#!/bin/bash

set -e  # Exit on error
trap 'log_message "ERROR: An error occurred while executing $COMMAND for $ENV_NAME. Exiting."' ERR

# Validate arguments
if [ $# -lt 2 ]; then
    echo "Usage: $0 <ENV_NAME> {backup|backup_wp_core|backup_uploads|backup_database|check_backup_repo|rotate_snapshots|create_snapshot|update_restic}"
    exit 1
fi

# Extract ENV_NAME and COMMAND
ENV_NAME="$1"
COMMAND="$2"

# Set dynamic configurations based on ENV_NAME
LOG_FILE="/var/log/${ENV_NAME}_backup_script.log"
BACKUP_REPO_PATH="/mnt/backups/${ENV_NAME}"
PASSWORD_FILE="/etc/restic-password"
LOCK_FILE="/tmp/restic_global.lock"

# Ensure dynamic paths exist
mkdir -p "$BACKUP_REPO_PATH"

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

# Validate password file and set Restic password
if [ ! -f "$PASSWORD_FILE" ]; then
    log_message "ERROR: Password file not found at $PASSWORD_FILE."
    exit 1
fi
export RESTIC_PASSWORD=$(cat "$PASSWORD_FILE")

# Ensure Restic is installed
install_restic() {
    if ! which restic &>/dev/null; then
        log_message "Restic not found. Installing..."
        if which dnf &>/dev/null; then
            dnf install -y epel-release && dnf install -y restic
        elif which yum &>/dev/null; then
            yum install -y restic
        else
            log_message "ERROR: Unsupported package manager."
            exit 1
        fi
    fi
    log_message "Restic is installed."
}

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

# Release global lock
release_lock() {
    exec 9>&-
}

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

# Initialize or validate repository
check_backup_repo() {
    if ! restic -r "$BACKUP_REPO_PATH" snapshots &>/dev/null; then
        log_message "Initializing new Restic repository..."
        restic -r "$BACKUP_REPO_PATH" init
    else
        log_message "Restic repository validated."
    fi
}

# Perform backup operations
perform_backup() {
    local path="$1"
    local tag="$2"
    local exclude="$3"

    log_message "Backing up $path with tag $tag..."
    restic -r "$BACKUP_REPO_PATH" backup "$path" --tag "$tag" $exclude
    log_message "Backup for $path completed."
}

# Backup database
backup_database() {
    log_message "Starting database backup for $ENV_NAME..."
    local db_dump
    db_dump=$(mktemp)

    mysqldump -h "$DB_HOST" -u "$DB_USER" -p"$DB_PASSWORD" "$DB_NAME" > "$db_dump"
    perform_backup "$db_dump" "database-backup"
    rm -f "$db_dump"
    log_message "Database backup completed."
}

# Handle commands
case "$COMMAND" in
    backup)
        log_message "Starting full backup for environment: $ENV_NAME"
        install_restic
        acquire_lock
        check_stale_locks
        check_backup_repo
        perform_backup "/var/www/webroot/ROOT/wp-content" "wp-core" "--exclude /var/www/webroot/ROOT/wp-content/uploads"
        perform_backup "/var/www/webroot/ROOT/wp-content/uploads" "wp-uploads"
        backup_database
        release_lock
        ;;
    backup_wp_core)
        log_message "Backing up WordPress core files for environment: $ENV_NAME"
        acquire_lock
        check_stale_locks
        perform_backup "/var/www/webroot/ROOT/wp-content" "wp-core" "--exclude /var/www/webroot/ROOT/wp-content/uploads"
        release_lock
        ;;
    backup_uploads)
        log_message "Backing up WordPress uploads for environment: $ENV_NAME"
        acquire_lock
        check_stale_locks
        perform_backup "/var/www/webroot/ROOT/wp-content/uploads" "wp-uploads"
        release_lock
        ;;
    backup_database)
        acquire_lock
        check_stale_locks
        backup_database
        release_lock
        ;;
    check_backup_repo)
        log_message "Checking backup repository for environment: $ENV_NAME"
        acquire_lock
        check_stale_locks
        check_backup_repo
        release_lock
        ;;
    rotate_snapshots)
        log_message "Rotating snapshots for environment: $ENV_NAME"
        acquire_lock
        restic -r "$BACKUP_REPO_PATH" forget --keep-last 5 --prune
        release_lock
        log_message "Snapshot rotation completed."
        ;;
    create_snapshot)
        log_message "Creating snapshot for environment: $ENV_NAME"
        acquire_lock
        check_stale_locks
        restic -r "$BACKUP_REPO_PATH" backup --tag "manual-snapshot"
        release_lock
        log_message "Snapshot creation completed."
        ;;
    update_restic)
        log_message "Updating Restic for environment: $ENV_NAME"
        restic self-update
        ;;
    *)
        echo "Invalid command: $COMMAND"
        echo "Usage: $0 <ENV_NAME> {backup|backup_wp_core|backup_uploads|backup_database|check_backup_repo|rotate_snapshots|create_snapshot|update_restic}"
        exit 1
        ;;
esac