package server

import (
	"io"
	"log"
	"net/http"

	"gitee.com/lople/geerpc/codec"
)

/*
客户端和服务端封装HTTP层
服务端支持 HTTP 协议:
1.客户端向 RPC 服务器发送 CONNECT 请求
CONNECT 10.0.0.1:9999/_geerpc_ HTTP/1.0
2.RPC 服务器返回 HTTP 200 状态码表示连接建立。
HTTP/1.0 200 Connected to Gee RPC
3.客户端使用创建好的连接发送 RPC 报文，先发送 Option，再发送 N 个请求报文，服务端处理 RPC 请求并响应。
*/

const (
	connected        = "200 connected to Gee RPC"
	defalutRPCPath   = "/geerpc"
	defalutDebugPath = "/debug/geerpc"
)

// ServeHTTP implements an http.Handler that answers RPC requests.
func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	if req.Method != "CONNECT" {
		w.Header().Set("Content-Type", "text/plain;charset=utf-8")
		w.WriteHeader(http.StatusMethodNotAllowed)
		io.WriteString(w, "405 must CONNECT\n")
		return
	}
	//type assert,Hijack return origin tcp conn
	conn, _, err := w.(http.Hijacker).Hijack()
	if err != nil {
		log.Print("rpc hijacking", req.RemoteAddr, ":", err.Error())
		return
	}
	//return connected status ok
	io.WriteString(conn, "HTTP/1.0 "+connected+"\n\n")
	s.ServerConn(conn)
}

// HandleHTTP registers an HTTP handler for RPC messages on rpcPath.
// It is still necessary to invoke http.Serve(), typically in a go statement.
func (s *Server) HandleHTTP() {
	codec.Init()
	http.Handle(defalutRPCPath, s)
	http.Handle(defalutDebugPath, debugHTTP{s})
	log.Println("rpc server debug path:", defalutDebugPath)
}

// HandleHTTP is a convenient approach for default server to register HTTP handlers
func HandleHTTP() {
	defaultServer.HandleHTTP()
}