package middleware

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

	"github.com/gofiber/fiber/v3"
)

// newTestApp creates a fiber app, registers the given middleware via Use,
// then a final GET handler that returns 200 "ok".
// The last argument is the final route handler; preceding args are middleware.
func newTestApp(t *testing.T, handlers ...fiber.Handler) *fiber.App {
	t.Helper()
	app := fiber.New()
	mws := handlers
	if len(mws) > 0 {
		middlewares := make([]any, len(mws))
		for i, h := range mws {
			middlewares[i] = h
		}
		app.Use(middlewares...)
	}
	app.Get("/test", func(c fiber.Ctx) error {
		return c.SendString("ok")
	})
	return app
}

// newTestAppWithHandler creates a fiber app with middleware and a custom final route handler.
// The last argument is the final route handler; preceding args are middleware.
func newTestAppWithHandler(t *testing.T, handlers ...fiber.Handler) *fiber.App {
	t.Helper()
	app := fiber.New()
	if len(handlers) == 0 {
		app.Get("/test", func(c fiber.Ctx) error { return c.SendString("ok") })
		return app
	}
	mws := handlers[:len(handlers)-1]
	final := handlers[len(handlers)-1]
	if len(mws) > 0 {
		middlewares := make([]any, len(mws))
		for i, h := range mws {
			middlewares[i] = h
		}
		app.Use(middlewares...)
	}
	app.Get("/test", final)
	return app
}

// handlersToAny converts []fiber.Handler to []any for variadic registration.
func handlersToAny(hs []fiber.Handler) []any {
	out := make([]any, len(hs))
	for i, h := range hs {
		out[i] = h
	}
	return out
}

// ---------- auth.go ----------

func TestExtractToken(t *testing.T) {
	tests := []struct {
		name   string
		setReq func(*http.Request)
		want   string
	}{
		{
			name: "Bearer header",
			setReq: func(r *http.Request) {
				r.Header.Set("Authorization", "Bearer my-token-123")
			},
			want: "my-token-123",
		},
		{
			name: "bearer lowercase",
			setReq: func(r *http.Request) {
				r.Header.Set("Authorization", "bearer lower-token")
			},
			want: "lower-token",
		},
		{
			name: "Bearer with extra spaces",
			setReq: func(r *http.Request) {
				r.Header.Set("Authorization", "Bearer   spaced-token  ")
			},
			want: "spaced-token",
		},
		{
			name: "query param token",
			setReq: func(r *http.Request) {
				q := r.URL.Query()
				q.Set("token", "query-token")
				r.URL.RawQuery = q.Encode()
			},
			want: "query-token",
		},
		{
			name: "x-sub-store-token header",
			setReq: func(r *http.Request) {
				r.Header.Set("X-Sub-Store-Token", "header-token")
			},
			want: "header-token",
		},
		{
			name: "Bearer takes priority over query",
			setReq: func(r *http.Request) {
				r.Header.Set("Authorization", "Bearer bearer-wins")
				q := r.URL.Query()
				q.Set("token", "query-loses")
				r.URL.RawQuery = q.Encode()
			},
			want: "bearer-wins",
		},
		{
			name: "query takes priority over x-sub-store-token",
			setReq: func(r *http.Request) {
				q := r.URL.Query()
				q.Set("token", "query-wins")
				r.URL.RawQuery = q.Encode()
				r.Header.Set("X-Sub-Store-Token", "header-loses")
			},
			want: "query-wins",
		},
		{
			name:   "no token anywhere",
			setReq: func(r *http.Request) {},
			want:   "",
		},
		{
			name: "Authorization without Bearer prefix",
			setReq: func(r *http.Request) {
				r.Header.Set("Authorization", "Basic abc123")
			},
			want: "",
		},
		{
			name: "empty Bearer",
			setReq: func(r *http.Request) {
				r.Header.Set("Authorization", "Bearer ")
			},
			want: "",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var got string
			app := fiber.New()
			app.Get("/test", func(c fiber.Ctx) error {
				got = ExtractToken(c)
				return c.SendString("ok")
			})

			req := httptest.NewRequest("GET", "/test", nil)
			tt.setReq(req)
			resp, err := app.Test(req)
			if err != nil {
				t.Fatalf("app.Test error: %v", err)
			}
			resp.Body.Close()

			if got != tt.want {
				t.Errorf("ExtractToken() = %q, want %q", got, tt.want)
			}
		})
	}
}

func TestRequireAdmin(t *testing.T) {
	adminToken := "secret-admin-token"

	t.Run("valid token passes", func(t *testing.T) {
		app := newTestAppWithHandler(t, RequireAdmin(adminToken), func(c fiber.Ctx) error {
			return c.SendString("protected")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("Authorization", "Bearer "+adminToken)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		body, _ := io.ReadAll(resp.Body)
		if string(body) != "protected" {
			t.Errorf("body = %q, want protected", string(body))
		}
		resp.Body.Close()
	})

	t.Run("invalid token returns 401", func(t *testing.T) {
		app := newTestAppWithHandler(t, RequireAdmin(adminToken), func(c fiber.Ctx) error {
			return c.SendString("protected")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("Authorization", "Bearer wrong-token")
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 401 {
			t.Errorf("status = %d, want 401", resp.StatusCode)
		}
		body, _ := io.ReadAll(resp.Body)
		if !strings.Contains(string(body), "invalid") && !strings.Contains(string(body), "failed") {
			t.Errorf("body should mention invalid, got: %s", string(body))
		}
		resp.Body.Close()
	})

	t.Run("no token returns 401", func(t *testing.T) {
		app := newTestAppWithHandler(t, RequireAdmin(adminToken), func(c fiber.Ctx) error {
			return c.SendString("protected")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 401 {
			t.Errorf("status = %d, want 401", resp.StatusCode)
		}
		resp.Body.Close()
	})

	t.Run("token via query param", func(t *testing.T) {
		app := newTestAppWithHandler(t, RequireAdmin(adminToken), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test?token="+adminToken, nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		resp.Body.Close()
	})

	t.Run("token via x-sub-store-token header", func(t *testing.T) {
		app := newTestAppWithHandler(t, RequireAdmin(adminToken), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("X-Sub-Store-Token", adminToken)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		resp.Body.Close()
	})
}

// ---------- cors.go ----------

func TestCORS(t *testing.T) {
	t.Run("allowed origin wildcard", func(t *testing.T) {
		app := newTestAppWithHandler(t, CORS("*"), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("Origin", "https://example.com")
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("Access-Control-Allow-Origin"); got != "https://example.com" {
			t.Errorf("ACAO = %q, want https://example.com", got)
		}
		if got := resp.Header.Get("Access-Control-Allow-Methods"); got == "" {
			t.Error("Access-Control-Allow-Methods should be set")
		}
		if got := resp.Header.Get("Access-Control-Allow-Headers"); !strings.Contains(got, "Authorization") {
			t.Errorf("Access-Control-Allow-Headers should contain Authorization, got %q", got)
		}
		resp.Body.Close()
	})

	t.Run("allowed origin specific", func(t *testing.T) {
		app := newTestAppWithHandler(t, CORS("https://allowed.com, https://also.com"), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("Origin", "https://allowed.com")
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("Access-Control-Allow-Origin"); got != "https://allowed.com" {
			t.Errorf("ACAO = %q, want https://allowed.com", got)
		}
		resp.Body.Close()
	})

	t.Run("disallowed origin", func(t *testing.T) {
		app := newTestAppWithHandler(t, CORS("https://allowed.com"), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("Origin", "https://evil.com")
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("Access-Control-Allow-Origin"); got != "" {
			t.Errorf("ACAO = %q, want empty (disallowed)", got)
		}
		resp.Body.Close()
	})

	t.Run("no origin header", func(t *testing.T) {
		app := newTestAppWithHandler(t, CORS("*"), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("Access-Control-Allow-Origin"); got != "" {
			t.Errorf("ACAO = %q, want empty (no origin)", got)
		}
		resp.Body.Close()
	})

	t.Run("empty allowed origins", func(t *testing.T) {
		app := newTestAppWithHandler(t, CORS(""), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		req.Header.Set("Origin", "https://example.com")
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("Access-Control-Allow-Origin"); got != "" {
			t.Errorf("ACAO = %q, want empty (no origins configured)", got)
		}
		resp.Body.Close()
	})
}

func TestHandleOptions(t *testing.T) {
	t.Run("OPTIONS preflight returns 204", func(t *testing.T) {
		app := fiber.New()
		app.Use(HandleOptions())
		app.Get("/test", func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("OPTIONS", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 204 {
			t.Errorf("status = %d, want 204", resp.StatusCode)
		}
		if got := resp.Header.Get("Access-Control-Allow-Methods"); got == "" {
			t.Error("Access-Control-Allow-Methods should be set for OPTIONS")
		}
		if got := resp.Header.Get("Access-Control-Allow-Headers"); !strings.Contains(got, "Authorization") {
			t.Errorf("Access-Control-Allow-Headers should contain Authorization, got %q", got)
		}
		resp.Body.Close()
	})

	t.Run("GET passes through", func(t *testing.T) {
		app := fiber.New()
		app.Use(HandleOptions())
		app.Get("/test", func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		resp.Body.Close()
	})
}

func TestParseOrigins(t *testing.T) {
	tests := []struct {
		name  string
		input string
		want  []string
	}{
		{"single", "https://example.com", []string{"https://example.com"}},
		{"multiple", "https://a.com, https://b.com", []string{"https://a.com", "https://b.com"}},
		{"with spaces", "  https://a.com  ,  https://b.com  ", []string{"https://a.com", "https://b.com"}},
		{"empty", "", []string{}},
		{"only commas", ",,,", []string{}},
		{"wildcard", "*", []string{"*"}},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := parseOrigins(tt.input)
			if len(got) != len(tt.want) {
				t.Errorf("parseOrigins(%q) = %v, want %v", tt.input, got, tt.want)
				return
			}
			for i := range got {
				if got[i] != tt.want[i] {
					t.Errorf("parseOrigins(%q)[%d] = %q, want %q", tt.input, i, got[i], tt.want[i])
				}
			}
		})
	}
}

func TestContainsHelper(t *testing.T) {
	list := []string{"a", "b", "c"}
	if !contains(list, "a") {
		t.Error("contains should find 'a'")
	}
	if contains(list, "z") {
		t.Error("contains should not find 'z'")
	}
	if contains([]string{}, "a") {
		t.Error("contains on empty list should be false")
	}
}

// ---------- security.go ----------

func TestSecurityHeaders(t *testing.T) {
	app := newTestAppWithHandler(t, SecurityHeaders(), func(c fiber.Ctx) error {
		return c.SendString("ok")
	})

	req := httptest.NewRequest("GET", "/test", nil)
	resp, err := app.Test(req)
	if err != nil {
		t.Fatalf("app.Test error: %v", err)
	}
	defer resp.Body.Close()

	csp := resp.Header.Get("Content-Security-Policy")
	if csp == "" {
		t.Fatal("Content-Security-Policy header should be set")
	}
	// Per review-resolution #27: CSP must NOT contain unsafe-eval
	if strings.Contains(csp, "unsafe-eval") {
		t.Errorf("CSP should not contain unsafe-eval: %s", csp)
	}
	// Should contain script-src 'self'
	if !strings.Contains(csp, "script-src 'self'") {
		t.Errorf("CSP should contain script-src 'self': %s", csp)
	}
	// Check other security headers
	if got := resp.Header.Get("Referrer-Policy"); got != "no-referrer" {
		t.Errorf("Referrer-Policy = %q, want no-referrer", got)
	}
	if got := resp.Header.Get("X-Content-Type-Options"); got != "nosniff" {
		t.Errorf("X-Content-Type-Options = %q, want nosniff", got)
	}
	if got := resp.Header.Get("X-Frame-Options"); got != "DENY" {
		t.Errorf("X-Frame-Options = %q, want DENY", got)
	}
	pp := resp.Header.Get("Permissions-Policy")
	if pp == "" {
		t.Error("Permissions-Policy should be set")
	}
	if !strings.Contains(pp, "camera=()") {
		t.Errorf("Permissions-Policy should contain camera=(): %s", pp)
	}
}

func TestBodyLimit(t *testing.T) {
	t.Run("within limit", func(t *testing.T) {
		app := fiber.New()
		app.Post("/test", BodyLimit(100), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("POST", "/test", strings.NewReader("small body"))
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		resp.Body.Close()
	})

	t.Run("exceeds limit", func(t *testing.T) {
		app := fiber.New()
		app.Post("/test", BodyLimit(10), func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("POST", "/test", strings.NewReader(strings.Repeat("x", 100)))
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 413 {
			t.Errorf("status = %d, want 413", resp.StatusCode)
		}
		body, _ := io.ReadAll(resp.Body)
		if !strings.Contains(string(body), "too large") {
			t.Errorf("body should mention too large: %s", string(body))
		}
		resp.Body.Close()
	})
}

func TestDownloadHostIsolation(t *testing.T) {
	t.Run("no download hosts configured - all allowed", func(t *testing.T) {
		app := fiber.New()
		app.Use(DownloadHostIsolation(nil))
		app.Get("/api/test", func(c fiber.Ctx) error {
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/api/test", nil)
		req.Host = "anyhost.com"
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		resp.Body.Close()
	})

	t.Run("download host serves /download/ path", func(t *testing.T) {
		app := fiber.New()
		app.Use(DownloadHostIsolation([]string{"dl.example.com"}))
		app.Get("/download/sub", func(c fiber.Ctx) error {
			return c.SendString("download")
		})

		req := httptest.NewRequest("GET", "/download/sub", nil)
		req.Host = "dl.example.com"
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		resp.Body.Close()
	})

	t.Run("download host blocked on non-download path", func(t *testing.T) {
		app := fiber.New()
		app.Use(DownloadHostIsolation([]string{"dl.example.com"}))
		app.Get("/api/test", func(c fiber.Ctx) error {
			return c.SendString("api")
		})

		req := httptest.NewRequest("GET", "/api/test", nil)
		req.Host = "dl.example.com"
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 404 {
			t.Errorf("status = %d, want 404", resp.StatusCode)
		}
		resp.Body.Close()
	})

	t.Run("non-download host allowed on any path", func(t *testing.T) {
		app := fiber.New()
		app.Use(DownloadHostIsolation([]string{"dl.example.com"}))
		app.Get("/api/test", func(c fiber.Ctx) error {
			return c.SendString("api")
		})

		req := httptest.NewRequest("GET", "/api/test", nil)
		req.Host = "api.example.com"
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 200 {
			t.Errorf("status = %d, want 200", resp.StatusCode)
		}
		resp.Body.Close()
	})

	t.Run("download host case-insensitive", func(t *testing.T) {
		app := fiber.New()
		app.Use(DownloadHostIsolation([]string{"DL.Example.COM"}))
		app.Get("/api/test", func(c fiber.Ctx) error {
			return c.SendString("api")
		})

		req := httptest.NewRequest("GET", "/api/test", nil)
		req.Host = "dl.example.com"
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if resp.StatusCode != 404 {
			t.Errorf("status = %d, want 404 (case-insensitive match)", resp.StatusCode)
		}
		resp.Body.Close()
	})
}

func TestSetSafeResponseHeader(t *testing.T) {
	t.Run("valid value sets header", func(t *testing.T) {
		app := fiber.New()
		app.Get("/test", func(c fiber.Ctx) error {
			SetSafeResponseHeader(c, "X-Custom", "safe-value")
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("X-Custom"); got != "safe-value" {
			t.Errorf("X-Custom = %q, want safe-value", got)
		}
		resp.Body.Close()
	})

	t.Run("empty value does not set header", func(t *testing.T) {
		app := fiber.New()
		app.Get("/test", func(c fiber.Ctx) error {
			SetSafeResponseHeader(c, "X-Custom", "")
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("X-Custom"); got != "" {
			t.Errorf("X-Custom = %q, want empty (not set)", got)
		}
		resp.Body.Close()
	})

	t.Run("CRLF injection blocked", func(t *testing.T) {
		app := fiber.New()
		app.Get("/test", func(c fiber.Ctx) error {
			SetSafeResponseHeader(c, "X-Custom", "safe\r\nX-Injected: evil")
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("X-Custom"); got != "" {
			t.Errorf("X-Custom = %q, want empty (CRLF blocked)", got)
		}
		if got := resp.Header.Get("X-Injected"); got != "" {
			t.Errorf("X-Injected = %q, want empty (injection blocked)", got)
		}
		resp.Body.Close()
	})

	t.Run("LF only blocked", func(t *testing.T) {
		app := fiber.New()
		app.Get("/test", func(c fiber.Ctx) error {
			SetSafeResponseHeader(c, "X-Custom", "safe\nX-Injected: evil")
			return c.SendString("ok")
		})

		req := httptest.NewRequest("GET", "/test", nil)
		resp, err := app.Test(req)
		if err != nil {
			t.Fatalf("app.Test error: %v", err)
		}
		if got := resp.Header.Get("X-Custom"); got != "" {
			t.Errorf("X-Custom = %q, want empty (LF blocked)", got)
		}
		resp.Body.Close()
	})
}

func TestSafeContentDisposition(t *testing.T) {
	tests := []struct {
		name  string
		input string
		want  string
	}{
		{
			name:  "simple filename",
			input: `attachment; filename="test.txt"`,
			want:  `attachment; filename="test.txt"`,
		},
		{
			name:  "filename without quotes",
			input: `attachment; filename=test.txt`,
			want:  `attachment; filename="test.txt"`,
		},
		{
			name:  "UTF-8 encoded filename",
			input: `attachment; filename*=UTF-8''test%20file.txt`,
			want:  `attachment; filename="test_20file.txt"`,
		},
		{
			name:  "empty input",
			input: "",
			want:  "",
		},
		{
			name:  "CRLF injection attempt",
			input: "attachment; filename=\"test\r\nX-Injected: evil\"",
			want:  "",
		},
		{
			name:  "no filename",
			input: "attachment",
			want:  "",
		},
		{
			name:  "special chars sanitized",
			input: `attachment; filename="test@#$%.txt"`,
			want:  `attachment; filename="test____.txt"`,
		},
		{
			name:  "CJK preserved",
			input: `attachment; filename="节点.txt"`,
			want:  `attachment; filename="节点.txt"`,
		},
		{
			name:  "long filename truncated",
			input: `attachment; filename="` + strings.Repeat("a", 200) + `.txt"`,
			want:  `attachment; filename="` + strings.Repeat("a", 120) + `"`,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := SafeContentDisposition(tt.input)
			if got != tt.want {
				t.Errorf("SafeContentDisposition(%q) = %q, want %q", tt.input, got, tt.want)
			}
		})
	}
}

func TestSafeContentDispositionEmptyFilename(t *testing.T) {
	// filename with only special chars → sanitized to underscores (non-empty) → returns valid
	got := SafeContentDisposition(`attachment; filename="!!!"`)
	want := `attachment; filename="___"`
	if got != want {
		t.Errorf("SafeContentDisposition with only-special filename = %q, want %q", got, want)
	}
}

func TestExtractFilename(t *testing.T) {
	tests := []struct {
		input string
		want  string
	}{
		{`attachment; filename="test.txt"`, "test.txt"},
		{`attachment; filename=test.txt`, "test.txt"},
		{`attachment; filename*=UTF-8''test.txt`, "test.txt"},
		{`attachment`, ""},
		{``, ""},
		{`filename="only"`, "only"},
	}
	for _, tt := range tests {
		t.Run(tt.input, func(t *testing.T) {
			got := extractFilename(tt.input)
			if got != tt.want {
				t.Errorf("extractFilename(%q) = %q, want %q", tt.input, got, tt.want)
			}
		})
	}
}

func TestSanitizeFilename(t *testing.T) {
	tests := []struct {
		input string
		want  string
	}{
		{"simple.txt", "simple.txt"},
		{"test@file.txt", "test_file.txt"},
		{"节点.txt", "节点.txt"}, // CJK preserved
		{"a b c.txt", "a b c.txt"}, // spaces preserved
		{"test(1).txt", "test(1).txt"}, // parens preserved
		{"test-1.txt", "test-1.txt"}, // hyphens preserved
	}
	for _, tt := range tests {
		t.Run(tt.input, func(t *testing.T) {
			got := sanitizeFilename(tt.input)
			if got != tt.want {
				t.Errorf("sanitizeFilename(%q) = %q, want %q", tt.input, got, tt.want)
			}
		})
	}

	// truncation
	long := strings.Repeat("a", 200)
	got := sanitizeFilename(long)
	if len(got) > 120 {
		t.Errorf("sanitizeFilename long input length = %d, want <= 120", len(got))
	}
}