package middleware

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

// 客户端超长 request_id 会被下游当作幂等键缓存，必须作废并换成服务端生成的 id（P2-6）。
func TestRequestIDClampsOversizedHeader(t *testing.T) {
	var (
		ctxID     string
		handlerID string
	)
	h := RequestID(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		ctxID = GetRequestID(r.Context())
		handlerID = r.Header.Get(HeaderRequestID)
	}))
	req := httptest.NewRequest(http.MethodPost, "/api/teams", nil)
	req.Header.Set(HeaderRequestID, strings.Repeat("x", maxRequestIDLen+1))
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)

	if ctxID == "" || len(ctxID) > maxRequestIDLen {
		t.Fatalf("超长 id 应换成服务端生成的短 id，得到 %q", ctxID)
	}
	if handlerID != ctxID {
		t.Fatalf("下游读到的 request_id 应与 ctx 一致，ctx=%q header=%q", ctxID, handlerID)
	}
	if got := rec.Header().Get(HeaderRequestID); got != ctxID {
		t.Fatalf("响应头 request_id 应为 %q，得到 %q", ctxID, got)
	}
}

// 合理长度的客户端 id 仍应原样复用，保证幂等回放。
func TestRequestIDKeepsNormalHeader(t *testing.T) {
	var ctxID string
	h := RequestID(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		ctxID = GetRequestID(r.Context())
	}))
	req := httptest.NewRequest(http.MethodPost, "/api/teams", nil)
	req.Header.Set(HeaderRequestID, "abc-123")
	h.ServeHTTP(httptest.NewRecorder(), req)

	if ctxID != "abc-123" {
		t.Fatalf("正常 id 应原样复用，得到 %q", ctxID)
	}
}

// 登录是 guest 请求，CSRF Token 校验被跳过，靠同源校验挡住 login CSRF（P2-6）。
func TestCSRFBlocksCrossOriginLogin(t *testing.T) {
	next := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusOK) })
	h := CSRF(nil, next)

	req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req.Host = "scoreboard.local"
	req.Header.Set("Origin", "http://evil.example")
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusForbidden {
		t.Fatalf("跨站登录应 403，得到 %d", rec.Code)
	}

	req = httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
	req.Host = "scoreboard.local"
	req.Header.Set("Origin", "http://scoreboard.local")
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusOK {
		t.Fatalf("同源登录应放行，得到 %d", rec.Code)
	}
}

// 同源判断：两个头都没有时放行脚本调用，Origin: null 与解析失败一律拒绝。
func TestSameOrigin(t *testing.T) {
	cases := []struct {
		name    string
		origin  string
		referer string
		want    bool
	}{
		{"无来源头", "", "", true},
		{"同源 Origin", "http://scoreboard.local", "", true},
		{"跨站 Origin", "http://evil.example", "", false},
		{"Origin 为 null", "null", "", false},
		{"同源 Referer", "", "http://scoreboard.local/admin", true},
		{"跨站 Referer", "", "http://evil.example/x", false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			req := httptest.NewRequest(http.MethodPost, "/api/auth/login", nil)
			req.Host = "scoreboard.local"
			if tc.origin != "" {
				req.Header.Set("Origin", tc.origin)
			}
			if tc.referer != "" {
				req.Header.Set("Referer", tc.referer)
			}
			if got := sameOrigin(req); got != tc.want {
				t.Fatalf("sameOrigin = %v，期望 %v", got, tc.want)
			}
		})
	}
}