#!/bin/bash

# Exit immediately if a command fails
set -e

# Validate input parameters
if [ "$#" -ne 2 ]; then
    echo "Usage: $0 <RESTIC_PASSWORD> <ADDITIONAL_TAG>"
    exit 1
fi

# Assign command line arguments to variables
RESTIC_PASSWORD="$1"
CUSTOM_TAG="$2"

# Configuration
APP_PATH='/var/www/webroot/ROOT'
WP_CONFIG="${APP_PATH}/wp-config.php"
BACKUP_PATH='/mnt/backups'
PASSWORD_FILE="/etc/restic-password"
LOG_DIR="/home/litespeed/mb-backups/logs"
LOG_FILE="${LOG_DIR}/backup_database_$(date +'%Y-%m-%d').log"
LOCK_FILE="/tmp/restic_global.lock"

# Ensure log directory exists
mkdir -p "$LOG_DIR"

# Logging function
log() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

log "Starting Database Backup process with tags: wordpress_db, $CUSTOM_TAG."

# Verify that the password file exists
if [ ! -f "$PASSWORD_FILE" ]; then
    log "ERROR: Password file not found at $PASSWORD_FILE."
    exit 1
fi

# Export the password from the file to ensure Restic uses it automatically
export RESTIC_PASSWORD=$(cat "$PASSWORD_FILE")

# Verify backup path exists
if [ ! -d "$BACKUP_PATH" ]; then
    log "ERROR: Backup path $BACKUP_PATH does not exist."
    exit 1
fi

# Acquire a global lock to serialize Restic operations
log "Acquiring global lock for Restic operations..."
exec 9>"$LOCK_FILE"
if ! flock -n 9; then
    log "Another Restic operation is running. Exiting."
    exit 1
fi
log "Global lock acquired."

# Check and remove stale locks
log "Checking for stale locks in the repository..."
if restic -r "$BACKUP_PATH" list locks | grep -q "lock"; then
    log "Stale locks detected. Unlocking the repository..."
    restic -r "$BACKUP_PATH" unlock
    log "Repository unlocked successfully."
else
    log "No stale locks found."
fi

# Extract database credentials from wp-config.php
if [ ! -f "$WP_CONFIG" ]; then
    log "ERROR: wp-config.php not found at $WP_CONFIG."
    exit 1
fi

DB_NAME=$(grep "define('DB_NAME'" "$WP_CONFIG" | cut -d "'" -f 4)
DB_USER=$(grep "define('DB_USER'" "$WP_CONFIG" | cut -d "'" -f 4)
DB_PASSWORD=$(grep "define('DB_PASSWORD'" "$WP_CONFIG" | cut -d "'" -f 4)
DB_HOST=$(grep "define('DB_HOST'" "$WP_CONFIG" | cut -d "'" -f 4)
DB_PORT=3306  # Default MySQL port

# Validate database credentials
if [ -z "$DB_NAME" ] || [ -z "$DB_USER" ] || [ -z "$DB_PASSWORD" ] || [ -z "$DB_HOST" ]; then
    log "ERROR: Failed to extract database credentials from wp-config.php."
    exit 1
fi

# Set MySQL environment variable
export MYSQL_PWD="$DB_PASSWORD"

# Perform database backup with Restic
BACKUP_TAGS="wordpress_db,$CUSTOM_TAG"
DUMP_FILE="/tmp/${DB_NAME}_$(date +'%Y-%m-%d_%H-%M-%S').sql"

log "Performing database dump for $DB_NAME..."
if mysqldump -h "$DB_HOST" -P "$DB_PORT" -u "$DB_USER" "$DB_NAME" > "$DUMP_FILE"; then
    log "Database dump created successfully: $DUMP_FILE"
else
    log "ERROR: Database dump failed."
    exit 1
fi

log "Backing up database dump to Restic repository with tags: $BACKUP_TAGS..."
if restic -r "$BACKUP_PATH" backup --stdin --stdin-filename "$(basename "$DUMP_FILE")" --tag "$BACKUP_TAGS" < "$DUMP_FILE"; then
    log "Database backup completed successfully with tags: $BACKUP_TAGS."
    rm -f "$DUMP_FILE"
else
    log "ERROR: Restic backup failed."
    rm -f "$DUMP_FILE"
    exit 1
fi

# Release global lock
exec 9>&-

log "Database Backup process finished successfully."