package httputil

import (
	"errors"
	"io"
	"net"
	"net/http"
	"net/url"
	"strconv"
	"sync"
	"time"
)

const defaultTimeOut = 10

var (
	defaultClient *http.Client
	httpClientMap sync.Map
	errProxyNil   = errors.New("proxy is nil")
)

func init() {
	defaultClient = &http.Client{
		Timeout: time.Second * time.Duration(defaultTimeOut),
		Transport: &http.Transport{
			Proxy: http.ProxyFromEnvironment,
			DialContext: (&net.Dialer{
				Timeout:   time.Second * 30,
				KeepAlive: time.Second * 30,
			}).DialContext,
			ForceAttemptHTTP2:     true,
			MaxIdleConns:          100,
			MaxIdleConnsPerHost:   100,
			IdleConnTimeout:       time.Second * 90,
			TLSHandshakeTimeout:   time.Second * 10,
			ExpectContinueTimeout: time.Second,
		},
	}
}

// 传入参数单位秒
func getClientByTimeoutSet(connTimeout int) *http.Client {
	if connTimeout == defaultTimeOut {
		return defaultClient
	}
	client, _ := httpClientMap.LoadOrStore(connTimeout, &http.Client{
		Timeout: time.Duration(connTimeout) * time.Second,
		Transport: &http.Transport{
			Proxy: http.ProxyFromEnvironment,
			DialContext: (&net.Dialer{
				Timeout:   time.Second * 30,
				KeepAlive: time.Second * 30,
			}).DialContext,
			ForceAttemptHTTP2:     true,
			MaxIdleConns:          100,
			MaxIdleConnsPerHost:   100,
			IdleConnTimeout:       time.Second * 90,
			TLSHandshakeTimeout:   time.Second * 10,
			ExpectContinueTimeout: time.Second,
		},
	})
	return client.(*http.Client)
}

type ProxyCfg struct {
	Host     string
	Timeout  int //秒
	Source   string
	IsActive bool //是否开启代理
}

func (p *ProxyCfg) Build(rawurl string, rawHeaders map[string]string) (string, map[string]string, error) {
	if !p.IsActive {
		return rawurl, rawHeaders, nil
	}
	u, err := url.Parse(rawurl)
	if err != nil {
		return "", nil, err
	}
	target := url.URL{Scheme: u.Scheme, Host: u.Host}
	u.Host = p.Host
	u.Scheme = "http"
	m := make(map[string]string)
	m["X-Proxy-Target-Host"] = target.String()
	m["X-Proxy-Source"] = "ys"
	if p.Timeout > 0 {
		m["X-Proxy-Timeout"] = strconv.Itoa(p.Timeout)
	}
	if len(rawHeaders) > 0 {
		for k, v := range rawHeaders {
			m[k] = v
		}
	}
	return u.String(), m, nil
}

// 提供关闭函数以防止内存泄露
func IgnoreResp(resp *http.Response) {
	_, _ = io.Copy(io.Discard, resp.Body)
	resp.Body.Close()
}