package main

import (
	"fmt"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

func TestGreetingHandler(t *testing.T) {
	tests := []struct {
		name       string
		method     string
		url        string
		wantStatus int
	}{
		{name: "valid", method: http.MethodGet, url: "/hello?name=Go", wantStatus: http.StatusOK},
		{name: "missing_name", method: http.MethodGet, url: "/hello", wantStatus: http.StatusBadRequest},
		{name: "wrong_method", method: http.MethodPost, url: "/hello?name=Go", wantStatus: http.StatusMethodNotAllowed},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			request := httptest.NewRequest(tt.method, tt.url, nil)
			response := httptest.NewRecorder()
			greetingHandler(response, request)
			if response.Code != tt.wantStatus {
				t.Errorf("状态码=%d，期望=%d", response.Code, tt.wantStatus)
			}
			if tt.wantStatus == http.StatusOK && !strings.Contains(response.Body.String(), "你好，Go！") {
				t.Errorf("响应内容不符合预期：%s", response.Body.String())
			}
		})
	}
}

func TestFetchGreeting(t *testing.T) {
	mux := http.NewServeMux()
	mux.HandleFunc("/hello", greetingHandler)
	server := httptest.NewServer(mux)
	defer server.Close()
	client := &http.Client{Timeout: 2 * time.Second}

	got, err := fetchGreeting(client, server.URL, "小 朱&Go")
	if err != nil {
		t.Fatalf("请求失败：%v", err)
	}
	if got.Message != "你好，小 朱&Go！" {
		t.Errorf("消息=%q", got.Message)
	}
	if _, err := fetchGreeting(client, server.URL, ""); err == nil {
		t.Error("空姓名应导致客户端返回错误")
	}
}

func TestFetchRejectsInvalidResponse(t *testing.T) {
	tests := []struct {
		name string
		body string
	}{
		{name: "invalid_json", body: "not json"},
		{name: "oversized", body: strings.Repeat("a", 64*1024+1)},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				fmt.Fprint(w, tt.body)
			}))
			defer server.Close()
			client := &http.Client{Timeout: 2 * time.Second}
			if _, err := fetchGreeting(client, server.URL, "Go"); err == nil {
				t.Error("无效响应应返回错误")
			}
		})
	}
}