#!/bin/bash

###############################################################################
# Docker Backup Script
# 功能：备份指定文件夹和 MySQL 容器数据库
###############################################################################

set -e  # 遇到错误立即退出
set -o pipefail  # 管道命令任何一个失败都返回失败

# 脚本所在目录
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# 配置文件路径（系统级配置）
CONFIG_FILE="${CONFIG_FILE:-/etc/docker-backup/config.yml}"

# 临时目录
TEMP_DIR=""

# 颜色输出
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# 日志级别映射
declare -A LOG_LEVEL_MAP=(
    ["DEBUG"]=0
    ["INFO"]=1
    ["WARN"]=2
    ["ERROR"]=3
)

# 当前日志级别（默认 INFO）
CURRENT_LOG_LEVEL=1

###############################################################################
# 日志函数
###############################################################################

log() {
    local level=$1
    shift
    local message="$@"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')

    # 获取当前日志级别的数值
    local level_value=${LOG_LEVEL_MAP[$level]:-1}

    # 如果日志级别低于配置的级别，则不输出
    if [[ $level_value -lt $CURRENT_LOG_LEVEL ]]; then
        return 0
    fi

    # 输出到 stderr，避免干扰函数返回值
    echo -e "[${timestamp}] [${level}] ${message}" >&2

    # 如果配置了日志文件，同时写入文件
    if [[ -n "${LOG_FILE}" ]] && [[ "${LOGGING_ENABLED}" == "true" ]]; then
        # 移除 ANSI 颜色代码后写入文件
        local clean_message=$(echo -e "${message}" | sed 's/\x1b\[[0-9;]*m//g')
        echo "[${timestamp}] [${level}] ${clean_message}" >> "${LOG_FILE}"
    fi
}

log_info() {
    log "INFO" "${GREEN}$@${NC}"
}

log_warn() {
    log "WARN" "${YELLOW}$@${NC}"
}

log_error() {
    log "ERROR" "${RED}$@${NC}"
}

###############################################################################
# 清理函数
###############################################################################

cleanup() {
    if [[ -n "${TEMP_DIR}" ]] && [[ -d "${TEMP_DIR}" ]]; then
        log_info "清理临时目录: ${TEMP_DIR}"
        rm -rf "${TEMP_DIR}"
    fi
}

# 注册清理函数
trap cleanup EXIT INT TERM

###############################################################################
# 检查依赖
###############################################################################

check_dependencies() {
    log_info "检查依赖工具..."

    local missing_deps=()

    # 检查 yq
    if ! command -v yq &> /dev/null; then
        missing_deps+=("yq")
    fi

    # 检查 tar
    if ! command -v tar &> /dev/null; then
        missing_deps+=("tar")
    fi

    # 检查 gzip
    if ! command -v gzip &> /dev/null; then
        missing_deps+=("gzip")
    fi

    # 检查 docker
    if ! command -v docker &> /dev/null; then
        missing_deps+=("docker")
    fi

    if [[ ${#missing_deps[@]} -gt 0 ]]; then
        log_error "缺少以下依赖工具: ${missing_deps[*]}"
        log_error "请运行 install.sh 安装依赖"
        exit 1
    fi

    log_info "依赖检查完成"
}

###############################################################################
# 加载配置
###############################################################################

load_config() {
    log_info "加载配置文件: ${CONFIG_FILE}"

    if [[ ! -f "${CONFIG_FILE}" ]]; then
        log_error "配置文件不存在: ${CONFIG_FILE}"
        exit 1
    fi

    # 读取备份基础配置
    OUTPUT_DIR=$(yq eval '.backup.output_dir' "${CONFIG_FILE}")
    BACKUP_PREFIX=$(yq eval '.backup.prefix' "${CONFIG_FILE}")

    # 读取清理策略
    RETENTION_ENABLED=$(yq eval '.backup.retention.enabled' "${CONFIG_FILE}")
    KEEP_DAYS=$(yq eval '.backup.retention.keep_days' "${CONFIG_FILE}")

    # 读取文件夹备份配置
    FOLDERS_ENABLED=$(yq eval '.folders.enabled' "${CONFIG_FILE}")

    # 读取 MySQL 配置
    MYSQL_ENABLED=$(yq eval '.mysql.enabled' "${CONFIG_FILE}")
    MYSQL_CONTAINER=$(yq eval '.mysql.container_name' "${CONFIG_FILE}")
    MYSQL_USERNAME=$(yq eval '.mysql.username' "${CONFIG_FILE}")
    MYSQL_PASSWORD=$(yq eval '.mysql.password' "${CONFIG_FILE}")

    # 读取日志配置
    LOGGING_ENABLED=$(yq eval '.logging.enabled' "${CONFIG_FILE}")
    LOG_FILE=$(yq eval '.logging.log_file' "${CONFIG_FILE}")
    LOG_LEVEL=$(yq eval '.logging.level' "${CONFIG_FILE}")

    # 设置日志级别
    if [[ -n "${LOG_LEVEL}" ]] && [[ "${LOG_LEVEL}" != "null" ]]; then
        # 转换为大写
        LOG_LEVEL=$(echo "${LOG_LEVEL}" | tr '[:lower:]' '[:upper:]')
        # 设置当前日志级别
        CURRENT_LOG_LEVEL=${LOG_LEVEL_MAP[$LOG_LEVEL]:-1}
        log_info "日志级别设置为: ${LOG_LEVEL}"
    else
        log_info "使用默认日志级别: INFO"
    fi

    # 创建输出目录
    mkdir -p "${OUTPUT_DIR}"

    # 创建日志目录
    if [[ "${LOGGING_ENABLED}" == "true" ]] && [[ -n "${LOG_FILE}" ]]; then
        mkdir -p "$(dirname "${LOG_FILE}")"
    fi

    log_info "配置加载完成"
}

###############################################################################
# 备份文件夹
###############################################################################

backup_folders() {
    if [[ "${FOLDERS_ENABLED}" != "true" ]]; then
        log_info "文件夹备份未启用，跳过"
        return 0
    fi

    log_info "开始备份文件夹..."

    # 创建临时目录
    local temp_backup_dir="${TEMP_DIR}/folders"
    mkdir -p "${temp_backup_dir}"

    # 获取要备份的文件夹数量
    local source_count=$(yq eval '.folders.sources | length' "${CONFIG_FILE}")

    if [[ "${source_count}" == "0" ]] || [[ "${source_count}" == "null" ]]; then
        log_warn "未配置要备份的文件夹"
        return 0
    fi

    # 构建排除参数
    local exclude_args=""
    local exclude_count=$(yq eval '.folders.excludes | length' "${CONFIG_FILE}")

    if [[ "${exclude_count}" != "0" ]] && [[ "${exclude_count}" != "null" ]]; then
        for i in $(seq 0 $((exclude_count - 1))); do
            local exclude_pattern=$(yq eval ".folders.excludes[$i]" "${CONFIG_FILE}")
            exclude_args+=" --exclude='${exclude_pattern}'"
        done
    fi

    # 备份每个文件夹
    local folders_tar="${temp_backup_dir}/folders.tar.gz"
    local tar_sources=""

    for i in $(seq 0 $((source_count - 1))); do
        local source_dir=$(yq eval ".folders.sources[$i]" "${CONFIG_FILE}")

        if [[ ! -d "${source_dir}" ]]; then
            log_warn "源目录不存在，跳过: ${source_dir}"
            continue
        fi

        tar_sources+=" ${source_dir}"
        log_info "添加备份源: ${source_dir}"
    done

    if [[ -z "${tar_sources}" ]]; then
        log_warn "没有有效的备份源目录"
        return 0
    fi

    # 执行打包
    log_info "开始打包文件夹..."
    log_info "排除规则: ${exclude_args}"
    # 将 tar 的 stdout 和 stderr 都重定向到 stderr，避免干扰函数返回值
    eval "tar -czf '${folders_tar}' ${exclude_args} ${tar_sources}" >&2 2>&1

    if [[ -f "${folders_tar}" ]]; then
        local tar_size=$(du -h "${folders_tar}" | cut -f1)
        log_info "文件夹备份完成: ${folders_tar} (大小: ${tar_size})"
        echo "${folders_tar}"
    else
        log_error "文件夹备份失败"
        return 1
    fi
}

###############################################################################
# 备份 MySQL 数据库
###############################################################################

backup_mysql() {
    if [[ "${MYSQL_ENABLED}" != "true" ]]; then
        log_info "MySQL 备份未启用，跳过"
        return 0
    fi

    log_info "开始备份 MySQL 数据库..."

    # 检查容器是否存在且运行中
    if ! docker ps --format '{{.Names}}' | grep -q "^${MYSQL_CONTAINER}$"; then
        log_error "MySQL 容器不存在或未运行: ${MYSQL_CONTAINER}"
        return 1
    fi

    # 创建临时目录
    local temp_mysql_dir="${TEMP_DIR}/mysql"
    mkdir -p "${temp_mysql_dir}"

    # 获取要备份的数据库列表
    local databases=$(yq eval '.mysql.databases' "${CONFIG_FILE}")

    local mysql_dump="${temp_mysql_dir}/mysql.sql.gz"

    if [[ "${databases}" == "all" ]] || [[ "${databases}" == "null" ]]; then
        # 备份所有数据库
        log_info "备份所有数据库..."
        docker exec "${MYSQL_CONTAINER}" mysqldump \
            --single-transaction \
            --quick \
            --skip-lock-tables \
            -u"${MYSQL_USERNAME}" \
            -p"${MYSQL_PASSWORD}" \
            --all-databases \
            | gzip > "${mysql_dump}"
    else
        # 备份指定数据库
        local db_count=$(yq eval '.mysql.databases | length' "${CONFIG_FILE}")
        local db_list=""

        for i in $(seq 0 $((db_count - 1))); do
            local db_name=$(yq eval ".mysql.databases[$i]" "${CONFIG_FILE}")
            db_list+=" ${db_name}"
            log_info "添加数据库: ${db_name}"
        done

        log_info "备份数据库: ${db_list}"
        docker exec "${MYSQL_CONTAINER}" mysqldump \
            --single-transaction \
            --quick \
            --skip-lock-tables \
            -u"${MYSQL_USERNAME}" \
            -p"${MYSQL_PASSWORD}" \
            --databases ${db_list} \
            | gzip > "${mysql_dump}"
    fi

    if [[ -f "${mysql_dump}" ]]; then
        log_info "MySQL 备份完成: ${mysql_dump}"
        echo "${mysql_dump}"
    else
        log_error "MySQL 备份失败"
        return 1
    fi
}

###############################################################################
# 合并备份文件
###############################################################################

merge_backups() {
    local folders_tar=$1
    local mysql_dump=$2

    log_info "开始合并备份文件..."

    # 生成时间戳
    local timestamp=$(date '+%Y%m%d-%H%M%S')
    local final_backup="${OUTPUT_DIR}/${BACKUP_PREFIX}-${timestamp}.tar.gz"

    # 要打包的文件列表
    local files_to_pack=""

    if [[ -n "${folders_tar}" ]] && [[ -f "${folders_tar}" ]]; then
        files_to_pack+=" ${folders_tar}"
    fi

    if [[ -n "${mysql_dump}" ]] && [[ -f "${mysql_dump}" ]]; then
        files_to_pack+=" ${mysql_dump}"
    fi

    if [[ -z "${files_to_pack}" ]]; then
        log_error "没有需要打包的文件"
        return 1
    fi

    # 合并打包
    # 构建相对于 TEMP_DIR 的路径列表
    local files_list=""
    if [[ -n "${folders_tar}" ]] && [[ -f "${folders_tar}" ]]; then
        files_list+=" ${folders_tar#${TEMP_DIR}/}"
        log_info "添加到合并: ${folders_tar#${TEMP_DIR}/} ($(du -h "${folders_tar}" | cut -f1))"
    fi
    if [[ -n "${mysql_dump}" ]] && [[ -f "${mysql_dump}" ]]; then
        files_list+=" ${mysql_dump#${TEMP_DIR}/}"
        log_info "添加到合并: ${mysql_dump#${TEMP_DIR}/} ($(du -h "${mysql_dump}" | cut -f1))"
    fi

    log_info "执行合并打包..."
    if ! tar -czf "${final_backup}" -C "${TEMP_DIR}" ${files_list} 2>&1; then
        log_error "tar 合并命令执行失败"
        return 1
    fi

    if [[ -f "${final_backup}" ]]; then
        local file_size=$(du -h "${final_backup}" | cut -f1)
        log_info "备份完成: ${final_backup} (大小: ${file_size})"
        echo "${final_backup}"
    else
        log_error "合并备份失败"
        return 1
    fi
}

###############################################################################
# 清理旧备份
###############################################################################

cleanup_old_backups() {
    if [[ "${RETENTION_ENABLED}" != "true" ]]; then
        log_info "自动清理未启用，跳过"
        return 0
    fi

    log_info "开始清理旧备份..."

    if [[ "${KEEP_DAYS}" != "null" ]] && [[ "${KEEP_DAYS}" =~ ^[0-9]+$ ]]; then
        log_info "删除 ${KEEP_DAYS} 天前的备份文件..."

        # 查找并删除旧文件
        find "${OUTPUT_DIR}" -name "${BACKUP_PREFIX}-*.tar.gz" -type f -mtime +${KEEP_DAYS} -print | while read old_file; do
            log_info "删除旧备份: ${old_file}"
            rm -f "${old_file}"
        done
    fi

    log_info "清理完成"
}

###############################################################################
# 主函数
###############################################################################

main() {
    log_info "=========================================="
    log_info "Docker Backup 开始执行"
    log_info "=========================================="

    # 检查依赖
    check_dependencies

    # 加载配置
    load_config

    # 创建临时目录
    TEMP_DIR=$(mktemp -d -t docker-backup.XXXXXX)
    log_info "临时目录: ${TEMP_DIR}"

    # 备份文件夹
    local folders_tar=$(backup_folders)

    # 备份 MySQL
    local mysql_dump=$(backup_mysql)

    # 合并备份
    local final_backup=$(merge_backups "${folders_tar}" "${mysql_dump}")

    # 清理旧备份
    cleanup_old_backups

    log_info "=========================================="
    log_info "Docker Backup 执行完成"
    log_info "备份文件: ${final_backup}"
    log_info "=========================================="
}

# 执行主函数
main "$@"