package service

import (
	"fmt"
	"io"
	"os"
	"time"

	"seeyon-filesystem/config"
	"seeyon-filesystem/model"
	"seeyon-filesystem/storage"
)

// StorageTestService 存储连通性测试服务
type StorageTestService struct{}

func NewStorageTestService() *StorageTestService {
	return &StorageTestService{}
}

// TestResult 测试结果
type TestResult struct {
	Success bool   `json:"success"`
	Message string `json:"message"`
	Latency int64  `json:"latency_ms"` // 耗时毫秒
	Detail  string `json:"detail,omitempty"`
}

// TestPolicy 测试存储策略连通性
func (s *StorageTestService) TestPolicy(policyID uint64) (*TestResult, error) {
	var policy model.StoragePolicy
	if err := config.DB.First(&policy, policyID).Error; err != nil {
		return nil, fmt.Errorf("存储策略不存在")
	}

	switch policy.Type {
	case "local":
		return s.testLocal(policy), nil
	case "minio":
		return s.testMinIO(policy), nil
	default:
		return &TestResult{Success: false, Message: "不支持的存储类型"}, nil
	}
}

// TestNewPolicy 测试新配置(未保存)
func (s *StorageTestService) TestNewPolicy(policyType string, cfg model.PolicyConfig) *TestResult {
	switch policyType {
	case "local":
		return s.testLocalConfig(cfg)
	case "minio":
		return s.testMinIOConfig(cfg)
	default:
		return &TestResult{Success: false, Message: "不支持的存储类型"}
	}
}

// testLocal 测试本地存储
func (s *StorageTestService) testLocal(policy model.StoragePolicy) *TestResult {
	return s.testLocalConfig(policy.Config)
}

func (s *StorageTestService) testLocalConfig(cfg model.PolicyConfig) *TestResult {
	start := time.Now()

	basePath := cfg.BasePath
	if basePath == "" {
		return &TestResult{Success: false, Message: "未配置存储路径"}
	}

	// 检查目录是否存在
	info, err := os.Stat(basePath)
	if err != nil {
		if os.IsNotExist(err) {
			// 尝试创建
			if err := os.MkdirAll(basePath, 0755); err != nil {
				return &TestResult{Success: false, Message: "目录不存在且无法创建: " + err.Error()}
			}
			return &TestResult{Success: true, Message: "目录已自动创建", Latency: time.Since(start).Milliseconds(), Detail: basePath}
		}
		return &TestResult{Success: false, Message: "访问目录失败: " + err.Error()}
	}

	if !info.IsDir() {
		return &TestResult{Success: false, Message: "路径不是目录"}
	}

	// 测试写入权限
	testFile := basePath + "/.connectivity_test"
	if err := os.WriteFile(testFile, []byte("test"), 0644); err != nil {
		return &TestResult{Success: false, Message: "目录无写入权限: " + err.Error()}
	}
	os.Remove(testFile)

	return &TestResult{
		Success: true,
		Message: "连接成功, 目录可读写",
		Latency: time.Since(start).Milliseconds(),
		Detail:  basePath,
	}
}

// testMinIO 测试MinIO连接
func (s *StorageTestService) testMinIO(policy model.StoragePolicy) *TestResult {
	return s.testMinIOConfig(policy.Config)
}

func (s *StorageTestService) testMinIOConfig(cfg model.PolicyConfig) *TestResult {
	start := time.Now()

	if cfg.Endpoint == "" {
		return &TestResult{Success: false, Message: "未配置Endpoint"}
	}
	if cfg.Bucket == "" {
		return &TestResult{Success: false, Message: "未配置Bucket"}
	}

	// AccessKey/SecretKey 可选(公开桶不需要)
	engine, err := storage.NewMinIOEngine(cfg.Endpoint, cfg.AccessKey, cfg.SecretKey, cfg.Bucket, cfg.UseSSL)
	if err != nil {
		return &TestResult{
			Success: false,
			Message: "连接失败: " + err.Error(),
			Latency: time.Since(start).Milliseconds(),
		}
	}

	// 测试上传和下载
	testKey := ".connectivity_test"
	testContent := []byte("minio connectivity test")
	if err := engine.Upload(testKey, bytesReader(testContent), int64(len(testContent))); err != nil {
		return &TestResult{
			Success: false,
			Message: "上传测试失败: " + err.Error(),
			Latency: time.Since(start).Milliseconds(),
		}
	}

	// 清理测试文件
	engine.Delete(testKey)

	latency := time.Since(start).Milliseconds()
	return &TestResult{
		Success: true,
		Message: fmt.Sprintf("连接成功, Bucket=%s, 延迟=%dms", cfg.Bucket, latency),
		Latency: latency,
		Detail:  fmt.Sprintf("%s/%s", cfg.Endpoint, cfg.Bucket),
	}
}

// bytesReader 创建bytes.Reader
func bytesReader(b []byte) *bytesReaderWrapper {
	return &bytesReaderWrapper{data: b, offset: 0}
}

type bytesReaderWrapper struct {
	data   []byte
	offset int
}

func (r *bytesReaderWrapper) Read(p []byte) (int, error) {
	if r.offset >= len(r.data) {
		return 0, io.EOF
	}
	n := copy(p, r.data[r.offset:])
	r.offset += n
	return n, nil
}