package server

import (
	"context"
	"encoding/json"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/coder/websocket"

	"glchat/internal/auth"
	"glchat/internal/config"
	"glchat/internal/database"
	"glchat/internal/gateway"
	"glchat/internal/permissions"
	"glchat/internal/source"
	"glchat/internal/store"
)

func newTestServer(t *testing.T) (*Server, *database.DB) {
	t.Helper()
	ctx := context.Background()
	db, err := database.Open(ctx, database.Options{
		Path:     filepath.Join(t.TempDir(), "glchat.db"),
		ReadPool: 2,
		Migrate:  true,
	})
	if err != nil {
		t.Fatalf("open test database: %v", err)
	}
	t.Cleanup(func() {
		if err := db.Close(); err != nil {
			t.Errorf("close test database: %v", err)
		}
	})

	cfg := config.Config{
		// Данные (в том числе загруженные файлы) — во временном каталоге,
		// иначе тесты пишут в рабочее дерево репозитория.
		DataDir:           t.TempDir(),
		Domain:            "gl.mhspx.su",
		WebRoot:           filepath.Join("testdata", "web"),
		FilesDomain:       "files.gl.mhspx.su",
		InstanceName:      "glchat",
		ListenAddr:        "127.0.0.1:0",
		Version:           "v0.1.0-test",
		Commit:            "deadbee",
		BuildDate:         "2026-09-19T00:00:00Z",
		MaxUploadSize:     26214400,
		TLSEnabled:        true,
		SessionPepper:     "test-pepper",
		MasterKey:         "00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff",
		Argon2MemoryKiB:   1024,
		Argon2Iterations:  1,
		Argon2Parallelism: 1,
		LogLevel:          "error",
		LogFormat:         "json",
	}
	logger := slog.New(slog.DiscardHandler)
	st := store.New(db)
	authService, err := auth.New(context.Background(), cfg, st, logger)
	if err != nil {
		t.Fatalf("initialize authentication: %v", err)
	}
	calculator := permissions.NewCalculator(source.New(st))
	gatewayService := gateway.New(st, authService, gateway.NewSnapshot(st, calculator), logger, cfg.AllowedOrigins())
	return New(cfg, db, logger, Deps{
		Store: st, Auth: authService, Gateway: gatewayService, Permissions: calculator,
	}), db
}

// TestGatewayRouteUpgrades проверяет связку: маршрут /gateway доступен через
// полный стек middleware, HELLO приходит до IDENTIFY (AGENT.md 8.3).
func TestGatewayRouteUpgrades(t *testing.T) {
	srv, _ := newTestServer(t)
	httpServer := httptest.NewServer(srv.Handler())
	t.Cleanup(httpServer.Close)

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	url := "ws" + strings.TrimPrefix(httpServer.URL, "http") + "/gateway"
	// coder/websocket закрывает тело ответа сам (dial.go: "You never need to
	// close resp.Body yourself") — отсюда nolint:bodyclose.
	conn, _, err := websocket.Dial(ctx, url, &websocket.DialOptions{ //nolint:bodyclose // тело закрывает библиотека
		HTTPHeader: map[string][]string{"Origin": {"https://gl.mhspx.su"}},
	})
	if err != nil {
		t.Fatalf("dial /gateway: %v", err)
	}
	t.Cleanup(func() { _ = conn.CloseNow() })

	_, data, err := conn.Read(ctx)
	if err != nil {
		t.Fatalf("read HELLO: %v", err)
	}
	var envelope struct {
		Op int `json:"op"`
	}
	if err := json.Unmarshal(data, &envelope); err != nil {
		t.Fatalf("decode HELLO: %v", err)
	}
	if envelope.Op != gateway.OpHello {
		t.Fatalf("op = %d, want HELLO (%d)", envelope.Op, gateway.OpHello)
	}
}

// TestGatewayRejectsForeignOrigin: подключение с чужого домена отклоняется
// (AGENT.md 9.7).
func TestGatewayRejectsForeignOrigin(t *testing.T) {
	srv, _ := newTestServer(t)
	httpServer := httptest.NewServer(srv.Handler())
	t.Cleanup(httpServer.Close)

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	url := "ws" + strings.TrimPrefix(httpServer.URL, "http") + "/gateway"
	conn, _, err := websocket.Dial(ctx, url, &websocket.DialOptions{ //nolint:bodyclose // тело закрывает библиотека
		HTTPHeader: map[string][]string{"Origin": {"https://evil.example"}},
	})
	if err == nil {
		_ = conn.CloseNow()
		t.Fatal("connection from a foreign origin must be rejected")
	}
}

func TestHealthz(t *testing.T) {
	srv, _ := newTestServer(t)
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/healthz", nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", rec.Code)
	}
	var body map[string]any
	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if body["status"] != "ok" {
		t.Errorf("status field = %v, want ok", body["status"])
	}
	if body["version"] != "v0.1.0-test" {
		t.Errorf("version field = %v", body["version"])
	}
	if rec.Header().Get("X-Request-Id") == "" {
		t.Error("X-Request-Id header is missing")
	}
	if rec.Header().Get("X-Content-Type-Options") != "nosniff" {
		t.Error("security headers are missing")
	}
}

func TestReadyzReportsDatabase(t *testing.T) {
	srv, _ := newTestServer(t)
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/readyz", nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", rec.Code)
	}
	var body struct {
		Status string            `json:"status"`
		Checks map[string]string `json:"checks"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if body.Status != "ready" {
		t.Errorf("status = %q, want ready", body.Status)
	}
	if body.Checks["database"] != "ok" {
		t.Errorf("database check = %q, want ok", body.Checks["database"])
	}
}

func TestReadyzFailsWhenDatabaseClosed(t *testing.T) {
	srv, db := newTestServer(t)
	if err := db.Close(); err != nil {
		t.Fatalf("close database: %v", err)
	}
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/readyz", nil))

	if rec.Code != http.StatusServiceUnavailable {
		t.Fatalf("status = %d, want 503", rec.Code)
	}
}

func TestMetaEndpoint(t *testing.T) {
	srv, _ := newTestServer(t)
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/api/v1/meta", nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", rec.Code)
	}
	var body struct {
		APIVersion string `json:"api_version"`
		BaseURL    string `json:"base_url"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode response: %v", err)
	}
	if body.APIVersion != "v1" {
		t.Errorf("api_version = %q, want v1", body.APIVersion)
	}
	if body.BaseURL != "https://gl.mhspx.su" {
		t.Errorf("base_url = %q", body.BaseURL)
	}
}

func TestOpenAPIDocumentIsServed(t *testing.T) {
	srv, _ := newTestServer(t)
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/api/v1/openapi.json", nil))

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", rec.Code)
	}
	var doc map[string]any
	if err := json.Unmarshal(rec.Body.Bytes(), &doc); err != nil {
		t.Fatalf("openapi document is not valid json: %v", err)
	}
	if doc["openapi"] != "3.1.0" {
		t.Errorf("openapi version = %v, want 3.1.0", doc["openapi"])
	}
	if _, ok := doc["paths"].(map[string]any)["/meta"]; !ok {
		t.Error("openapi document does not describe /meta")
	}
}

func TestUnknownAPIRouteUsesErrorEnvelope(t *testing.T) {
	srv, _ := newTestServer(t)
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/api/v1/does-not-exist", nil))

	if rec.Code != http.StatusNotFound {
		t.Fatalf("status = %d, want 404", rec.Code)
	}
	var body struct {
		Error struct {
			Code    string `json:"code"`
			Message string `json:"message"`
		} `json:"error"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode error envelope: %v", err)
	}
	if body.Error.Code == "" || body.Error.Message == "" {
		t.Errorf("error envelope is incomplete: %s", rec.Body.String())
	}
}

func TestServesWebClientWithSPAFallback(t *testing.T) {
	srv, _ := newTestServer(t)

	cases := []struct {
		path        string
		wantStatus  int
		wantSubstr  string
		wantHeaders map[string]string
	}{
		{path: "/", wantStatus: http.StatusOK, wantSubstr: "glchat"},
		{path: "/app/guild/1/channel/2", wantStatus: http.StatusOK, wantSubstr: "glchat"},
		{path: "/assets/app.js", wantStatus: http.StatusOK, wantSubstr: "console.log"},
	}
	for _, tc := range cases {
		rec := httptest.NewRecorder()
		srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, tc.path, nil))
		if rec.Code != tc.wantStatus {
			t.Errorf("GET %s status = %d, want %d", tc.path, rec.Code, tc.wantStatus)
		}
		if !strings.Contains(rec.Body.String(), tc.wantSubstr) {
			t.Errorf("GET %s body = %q, want it to contain %q", tc.path, rec.Body.String(), tc.wantSubstr)
		}
	}

	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/assets/app.js", nil))
	if got := rec.Header().Get("Cache-Control"); !strings.Contains(got, "immutable") {
		t.Errorf("assets Cache-Control = %q, want immutable", got)
	}
}

func TestServeWebClientReportsMissingBundle(t *testing.T) {
	ctx := context.Background()
	db, err := database.Open(ctx, database.Options{
		Path:     filepath.Join(t.TempDir(), "glchat.db"),
		ReadPool: 2,
		Migrate:  true,
	})
	if err != nil {
		t.Fatalf("open test database: %v", err)
	}
	t.Cleanup(func() { _ = db.Close() })

	cfg := config.Config{Domain: "localhost", WebRoot: t.TempDir(), LogFormat: "json", LogLevel: "error"}
	logger := slog.New(slog.DiscardHandler)
	srv := New(cfg, db, logger, Deps{})

	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/", nil))
	if rec.Code != http.StatusServiceUnavailable {
		t.Errorf("status = %d, want 503 when the bundle is absent", rec.Code)
	}
}

func TestMethodNotAllowedOnMeta(t *testing.T) {
	srv, _ := newTestServer(t)
	rec := httptest.NewRecorder()
	srv.Handler().ServeHTTP(rec, httptest.NewRequestWithContext(context.Background(), http.MethodPost, "/api/v1/meta", nil))

	if rec.Code != http.StatusMethodNotAllowed {
		t.Fatalf("status = %d, want 405", rec.Code)
	}
}