#!/bin/bash

# NAS Backup Script to Google Drive using rclone and 7zip
# For each folder on BACKUP_SOURCE, it gets the sha256 checksum of it, checks the checksum against the previous backup, and if it has changed, it creates a 7zip archive of the folder with encryption.
# It then uploads the archive to Google Drive using rclone.

# Install: curl -sSL https://git.ivanch.me/ivanch/server-scripts/raw/branch/main/nas-gdrive-backup.sh | bash -s -- --install
# Run manually: /usr/local/bin/nas-gdrive-backup.sh

# Configuration
BACKUP_SOURCE="/export/Backup"
META_DIR="/export/Backup/.gdrive"
TMP_DIR="/export/Backup/.gdrive/tmp"
ZIP_PASSWORD="password"
GDRIVE_REMOTE="gdrive"
GDRIVE_PATH="/NAS-Backups"
ARCHIVE_NAME="backup.7z"
LOG_FILE="/var/log/nas-gdrive-backup.log"

# Function for logging
log() {
    echo "$(date '+%Y-%m-%d %H:%M:%S') - $1" | tee -a "$LOG_FILE"
}

clean_up() {
    log "Cleaning up temporary files"
    rm -rf "$TMP_DIR"
}

trap clean_up EXIT

create_7z() {
    local folder="$1"
    local archive_name="$2"
    log "Creating 7zip archive of $folder"
    7z a -p"$ZIP_PASSWORD" -mhe=on -mx=3 "$archive_name" "$folder"
    if [ $? -ne 0 ]; then
        log "ERROR: Failed to create 7zip archive of $folder"
    fi
}

upload_to_gdrive() {
    local archive_name="$1"
    log "Uploading $archive_name to Google Drive"

    # Should replace existing file if it exists
    rclone copy "$archive_name" "$GDRIVE_REMOTE:$GDRIVE_PATH" \
        --progress \
        --check-first \
        --transfers 1 \
        --checkers 1 \
        --retries 1 \
        --low-level-retries 10
    if [ $? -ne 0 ]; then
        log "ERROR: Failed to upload $archive_name to Google Drive"
    fi
}

main() {
    # Check if 7z is installed
    if ! which 7z > /dev/null; then
        log "ERROR: 7z is not installed"
        exit 1
    fi

    # Check if rclone is installed
    if ! which rclone > /dev/null; then
        log "ERROR: rclone is not installed"
        exit 1
    fi

    # Create meta directory if it doesn't exist
    if [ ! -d "$META_DIR" ]; then
        log "Creating meta directory: $META_DIR"
        mkdir -p "$META_DIR"
    fi

    # Fix permissions for the meta directory (777 recursively)
    chmod -R 777 "$META_DIR"

    # Loop through each folder in the backup source
    for folder in "$BACKUP_SOURCE"/*; do
        if [ -d "$folder" ]; then
            log "Processing folder: $folder"
            # Get the sha256 checksum of the folder
            CHECKSUM=$(find "$folder" -type f -exec sha256sum {} + | sha256sum | awk '{print $1}')
            META_FILE="$META_DIR/$(basename "$folder").sha256"
            # Check if the checksum file exists
            if [ -f "$META_FILE" ]; then
                # Read the previous checksum from the file
                PREV_CHECKSUM=$(cat "$META_FILE")
                # Compare the checksums
                if [ "$CHECKSUM" != "$PREV_CHECKSUM" ]; then
                    log "Changes detected in $folder - creating new archive"

                    create_7z "$folder" "$TMP_DIR/$(basename "$folder")_$ARCHIVE_NAME"
                    upload_to_gdrive "$TMP_DIR/$(basename "$folder")_$ARCHIVE_NAME"

                    # Update the checksum file
                    echo "$CHECKSUM" > "$META_FILE"
                    
                    # Remove the temporary archive file
                    log "Removing temporary archive file"
                    rm "$TMP_DIR/$(basename "$folder")_$ARCHIVE_NAME"
                else
                    log "No changes detected in $folder"
                fi
            else
                log "No previous checksum found for $folder - creating new archive"

                create_7z "$folder" "$TMP_DIR/$(basename "$folder")_$ARCHIVE_NAME"
                upload_to_gdrive "$TMP_DIR/$(basename "$folder")_$ARCHIVE_NAME"
                
                # Create a checksum file for the folder
                echo "$CHECKSUM" > "$META_FILE"

                # Remove the temporary archive file
                log "Removing temporary archive file"
                rm "$TMP_DIR/$(basename "$folder")_$ARCHIVE_NAME"
            fi
        else
            log "Skipping $folder, not a directory"
        fi
        log ""
    done

    # Fix permissions for the meta directory (777 recursively)
    chmod -R 777 "$META_DIR"

    log "Backup process completed successfully"

    # Exit with success
    exit 0
}

###########################
### Installation script ###
###########################
# Function to install a dependency if not already installed
install_dependency() {
    local package="$1"
    if ! dpkg -l | grep -q "$package"; then
        install_log_info "Installing $package"
        apt-get update && apt-get install -y "$package"
        if [ $? -ne 0 ]; then
            install_log_error "ERROR: Failed to install $package"
            exit 1
        fi
        install_log_ok "$package installed successfully"
    else
        install_log_ok "$package is already installed"
    fi
}

install_log_ok() {
    echo -e "\e[32m[✓]\e[0m $1"
}
install_log_error() {
    echo -e "\e[31m[✗]\e[0m $1"
}
install_log_info() {
    echo -e "\e[34m[!]\e[0m $1"
}
install_log_separator() {
    echo -e "\e[36m========================================\e[0m"
}

install_script() {
    echo -e ""
    install_log_separator
    install_log_info "Starting installation of NAS to Google Drive backup script"
    install_log_separator
    echo -e ""
    
    install_log_separator
    # Check if running as root
    install_log_info "Checking if the script is running as root"
    if [ "$(id -u)" -ne 0 ]; then
        install_log_error "ERROR: This script must be run as root"
        exit 1
    else
        install_log_ok "Running as root"
    fi
    install_log_separator
    
    # Check for dependencies
    install_log_info "Checking for required dependencies"
    install_dependency "rclone"
    install_dependency "p7zip-full"
    install_log_separator

    # Check if crontab exists
    install_log_info "Checking if crontab is installed"
    if ! command -v crontab &>/dev/null; then
        install_log_error "crontab is not installed"
        exit 1
    else
        install_log_ok "crontab is installed"
    fi
    install_log_separator

    install_log_info "Installing script to /usr/local/bin/nas-gdrive-backup.sh"
    curl -sSL https://git.ivanch.me/ivanch/server-scripts/raw/branch/main/nas-gdrive-backup.sh -o /usr/local/bin/nas-gdrive-backup.sh
    chmod +x /usr/local/bin/nas-gdrive-backup.sh

    install_log_info "Setting up ZIP_PASSWORD in $0"
    if [ -z "$ZIP_PASSWORD" ]; then
        install_log_error "ERROR: ZIP_PASSWORD is not set"
        exit 1
    fi
    read -p "Enter ZIP_PASSWORD: " ZIP_PASSWORD </dev/tty
    if [ -z "$ZIP_PASSWORD" ]; then
        install_log_error "ERROR: ZIP_PASSWORD cannot be empty"
        exit 1
    fi
    # Update the ZIP_PASSWORD in the script
    sed -i "s/^ZIP_PASSWORD=.*/ZIP_PASSWORD=\"$ZIP_PASSWORD\"/" /usr/local/bin/nas-gdrive-backup.sh
    log "ZIP_PASSWORD updated in /usr/local/bin/nas-gdrive-backup.sh"
    install_log_separator

    # Check for existence of source directories
    install_log_info "Checking if BACKUP_SOURCE, META_DIR, and TMP_DIR exists"
    if ! [ -d "$BACKUP_SOURCE" ]; then
        install_log_error "ERROR: BACKUP_SOURCE directory does not exist"
        exit 1
    else
        install_log_ok "BACKUP_SOURCE directory exists: $BACKUP_SOURCE"
    fi
    if ! [ -d "$META_DIR" ]; then
        install_log_info "Creating META_DIR: $META_DIR"
        mkdir -p "$META_DIR"
    fi
    if ! [ -d "$TMP_DIR" ]; then
        install_log_info "Creating TMP_DIR: $TMP_DIR"
        mkdir -p "$TMP_DIR"
    fi
    install_log_info "Setting permissions for $META_DIR and $TMP_DIR to 777"
    chmod -R 777 "$META_DIR" "$TMP_DIR"
    install_log_ok "Directories checked and are ok"

    # Check for existing .sha256 files, if there are any, prompt to remove them
    install_log_info "Verifying existing .sha256 files in $META_DIR"
    for file in "$META_DIR"/*; do
        if [ -f "$file" ] && [[ "$file" == *.sha256 ]]; then
            install_log_info "Found .sha256 file: \e[96m\e[4m$file\e[0m"
            read -p "Do you want to remove this file? [y/N]: " choice </dev/tty
            if [[ "$choice" == "y" || "$choice" == "Y" ]]; then
                install_log_info "Removing $file"
                rm "$file"
            else
                install_log_info "Skipping $file"
            fi
        fi
    done
    install_log_ok "Existing .sha256 files checked"

    install_log_separator
    
    install_log_info "Setting up rclone configuration"
    if ! rclone config show gdrive &>/dev/null; then
        install_log_error "ERROR: rclone gdrive remote is not configured"
        install_log_error "Please run 'rclone config' to set up your Google Drive remote"
        exit 1
    fi
    install_log_ok "rclone gdrive remote is configured"
    install_log_separator

    install_log_info "Setting up cron job for backup script"
    (crontab -l 2>/dev/null; echo "55 23 * * 1 $0 > /tmp/nas-gdrive-backup.log") | crontab -
    install_log_ok "Cron job set up to run $0 every Monday at 23:55"
    install_log_separator
    
    echo -e ""
    install_log_separator
    install_log_ok "Installation completed successfully!"
    install_log_separator
    echo -e ""
    echo -e "You can now run the script manually with: \e[32m/usr/local/bin/nas-gdrive-backup.sh\e[0m"
    echo -e "Or it will run automatically according to the cron schedule."

    # Exit with success
    exit 0
}

# Check for install flag
if [[ "$1" == "--install" ]]; then
    install_script
    exit 0
fi

main "$@"
exit 0