_mount_points() {
    local line
    local device

    echo "Backing up current mount points and options..."
    while IFS= read -r line; do
        device=$(echo "$line" | awk '{print $1}')
        # Skip excluded devices
        if is_excluded "$device"; then
            echo "Skipping excluded device $device"
            continue
        fi
        backup_partition "$device"
        backup_uuid "$device"
    done < <(mount | grep "^/dev")
    #mount | grep "^/dev" > "${backupDir}/mount_points.backup"
    echo "Mount points backed up to ${backupDir}/mount_points.backup"
}

# Function to restore Btrfs subvolumes to /mnt/restore, excluding snapshots and nested subvolumes
restore_btrfs_subvolumes() {
    local mount_point="$1"
    local subvol_snapshot
    local subvol_name

    echo "Restoring Btrfs subvolumes from ${backupDir}/btrfs_subvolumes to /mnt/restore/$mount_point..."
    mkdir -p "/mnt/restore$mount_point"
    for subvol_snapshot in "${backupDir}/btrfs_subvolumes"/*; do
        if [[ -d "$subvol_snapshot" ]]; then
            subvol_name=$(basename "$subvol_snapshot")

            # Restore subvolume to the mount point
            echo "Restoring subvolume $subvol_name"
            btrfs subvolume snapshot "$subvol_snapshot" "/mnt/restore$mount_point/$subvol_name"
        fi
    done
    echo "Btrfs subvolumes restored to /mnt/restore$mount_point"
}

# Function to restore mount points to /mnt/restore, supporting Btrfs subvolumes
restore_mount_points() {
    local original_device
    local device
    local mount_point
    local mount_opts
    local subvol
    local fs_type

    if [[ -f "${backupDir}/mount_points.backup" ]]; then
        echo "Restoring mount points from ${backupDir}/mount_points.backup to /mnt/restore..."
        mkdir -p /mnt/restore
        while IFS= read -r line; do
            original_device=$(echo "$line" | awk '{print $1}')
            mount_point=$(echo "$line" | awk '{print $3}')
            mount_opts=$(echo "$line" | awk -F' ' '{for(i=4;i<=NF;i++){print $i}}' | tr -d '()')

            # Extract and remove subvol and subvolid from mount options
            subvol=$(echo "$mount_opts" | grep -oP 'subvol=\K[^,]*')
            mount_opts=$(echo "$mount_opts" | sed -e 's/subvol=[^,]*,//g' -e 's/subvolid=[^,]*,//g')

            # Rename device if specified
            device="$original_device"
            if [[ -n "${rename_map[$device]}" ]]; then
                device="${rename_map[$device]}"
            fi

            mkdir -p "/mnt/restore$mount_point"
            fs_type=$(blkid -o value -s TYPE "$device")

            if [[ "$fs_type" == "btrfs" ]]; then
                if [[ -n "$subvol" ]]; then
                    echo "Mounting Btrfs subvolume $subvol on /mnt/restore$mount_point"
                    mount -t btrfs -o subvol="$subvol,$mount_opts" "$device" "/mnt/restore$mount_point"
                else
                    echo "Mounting Btrfs volume $device on /mnt/restore$mount_point"
                    mount -t btrfs -o "$mount_opts" "$device" "/mnt/restore$mount_point"
                fi
            else
                echo "Mounting $device on /mnt/restore$mount_point with options $mount_opts"
                mount -o "$mount_opts" "$device" "/mnt/restore$mount_point"
            fi
        done < "${backupDir}/mount_points.backup"
        echo "Mount points restored to /mnt/restore."
    else
        echo "Backup file ${backupDir}/mount_points.backup not found."
        return 1
    fi
}

# Function to restore a partition table with optional device renaming
restore_partition() {
    local device="$1"
    local original_device="$device"
    local backup_file
    local temp_file

    # Check if the device should be renamed
    if [[ -n "${rename_map[$device]}" ]]; then
        echo "Renaming device $device to ${rename_map[$device]}"
        device="${rename_map[$device]}"
    fi

    backup_file="${backupDir}/partition_table_$(basename "$original_device").backup"
    if [[ ! -f "$backup_file" ]]; then
        echo "Backup file $backup_file not found."
        return 1
    fi

    # Create a temporary file for the modified backup
    temp_file=$(mktemp)
    trap 'rm -f "$temp_file"' EXIT

    # Modify the backup file to use the new device name
    sed "s|$original_device|$device|g" "$backup_file" > "$temp_file"

    echo "Restoring partition table for $device..."
    sfdisk "$device" < "$temp_file"
    echo "Partition table restored from $temp_file"
}

# Function to restore filesystem UUID with optional device renaming
restore_uuid() {
    local partition="$1"
    local original_partition="$partition"
    local uuid

    # Check if the partition should be renamed
    if [[ -n "${rename_map[$partition]}" ]]; then
        partition="${rename_map[$partition]}"
    fi

    if [[ -f "${backupDir}/uuid_$(basename "$original_partition").backup" ]]; then
        uuid=$(cut -d'=' -f2 < "${backupDir}/uuid_$(basename "$original_partition").backup" | tr -d '"')
        echo "Restoring UUID $uuid to $partition..."
        
        case "$(blkid -o value -s TYPE "$partition")" in
            ext4)
                tune2fs -U "$uuid" "$partition"
                ;;
            xfs)
                xfs_admin -U "$uuid" "$partition"
                ;;
            btrfs)
                btrfstune -u "$uuid" "$partition"
                ;;
            *)
                echo "Unsupported filesystem type."
                return 1
                ;;
        esac

        echo "UUID restored."
    else
        echo "Backup file ${backupDir}/uuid_$(basename "$original_partition").backup not found."
        return 1
    fi
}

# Function to handle exclusion list with wildcard and reverse matching
is_excluded() {
    local pattern="$1"
    local device="$2"

    for exclude in "${exclude_opts[@]}"; do
        if [[ "$exclude" == !* ]]; then
            pattern="${exclude#!}"
            if [[ "$device" == $pattern ]]; then
                return 1
            fi
        else
            pattern="$exclude"
            if [[ "$device" == $pattern ]]; then
                return 0
            fi
        fi
    done

    return 1
}


# Function to handle all backup operations
backup_all_partitions() {
    local device
    local mount_point
    local fs_type

    echo "Backing up all partitions..."
    backup_mount_points

    while IFS= read -r line; do
        local device
        device=$(echo "$line" | awk '{print $1}')
        mount_point=$(echo "$line" | awk '{print $3}')
        fs_type=$(echo "$line" | awk '{print $5}')
        # Skip excluded devices
        if is_excluded "$device"; then
            echo "Skipping excluded device $device"
            continue
        fi
        backup_partition "$device"
        backup_uuid "$device"
    done < "${backupDir}/mount_points.backup"

    backup_btrfs_subvolumes "/mnt"
}

# Function to restore all partitions and filesystems from backup files
restore_all() {
    echo "Restoring all partitions and filesystems from backup..."

    # Restore partition tables
    while IFS= read -r line; do
        local device
        device=$(echo "$line" | awk '{print $1}')
        # Rename device if specified
        if [[ -n "${rename_map[$device]}" ]]; then
            device="${rename_map[$device]}"
        fi
        restore_partition "$device"
    done < "${backupDir}/mount_points.backup"

    if [[ "$restore_uuid" == true ]]; then
        while IFS= read -r line; do
            local partition
            partition=$(echo "$line" | awk '{print $1}')
            # Rename partition if specified
            if [[ -n "${rename_map[$partition]}" ]]; then
                partition="${rename_map[$partition]}"
            fi
            restore_uuid "$partition"
        done < "${backupDir}/mount_points.backup"
    fi

    restore_btrfs_subvolumes "/mnt/restore"
}

# Main function to handle command-line arguments and invoke appropriate functions
main() {
    local exclude_file

    case "$1" in
        backup)
            shift
            while [[ "$#" -gt 0 ]]; do
                case "$1" in
                    --exclude)
                        shift
                        exclude_opts+=("$1")
                        shift
                        ;;
                    --exclude-file)
                        shift
                        exclude_file="$1"
                        if [[ -f "$exclude_file" ]]; then
                            while IFS= read -r line; do
                                exclude_opts+=("$line")
                            done < "$exclude_file"
                        else
                            echo "Exclude file $exclude_file does not exist."
                            exit 1
                        fi
                        shift
                        ;;
                    *)
                        echo "Usage: $0 backup [--exclude <pattern>]... [--exclude-file <file>]"
                        exit 1
                        ;;
                esac
            done

            create_backup_dir
            backup_all_partitions
            ;;

        restore)
            shift
            while [[ "$#" -gt 0 ]]; do
                case "$1" in
                    --no-uuid)
                        restore_uuid=false
                        shift
                        ;;
                    --exclude)
                        shift
                        exclude_opts+=("$1")
                        shift
                        ;;
                    --exclude-file)
                        shift
                        exclude_file="$1"
                        if [[ -f "$exclude_file" ]]; then
                            while IFS= read -r line; do
                                exclude_opts+=("$line")
                            done < "$exclude_file"
                        else
                            echo "Exclude file $exclude_file does not exist."
                            exit 1
                        fi
                        shift
                        ;;
                    --rename)
                        shift
                        local old_device="$1"
                        shift
                        local new_device="$1"
                        rename_map["$old_device"]="$new_device"
                        shift
                        ;;
                    *)
                        echo "Usage: $0 restore [--no-uuid] [--exclude <pattern>]... [--exclude-file <file>] [--rename <old_device> <new_device>]"
                        exit 1
                        ;;
                esac
            done

            restore_all
            ;;

        *)
            echo "Usage: $0 {backup|restore} [options]"
            exit 1
            ;;
    esac
}

# Call the main function with all arguments
main "$@"