package app

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"time"

	aliyunoss "github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
	aliyuncredentials "github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss/credentials"
	huaweiobs "github.com/huaweicloud/huaweicloud-sdk-go-obs/obs"
	qiniuauth "github.com/qiniu/go-sdk/v7/auth/qbox"
	qiniustorage "github.com/qiniu/go-sdk/v7/storage"
	qiniucredentials "github.com/qiniu/go-sdk/v7/storagev2/credentials"
	qiniuhttpclient "github.com/qiniu/go-sdk/v7/storagev2/http_client"
	qiniuuploader "github.com/qiniu/go-sdk/v7/storagev2/uploader"
	tencentcos "github.com/tencentyun/cos-go-sdk-v5"
)

var (
	storageBucketPattern = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9._-]{1,126}[A-Za-z0-9]$`)
	storagePrefixPattern = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9/_-]{0,119}$`)
)

type mediaObjectStorage interface {
	Put(context.Context, string, string, int64, io.Reader) error
	Delete(context.Context, string) error
	Bucket() string
}

func storageProviderName(provider string) string {
	switch provider {
	case "local":
		return "本地存储"
	case "aliyun_oss":
		return "阿里云 OSS"
	case "tencent_cos":
		return "腾讯云 COS"
	case "qiniu":
		return "七牛云存储"
	case "huawei_obs":
		return "华为云 OBS"
	case "huawei_flexus":
		return "华为云 Flexus 对象存储"
	default:
		return provider
	}
}

func parseStorageHTTPSURL(raw string, allowPath bool) (*url.URL, error) {
	parsed, err := url.Parse(strings.TrimSpace(raw))
	if err != nil || parsed.Scheme != "https" || parsed.Host == "" || parsed.User != nil || parsed.RawQuery != "" || parsed.Fragment != "" {
		return nil, fmt.Errorf("必须是无账号、查询参数和片段的有效 HTTPS 地址")
	}
	if !allowPath && strings.Trim(parsed.EscapedPath(), "/") != "" {
		return nil, fmt.Errorf("地址不能包含路径")
	}
	return parsed, nil
}

func validateLocalStorageDirectory(raw string) error {
	directory := strings.TrimSpace(raw)
	if directory == "" {
		return fmt.Errorf("请填写本地存储目录")
	}
	abs, err := filepath.Abs(filepath.Clean(directory))
	if err != nil {
		return fmt.Errorf("本地存储目录无效")
	}
	root := filepath.VolumeName(abs) + string(os.PathSeparator)
	if strings.EqualFold(filepath.Clean(abs), filepath.Clean(root)) {
		return fmt.Errorf("本地存储目录不能是磁盘根目录")
	}
	if info, statErr := os.Stat(abs); statErr == nil && !info.IsDir() {
		return fmt.Errorf("本地存储目录指向了文件")
	} else if statErr != nil && !os.IsNotExist(statErr) {
		return fmt.Errorf("无法访问本地存储目录")
	}
	return nil
}

func (a *App) validateStorageProviderConfig(ctx context.Context) error {
	provider := a.configPlain(ctx, "storage.provider", "local")
	providers := []string{"local", "aliyun_oss", "tencent_cos", "qiniu", "huawei_obs", "huawei_flexus"}
	if !containsString(providers, provider) {
		return fmt.Errorf("不支持的文件存储厂商 %q", provider)
	}
	for _, spec := range integrationSpecs["storage"] {
		if !spec.Required || (len(spec.Providers) > 0 && !containsString(spec.Providers, provider)) {
			continue
		}
		if strings.TrimSpace(a.configPlain(ctx, spec.Key, "")) == "" {
			return fmt.Errorf("请填写%s", spec.Label)
		}
	}
	prefix := strings.Trim(strings.TrimSpace(a.configPlain(ctx, "storage.object_prefix", "media")), "/")
	if !storagePrefixPattern.MatchString(prefix) || strings.Contains(prefix, "//") || strings.Contains(prefix, "..") {
		return fmt.Errorf("云端对象前缀格式无效")
	}

	if provider == "local" {
		if err := validateLocalStorageDirectory(a.configPlain(ctx, "storage.local.directory", a.config.MediaDir)); err != nil {
			return err
		}
		baseURL := strings.TrimSpace(a.configPlain(ctx, "storage.local.public_base_url", ""))
		if baseURL != "" {
			parsed, err := url.Parse(baseURL)
			if err != nil || parsed.Host == "" || parsed.User != nil || parsed.RawQuery != "" || parsed.Fragment != "" || (parsed.Scheme != "http" && parsed.Scheme != "https") {
				return fmt.Errorf("本地公开访问地址无效")
			}
			if a.config.Environment == "production" && parsed.Scheme != "https" {
				return fmt.Errorf("生产环境本地公开访问地址必须使用 HTTPS")
			}
		}
		return nil
	}

	keyPrefix := "storage." + provider + "."
	if provider == "qiniu" {
		if !storageBucketPattern.MatchString(a.configPlain(ctx, keyPrefix+"bucket", "")) {
			return fmt.Errorf("七牛云空间名称格式无效")
		}
	} else {
		if _, err := parseStorageHTTPSURL(a.configPlain(ctx, keyPrefix+"endpoint", ""), false); err != nil {
			return fmt.Errorf("%s Endpoint %v", storageProviderName(provider), err)
		}
		if !storageBucketPattern.MatchString(a.configPlain(ctx, keyPrefix+"bucket", "")) {
			return fmt.Errorf("%s Bucket 名称格式无效", storageProviderName(provider))
		}
	}
	if _, err := parseStorageHTTPSURL(a.configPlain(ctx, keyPrefix+"public_base_url", ""), true); err != nil {
		return fmt.Errorf("%s文件访问域名%v", storageProviderName(provider), err)
	}
	return nil
}

func storagePublicURL(baseURL, objectKey string) string {
	return strings.TrimRight(strings.TrimSpace(baseURL), "/") + "/" + strings.TrimLeft(objectKey, "/")
}

func storageHTTPClient() *http.Client {
	return &http.Client{
		Timeout: 30 * time.Second,
		CheckRedirect: func(_ *http.Request, _ []*http.Request) error {
			return http.ErrUseLastResponse
		},
	}
}

type aliyunOSSStorage struct {
	bucket string
	client *aliyunoss.Client
}

func (s *aliyunOSSStorage) Bucket() string { return s.bucket }
func (s *aliyunOSSStorage) Put(ctx context.Context, key, contentType string, size int64, body io.Reader) error {
	_, err := s.client.PutObject(ctx, &aliyunoss.PutObjectRequest{
		Bucket: aliyunoss.Ptr(s.bucket), Key: aliyunoss.Ptr(key), Body: body,
		ContentType: aliyunoss.Ptr(contentType), ContentLength: aliyunoss.Ptr(size),
	})
	return err
}
func (s *aliyunOSSStorage) Delete(ctx context.Context, key string) error {
	_, err := s.client.DeleteObject(ctx, &aliyunoss.DeleteObjectRequest{Bucket: aliyunoss.Ptr(s.bucket), Key: aliyunoss.Ptr(key)})
	return err
}

type tencentCOSStorage struct {
	bucket string
	client *tencentcos.Client
}

func (s *tencentCOSStorage) Bucket() string { return s.bucket }
func (s *tencentCOSStorage) Put(ctx context.Context, key, contentType string, size int64, body io.Reader) error {
	_, err := s.client.Object.Put(ctx, key, body, &tencentcos.ObjectPutOptions{ObjectPutHeaderOptions: &tencentcos.ObjectPutHeaderOptions{ContentType: contentType, ContentLength: size}})
	return err
}
func (s *tencentCOSStorage) Delete(ctx context.Context, key string) error {
	_, err := s.client.Object.Delete(ctx, key)
	return err
}

type qiniuStorage struct {
	bucket    string
	uploader  *qiniuuploader.UploadManager
	deleteMac *qiniuauth.Mac
}

func (s *qiniuStorage) Bucket() string { return s.bucket }
func (s *qiniuStorage) Put(ctx context.Context, key, contentType string, _ int64, body io.Reader) error {
	return s.uploader.UploadReader(ctx, body, &qiniuuploader.ObjectOptions{BucketName: s.bucket, ObjectName: &key, FileName: filepath.Base(key), ContentType: contentType}, nil)
}
func (s *qiniuStorage) Delete(_ context.Context, key string) error {
	manager := qiniustorage.NewBucketManager(s.deleteMac, &qiniustorage.Config{UseHTTPS: true})
	return manager.Delete(s.bucket, key)
}

type huaweiOBSStorage struct {
	bucket string
	client *huaweiobs.ObsClient
}

func (s *huaweiOBSStorage) Bucket() string { return s.bucket }
func (s *huaweiOBSStorage) Put(_ context.Context, key, contentType string, size int64, body io.Reader) error {
	_, err := s.client.PutObject(&huaweiobs.PutObjectInput{PutObjectBasicInput: huaweiobs.PutObjectBasicInput{
		ObjectOperationInput: huaweiobs.ObjectOperationInput{Bucket: s.bucket, Key: key},
		HttpHeader:           huaweiobs.HttpHeader{ContentType: contentType}, ContentLength: size,
	}, Body: body})
	return err
}
func (s *huaweiOBSStorage) Delete(_ context.Context, key string) error {
	_, err := s.client.DeleteObject(&huaweiobs.DeleteObjectInput{Bucket: s.bucket, Key: key})
	return err
}

func (a *App) newMediaObjectStorage(ctx context.Context) (mediaObjectStorage, func(), error) {
	if err := a.validateStorageProviderConfig(ctx); err != nil {
		return nil, func() {}, err
	}
	provider := a.configPlain(ctx, "storage.provider", "local")
	return a.newMediaObjectStorageForProvider(ctx, provider, "")
}

// Historical media must be deleted through the provider that originally
// stored it, even when uploads have since moved to another provider. The
// credentials remain in system_configs and the recorded bucket protects us
// from deleting an object with the same key from a newly configured bucket.
func (a *App) newMediaObjectStorageForProvider(ctx context.Context, provider, recordedBucket string) (mediaObjectStorage, func(), error) {
	provider = strings.TrimSpace(provider)
	if provider == "local" {
		directory := a.configPlain(ctx, "storage.local.directory", a.config.MediaDir)
		if err := validateLocalStorageDirectory(directory); err != nil {
			return nil, func() {}, err
		}
		return localMediaStorage{directory: directory}, func() {}, nil
	}
	keyPrefix := "storage." + provider + "."
	configuredBucket := strings.TrimSpace(a.configPlain(ctx, keyPrefix+"bucket", ""))
	if configuredBucket == "" {
		return nil, func() {}, fmt.Errorf("%s Bucket 未配置", storageProviderName(provider))
	}
	if recordedBucket != "" && configuredBucket != recordedBucket {
		return nil, func() {}, fmt.Errorf("记录 Bucket %q 与当前配置 %q 不一致", recordedBucket, configuredBucket)
	}
	switch provider {
	case "aliyun_oss":
		if a.configPlain(ctx, keyPrefix+"access_key_id", "") == "" || a.configPlain(ctx, keyPrefix+"access_key_secret", "") == "" {
			return nil, func() {}, fmt.Errorf("阿里云 OSS 凭证未配置")
		}
		config := aliyunoss.LoadDefaultConfig().
			WithCredentialsProvider(aliyuncredentials.NewStaticCredentialsProvider(a.configPlain(ctx, keyPrefix+"access_key_id", ""), a.configPlain(ctx, keyPrefix+"access_key_secret", ""))).
			WithRegion(a.configPlain(ctx, keyPrefix+"region", "")).
			WithEndpoint(a.configPlain(ctx, keyPrefix+"endpoint", "")).
			WithConnectTimeout(5 * time.Second).
			WithReadWriteTimeout(30 * time.Second).
			WithRetryMaxAttempts(3)
		return &aliyunOSSStorage{bucket: configuredBucket, client: aliyunoss.NewClient(config)}, func() {}, nil
	case "tencent_cos":
		endpoint, err := url.Parse(a.configPlain(ctx, keyPrefix+"endpoint", ""))
		if err != nil || endpoint.Host == "" || a.configPlain(ctx, keyPrefix+"secret_id", "") == "" || a.configPlain(ctx, keyPrefix+"secret_key", "") == "" {
			return nil, func() {}, fmt.Errorf("腾讯云 COS 地址或凭证未配置")
		}
		client := tencentcos.NewClient(&tencentcos.BaseURL{BucketURL: endpoint}, &http.Client{
			Timeout:   30 * time.Second,
			Transport: &tencentcos.AuthorizationTransport{SecretID: a.configPlain(ctx, keyPrefix+"secret_id", ""), SecretKey: a.configPlain(ctx, keyPrefix+"secret_key", "")},
		})
		return &tencentCOSStorage{bucket: configuredBucket, client: client}, func() {}, nil
	case "qiniu":
		accessKey, secretKey := a.configPlain(ctx, keyPrefix+"access_key", ""), a.configPlain(ctx, keyPrefix+"secret_key", "")
		if accessKey == "" || secretKey == "" {
			return nil, func() {}, fmt.Errorf("七牛云凭证未配置")
		}
		manager := qiniuuploader.NewUploadManager(&qiniuuploader.UploadManagerOptions{Options: qiniuhttpclient.Options{Credentials: qiniucredentials.NewCredentials(accessKey, secretKey), BasicHTTPClient: storageHTTPClient()}, MultiPartsThreshold: 8 << 20, PartSize: 4 << 20, Concurrency: 2})
		return &qiniuStorage{bucket: configuredBucket, uploader: manager, deleteMac: qiniuauth.NewMac(accessKey, secretKey)}, func() {}, nil
	case "huawei_obs", "huawei_flexus":
		if a.configPlain(ctx, keyPrefix+"access_key", "") == "" || a.configPlain(ctx, keyPrefix+"secret_key", "") == "" {
			return nil, func() {}, fmt.Errorf("%s凭证未配置", storageProviderName(provider))
		}
		client, err := huaweiobs.New(a.configPlain(ctx, keyPrefix+"access_key", ""), a.configPlain(ctx, keyPrefix+"secret_key", ""), a.configPlain(ctx, keyPrefix+"endpoint", ""), huaweiobs.WithConnectTimeout(5), huaweiobs.WithSocketTimeout(30), huaweiobs.WithMaxRetryCount(2))
		if err != nil {
			return nil, func() {}, err
		}
		return &huaweiOBSStorage{bucket: configuredBucket, client: client}, client.Close, nil
	default:
		return nil, func() {}, fmt.Errorf("不支持的文件存储厂商 %q", provider)
	}
}