#!/bin/bash
# =============================================================================
# IGNY8 Database Backup Script
# =============================================================================
# Usage: ./backup-db.sh [daily|weekly|monthly|pre-deploy]
# Creates compressed database backup with automatic retention
# =============================================================================

set -e

# Configuration
BACKUP_TYPE="${1:-daily}"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
DATE_FOLDER=$(date +%Y%m%d)

# Directories
BACKUP_ROOT="/data/backups"
DAILY_DIR="${BACKUP_ROOT}/daily"
WEEKLY_DIR="${BACKUP_ROOT}/weekly"
MONTHLY_DIR="${BACKUP_ROOT}/monthly"
PREDEPLOY_DIR="${BACKUP_ROOT}/pre-deploy"

# Database settings (from docker environment)
DB_CONTAINER="postgres"
DB_NAME="igny8_db"
DB_USER="igny8"

# Retention settings
DAILY_RETENTION_DAYS=7
WEEKLY_RETENTION_WEEKS=4
MONTHLY_RETENTION_MONTHS=12
PREDEPLOY_RETENTION_COUNT=5

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

log() {
    echo -e "[$(date '+%Y-%m-%d %H:%M:%S')] $1"
}

log_success() {
    log "${GREEN}✅ $1${NC}"
}

log_warn() {
    log "${YELLOW}⚠️  $1${NC}"
}

log_error() {
    log "${RED}❌ $1${NC}"
}

# Create directories if they don't exist
create_dirs() {
    mkdir -p "${DAILY_DIR}"
    mkdir -p "${WEEKLY_DIR}"
    mkdir -p "${MONTHLY_DIR}"
    mkdir -p "${PREDEPLOY_DIR}"
}

# Determine backup destination based on type
get_backup_path() {
    case $BACKUP_TYPE in
        daily)
            echo "${DAILY_DIR}/${DATE_FOLDER}"
            ;;
        weekly)
            echo "${WEEKLY_DIR}/week_$(date +%Y_%W)"
            ;;
        monthly)
            echo "${MONTHLY_DIR}/$(date +%Y_%m)"
            ;;
        pre-deploy)
            echo "${PREDEPLOY_DIR}/${TIMESTAMP}"
            ;;
        *)
            log_error "Invalid backup type: $BACKUP_TYPE"
            exit 1
            ;;
    esac
}

# Perform database backup
backup_database() {
    local backup_dir="$1"
    local backup_file="${backup_dir}/db_${DB_NAME}_${TIMESTAMP}.sql.gz"
    
    mkdir -p "${backup_dir}"
    
    log "Starting database backup: ${DB_NAME}"
    log "Destination: ${backup_file}"
    
    # Check if postgres container is running
    if ! docker ps --format '{{.Names}}' | grep -q "^${DB_CONTAINER}$"; then
        log_error "PostgreSQL container '${DB_CONTAINER}' is not running"
        exit 1
    fi
    
    # Perform backup with compression
    if docker exec "${DB_CONTAINER}" pg_dump -U "${DB_USER}" "${DB_NAME}" | gzip > "${backup_file}"; then
        local size=$(du -h "${backup_file}" | cut -f1)
        log_success "Database backup complete: ${backup_file} (${size})"
        
        # Create latest symlink
        ln -sf "${backup_file}" "${BACKUP_ROOT}/latest_db.sql.gz"
        
        return 0
    else
        log_error "Database backup failed"
        rm -f "${backup_file}"
        return 1
    fi
}

# Clean up old backups based on retention policy
cleanup_old_backups() {
    log "Cleaning up old backups..."
    
    # Daily backups - keep last N days
    if [[ -d "${DAILY_DIR}" ]]; then
        find "${DAILY_DIR}" -type d -mtime +${DAILY_RETENTION_DAYS} -exec rm -rf {} \; 2>/dev/null || true
        local daily_count=$(find "${DAILY_DIR}" -type f -name "*.sql.gz" | wc -l)
        log "Daily backups: ${daily_count} files"
    fi
    
    # Weekly backups - keep last N weeks
    if [[ -d "${WEEKLY_DIR}" ]]; then
        find "${WEEKLY_DIR}" -type d -mtime +$((WEEKLY_RETENTION_WEEKS * 7)) -exec rm -rf {} \; 2>/dev/null || true
        local weekly_count=$(find "${WEEKLY_DIR}" -type f -name "*.sql.gz" | wc -l)
        log "Weekly backups: ${weekly_count} files"
    fi
    
    # Monthly backups - keep last N months
    if [[ -d "${MONTHLY_DIR}" ]]; then
        find "${MONTHLY_DIR}" -type d -mtime +$((MONTHLY_RETENTION_MONTHS * 30)) -exec rm -rf {} \; 2>/dev/null || true
        local monthly_count=$(find "${MONTHLY_DIR}" -type f -name "*.sql.gz" | wc -l)
        log "Monthly backups: ${monthly_count} files"
    fi
    
    # Pre-deploy backups - keep last N
    if [[ -d "${PREDEPLOY_DIR}" ]]; then
        local predeploy_dirs=$(ls -dt "${PREDEPLOY_DIR}"/*/ 2>/dev/null | tail -n +$((PREDEPLOY_RETENTION_COUNT + 1)))
        if [[ -n "$predeploy_dirs" ]]; then
            echo "$predeploy_dirs" | xargs rm -rf 2>/dev/null || true
        fi
        local predeploy_count=$(find "${PREDEPLOY_DIR}" -maxdepth 1 -type d | wc -l)
        log "Pre-deploy backups: $((predeploy_count - 1)) snapshots"
    fi
    
    log_success "Cleanup complete"
}

# Display backup summary
show_summary() {
    echo ""
    echo "=========================================="
    echo "BACKUP SUMMARY"
    echo "=========================================="
    echo "Type:      ${BACKUP_TYPE}"
    echo "Database:  ${DB_NAME}"
    echo "Timestamp: ${TIMESTAMP}"
    echo ""
    echo "Disk Usage:"
    du -sh "${BACKUP_ROOT}"/* 2>/dev/null || echo "No backups yet"
    echo ""
    echo "Latest backup: $(readlink -f ${BACKUP_ROOT}/latest_db.sql.gz 2>/dev/null || echo 'None')"
    echo "=========================================="
}

# Main execution
main() {
    echo "=========================================="
    echo "IGNY8 Database Backup"
    echo "=========================================="
    echo ""
    
    create_dirs
    
    local backup_path=$(get_backup_path)
    
    if backup_database "${backup_path}"; then
        cleanup_old_backups
        show_summary
        exit 0
    else
        exit 1
    fi
}

main "$@"