package api

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

	"github.com/gin-gonic/gin"
)

func init() {
	gin.SetMode(gin.TestMode)
}

// TestIsAllowedOrigin 驗證 CORS 白名單判斷邏輯（M8-8 / TDD §4.2）。
func TestIsAllowedOrigin(t *testing.T) {
	cases := []struct {
		origin string
		want   bool
	}{
		// 白名單合法情境
		{"http://127.0.0.1:3721", true},
		{"http://127.0.0.1", true},
		{"http://localhost:3000", true},
		{"http://localhost:8080", true},
		{"http://localhost", true},
		{"http://[::1]:3721", true},
		{"http://LOCALHOST:9999", true}, // hostname 應大小寫不敏感

		// scheme 不對
		{"https://127.0.0.1:3721", false},
		{"https://localhost:3000", false},
		{"ws://127.0.0.1:3721", false},

		// hostname 不在白名單
		{"http://192.168.1.5:3721", false},
		{"http://example.com", false},
		{"http://malicious.local", false},
		{"http://127.0.0.1.evil.com", false}, // suffix 攻擊
		{"http://evil-127.0.0.1.com", false},

		// 特殊情境
		{"", false},
		{"null", false},
		{"http://", false},
		{"not-a-url", false},
	}

	for _, tc := range cases {
		got := isAllowedOrigin(tc.origin)
		if got != tc.want {
			t.Errorf("isAllowedOrigin(%q) = %v, want %v", tc.origin, got, tc.want)
		}
	}
}

// newTestRouter 建一台只掛 CORSMiddleware 的最小 router，用於測試 middleware 行為。
func newTestRouter() *gin.Engine {
	r := gin.New()
	r.Use(CORSMiddleware())
	r.GET("/api/ping", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"ok": true})
	})
	r.POST("/api/do", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"ok": true})
	})
	return r
}

// TestCORSMiddleware_AllowedOriginGET：白名單 Origin 的 GET 應回 200 且帶 ACA header。
func TestCORSMiddleware_AllowedOriginGET(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodGet, "/api/ping", nil)
	req.Header.Set("Origin", "http://127.0.0.1:3000")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "http://127.0.0.1:3000" {
		t.Errorf("ACA-Origin = %q, want http://127.0.0.1:3000", got)
	}
	if got := w.Header().Get("Access-Control-Allow-Credentials"); got != "true" {
		t.Errorf("ACA-Credentials = %q, want true", got)
	}
	if got := w.Header().Get("Vary"); got != "Origin" {
		t.Errorf("Vary = %q, want Origin", got)
	}
}

// TestCORSMiddleware_LocalhostAllowed：localhost 任意 port 都應放行。
func TestCORSMiddleware_LocalhostAllowed(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodGet, "/api/ping", nil)
	req.Header.Set("Origin", "http://localhost:8080")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "http://localhost:8080" {
		t.Errorf("ACA-Origin = %q, want http://localhost:8080", got)
	}
}

// TestCORSMiddleware_DisallowedOriginPOST：非白名單 Origin 的 POST 必須 403。
func TestCORSMiddleware_DisallowedOriginPOST(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodPost, "/api/do", nil)
	req.Header.Set("Origin", "https://example.com")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusForbidden {
		t.Fatalf("status = %d, want 403", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "" {
		t.Errorf("非白名單不應回 ACA-Origin，got %q", got)
	}
}

// TestCORSMiddleware_DisallowedOriginGET：非白名單 GET 應該執行 handler 但不回 ACA。
func TestCORSMiddleware_DisallowedOriginGET(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodGet, "/api/ping", nil)
	req.Header.Set("Origin", "http://malicious.local")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200 (handler 仍執行，瀏覽器層擋讀取)", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "" {
		t.Errorf("非白名單不應回 ACA-Origin，got %q", got)
	}
}

// TestCORSMiddleware_PreflightAllowed：白名單 Origin 的 OPTIONS preflight 應回 204 + 完整 headers。
func TestCORSMiddleware_PreflightAllowed(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodOptions, "/api/do", nil)
	req.Header.Set("Origin", "http://127.0.0.1:9999")
	req.Header.Set("Access-Control-Request-Method", "POST")
	req.Header.Set("Access-Control-Request-Headers", "Content-Type")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusNoContent {
		t.Fatalf("status = %d, want 204", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "http://127.0.0.1:9999" {
		t.Errorf("ACA-Origin = %q, want http://127.0.0.1:9999", got)
	}
	if got := w.Header().Get("Access-Control-Allow-Methods"); got == "" {
		t.Errorf("ACA-Methods 不應為空")
	}
	if got := w.Header().Get("Access-Control-Allow-Headers"); got == "" {
		t.Errorf("ACA-Headers 不應為空")
	}
}

// TestCORSMiddleware_PreflightDisallowed：非白名單 OPTIONS preflight 應 403，不回 ACA。
func TestCORSMiddleware_PreflightDisallowed(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodOptions, "/api/do", nil)
	req.Header.Set("Origin", "http://evil.com")
	req.Header.Set("Access-Control-Request-Method", "POST")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusForbidden {
		t.Fatalf("status = %d, want 403", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "" {
		t.Errorf("非白名單不應回 ACA-Origin，got %q", got)
	}
}

// TestCORSMiddleware_SameOrigin：沒帶 Origin（same-origin）應放行。
func TestCORSMiddleware_SameOrigin(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodGet, "/api/ping", nil)
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "" {
		t.Errorf("same-origin 不應回 ACA-Origin，got %q", got)
	}
}

// ----- ADR-019 WP-1：雲端 origin 精確比對 + PNA + HostGuard -----

// TestLoadCloudOrigins 驗證 VISIONA_CLOUD_ORIGINS 解析（逗號分隔、TrimSpace、過濾空字串）。
func TestLoadCloudOrigins(t *testing.T) {
	cases := []struct {
		name string
		raw  string
		want map[string]bool
	}{
		{"empty", "", map[string]bool{}},
		{"single", "https://stage-9527.innovedus.com:9527",
			map[string]bool{"https://stage-9527.innovedus.com:9527": true}},
		{"multi with spaces", " https://a.com:443 , http://192.168.0.130:9527 ",
			map[string]bool{"https://a.com:443": true, "http://192.168.0.130:9527": true}},
		{"trailing comma", "http://localhost:3000,,",
			map[string]bool{"http://localhost:3000": true}},
	}
	for _, tc := range cases {
		got := loadCloudOrigins(tc.raw)
		if len(got) != len(tc.want) {
			t.Errorf("%s: len = %d, want %d (%v)", tc.name, len(got), len(tc.want), got)
			continue
		}
		for k := range tc.want {
			if !got[k] {
				t.Errorf("%s: missing origin %q in %v", tc.name, k, got)
			}
		}
	}
}

// TestIsAllowedCloudOrigin_ExactMatch 驗證雲端 origin 必須 scheme+host+port 全等（M3）。
// 關鍵：不可像 loopback 那樣 hostname-only + 任意 port。
func TestIsAllowedCloudOrigin_ExactMatch(t *testing.T) {
	// 直接注入測試白名單，避免依賴環境變數。
	saved := cloudOrigins
	cloudOrigins = map[string]bool{
		"https://stage-9527.innovedus.com:9527": true,
		"http://192.168.0.130:9527":             true,
	}
	defer func() { cloudOrigins = saved }()

	cases := []struct {
		origin string
		want   bool
	}{
		// 完全相符
		{"https://stage-9527.innovedus.com:9527", true},
		{"http://192.168.0.130:9527", true},

		// 同 host 不同 port → 不通過（證明不是 hostname-only）
		{"https://stage-9527.innovedus.com:8080", false},
		{"https://stage-9527.innovedus.com", false},
		{"http://192.168.0.130:8080", false},

		// 同 host 不同 scheme → 不通過（證明不放寬 scheme）
		{"http://stage-9527.innovedus.com:9527", false},
		{"https://192.168.0.130:9527", false},

		// 其他
		{"", false},
		{"null", false},
		{"https://evil.com:9527", false},
		{"https://stage-9527.innovedus.com:9527.evil.com", false},
	}
	for _, tc := range cases {
		if got := isAllowedCloudOrigin(tc.origin); got != tc.want {
			t.Errorf("isAllowedCloudOrigin(%q) = %v, want %v", tc.origin, got, tc.want)
		}
	}
}

// newCloudTestRouter 建一台掛 CORSMiddleware 的 router，並注入測試用雲端白名單。
func newCloudTestRouter(t *testing.T) *gin.Engine {
	t.Helper()
	saved := cloudOrigins
	cloudOrigins = map[string]bool{"https://cloud.example.com:9527": true}
	t.Cleanup(func() { cloudOrigins = saved })
	return newTestRouter()
}

// TestCORSMiddleware_CloudOriginPOST：雲端白名單 origin 的 POST 應放行 + Credentials:false。
func TestCORSMiddleware_CloudOriginPOST(t *testing.T) {
	r := newCloudTestRouter(t)

	req := httptest.NewRequest(http.MethodPost, "/api/do", nil)
	req.Header.Set("Origin", "https://cloud.example.com:9527")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "https://cloud.example.com:9527" {
		t.Errorf("ACA-Origin = %q, want cloud origin", got)
	}
	if got := w.Header().Get("Access-Control-Allow-Credentials"); got != "false" {
		t.Errorf("ACA-Credentials = %q, want false (M3)", got)
	}
	if got := w.Header().Get("Access-Control-Allow-Headers"); !strings.Contains(got, "X-Visiona-Local-Token") {
		t.Errorf("ACA-Headers = %q, 必須含 X-Visiona-Local-Token", got)
	}
}

// TestCORSMiddleware_CloudPreflightPNA：雲端 origin preflight 帶 PNA request → 回 PNA header + Max-Age。
func TestCORSMiddleware_CloudPreflightPNA(t *testing.T) {
	r := newCloudTestRouter(t)

	req := httptest.NewRequest(http.MethodOptions, "/api/do", nil)
	req.Header.Set("Origin", "https://cloud.example.com:9527")
	req.Header.Set("Access-Control-Request-Method", "POST")
	req.Header.Set("Access-Control-Request-Private-Network", "true")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusNoContent {
		t.Fatalf("status = %d, want 204", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Private-Network"); got != "true" {
		t.Errorf("ACA-Private-Network = %q, want true (PNA 必做)", got)
	}
	if got := w.Header().Get("Access-Control-Max-Age"); got != "600" {
		t.Errorf("Max-Age = %q, want 600", got)
	}
	if got := w.Header().Get("Access-Control-Allow-Credentials"); got != "false" {
		t.Errorf("ACA-Credentials = %q, want false", got)
	}
}

// TestCORSMiddleware_CloudPreflightNoPNARequest：preflight 未帶 PNA request → 不回 PNA header。
func TestCORSMiddleware_CloudPreflightNoPNARequest(t *testing.T) {
	r := newCloudTestRouter(t)

	req := httptest.NewRequest(http.MethodOptions, "/api/do", nil)
	req.Header.Set("Origin", "https://cloud.example.com:9527")
	req.Header.Set("Access-Control-Request-Method", "POST")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusNoContent {
		t.Fatalf("status = %d, want 204", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Private-Network"); got != "" {
		t.Errorf("未帶 PNA request 不應回 PNA header，got %q", got)
	}
}

// TestCORSMiddleware_NonWhitelistedCloudPortPOST：同 host 但不在白名單的 port → 403。
func TestCORSMiddleware_NonWhitelistedCloudPortPOST(t *testing.T) {
	r := newCloudTestRouter(t)

	req := httptest.NewRequest(http.MethodPost, "/api/do", nil)
	req.Header.Set("Origin", "https://cloud.example.com:8080") // 不同 port
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if w.Code != http.StatusForbidden {
		t.Fatalf("status = %d, want 403（不同 port 不應通過精確比對）", w.Code)
	}
	if got := w.Header().Get("Access-Control-Allow-Origin"); got != "" {
		t.Errorf("不應回 ACA-Origin，got %q", got)
	}
}

// TestCORSMiddleware_LoopbackCredentialsUnchanged：loopback origin 仍回 Credentials:true（M8-8 保留不動）。
func TestCORSMiddleware_LoopbackCredentialsUnchanged(t *testing.T) {
	r := newTestRouter()

	req := httptest.NewRequest(http.MethodGet, "/api/ping", nil)
	req.Header.Set("Origin", "http://127.0.0.1:3721")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	if got := w.Header().Get("Access-Control-Allow-Credentials"); got != "true" {
		t.Errorf("loopback ACA-Credentials = %q, want true（ADR-019 保留 loopback 舊規則）", got)
	}
}

// ----- HostGuard -----

// newHostGuardRouter 建一台掛 HostGuard 的 router。
func newHostGuardRouter() *gin.Engine {
	r := gin.New()
	r.POST("/api/media/upload/video", HostGuard(), func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"ok": true})
	})
	return r
}

// TestHostGuard 驗證 Host header 必須 = loopback，否則 400。
func TestHostGuard(t *testing.T) {
	cases := []struct {
		name     string
		host     string
		wantCode int
	}{
		{"127.0.0.1 with port", "127.0.0.1:3721", http.StatusOK},
		{"localhost with port", "localhost:3721", http.StatusOK},
		{"localhost no port", "localhost", http.StatusOK},
		{"127.0.0.1 no port", "127.0.0.1", http.StatusOK},
		{"ipv6 loopback with port", "[::1]:3721", http.StatusOK},
		{"uppercase LOCALHOST", "LOCALHOST:3721", http.StatusOK},
		// DNS rebinding：Host 為攻擊者網域 → 400
		{"evil domain", "evil.com:3721", http.StatusBadRequest},
		{"evil domain no port", "evil.com", http.StatusBadRequest},
		{"lan ip", "192.168.0.130:9527", http.StatusBadRequest},
		{"public ip", "8.8.8.8:80", http.StatusBadRequest},
		// suffix 攻擊
		{"loopback suffix attack", "127.0.0.1.evil.com:3721", http.StatusBadRequest},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			r := newHostGuardRouter()
			req := httptest.NewRequest(http.MethodPost, "/api/media/upload/video", nil)
			req.Host = tc.host
			w := httptest.NewRecorder()
			r.ServeHTTP(w, req)
			if w.Code != tc.wantCode {
				t.Errorf("Host=%q → %d, want %d", tc.host, w.Code, tc.wantCode)
			}
		})
	}
}

// TestIsLoopbackHost 直接單元測試 host 判斷邏輯。
func TestIsLoopbackHost(t *testing.T) {
	cases := []struct {
		host string
		want bool
	}{
		{"127.0.0.1:3721", true},
		{"127.0.0.1", true},
		{"localhost:8080", true},
		{"localhost", true},
		{"[::1]:3721", true},
		{"::1", true},
		{"", false},
		{"evil.com", false},
		{"evil.com:3721", false},
		{"192.168.0.130:9527", false},
		{"127.0.0.1.evil.com:80", false},
	}
	for _, tc := range cases {
		if got := isLoopbackHost(tc.host); got != tc.want {
			t.Errorf("isLoopbackHost(%q) = %v, want %v", tc.host, got, tc.want)
		}
	}
}