#!/bin/bash

# 生产环境数据库迁移脚本
# 使用方法: ./scripts/production-migrate.sh [options]

set -e  # 遇到错误立即退出

# 默认配置
CONFIG_FILE="etc/photographyapi-api.yaml"
BACKUP_DIR="data/backups"
LOG_FILE="migration.log"
DRY_RUN=false
VERBOSE=false
FORCE=false

# 颜色定义
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

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

error() {
    echo -e "${RED}[ERROR]${NC} $1" | tee -a "$LOG_FILE"
}

warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1" | tee -a "$LOG_FILE"
}

success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1" | tee -a "$LOG_FILE"
}

# 显示帮助
show_help() {
    cat << EOF
生产环境数据库迁移脚本

使用方法:
  $0 [选项] [命令]

选项:
  -c, --config FILE    配置文件路径 (默认: etc/photographyapi-api.yaml)
  -b, --backup-dir DIR 备份目录 (默认: data/backups)
  -l, --log-file FILE  日志文件 (默认: migration.log)
  -d, --dry-run        预览模式，不执行实际操作
  -v, --verbose        详细输出
  -f, --force          强制执行，跳过确认
  -h, --help           显示帮助信息

命令:
  status               显示迁移状态
  migrate              执行待处理的迁移
  rollback STEPS       回滚指定步数的迁移
  backup               创建数据库备份
  restore BACKUP       恢复数据库备份
  check                检查系统状态

示例:
  $0 status
  $0 migrate
  $0 rollback 1
  $0 backup
  $0 restore photography_20250711_120000.db
  $0 -d migrate  # 预览模式

注意:
  - 生产环境操作前会自动创建备份
  - 建议先使用 -d 选项进行预览
  - 所有操作都会记录到日志文件
EOF
}

# 解析命令行参数
parse_args() {
    while [[ $# -gt 0 ]]; do
        case $1 in
            -c|--config)
                CONFIG_FILE="$2"
                shift 2
                ;;
            -b|--backup-dir)
                BACKUP_DIR="$2"
                shift 2
                ;;
            -l|--log-file)
                LOG_FILE="$2"
                shift 2
                ;;
            -d|--dry-run)
                DRY_RUN=true
                shift
                ;;
            -v|--verbose)
                VERBOSE=true
                shift
                ;;
            -f|--force)
                FORCE=true
                shift
                ;;
            -h|--help)
                show_help
                exit 0
                ;;
            -*)
                error "未知选项: $1"
                exit 1
                ;;
            *)
                COMMAND="$1"
                shift
                break
                ;;
        esac
    done
    
    # 保存剩余参数
    ARGS=("$@")
}

# 检查依赖
check_dependencies() {
    log "检查系统依赖..."
    
    # 检查 Go
    if ! command -v go &> /dev/null; then
        error "Go 未安装或不在 PATH 中"
        exit 1
    fi
    
    # 检查配置文件
    if [[ ! -f "$CONFIG_FILE" ]]; then
        error "配置文件不存在: $CONFIG_FILE"
        exit 1
    fi
    
    # 检查迁移工具
    if [[ ! -f "cmd/migrate/main.go" ]]; then
        error "迁移工具不存在: cmd/migrate/main.go"
        exit 1
    fi
    
    # 创建必要目录
    mkdir -p "$BACKUP_DIR"
    
    success "依赖检查通过"
}

# 创建备份
create_backup() {
    log "创建数据库备份..."
    
    if [[ "$DRY_RUN" == true ]]; then
        log "[DRY RUN] 将创建备份到: $BACKUP_DIR"
        return 0
    fi
    
    local backup_name="photography_$(date +%Y%m%d_%H%M%S).db"
    local backup_path="$BACKUP_DIR/$backup_name"
    
    if [[ -f "data/photography.db" ]]; then
        cp "data/photography.db" "$backup_path"
        success "备份创建成功: $backup_path"
        echo "$backup_path" > ".last_backup"
    else
        warning "数据库文件不存在，跳过备份"
    fi
}

# 检查迁移状态
check_migration_status() {
    log "检查迁移状态..."
    
    if [[ "$VERBOSE" == true ]]; then
        go run cmd/migrate/main.go -f "$CONFIG_FILE" -c status
    else
        go run cmd/migrate/main.go -f "$CONFIG_FILE" -c status | grep -E "(Applied|Pending)" || true
    fi
}

# 获取待处理迁移数量
get_pending_count() {
    go run cmd/migrate/main.go -f "$CONFIG_FILE" -c status | grep -c "Pending" || echo "0"
}

# 执行迁移
execute_migration() {
    log "执行数据库迁移..."
    
    local pending_count=$(get_pending_count)
    
    if [[ "$pending_count" -eq 0 ]]; then
        success "没有待处理的迁移"
        return 0
    fi
    
    log "发现 $pending_count 个待处理迁移"
    
    if [[ "$DRY_RUN" == true ]]; then
        log "[DRY RUN] 将执行 $pending_count 个迁移"
        check_migration_status
        return 0
    fi
    
    # 确认执行
    if [[ "$FORCE" != true ]]; then
        warning "即将执行 $pending_count 个数据库迁移"
        echo -n "确认继续? (y/N): "
        read -r confirm
        if [[ "$confirm" != "y" && "$confirm" != "Y" ]]; then
            log "用户取消操作"
            exit 0
        fi
    fi
    
    # 创建备份
    create_backup
    
    # 执行迁移
    log "开始执行迁移..."
    if go run cmd/migrate/main.go -f "$CONFIG_FILE" -c up; then
        success "迁移执行成功"
    else
        error "迁移执行失败"
        
        # 提供回滚选项
        if [[ -f ".last_backup" ]]; then
            local last_backup=$(cat ".last_backup")
            warning "可以使用以下命令回滚到备份:"
            echo "  $0 restore $(basename "$last_backup")"
        fi
        
        exit 1
    fi
}

# 执行回滚
execute_rollback() {
    local steps="${ARGS[0]}"
    
    if [[ -z "$steps" ]]; then
        error "请指定回滚步数"
        exit 1
    fi
    
    if ! [[ "$steps" =~ ^[0-9]+$ ]]; then
        error "回滚步数必须是正整数"
        exit 1
    fi
    
    log "准备回滚 $steps 步迁移..."
    
    if [[ "$DRY_RUN" == true ]]; then
        log "[DRY RUN] 将回滚 $steps 步迁移"
        return 0
    fi
    
    # 确认回滚
    if [[ "$FORCE" != true ]]; then
        warning "即将回滚 $steps 步数据库迁移"
        echo -n "确认继续? (y/N): "
        read -r confirm
        if [[ "$confirm" != "y" && "$confirm" != "Y" ]]; then
            log "用户取消操作"
            exit 0
        fi
    fi
    
    # 创建备份
    create_backup
    
    # 执行回滚
    log "开始执行回滚..."
    if go run cmd/migrate/main.go -f "$CONFIG_FILE" -c down -s "$steps"; then
        success "回滚执行成功"
    else
        error "回滚执行失败"
        exit 1
    fi
}

# 恢复备份
restore_backup() {
    local backup_file="${ARGS[0]}"
    
    if [[ -z "$backup_file" ]]; then
        error "请指定备份文件名"
        echo "可用备份:"
        ls -la "$BACKUP_DIR"/ || true
        exit 1
    fi
    
    local backup_path="$BACKUP_DIR/$backup_file"
    
    if [[ ! -f "$backup_path" ]]; then
        error "备份文件不存在: $backup_path"
        exit 1
    fi
    
    log "准备恢复备份: $backup_file"
    
    if [[ "$DRY_RUN" == true ]]; then
        log "[DRY RUN] 将恢复备份: $backup_path"
        return 0
    fi
    
    # 确认恢复
    if [[ "$FORCE" != true ]]; then
        warning "即将恢复数据库备份，当前数据将被覆盖"
        echo -n "确认继续? (y/N): "
        read -r confirm
        if [[ "$confirm" != "y" && "$confirm" != "Y" ]]; then
            log "用户取消操作"
            exit 0
        fi
    fi
    
    # 执行恢复
    log "开始恢复备份..."
    if cp "$backup_path" "data/photography.db"; then
        success "备份恢复成功"
    else
        error "备份恢复失败"
        exit 1
    fi
}

# 系统检查
system_check() {
    log "执行系统检查..."
    
    # 检查配置文件
    if [[ -f "$CONFIG_FILE" ]]; then
        success "配置文件存在: $CONFIG_FILE"
    else
        error "配置文件不存在: $CONFIG_FILE"
    fi
    
    # 检查数据库文件
    if [[ -f "data/photography.db" ]]; then
        success "数据库文件存在: data/photography.db"
        local db_size=$(du -h "data/photography.db" | cut -f1)
        log "数据库大小: $db_size"
    else
        warning "数据库文件不存在: data/photography.db"
    fi
    
    # 检查备份目录
    if [[ -d "$BACKUP_DIR" ]]; then
        success "备份目录存在: $BACKUP_DIR"
        local backup_count=$(ls -1 "$BACKUP_DIR"/ | wc -l)
        log "备份数量: $backup_count"
    else
        warning "备份目录不存在: $BACKUP_DIR"
    fi
    
    # 检查迁移状态
    check_migration_status
}

# 主函数
main() {
    parse_args "$@"
    
    # 初始化日志
    log "开始执行生产环境数据库迁移脚本"
    log "配置文件: $CONFIG_FILE"
    log "备份目录: $BACKUP_DIR"
    log "日志文件: $LOG_FILE"
    
    if [[ "$DRY_RUN" == true ]]; then
        log "运行模式: 预览 (DRY RUN)"
    fi
    
    # 检查依赖
    check_dependencies
    
    # 执行命令
    case "${COMMAND:-status}" in
        status)
            check_migration_status
            ;;
        migrate)
            execute_migration
            ;;
        rollback)
            execute_rollback
            ;;
        backup)
            create_backup
            ;;
        restore)
            restore_backup
            ;;
        check)
            system_check
            ;;
        *)
            error "未知命令: $COMMAND"
            show_help
            exit 1
            ;;
    esac
    
    log "脚本执行完成"
}

# 运行主函数
main "$@"