package service

import (
	"bufio"
	"bytes"
	"compress/flate"
	"compress/gzip"
	"context"
	"github.com/gogf/gf/v2/frame/g"
	"io"
	"net"
	"net/http"
	"net/http/httputil"
	"net/url"
	"time"
)

func CreateDefaultProxyClient(remoteUrl *url.URL) *httputil.ReverseProxy {
	rp := httputil.NewSingleHostReverseProxy(remoteUrl)
	dialer := &net.Dialer{
		Timeout:   time.Duration(g.Cfg().MustGet(context.Background(), "elasticSearch.reverseProxy.timeout", 15).Int()) * time.Second,
		KeepAlive: time.Duration(g.Cfg().MustGet(context.Background(), "elasticSearch.reverseProxy.keepAlive", 60).Int()) * time.Second,
	}
	rp.Transport = &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
			// 在这里可以自定义网络连接的创建方式
			conn, err := dialer.DialContext(ctx, network, addr)
			if err != nil {
				return nil, err
			}
			return conn, nil
		},
		MaxIdleConns:          g.Cfg().MustGet(context.Background(), "elasticSearch.reverseProxy.maxIdleConns", 100).Int(),                                      //空闲链接数量
		IdleConnTimeout:       time.Duration(g.Cfg().MustGet(context.Background(), "elasticSearch.reverseProxy.idleConnTimeout", 60).Int()) * time.Second,       //空闲连接自动关闭时间 0不会被关闭
		TLSHandshakeTimeout:   time.Duration(g.Cfg().MustGet(context.Background(), "elasticSearch.reverseProxy.tLSHandshakeTimeout", 15).Int()) * time.Second,   //TLS握手的超时时间
		ExpectContinueTimeout: time.Duration(g.Cfg().MustGet(context.Background(), "elasticSearch.reverseProxy.expectContinueTimeout", 30).Int()) * time.Second, //等待服务器响应的时间 0一直等待
		MaxIdleConnsPerHost:   g.Cfg().MustGet(context.Background(), "elasticSearch.reverseProxy.maxIdleConnsPerHost", 2).Int(),                                 //最大空闲
	}
	//http.DefaultTransport
	//rp.ModifyResponse = ChangeResponse
	return rp
}

func ChangeResponse(resp *http.Response) (err error) {
	content := []byte{}
	encoding := resp.Header.Get("Content-Encoding")
	if encoding == "gzip" { //处理解压
		body, _ := gzip.NewReader(resp.Body)
		content, err = io.ReadAll(body) //Read html
	} else if encoding == "deflate" {
		content, err = io.ReadAll(flate.NewReader(resp.Body)) //Read html
	} else { //无设置压缩
		content, err = io.ReadAll(resp.Body) //Read html
	}
	if err != nil {
		return err
	}
	err = resp.Body.Close()
	if err != nil {
		return err
	}

	//压缩内容
	var zBuf bytes.Buffer
	var output_writer io.Writer
	if encoding == "gzip" || encoding == "deflate" { //压缩
		if encoding == "gzip" {
			output_writer, _ = gzip.NewWriterLevel(&zBuf, gzip.BestSpeed)
		} else {
			output_writer, _ = flate.NewWriter(&zBuf, flate.BestSpeed)
		}
	} else {
		output_writer = bufio.NewWriter(&zBuf)
		resp.ContentLength = int64(len(content))
	}
	if _, err = output_writer.Write(content); err != nil {
		return err
	}
	switch output_writer.(type) {
	case *gzip.Writer:
		_ = output_writer.(*gzip.Writer).Close()
	case *flate.Writer:
		_ = output_writer.(*flate.Writer).Close()
	case *bufio.Writer:
		_ = output_writer.(*bufio.Writer).Flush()
	}
	resp.Body = io.NopCloser(bytes.NewReader(zBuf.Bytes()))
	return nil
}