package haiyuapi

import (
	"bytes"
	"context"
	"crypto/md5"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"
	"time"

	"tyapi-server/internal/shared/external_logger"
)

const defaultRequestTimeout = 60 * time.Second

// serviceConfig 海宇API服务运行时配置（Access Key 为 16 进制 AES-128 密钥）
type serviceConfig struct {
	BaseURL   string
	AccessID  string
	SecretKey string
	Timeout   time.Duration
}

// HaiyuapiService 海宇API上游服务客户端
type HaiyuapiService struct {
	config serviceConfig
	logger *external_logger.ExternalServiceLogger
}

// NewHaiyuapiService 创建海宇API服务实例
func NewHaiyuapiService(baseURL, accessID, secretKey string, timeout time.Duration, logger *external_logger.ExternalServiceLogger) *HaiyuapiService {
	if timeout <= 0 {
		timeout = defaultRequestTimeout
	}
	return &HaiyuapiService{
		config: serviceConfig{
			BaseURL:   strings.TrimRight(baseURL, "/"),
			AccessID:  accessID,
			SecretKey: secretKey,
			Timeout:   timeout,
		},
		logger: logger,
	}
}

// CallAPI 调用海宇API：apiPath 如 /api/v1/FLXGHB4F，自动拼接 base_url 与 ?t=13位毫秒时间戳，返回解密后的明文 JSON
func (s *HaiyuapiService) CallAPI(ctx context.Context, apiPath string, params map[string]interface{}) ([]byte, error) {
	startTime := time.Now()
	hash := md5.Sum([]byte(fmt.Sprintf("%d_%s", time.Now().UnixNano(), s.config.SecretKey)))
	requestID := fmt.Sprintf("haiyuapi_%x", hash[:8])

	var transactionID string
	if id, ok := ctx.Value("transaction_id").(string); ok {
		transactionID = id
	}

	path := apiPath
	if !strings.HasPrefix(path, "/") {
		path = "/" + path
	}
	timestamp := strconv.FormatInt(time.Now().UnixMilli(), 10)
	reqURL := s.config.BaseURL + path + "?t=" + timestamp

	if s.logger != nil {
		s.logger.LogRequest(requestID, transactionID, apiPath, reqURL)
	}

	encryptedData, err := EncryptParams(params, s.config.SecretKey)
	if err != nil {
		err = errors.Join(ErrSystem, fmt.Errorf("请求加密失败: %w", err))
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}

	bodyBytes, err := json.Marshal(RequestPayload{Data: encryptedData})
	if err != nil {
		err = errors.Join(ErrSystem, err)
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, reqURL, bytes.NewBuffer(bodyBytes))
	if err != nil {
		err = errors.Join(ErrSystem, err)
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}
	req.Header.Set(HeaderContentType, ContentTypeJSON)
	req.Header.Set(HeaderAccessID, s.config.AccessID)

	resp, err := (&http.Client{Timeout: s.config.Timeout}).Do(req)
	if err != nil {
		err = wrapHTTPError(err)
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		err = errors.Join(ErrSystem, err)
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}

	duration := time.Since(startTime)

	if resp.StatusCode != http.StatusOK {
		err = errors.Join(ErrDatasource, fmt.Errorf("HTTP状态码 %d", resp.StatusCode))
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}

	var apiResp APIResponse
	if err := json.Unmarshal(respBody, &apiResp); err != nil {
		err = errors.Join(ErrSystem, fmt.Errorf("响应解析失败: %w", err))
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}

	if apiResp.Code != CodeSuccess {
		apiErr := NewHaiyuapiAPIError(apiResp.Code, apiResp.Message)
		err = errors.Join(GetErrByCode(apiResp.Code), apiErr)
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, apiErr, params)
		}
		return nil, err
	}

	plainResp, err := DecryptData(apiResp.Data, s.config.SecretKey)
	if err != nil {
		err = errors.Join(ErrSystem, fmt.Errorf("响应解密失败: %w", err))
		if s.logger != nil {
			s.logger.LogError(requestID, transactionID, apiPath, err, params)
		}
		return nil, err
	}

	if s.logger != nil {
		s.logger.LogResponse(requestID, transactionID, apiPath, resp.StatusCode, duration)
	}

	return plainResp, nil
}

func wrapHTTPError(err error) error {
	if err == context.DeadlineExceeded {
		return errors.Join(ErrDatasource, err)
	}
	if netErr, ok := err.(interface{ Timeout() bool }); ok && netErr.Timeout() {
		return errors.Join(ErrDatasource, err)
	}
	switch err.Error() {
	case "context deadline exceeded", "timeout", "Client.Timeout exceeded", "net/http: request canceled":
		return errors.Join(ErrDatasource, err)
	default:
		return errors.Join(ErrSystem, err)
	}
}