package server

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"os/signal"
	"strconv"
	"strings"
	"syscall"
	"time"
	"videoweb/app/appg"
	"videoweb/app/router"

	// "videoweb/app/service/configser"
	// "videoweb/app/service/translationser"
	"videoweb/pub/common/log"
	"videoweb/pub/common/srvversion"

	// "videoweb/pub/storage/proxy"
	// "videoweb/web/service"

	"gopkg.in/yaml.v2"
)

func init() {
	time.Local, _ = time.LoadLocation("Asia/Shanghai")
}
func Run(args []string) {
	showVersion()
	if err := initConfig(); err != nil {
		log.Error("init config failed", log.E(err))
		os.Exit(1)
	}

	initHttpServer()
	initDHServer()
	//tgbot.SendToProgram("启动", "app启动完毕")
	shutdownHandler()
}

func initConfig() error {

	buf, err := ioutil.ReadFile("conf/app.yaml")
	if err != nil {
		return err
	}
	if err = yaml.Unmarshal(buf, &appg.Conf); err != nil {
		return err
	}

	return nil
}

func showVersion() {
	log.Info(fmt.Sprintf("sevice version:%s", srvversion.SERVICE_VERSION))
	log.Info(fmt.Sprintf("git version:%s", srvversion.GIT_VERSION))
	log.Info(fmt.Sprintf("build date:%s", srvversion.BUILD_DATE))
	log.Info(fmt.Sprintf("build ip:%s", srvversion.BUILD_IP))
}

// headWriter 拦截 WriteHeader 和 Write，丢弃 body 并记录长度，
// 在 flush 时补设 Content-Length 后再发送真正的状态码。
type headWriter struct {
	http.ResponseWriter
	contentLength int
	statusCode    int
	wroteHeader   bool
}

func (w *headWriter) WriteHeader(code int) {
	if !w.wroteHeader {
		w.statusCode = code
		w.wroteHeader = true
	}
}

func (w *headWriter) Write(b []byte) (int, error) {
	if !w.wroteHeader {
		w.statusCode = http.StatusOK
		w.wroteHeader = true
	}
	w.contentLength += len(b)
	return len(b), nil
}

// Flush 实现 http.Flusher，HEAD 响应无 body，做 no-op
func (w *headWriter) Flush() {}

// Unwrap 让 http.NewResponseController 能发现底层 writer 的其他接口
func (w *headWriter) Unwrap() http.ResponseWriter { return w.ResponseWriter }

// flush 将缓存的 Content-Length 和状态码写入底层 ResponseWriter
func (w *headWriter) flush() {
	if !w.wroteHeader {
		w.statusCode = http.StatusOK
		w.wroteHeader = true
	}
	if w.contentLength > 0 && w.Header().Get("Content-Length") == "" {
		w.Header().Set("Content-Length", strconv.Itoa(w.contentLength))
	}
	w.ResponseWriter.WriteHeader(w.statusCode)
}

// headToGet 将 HEAD 改写为 GET 让 Gin 路由匹配，同时用 headWriter 丢弃 body。
// 通过 X-Origin-Head 内部 header 让 templatecache / filecache 等中间件识别出原始 HEAD 请求，
// 从而避免一次性 URL 污染缓存造成 DoS 放大（进入前先 Del 防客户端伪造）。
func headToGet(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		r.Header.Del("X-Origin-Head")
		if r.Method == http.MethodHead {
			r.Method = http.MethodGet
			r.Header.Set("X-Origin-Head", "1")
			hw := &headWriter{ResponseWriter: w}
			h.ServeHTTP(hw, r)
			hw.flush()
			return
		}
		h.ServeHTTP(w, r)
	})
}

func initHttpServer() {
	addr := fmt.Sprintf(":%s", appg.Conf.ListenAddr)
	srv := &http.Server{
		Addr:    addr,
		Handler: headToGet(router.Init()),
	}
	go func() {
		// service connections
		log.Info("服务已启动", log.Any("地址", addr))
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatal("listen:", log.E(err))
		}
	}()
}

func initDHServer() {
	if strings.TrimSpace(appg.Conf.DHListenAddr) == "" {
		return
	}
	addr := fmt.Sprintf(":%s", appg.Conf.DHListenAddr)
	srv := &http.Server{
		Addr:    addr,
		Handler: headToGet(router.DHInit()),
	}
	go func() {
		log.Info("导航服务已启动", log.Any("地址", addr))
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			log.Fatal("listen:", log.E(err))
		}
	}()
}

func shutdownHandler() {
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM, os.Kill)
	<-quit
	log.Warn("Shutdown... server")
}