#!/bin/bash
# Database Backup Script for Lottery Application
# This script creates a MySQL dump and transfers it to the backup VPS
#
# Usage:
#   ./scripts/backup-database.sh [--keep-local] [--compress]
#
# Options:
#   --keep-local    Keep a local copy of the backup (default: delete after transfer)
#   --compress      Compress the backup before transfer (default: gzip)
#
# Prerequisites:
#   1. SSH key-based authentication to backup VPS (5.45.77.77)
#   2. Database password accessible via /run/secrets/honey-config.properties
#   3. Docker container 'honey-mysql' running
#
# Backup location on backup VPS: /raid/backup/acc_260182/

set -euo pipefail

# Configuration
BACKUP_VPS_HOST="5.45.77.77"
BACKUP_VPS_USER="acc_260182"  # User account on backup VPS
BACKUP_VPS_PATH="/raid/backup/acc_260182"
MYSQL_CONTAINER="honey-mysql"
MYSQL_DATABASE="lottery_db"
SECRET_FILE="/run/secrets/honey-config.properties"
BACKUP_DIR="/opt/app/backups"
KEEP_LOCAL=false
COMPRESS=true

# Parse command line arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        --keep-local)
            KEEP_LOCAL=true
            shift
            ;;
        --no-compress)
            COMPRESS=false
            shift
            ;;
        *)
            echo "Unknown option: $1"
            echo "Usage: $0 [--keep-local] [--no-compress]"
            exit 1
            ;;
    esac
done

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

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

error() {
    echo -e "${RED}[ERROR]${NC} $1" >&2
}

warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

# Check if running as root or with sudo
if [ "$EUID" -ne 0 ]; then
    error "This script must be run as root (or with sudo)"
    exit 1
fi

# Load database password
if [ ! -f "$SECRET_FILE" ]; then
    error "Secret file not found at $SECRET_FILE"
    exit 1
fi

DB_PASSWORD=$(grep "^SPRING_DATASOURCE_PASSWORD=" "$SECRET_FILE" | cut -d'=' -f2- | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')

if [ -z "$DB_PASSWORD" ]; then
    error "SPRING_DATASOURCE_PASSWORD not found in secret file"
    exit 1
fi

# Check if MySQL container is running
if ! docker ps --format '{{.Names}}' | grep -q "^${MYSQL_CONTAINER}$"; then
    error "MySQL container '${MYSQL_CONTAINER}' is not running"
    exit 1
fi

# Create backup directory if it doesn't exist
mkdir -p "$BACKUP_DIR"

# Generate backup filename with timestamp
TIMESTAMP=$(date +'%Y%m%d_%H%M%S')
BACKUP_FILENAME="lottery_db_backup_${TIMESTAMP}.sql"
BACKUP_PATH="${BACKUP_DIR}/${BACKUP_FILENAME}"

# If compression is enabled, add .gz extension
if [ "$COMPRESS" = true ]; then
    BACKUP_FILENAME="${BACKUP_FILENAME}.gz"
    BACKUP_PATH="${BACKUP_DIR}/${BACKUP_FILENAME}"
fi

log "Starting database backup..."
log "Database: ${MYSQL_DATABASE}"
log "Container: ${MYSQL_CONTAINER}"
log "Backup file: ${BACKUP_FILENAME}"

# Create MySQL dump
log "Creating MySQL dump..."

if [ "$COMPRESS" = true ]; then
    # Dump and compress in one step (saves disk space)
    if docker exec "${MYSQL_CONTAINER}" mysqldump \
        -u root \
        -p"${DB_PASSWORD}" \
        --single-transaction \
        --routines \
        --triggers \
        --events \
        --quick \
        --lock-tables=false \
        "${MYSQL_DATABASE}" | gzip > "${BACKUP_PATH}"; then
        log "✅ Database dump created and compressed: ${BACKUP_PATH}"
    else
        error "Failed to create database dump"
        exit 1
    fi
else
    # Dump without compression
    if docker exec "${MYSQL_CONTAINER}" mysqldump \
        -u root \
        -p"${DB_PASSWORD}" \
        --single-transaction \
        --routines \
        --triggers \
        --events \
        --quick \
        --lock-tables=false \
        "${MYSQL_DATABASE}" > "${BACKUP_PATH}"; then
        log "✅ Database dump created: ${BACKUP_PATH}"
    else
        error "Failed to create database dump"
        exit 1
    fi
fi

# Get backup file size
BACKUP_SIZE=$(du -h "${BACKUP_PATH}" | cut -f1)
log "Backup size: ${BACKUP_SIZE}"

# Transfer to backup VPS
log "Transferring backup to backup VPS (${BACKUP_VPS_HOST})..."

# Test SSH connection first
if ! ssh -o ConnectTimeout=10 -o BatchMode=yes "${BACKUP_VPS_USER}@${BACKUP_VPS_HOST}" "echo 'SSH connection successful'" > /dev/null 2>&1; then
    error "Cannot connect to backup VPS via SSH"
    error "Please ensure:"
    error "  1. SSH key-based authentication is set up"
    error "  2. Backup VPS is accessible from this server"
    error "  3. User '${BACKUP_VPS_USER}' has access to ${BACKUP_VPS_PATH}"
    
    if [ "$KEEP_LOCAL" = true ]; then
        warn "Keeping local backup despite transfer failure: ${BACKUP_PATH}"
    else
        rm -f "${BACKUP_PATH}"
    fi
    exit 1
fi

# Create backup directory on remote VPS if it doesn't exist
ssh "${BACKUP_VPS_USER}@${BACKUP_VPS_HOST}" "mkdir -p ${BACKUP_VPS_PATH}"

# Transfer the backup file
if scp "${BACKUP_PATH}" "${BACKUP_VPS_USER}@${BACKUP_VPS_HOST}:${BACKUP_VPS_PATH}/"; then
    log "✅ Backup transferred successfully to ${BACKUP_VPS_HOST}:${BACKUP_VPS_PATH}/${BACKUP_FILENAME}"
    
    # Verify remote file exists
    REMOTE_SIZE=$(ssh "${BACKUP_VPS_USER}@${BACKUP_VPS_HOST}" "du -h ${BACKUP_VPS_PATH}/${BACKUP_FILENAME} 2>/dev/null | cut -f1" || echo "0")
    if [ "$REMOTE_SIZE" != "0" ]; then
        log "✅ Remote backup verified (size: ${REMOTE_SIZE})"
    else
        warn "Could not verify remote backup file"
    fi
else
    error "Failed to transfer backup to backup VPS"
    if [ "$KEEP_LOCAL" = true ]; then
        warn "Keeping local backup despite transfer failure: ${BACKUP_PATH}"
    else
        rm -f "${BACKUP_PATH}"
    fi
    exit 1
fi

# Clean up local backup if not keeping it
if [ "$KEEP_LOCAL" = false ]; then
    rm -f "${BACKUP_PATH}"
    log "Local backup file removed (transferred successfully)"
fi

# Clean up old backups on remote VPS (keep last 10 days)
log "Cleaning up old backups on remote VPS (keeping last 10 days)..."
ssh "${BACKUP_VPS_USER}@${BACKUP_VPS_HOST}" "find ${BACKUP_VPS_PATH} -name 'lottery_db_backup_*.sql*' -type f -mtime +10 -delete" || warn "Failed to clean up old backups"

# Count remaining backups
BACKUP_COUNT=$(ssh "${BACKUP_VPS_USER}@${BACKUP_VPS_HOST}" "ls -1 ${BACKUP_VPS_PATH}/lottery_db_backup_*.sql* 2>/dev/null | wc -l" || echo "0")
log "Total backups on remote VPS: ${BACKUP_COUNT}"

log "✅ Backup completed successfully!"
log "   Remote location: ${BACKUP_VPS_HOST}:${BACKUP_VPS_PATH}/${BACKUP_FILENAME}"