package server

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

	"glchat/internal/config"
	"glchat/internal/database"
)

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{
		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,
		LogLevel:      "error",
		LogFormat:     "json",
	}
	logger := slog.New(slog.DiscardHandler)
	return New(cfg, db, logger), db
}

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)

	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)
	}
}