#!/bin/bash
"""
QR Code Manager - Docker Backup Script

This script provides backup and restore functionality for dockerized QR Code Manager.
It handles both data volumes and complete application backups.

Usage:
    ./docker_backup.sh [command] [options]

Commands:
    backup-data     - Backup data volumes only
    backup-full     - Full backup including application and data
    restore         - Restore from backup
    list            - List available backups
    cleanup         - Remove old backups
    schedule        - Set up automated backups

Examples:
    ./docker_backup.sh backup-data
    ./docker_backup.sh backup-full
    ./docker_backup.sh restore backup_20240801_120000.tar.gz
    ./docker_backup.sh list
"""

set -e  # Exit on any error

# Configuration
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
BACKUP_DIR="${SCRIPT_DIR}/backups"
CONTAINER_NAME="qr-code-manager"
COMPOSE_FILE="${SCRIPT_DIR}/docker-compose.yml"

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Helper functions
log_info() {
    echo -e "${BLUE}ℹ️  $1${NC}"
}

log_success() {
    echo -e "${GREEN}✅ $1${NC}"
}

log_warning() {
    echo -e "${YELLOW}⚠️  $1${NC}"
}

log_error() {
    echo -e "${RED}❌ $1${NC}"
}

# Ensure backup directory exists
mkdir -p "${BACKUP_DIR}"

# Check if Docker and docker-compose are available
check_dependencies() {
    if ! command -v docker &> /dev/null; then
        log_error "Docker is not installed or not in PATH"
        exit 1
    fi
    
    if command -v docker &> /dev/null && docker compose version &> /dev/null 2>&1; then
        # Use docker compose (newer syntax)
        COMPOSE_CMD="docker compose"
    elif command -v docker-compose &> /dev/null; then
        # Fallback to docker-compose (older syntax)
        COMPOSE_CMD="docker-compose"
    else
        log_error "Neither 'docker compose' nor 'docker-compose' is available"
        exit 1
    fi
}

# Get timestamp for backup naming
get_timestamp() {
    date +"%Y%m%d_%H%M%S"
}

# Check if container is running
is_container_running() {
    docker ps --format "{{.Names}}" | grep -q "^${CONTAINER_NAME}$"
}

# Backup data volumes only
backup_data() {
    local timestamp=$(get_timestamp)
    local backup_name="qr_data_backup_${timestamp}.tar.gz"
    local backup_path="${BACKUP_DIR}/${backup_name}"
    
    log_info "Creating data backup: ${backup_name}"
    
    if is_container_running; then
        log_info "Container is running, creating hot backup..."
        
        # Create backup from running container
        docker exec "${CONTAINER_NAME}" tar czf /tmp/data_backup.tar.gz \
            -C /app data/ || {
            log_error "Failed to create backup inside container"
            return 1
        }
        
        # Copy backup from container to host
        docker cp "${CONTAINER_NAME}:/tmp/data_backup.tar.gz" "${backup_path}" || {
            log_error "Failed to copy backup from container"
            return 1
        }
        
        # Cleanup temp file in container
        docker exec "${CONTAINER_NAME}" rm -f /tmp/data_backup.tar.gz
        
    else
        log_info "Container is not running, creating backup from volumes..."
        
        # Create backup using temporary container
        docker run --rm \
            -v "${SCRIPT_DIR}/data:/source/data:ro" \
            -v "${BACKUP_DIR}:/backup" \
            alpine:latest tar czf "/backup/${backup_name}" -C /source data/ || {
            log_error "Failed to create backup from volumes"
            return 1
        }
    fi
    
    # Add metadata
    local metadata_file="${BACKUP_DIR}/${backup_name%.tar.gz}.json"
    cat > "${metadata_file}" << EOF
{
    "backup_type": "data",
    "timestamp": "$(date -Iseconds)",
    "container_name": "${CONTAINER_NAME}",
    "backup_method": "$(if is_container_running; then echo 'hot'; else echo 'cold'; fi)",
    "backup_size": "$(stat -f%z "${backup_path}" 2>/dev/null || stat -c%s "${backup_path}" 2>/dev/null || echo 'unknown')"
}
EOF
    
    log_success "Data backup created: ${backup_path}"
    log_info "Backup size: $(du -h "${backup_path}" | cut -f1)"
}

# Full backup including application
backup_full() {
    local timestamp=$(get_timestamp)
    local backup_name="qr_full_backup_${timestamp}.tar.gz"
    local backup_path="${BACKUP_DIR}/${backup_name}"
    
    log_info "Creating full backup: ${backup_name}"
    
    # Stop container for consistent backup
    local was_running=false
    if is_container_running; then
        log_warning "Stopping container for consistent backup..."
        ${COMPOSE_CMD} -f "${COMPOSE_FILE}" down
        was_running=true
    fi
    
    # Create full backup
    tar czf "${backup_path}" \
        --exclude="backups" \
        --exclude=".git" \
        --exclude="__pycache__" \
        --exclude="*.pyc" \
        --exclude="*.log" \
        -C "${SCRIPT_DIR}/.." \
        "$(basename "${SCRIPT_DIR}")" || {
        log_error "Failed to create full backup"
        return 1
    }
    
    # Restart container if it was running
    if [ "$was_running" = true ]; then
        log_info "Restarting container..."
        ${COMPOSE_CMD} -f "${COMPOSE_FILE}" up -d
    fi
    
    # Add metadata
    local metadata_file="${BACKUP_DIR}/${backup_name%.tar.gz}.json"
    cat > "${metadata_file}" << EOF
{
    "backup_type": "full",
    "timestamp": "$(date -Iseconds)",
    "container_name": "${CONTAINER_NAME}",
    "backup_method": "cold",
    "backup_size": "$(stat -f%z "${backup_path}" 2>/dev/null || stat -c%s "${backup_path}" 2>/dev/null || echo 'unknown')"
}
EOF
    
    log_success "Full backup created: ${backup_path}"
    log_info "Backup size: $(du -h "${backup_path}" | cut -f1)"
}

# List available backups
list_backups() {
    log_info "Available backups:"
    echo "$(printf '%s' '─%.0s' {1..80})"
    
    if [ ! "$(ls -A "${BACKUP_DIR}"/*.tar.gz 2>/dev/null)" ]; then
        echo "No backups found"
        return
    fi
    
    for backup_file in "${BACKUP_DIR}"/*.tar.gz; do
        if [ -f "$backup_file" ]; then
            local basename=$(basename "$backup_file")
            local size=$(du -h "$backup_file" | cut -f1)
            local date=$(stat -f%Sm -t "%Y-%m-%d %H:%M" "$backup_file" 2>/dev/null || \
                        stat -c%y "$backup_file" 2>/dev/null | cut -d' ' -f1-2)
            
            # Determine backup type
            local type="Unknown"
            if [[ "$basename" == *"data"* ]]; then
                type="📄 Data"
            elif [[ "$basename" == *"full"* ]]; then
                type="📦 Full"
            fi
            
            printf "   %-12s | %-40s | %8s | %s\n" "$type" "$basename" "$size" "$date"
        fi
    done
}

# Restore from backup
restore_backup() {
    local backup_file="$1"
    
    if [ -z "$backup_file" ]; then
        log_error "Please specify backup file to restore"
        echo "Available backups:"
        list_backups
        return 1
    fi
    
    # Check if backup file exists
    local backup_path="${backup_file}"
    if [ ! -f "$backup_path" ]; then
        backup_path="${BACKUP_DIR}/${backup_file}"
        if [ ! -f "$backup_path" ]; then
            log_error "Backup file not found: $backup_file"
            return 1
        fi
    fi
    
    log_warning "Restoring from backup: $(basename "$backup_path")"
    
    # Confirm restoration
    echo -n "This will overwrite current data. Continue? (y/N): "
    read -r confirm
    if [ "$confirm" != "y" ] && [ "$confirm" != "Y" ]; then
        log_info "Restoration cancelled"
        return 0
    fi
    
    # Stop container
    if is_container_running; then
        log_info "Stopping container..."
        ${COMPOSE_CMD} -f "${COMPOSE_FILE}" down
    fi
    
    # Determine backup type and restore accordingly
    if [[ "$(basename "$backup_path")" == *"data"* ]]; then
        log_info "Restoring data backup..."
        
        # Backup current data
        if [ -d "${SCRIPT_DIR}/data" ]; then
            mv "${SCRIPT_DIR}/data" "${SCRIPT_DIR}/data.backup.$(get_timestamp)"
        fi
        
        # Extract data backup
        tar xzf "$backup_path" -C "${SCRIPT_DIR}" || {
            log_error "Failed to extract data backup"
            return 1
        }
        
    elif [[ "$(basename "$backup_path")" == *"full"* ]]; then
        log_info "Restoring full backup..."
        
        # Create restoration directory
        local restore_dir="${SCRIPT_DIR}/../qr-restore-$(get_timestamp)"
        mkdir -p "$restore_dir"
        
        # Extract full backup
        tar xzf "$backup_path" -C "$restore_dir" || {
            log_error "Failed to extract full backup"
            return 1
        }
        
        log_warning "Full backup extracted to: $restore_dir"
        log_warning "Please manually review and copy files as needed"
        return 0
    fi
    
    # Restart container
    log_info "Starting container..."
    ${COMPOSE_CMD} -f "${COMPOSE_FILE}" up -d
    
    log_success "Restoration completed successfully"
}

# Cleanup old backups
cleanup_backups() {
    local keep_count=${1:-10}
    
    log_info "Cleaning up old backups (keeping $keep_count most recent)"
    
    # Get list of backup files sorted by modification time (newest first)
    local backup_files=($(ls -t "${BACKUP_DIR}"/*.tar.gz 2>/dev/null || true))
    
    if [ ${#backup_files[@]} -le $keep_count ]; then
        log_info "No cleanup needed (${#backup_files[@]} backups found)"
        return
    fi
    
    # Remove old backups
    for ((i=$keep_count; i<${#backup_files[@]}; i++)); do
        local backup_file="${backup_files[$i]}"
        local metadata_file="${backup_file%.tar.gz}.json"
        
        log_info "Removing old backup: $(basename "$backup_file")"
        rm -f "$backup_file" "$metadata_file"
    done
    
    log_success "Cleanup completed"
}

# Set up automated backups
schedule_backups() {
    log_info "Setting up automated backups with cron..."
    
    # Create backup script for cron
    local cron_script="${SCRIPT_DIR}/automated_backup.sh"
    cat > "$cron_script" << 'EOF'
#!/bin/bash
# Automated backup script for QR Code Manager
cd "$(dirname "$0")"
./docker_backup.sh backup-data
if [ $(date +%u) -eq 1 ]; then  # Monday
    ./docker_backup.sh backup-full
fi
./docker_backup.sh cleanup 15
EOF
    chmod +x "$cron_script"
    
    # Suggest cron entries
    echo
    log_info "Automated backup script created: $cron_script"
    echo
    echo "Add this to your crontab (crontab -e) for daily backups:"
    echo "# QR Code Manager daily backup at 2 AM"
    echo "0 2 * * * $cron_script >> ${SCRIPT_DIR}/backup.log 2>&1"
    echo
    echo "Or for hourly data backups:"
    echo "# QR Code Manager hourly data backup"
    echo "0 * * * * ${SCRIPT_DIR}/docker_backup.sh backup-data >> ${SCRIPT_DIR}/backup.log 2>&1"
}

# Main script logic
main() {
    check_dependencies
    
    case "${1:-}" in
        "backup-data")
            backup_data
            ;;
        "backup-full")
            backup_full
            ;;
        "restore")
            restore_backup "$2"
            ;;
        "list")
            list_backups
            ;;
        "cleanup")
            cleanup_backups "$2"
            ;;
        "schedule")
            schedule_backups
            ;;
        *)
            echo "QR Code Manager - Docker Backup Script"
            echo
            echo "Usage: $0 [command] [options]"
            echo
            echo "Commands:"
            echo "  backup-data     - Backup data volumes only"
            echo "  backup-full     - Full backup including application and data"
            echo "  restore <file>  - Restore from backup"
            echo "  list           - List available backups"
            echo "  cleanup [n]    - Remove old backups (keep n most recent, default: 10)"
            echo "  schedule       - Set up automated backups"
            echo
            echo "Examples:"
            echo "  $0 backup-data"
            echo "  $0 backup-full"
            echo "  $0 restore qr_data_backup_20240801_120000.tar.gz"
            echo "  $0 list"
            echo "  $0 cleanup 5"
            ;;
    esac
}

main "$@"