#!/bin/bash
# ====================================================
# 工作日志服务平台 - 数据库备份脚本
# ====================================================
# 说明：
# 1. 支持全量备份和增量备份
# 2. 自动压缩备份文件
# 3. 自动清理过期备份
# 4. 建议配置到 crontab 定时执行
# ====================================================

# ==================== 配置参数 ====================
# 数据库配置
DB_HOST="localhost"
DB_PORT="3306"
DB_NAME="worklog"
DB_USER="worklog"
DB_PASSWORD="Wlog@123"

# 备份目录配置
BACKUP_ROOT="/backup/mysql"
BACKUP_DIR="${BACKUP_ROOT}/${DB_NAME}"
FULL_BACKUP_DIR="${BACKUP_DIR}/full"
INCR_BACKUP_DIR="${BACKUP_DIR}/incr"

# 保留策略（天数）
FULL_KEEP_DAYS=28    # 全量备份保留 4 周
INCR_KEEP_DAYS=7     # 增量备份保留 7 天

# 日志文件
LOG_FILE="${BACKUP_DIR}/backup.log"

# ==================== 初始化 ====================
# 创建备份目录
mkdir -p "${FULL_BACKUP_DIR}"
mkdir -p "${INCR_BACKUP_DIR}"
mkdir -p "$(dirname ${LOG_FILE})"

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

# ==================== 全量备份 ====================
full_backup() {
    log "========== 开始全量备份 =========="
    
    DATE=$(date +%Y%m%d_%H%M%S)
    BACKUP_FILE="${FULL_BACKUP_DIR}/full_${DATE}.sql"
    
    log "备份文件: ${BACKUP_FILE}"
    
    # 执行备份
    mysqldump \
        -h"${DB_HOST}" \
        -P"${DB_PORT}" \
        -u"${DB_USER}" \
        -p"${DB_PASSWORD}" \
        --single-transaction \
        --routines \
        --triggers \
        --events \
        --hex-blob \
        --default-character-set=utf8mb4 \
        "${DB_NAME}" > "${BACKUP_FILE}" 2>> "${LOG_FILE}"
    
    if [ $? -eq 0 ]; then
        log "数据库备份成功"
        
        # 压缩备份文件
        log "开始压缩备份文件..."
        gzip "${BACKUP_FILE}"
        
        if [ $? -eq 0 ]; then
            BACKUP_SIZE=$(du -h "${BACKUP_FILE}.gz" | awk '{print $1}')
            log "压缩完成，文件大小: ${BACKUP_SIZE}"
            log "备份文件路径: ${BACKUP_FILE}.gz"
        else
            log "ERROR: 压缩失败"
            return 1
        fi
    else
        log "ERROR: 数据库备份失败"
        return 1
    fi
    
    log "========== 全量备份完成 =========="
    return 0
}

# ==================== 增量备份 ====================
# 注意：MySQL 增量备份需要启用 binlog
# 本脚本暂不实现增量备份，可根据需要扩展
incr_backup() {
    log "========== 增量备份 =========="
    log "INFO: 增量备份功能暂未实现，建议每日执行全量备份"
    log "如需增量备份，请启用 MySQL binlog 并配置 mysqlbinlog 工具"
}

# ==================== 清理过期备份 ====================
cleanup_old_backups() {
    log "========== 开始清理过期备份 =========="
    
    # 清理过期全量备份
    log "清理 ${FULL_KEEP_DAYS} 天前的全量备份..."
    find "${FULL_BACKUP_DIR}" -name "full_*.sql.gz" -type f -mtime +${FULL_KEEP_DAYS} -delete
    FULL_COUNT=$(find "${FULL_BACKUP_DIR}" -name "full_*.sql.gz" -type f | wc -l)
    log "当前保留全量备份文件数: ${FULL_COUNT}"
    
    # 清理过期增量备份
    log "清理 ${INCR_KEEP_DAYS} 天前的增量备份..."
    find "${INCR_BACKUP_DIR}" -name "incr_*.sql.gz" -type f -mtime +${INCR_KEEP_DAYS} -delete
    INCR_COUNT=$(find "${INCR_BACKUP_DIR}" -name "incr_*.sql.gz" -type f | wc -l)
    log "当前保留增量备份文件数: ${INCR_COUNT}"
    
    log "========== 清理完成 =========="
}

# ==================== 恢复脚本 ====================
restore_backup() {
    BACKUP_FILE=$1
    
    if [ -z "${BACKUP_FILE}" ]; then
        log "ERROR: 请指定要恢复的备份文件"
        echo "用法: $0 restore <backup_file.sql.gz>"
        exit 1
    fi
    
    if [ ! -f "${BACKUP_FILE}" ]; then
        log "ERROR: 备份文件不存在: ${BACKUP_FILE}"
        exit 1
    fi
    
    log "========== 开始恢复数据库 =========="
    log "WARNING: 此操作将覆盖当前数据库，请确认！"
    read -p "确认恢复? (yes/no): " CONFIRM
    
    if [ "${CONFIRM}" != "yes" ]; then
        log "取消恢复操作"
        exit 0
    fi
    
    log "正在恢复备份文件: ${BACKUP_FILE}"
    
    # 解压并恢复
    gunzip -c "${BACKUP_FILE}" | mysql \
        -h"${DB_HOST}" \
        -P"${DB_PORT}" \
        -u"${DB_USER}" \
        -p"${DB_PASSWORD}" \
        "${DB_NAME}" 2>> "${LOG_FILE}"
    
    if [ $? -eq 0 ]; then
        log "数据库恢复成功"
    else
        log "ERROR: 数据库恢复失败"
        exit 1
    fi
    
    log "========== 恢复完成 =========="
}

# ==================== 主函数 ====================
main() {
    case "$1" in
        full)
            full_backup
            cleanup_old_backups
            ;;
        incr)
            incr_backup
            cleanup_old_backups
            ;;
        restore)
            restore_backup "$2"
            ;;
        cleanup)
            cleanup_old_backups
            ;;
        *)
            echo "用法: $0 {full|incr|restore|cleanup}"
            echo ""
            echo "命令说明:"
            echo "  full     - 执行全量备份"
            echo "  incr     - 执行增量备份（暂未实现）"
            echo "  restore  - 恢复备份（需指定备份文件）"
            echo "  cleanup  - 清理过期备份"
            echo ""
            echo "示例:"
            echo "  $0 full                                    # 全量备份"
            echo "  $0 restore /backup/mysql/worklog/full/full_20260224_020000.sql.gz"
            exit 1
            ;;
    esac
}

# 执行主函数
main "$@"