package httpclient

import (
    "bufio"
    "bytes"
    "io"
    "net/http"
    "strings"
    "time"
)

// NetHTTPClient 使用 net/http 实现 HTTPClient 接口
type NetHTTPClient struct {
    client *http.Client
    // 可根据需要添加对象池
}

// NewNetHTTPClient 返回一个初始化的 NetHTTPClient
func NewNetHTTPClient() *NetHTTPClient {
    return &NetHTTPClient{client: &http.Client{}}
}

// Do 发送非流式请求
func (c *NetHTTPClient) Do(req *Request) (*Response, error) {
    r, err := http.NewRequest(req.Method, req.URL, bytes.NewReader(req.Body))
    if err != nil {
        return nil, err
    }
    for k, v := range req.Headers {
        r.Header.Set(k, v)
    }
    resp, err := c.client.Do(r)
    if err != nil {
        return nil, err
    }
    defer resp.Body.Close()
    body, err := io.ReadAll(resp.Body)
    if err != nil {
        return nil, err
    }
    headers := make(map[string]string)
    for k, v := range resp.Header {
        headers[k] = v[0]
    }
    return &Response{StatusCode: resp.StatusCode, Body: body, Headers: headers}, nil
}

// Stream 发送流式请求，逐块通过 callback 回调 SSE 数据
func (c *NetHTTPClient) Stream(req *Request, callback func(chunk SSEChunk) error) error {
    r, err := http.NewRequest(req.Method, req.URL, bytes.NewReader(req.Body))
    if err != nil {
        return err
    }
    for k, v := range req.Headers {
        r.Header.Set(k, v)
    }
    resp, err := c.client.Do(r)
    if err != nil {
        return err
    }
    defer resp.Body.Close()
    scanner := bufio.NewScanner(resp.Body)
    for scanner.Scan() {
        text := scanner.Text()
        if text == "" {
            continue
        }
        const prefix = "data: "
        if strings.HasPrefix(text, prefix) {
            payload := text[len(prefix):]
            isDone := payload == "[DONE]"
            var dataBytes []byte
            if !isDone {
                dataBytes = []byte(payload)
            }
            chunk := SSEChunk{
                Data:      dataBytes,
                Timestamp: time.Now().UnixNano(),
                IsDone:    isDone,
            }
            if err := callback(chunk); err != nil {
                return err
            }
        }
    }
    if err := scanner.Err(); err != nil {
        return err
    }
    return nil
}