package publichttp

import (
	"bytes"
	"context"
	"encoding/json"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"galaxy/lobby/internal/adapters/gamestub"
	"galaxy/lobby/internal/domain/common"
	"galaxy/lobby/internal/domain/game"
	"galaxy/lobby/internal/ports"
	"galaxy/lobby/internal/service/cancelgame"
	"galaxy/lobby/internal/service/creategame"
	"galaxy/lobby/internal/service/openenrollment"
	"galaxy/lobby/internal/service/updategame"

	"github.com/stretchr/testify/require"
)

type stubIDGenerator struct {
	next common.GameID
}

func (g *stubIDGenerator) NewGameID() (common.GameID, error) {
	return g.next, nil
}

func (g *stubIDGenerator) NewApplicationID() (common.ApplicationID, error) {
	return "application-stub", nil
}

func (g *stubIDGenerator) NewInviteID() (common.InviteID, error) {
	return "invite-stub", nil
}

func (g *stubIDGenerator) NewMembershipID() (common.MembershipID, error) {
	return "membership-stub", nil
}

func silentLogger() *slog.Logger {
	return slog.New(slog.NewTextHandler(io.Discard, nil))
}

func buildHandler(t *testing.T, store *gamestub.Store, ids ports.IDGenerator, clock func() time.Time) http.Handler {
	t.Helper()

	logger := silentLogger()

	createSvc, err := creategame.NewService(creategame.Dependencies{
		Games:  store,
		IDs:    ids,
		Clock:  clock,
		Logger: logger,
	})
	require.NoError(t, err)
	updateSvc, err := updategame.NewService(updategame.Dependencies{
		Games:  store,
		Clock:  clock,
		Logger: logger,
	})
	require.NoError(t, err)
	openSvc, err := openenrollment.NewService(openenrollment.Dependencies{
		Games:  store,
		Clock:  clock,
		Logger: logger,
	})
	require.NoError(t, err)
	cancelSvc, err := cancelgame.NewService(cancelgame.Dependencies{
		Games:  store,
		Clock:  clock,
		Logger: logger,
	})
	require.NoError(t, err)

	return newHandler(Dependencies{
		Logger:         logger,
		CreateGame:     createSvc,
		UpdateGame:     updateSvc,
		OpenEnrollment: openSvc,
		CancelGame:     cancelSvc,
	}, logger)
}

func doRequest(t *testing.T, handler http.Handler, method, path, userID string, body any) *httptest.ResponseRecorder {
	t.Helper()

	var reader io.Reader
	if body != nil {
		data, err := json.Marshal(body)
		require.NoError(t, err)
		reader = bytes.NewReader(data)
	}

	req := httptest.NewRequestWithContext(context.Background(), method, path, reader)
	if userID != "" {
		req.Header.Set(xUserIDHeader, userID)
	}
	if reader != nil {
		req.Header.Set("Content-Type", "application/json")
	}

	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	return rec
}

func decodeGameRecord(t *testing.T, rec *httptest.ResponseRecorder) gameRecordResponse {
	t.Helper()

	var payload gameRecordResponse
	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &payload))
	return payload
}

func decodeError(t *testing.T, rec *httptest.ResponseRecorder) errorResponse {
	t.Helper()

	var payload errorResponse
	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &payload))
	return payload
}

func fixedClock(at time.Time) func() time.Time {
	return func() time.Time { return at }
}

func TestCreateGameHappyPath(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	store := gamestub.NewStore()
	handler := buildHandler(t, store, &stubIDGenerator{next: "game-first"}, fixedClock(now))

	body := createGameRequest{
		GameName:            "Friends Game",
		GameType:            "private",
		MinPlayers:          2,
		MaxPlayers:          4,
		StartGapHours:       4,
		StartGapPlayers:     1,
		EnrollmentEndsAt:    now.Add(12 * time.Hour).Unix(),
		TurnSchedule:        "0 0 * * *",
		TargetEngineVersion: "1.0.0",
	}
	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games", "user-42", body)
	require.Equal(t, http.StatusCreated, rec.Code)

	decoded := decodeGameRecord(t, rec)
	require.Equal(t, "game-first", decoded.GameID)
	require.Equal(t, "private", decoded.GameType)
	require.Equal(t, "user-42", decoded.OwnerUserID)
	require.Equal(t, "draft", decoded.Status)
	require.Equal(t, body.EnrollmentEndsAt, decoded.EnrollmentEndsAt)
	require.Equal(t, now.UnixMilli(), decoded.CreatedAt)
}

func TestCreateGameMissingUserIDHeader(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	handler := buildHandler(t, gamestub.NewStore(), &stubIDGenerator{next: "game-x"}, fixedClock(now))

	body := createGameRequest{
		GameName:            "x",
		GameType:            "private",
		MinPlayers:          2,
		MaxPlayers:          4,
		StartGapHours:       4,
		StartGapPlayers:     1,
		EnrollmentEndsAt:    now.Add(time.Hour).Unix(),
		TurnSchedule:        "0 0 * * *",
		TargetEngineVersion: "1.0.0",
	}
	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games", "", body)
	require.Equal(t, http.StatusBadRequest, rec.Code)

	decoded := decodeError(t, rec)
	require.Equal(t, "invalid_request", decoded.Error.Code)
	require.Contains(t, decoded.Error.Message, "X-User-ID")
}

func TestCreateGameUnknownJSONFieldRejected(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	handler := buildHandler(t, gamestub.NewStore(), &stubIDGenerator{next: "game-x"}, fixedClock(now))

	reqBody := map[string]any{
		"game_name":             "x",
		"game_type":             "private",
		"min_players":           2,
		"max_players":           4,
		"start_gap_hours":       4,
		"start_gap_players":     1,
		"enrollment_ends_at":    now.Add(time.Hour).Unix(),
		"turn_schedule":         "0 0 * * *",
		"target_engine_version": "1.0.0",
		"owner_user_id":         "user-42", // unknown — must be rejected
	}
	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games", "user-42", reqBody)
	require.Equal(t, http.StatusBadRequest, rec.Code)
}

func TestCreateGameUserCannotCreatePublic(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	handler := buildHandler(t, gamestub.NewStore(), &stubIDGenerator{next: "game-x"}, fixedClock(now))

	body := createGameRequest{
		GameName:            "x",
		GameType:            "public",
		MinPlayers:          2,
		MaxPlayers:          4,
		StartGapHours:       4,
		StartGapPlayers:     1,
		EnrollmentEndsAt:    now.Add(time.Hour).Unix(),
		TurnSchedule:        "0 0 * * *",
		TargetEngineVersion: "1.0.0",
	}
	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games", "user-42", body)
	require.Equal(t, http.StatusForbidden, rec.Code)
	decoded := decodeError(t, rec)
	require.Equal(t, "forbidden", decoded.Error.Code)
}

func TestUpdateGameNotFound(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	handler := buildHandler(t, gamestub.NewStore(), &stubIDGenerator{next: "game-x"}, fixedClock(now))

	desc := "new"
	body := updateGameRequest{Description: &desc}
	rec := doRequest(t, handler, http.MethodPatch, "/api/v1/lobby/games/game-missing", "user-1", body)
	require.Equal(t, http.StatusNotFound, rec.Code)
	decoded := decodeError(t, rec)
	require.Equal(t, "subject_not_found", decoded.Error.Code)
}

func TestOpenEnrollmentHappyPath(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	store := gamestub.NewStore()

	seedDraftForTest(t, store, "game-oe", game.GameTypePrivate, "user-1", now)

	handler := buildHandler(t, store, &stubIDGenerator{next: "unused"}, fixedClock(now.Add(time.Hour)))

	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games/game-oe/open-enrollment", "user-1", nil)
	require.Equal(t, http.StatusOK, rec.Code)
	decoded := decodeGameRecord(t, rec)
	require.Equal(t, "enrollment_open", decoded.Status)
}

func TestOpenEnrollmentForbidden(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	store := gamestub.NewStore()

	seedDraftForTest(t, store, "game-oe", game.GameTypePrivate, "user-1", now)

	handler := buildHandler(t, store, &stubIDGenerator{next: "unused"}, fixedClock(now.Add(time.Hour)))

	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games/game-oe/open-enrollment", "user-2", nil)
	require.Equal(t, http.StatusForbidden, rec.Code)
}

func TestOpenEnrollmentConflict(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	store := gamestub.NewStore()

	seedDraftForTest(t, store, "game-oe", game.GameTypePrivate, "user-1", now)
	require.NoError(t, store.UpdateStatus(context.Background(), ports.UpdateStatusInput{
		GameID:       "game-oe",
		ExpectedFrom: game.StatusDraft,
		To:           game.StatusEnrollmentOpen,
		Trigger:      game.TriggerCommand,
		At:           now.Add(5 * time.Minute),
	}))

	handler := buildHandler(t, store, &stubIDGenerator{next: "unused"}, fixedClock(now.Add(time.Hour)))

	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games/game-oe/open-enrollment", "user-1", nil)
	require.Equal(t, http.StatusConflict, rec.Code)
	decoded := decodeError(t, rec)
	require.Equal(t, "conflict", decoded.Error.Code)
}

func TestCancelGameHappyPath(t *testing.T) {
	t.Parallel()

	now := time.Date(2026, 4, 24, 10, 0, 0, 0, time.UTC)
	store := gamestub.NewStore()

	seedDraftForTest(t, store, "game-cx", game.GameTypePrivate, "user-1", now)

	handler := buildHandler(t, store, &stubIDGenerator{next: "unused"}, fixedClock(now.Add(time.Hour)))

	rec := doRequest(t, handler, http.MethodPost, "/api/v1/lobby/games/game-cx/cancel", "user-1", nil)
	require.Equal(t, http.StatusOK, rec.Code)
	decoded := decodeGameRecord(t, rec)
	require.Equal(t, "cancelled", decoded.Status)
}

func seedDraftForTest(
	t *testing.T,
	store *gamestub.Store,
	id common.GameID,
	gameType game.GameType,
	ownerUserID string,
	now time.Time,
) {
	t.Helper()

	record, err := game.New(game.NewGameInput{
		GameID:              id,
		GameName:            "Seed",
		GameType:            gameType,
		OwnerUserID:         ownerUserID,
		MinPlayers:          2,
		MaxPlayers:          4,
		StartGapHours:       4,
		StartGapPlayers:     1,
		EnrollmentEndsAt:    now.Add(24 * time.Hour),
		TurnSchedule:        "0 */6 * * *",
		TargetEngineVersion: "1.0.0",
		Now:                 now,
	})
	require.NoError(t, err)
	require.NoError(t, store.Save(context.Background(), record))
}

func TestIsValidationErrorHeuristic(t *testing.T) {
	t.Parallel()

	require.True(t, isValidationError(errStr("game name must not be empty")))
	require.True(t, isValidationError(errStr("status \"ghost\" is unsupported")))
	require.True(t, isValidationError(errStr("invalid cron expression")))
	require.False(t, isValidationError(nil))
	require.False(t, isValidationError(errStr("redis down")))
}

type errString string

func (e errString) Error() string { return string(e) }

func errStr(s string) error { return errString(s) }