package youlianghui

import (
	"bytes"
	"fmt"
	"io"
	"io/ioutil"
	"mime/multipart"
	"net/http"
	"os"
)

// MultipartFormDataRequest 封装 multipart/form-data 请求
func MultipartFormDataRequest(url string, fields map[string]string, files map[string]string, headers map[string]string) ([]byte, error) {
	// 创建一个缓冲区来存储表单数据
	var b bytes.Buffer
	w := multipart.NewWriter(&b)

	// 添加文本字段
	for key, value := range fields {
		if err := addFormValue(w, key, value); err != nil {
			return nil, err
		}
	}

	// 添加文件字段
	for fieldName, filePath := range files {
		file, err := os.Open(filePath)
		if err != nil {
			return nil, fmt.Errorf("error opening file %s: %v", filePath, err)
		}
		defer file.Close()

		part, err := w.CreateFormFile(fieldName, filePath)
		if err != nil {
			return nil, fmt.Errorf("error creating form file %s: %v", fieldName, err)
		}

		if _, err := io.Copy(part, file); err != nil {
			return nil, fmt.Errorf("error copying file %s to part: %v", filePath, err)
		}
	}

	// 完成多部分表单
	if err := w.Close(); err != nil {
		return nil, fmt.Errorf("error closing multipart writer: %v", err)
	}

	// 创建请求
	req, err := http.NewRequest("POST", url, &b)
	if err != nil {
		return nil, fmt.Errorf("error creating request: %v", err)
	}

	// 设置头部
	req.Header.Set("Content-Type", w.FormDataContentType())
	for key, value := range headers {
		req.Header.Set(key, value)
	}

	// 发送请求
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("error sending request: %v", err)
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body) // 读取响应
	if err != nil {
		return nil, err
	}

	return body, nil
}

// addFormValue 辅助函数：添加表单值
func addFormValue(w *multipart.Writer, key, value string) error {
	fw, err := w.CreateFormField(key)
	if err != nil {
		return fmt.Errorf("error creating form field %s: %v", key, err)
	}
	_, err = fw.Write([]byte(value))
	return err
}