package tests

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

	"github.com/gofiber/fiber/v3"
	"github.com/gofiber/fiber/v3/middleware/adaptor"
	"github.com/prometheus/client_golang/prometheus"

	applb "knowfoolery/backend/services/leaderboard-service/internal/application/leaderboard"
	domain "knowfoolery/backend/services/leaderboard-service/internal/domain/leaderboard"
	httpapi "knowfoolery/backend/services/leaderboard-service/internal/interfaces/http"
	sharedtypes "knowfoolery/backend/shared/domain/types"
	sharedmetrics "knowfoolery/backend/shared/infra/observability/metrics"
	"knowfoolery/backend/shared/infra/utils/validation"
	sharedhttpx "knowfoolery/backend/shared/testutil/httpx"
)

type inMemoryRepo struct {
	entries []*domain.LeaderboardEntry
	stats   map[string]*domain.PlayerStats
}

func newInMemoryRepo() *inMemoryRepo {
	return &inMemoryRepo{
		entries: make([]*domain.LeaderboardEntry, 0),
		stats:   map[string]*domain.PlayerStats{},
	}
}

func (r *inMemoryRepo) EnsureSchema(ctx context.Context) error { return nil }
func (r *inMemoryRepo) IngestEntry(
	ctx context.Context,
	entry *domain.LeaderboardEntry,
) (*domain.LeaderboardEntry, bool, error) {
	for _, e := range r.entries {
		if e.SessionID == entry.SessionID {
			return e, true, nil
		}
	}
	cp := *entry
	cp.ID = "id-" + entry.SessionID
	cp.CreatedAt = time.Now().UTC()
	r.entries = append(r.entries, &cp)
	stats := r.stats[entry.PlayerID]
	if stats == nil {
		best := entry.DurationSeconds
		stats = &domain.PlayerStats{
			PlayerID:        entry.PlayerID,
			PlayerName:      entry.PlayerName,
			GamesPlayed:     1,
			GamesCompleted:  1,
			TotalScore:      int64(entry.Score),
			BestScore:       entry.Score,
			AvgScore:        float64(entry.Score),
			AvgSuccessRate:  entry.SuccessRate,
			TotalQuestions:  int64(entry.QuestionsAsked),
			TotalCorrect:    int64(entry.QuestionsCorrect),
			BestDurationSec: &best,
		}
		r.stats[entry.PlayerID] = stats
	}
	return &cp, false, nil
}
func (r *inMemoryRepo) ListTop(
	ctx context.Context,
	filter domain.TopFilter,
	limit int,
) ([]*domain.LeaderboardEntry, error) {
	if len(r.entries) < limit {
		limit = len(r.entries)
	}
	out := make([]*domain.LeaderboardEntry, 0, limit)
	for i := 0; i < limit; i++ {
		out = append(out, r.entries[i])
	}
	return out, nil
}
func (r *inMemoryRepo) GetPlayerStats(ctx context.Context, playerID string) (*domain.PlayerStats, error) {
	stats := r.stats[playerID]
	if stats == nil {
		return nil, domain.ErrPlayerNotFound
	}
	cp := *stats
	return &cp, nil
}
func (r *inMemoryRepo) GetPlayerRank(ctx context.Context, playerID string) (int64, error) {
	if _, ok := r.stats[playerID]; !ok {
		return 0, domain.ErrPlayerNotFound
	}
	return 1, nil
}
func (r *inMemoryRepo) ListPlayerHistory(
	ctx context.Context,
	playerID string,
	pagination sharedtypes.Pagination,
) ([]*domain.LeaderboardEntry, int64, error) {
	out := make([]*domain.LeaderboardEntry, 0)
	for _, e := range r.entries {
		if e.PlayerID == playerID {
			out = append(out, e)
		}
	}
	return out, int64(len(out)), nil
}
func (r *inMemoryRepo) GetGlobalStats(ctx context.Context, filter domain.TopFilter) (*domain.GlobalStats, error) {
	return &domain.GlobalStats{
		TotalGames:   int64(len(r.entries)),
		TotalPlayers: int64(len(r.stats)),
		UpdatedAt:    time.Now().UTC(),
	}, nil
}

type fakeState struct{}

func (s *fakeState) Get(ctx context.Context, key string) (string, bool) { return "", false }
func (s *fakeState) Set(ctx context.Context, key, value string, ttl time.Duration) error {
	return nil
}
func (s *fakeState) Delete(ctx context.Context, keys ...string) error { return nil }

func setupApp(t *testing.T) *fiber.App {
	t.Helper()
	repo := newInMemoryRepo()
	svc := applb.NewService(repo, &fakeState{}, applb.Config{UpdateRequireAuth: true})
	metrics := sharedmetrics.NewMetrics(sharedmetrics.Config{
		ServiceName: "leaderboard-service-test",
		Enabled:     true,
		Registry:    prometheus.NewRegistry(),
	})
	h := httpapi.NewHandler(svc, validation.NewValidator(), nil, metrics, true, 20, 100)
	app := fiber.New()

	auth := func(c fiber.Ctx) error {
		switch c.Get("Authorization") {
		case "Bearer player":
			c.Locals("user_id", "user-1")
			c.Locals("user_roles", []string{"player"})
			return c.Next()
		case "Bearer service":
			c.Locals("user_id", "svc")
			c.Locals("user_roles", []string{"service"})
			return c.Next()
		default:
			return c.SendStatus(http.StatusUnauthorized)
		}
	}
	httpapi.RegisterRoutes(app, h, auth)
	app.Get("/metrics", adaptor.HTTPHandler(sharedmetrics.Handler()))
	return app
}

func TestUpdateAndTop10(t *testing.T) {
	app := setupApp(t)

	payload, _ := json.Marshal(map[string]any{
		"session_id":        "s1",
		"player_id":         "user-1",
		"player_name":       "Alice",
		"total_score":       10,
		"questions_asked":   12,
		"questions_correct": 9,
		"hints_used":        1,
		"duration_seconds":  200,
		"completed_at":      time.Now().UTC().Format(time.RFC3339),
		"completion_type":   "completed",
	})
	req := httptest.NewRequest(http.MethodPost, "/leaderboard/update", bytes.NewReader(payload))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer service")
	{
		resp := sharedhttpx.MustTest(t, app, req)
		defer func() { _ = resp.Body.Close() }()
		assertStatus(t, resp, http.StatusOK, "update failed")
	}

	req = httptest.NewRequest(http.MethodGet, "/leaderboard/top10", nil)
	{
		resp := sharedhttpx.MustTest(t, app, req)
		defer func() { _ = resp.Body.Close() }()
		assertStatus(t, resp, http.StatusOK, "top10 failed")
	}
}

func TestPlayerAuthAndStats(t *testing.T) {
	app := setupApp(t)

	req := httptest.NewRequest(http.MethodGet, "/leaderboard/players/user-1", nil)
	req.Header.Set("Authorization", "Bearer player")
	{
		resp := sharedhttpx.MustTest(t, app, req)
		defer func() { _ = resp.Body.Close() }()
		assertStatus(t, resp, http.StatusNotFound, "expected not found before update")
	}

	req = httptest.NewRequest(http.MethodGet, "/leaderboard/players/user-2", nil)
	req.Header.Set("Authorization", "Bearer player")
	{
		resp := sharedhttpx.MustTest(t, app, req)
		defer func() { _ = resp.Body.Close() }()
		assertStatus(t, resp, http.StatusForbidden, "expected forbidden for other player")
	}

	req = httptest.NewRequest(http.MethodGet, "/leaderboard/stats", nil)
	{
		resp := sharedhttpx.MustTest(t, app, req)
		defer func() { _ = resp.Body.Close() }()
		assertStatus(t, resp, http.StatusOK, "stats failed")
	}
}

func TestMetricsEndpoint(t *testing.T) {
	app := setupApp(t)
	req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
	{
		resp := sharedhttpx.MustTest(t, app, req)
		defer func() { _ = resp.Body.Close() }()
		assertStatus(t, resp, http.StatusOK, "metrics failed")
	}
}

func assertStatus(t *testing.T, resp *http.Response, want int, msg string) {
	t.Helper()
	if resp.StatusCode != want {
		t.Fatalf("%s: status=%d want=%d", msg, resp.StatusCode, want)
	}
}