package httpClient

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

	"go.uber.org/zap"
)

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

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
}

func HttpGet(url string, params url.Values, opt *HttpClientOptions) ([]byte, error) {
	// 拼接参数到 URL
	finalURL := url + "?" + params.Encode()

	// 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
	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()

	return io.ReadAll(resp.Body)
}

// 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 HttpPost(url string, body any, opt *HttpClientOptions) ([]byte, 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
	}

	// 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
	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()

	return io.ReadAll(resp.Body)
}