package httpClient

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"

	"go.uber.org/zap"
)

const (
	DefaultTimeout time.Duration = 5 // 默认超时时间5s
)

type HttpClient struct {
	reLogin *func() string
}

type HttpClientOptions struct {
	Timeout *time.Duration // 单位：s
	Header  *http.Header
}

// PostBody 包含转换后的 Reader 和推荐的 Content-Type
type PostBody struct {
	Reader      io.Reader
	ContentType string
}

type ResponseData struct {
	Code int `json:"code"`
}

// 封装模块的响应结构数据
type Response struct {
	Status     string // e.g. "200 OK"
	StatusCode int    // e.g. 200

	// Header maps header keys to values. If the response had multiple
	// headers with the same key, they may be concatenated, with comma
	// delimiters.  (RFC 7230, section 3.2.2 requires that multiple headers
	// be semantically equivalent to a comma-delimited sequence.) When
	// Header values are duplicated by other fields in this struct (e.g.,
	// ContentLength, TransferEncoding, Trailer), the field values are
	// authoritative.
	//
	// Keys in the map are canonicalized (see CanonicalHeaderKey).
	Header http.Header

	// Body represents the response body.
	Body []byte

	// ContentLength records the length of the associated content. The
	// value -1 indicates that the length is unknown. Unless Request.Method
	// is "HEAD", values >= 0 indicate that the given number of bytes may
	// be read from Body.
	ContentLength int64
}

// var reLogin = func() string {
// 	// empty function
// 	return ""
// }

func (c *HttpClient) responseInterceptor(response *Response, retry func(*string) (*Response, error)) *Response {
	// 判断是否回复code 401
	// var data ResponseData
	// if err := json.Unmarshal(response.Body, &data); err != nil {
	// 	zap.L().Warn("ResponseData 解析失败", zap.String("Status", response.Status), zap.String("body", string(response.Body)), zap.String("err", err.Error()))
	// 	return response
	// }
	// if data.Code == 401 {
	// TODO 调整401判断逻辑，待观察是否有问题
	if response.StatusCode == 401 {
		if c.reLogin == nil {
			return response
		}
		tokenStr := (*c.reLogin)()
		retryBody, err := retry(&tokenStr)
		if err != nil {
			zap.L().Warn("http retry 失败", zap.String("token", tokenStr), zap.String("err", err.Error()))
			return response
		}
		return retryBody
	}
	return response
}

func (c *HttpClient) RegisterLogin(login func() string) {
	c.reLogin = &login
}

func (c *HttpClient) HttpGet(url string, params *url.Values, opt *HttpClientOptions) (*Response, error) {
	// 拼接参数到 URL
	finalURL := url
	if params != nil {
		finalURL = finalURL + "?" + params.Encode()
	}

	zap.L().Debug("HttpGet", zap.String("url", finalURL))

	// 创建请求
	req, err := http.NewRequest(
		http.MethodGet,
		finalURL,
		nil)
	if err != nil {
		zap.L().Error("NewRequest failed.", zap.String("err", err.Error()))
		return nil, err
	}

	// 设置 Header
	if opt != nil && opt.Header != nil {
		for key, values := range *opt.Header {
			for _, v := range values {
				req.Header.Add(key, v)
			}
		}
	}

	// 设置 Timeout
	timeout := DefaultTimeout
	if opt != nil && opt.Timeout != nil {
		timeout = *opt.Timeout
	}

	// 发送请求 - 封装成函数用于重试
	var reqFunc = func(token *string) (*Response, error) {
		client := &http.Client{Timeout: timeout * time.Second}
		resp, err := client.Do(req)
		if err != nil {
			zap.L().Error("Do Send failed.", zap.String("err", err.Error()))
			return nil, err
		}
		defer resp.Body.Close()

		respBody, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, err
		}

		return &Response{
			Status:        resp.Status,
			StatusCode:    resp.StatusCode,
			Header:        resp.Header,
			Body:          respBody,
			ContentLength: resp.ContentLength,
		}, nil
	}

	response, err := reqFunc(nil)
	if err != nil {
		return nil, err
	}

	// 应答失败，直接返回
	if response.StatusCode != 200 {
		zap.L().Warn("[HttpGet] Response failed", zap.String("Status", response.Status), zap.String("Body", string(response.Body)))
		return response, fmt.Errorf("[HttpGet] Response failed")
	}

	return c.responseInterceptor(response, reqFunc), nil
}

// toPostBody 将任意 body 转换为 http POST 可用的 io.Reader
func toPostBody(body any) (*PostBody, error) {
	if body == nil {
		return &PostBody{Reader: nil, ContentType: ""}, nil
	}

	switch v := body.(type) {
	case io.Reader:
		// 直接传 io.Reader
		return &PostBody{Reader: v}, nil

	case string:
		// 字符串默认 text/plain
		return &PostBody{Reader: strings.NewReader(v), ContentType: "text/plain"}, nil

	case []byte:
		// []byte 默认 application/octet-stream
		return &PostBody{Reader: bytes.NewReader(v), ContentType: "application/octet-stream"}, nil

	case url.Values:
		// 表单类型 application/x-www-form-urlencoded
		return &PostBody{
			Reader:      strings.NewReader(v.Encode()),
			ContentType: "application/x-www-form-urlencoded; charset=UTF-8",
		}, nil

	default:
		// 尝试序列化为 JSON
		jsonData, err := json.Marshal(v)
		if err != nil {
			return nil, errors.New("unsupported body type and failed to marshal to JSON")
		}
		return &PostBody{
			Reader:      bytes.NewReader(jsonData),
			ContentType: "application/json",
		}, nil
	}
}

func (c *HttpClient) HttpPost(url string, body any, opt *HttpClientOptions) (*Response, error) {
	// 转换body数据
	payload, err := toPostBody(body)
	if err != nil {
		zap.L().Error("to PostBody failed.", zap.String("err", err.Error()))
		return nil, err
	}

	zap.L().Debug("HttpPost", zap.String("url", url))

	// 创建请求
	req, err := http.NewRequest(
		http.MethodPost,
		url,
		payload.Reader)
	if err != nil {
		zap.L().Error("NewRequest failed.", zap.String("err", err.Error()))
		return nil, err
	}

	// 设置 Content-Type
	req.Header.Set("Content-Type", payload.ContentType)

	// 设置 Header
	if opt != nil && opt.Header != nil {
		for key, values := range *opt.Header {
			for _, v := range values {
				req.Header.Add(key, v)
			}
		}
	}

	// 设置 Timeout
	timeout := DefaultTimeout
	if opt != nil && opt.Timeout != nil {
		timeout = *opt.Timeout
	}

	// 发送请求 - 封装成函数用于重试
	var reqFunc = func(token *string) (*Response, error) {
		client := &http.Client{Timeout: timeout * time.Second}
		resp, err := client.Do(req)
		if err != nil {
			zap.L().Error("Do Send failed.", zap.String("err", err.Error()))
			return nil, err
		}
		defer resp.Body.Close()

		respBody, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, err
		}

		return &Response{
			Status:        resp.Status,
			StatusCode:    resp.StatusCode,
			Header:        resp.Header,
			Body:          respBody,
			ContentLength: resp.ContentLength,
		}, nil
	}
	response, err := reqFunc(nil)
	if err != nil {
		return nil, err
	}

	// 应答失败，直接返回
	if response.StatusCode != 200 {
		zap.L().Warn("[HttpPost] Response failed", zap.String("Status", response.Status), zap.String("Body", string(response.Body)))
		return response, fmt.Errorf("[HttpPost] Response failed")
	}

	return c.responseInterceptor(response, reqFunc), nil
}