package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"time"
)

// User 结构体，用于返回 JSON 数据
type User struct {
	ID   int    `json:"id"`
	Name string `json:"name"`
}

// 根路径处理器
func homeHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "Hello, World! 👋")
}

// /time 路径处理器，返回当前服务器时间
func timeHandler(w http.ResponseWriter, r *http.Request) {
	currentTime := time.Now().Format("2006-01-02 15:04:05")
	fmt.Fprintf(w, "当前服务器时间: %s", currentTime)
}

// /api/user 路径处理器，返回 JSON 数据
func userHandler(w http.ResponseWriter, r *http.Request) {
	user := User{
		ID:   1,
		Name: "张三",
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(user)
}

// 带请求参数处理的处理器
func helloHandler(w http.ResponseWriter, r *http.Request) {
	name := r.URL.Query().Get("name")
	if name == "" {
		name = "World"
	}
	fmt.Fprintf(w, "Hello, %s!", name)
}

func main() {
	// 注册路由
	mux := http.NewServeMux()
	mux.HandleFunc("/", homeHandler)
	mux.HandleFunc("/time", timeHandler)
	mux.HandleFunc("/api/user", userHandler)
	mux.HandleFunc("/hello", helloHandler)

	// 启动 HTTP 服务
	addr := ":8080"
	log.Printf("启动 HTTP 服务，监听端口 %s\n", addr)
	if err := http.ListenAndServe(addr, mux); err != nil {
		log.Fatalf("服务器启动失败: %v", err)
	}
}