package grpc

import (
	"context"
	"errors"
	"testing"

	"datarush/internal/results/domain"
	pb "datarush/pkg/api/results"

	"github.com/google/uuid"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type MockResultService struct {
	CreateResultFunc            func(ctx context.Context, result *domain.Result) (*domain.Result, error)
	GetResultFunc               func(ctx context.Context, id uuid.UUID) (*domain.Result, error)
	UpdateResultFunc            func(ctx context.Context, result *domain.Result) (*domain.Result, error)
	DeleteResultFunc            func(ctx context.Context, id uuid.UUID) error
	ListResultsFunc             func(ctx context.Context, pageSize int32, pageToken int32, competitionID *uuid.UUID, userID *uuid.UUID, status *domain.ResultStatus, minScore *float64, maxScore *float64) (results []domain.Result, totalCount int32, nextPageToken int32, err error)
	GetByCompetitionAndUserFunc func(ctx context.Context, competitionID uuid.UUID, userID uuid.UUID) (*domain.Result, error)
	GetLeaderboardFunc          func(ctx context.Context, competitionID uuid.UUID, limit int32, offset int32) ([]domain.Result, int32, error)
	UpdateStatusFunc            func(ctx context.Context, id uuid.UUID, status domain.ResultStatus) (*domain.Result, error)
	RecalculateRanksFunc        func(ctx context.Context, competitionID uuid.UUID) error
}

func (m *MockResultService) CreateResult(ctx context.Context, result *domain.Result) (*domain.Result, error) {
	if m.CreateResultFunc != nil {
		return m.CreateResultFunc(ctx, result)
	}
	return nil, errors.New("not implemented")
}

func (m *MockResultService) GetResult(ctx context.Context, id uuid.UUID) (*domain.Result, error) {
	if m.GetResultFunc != nil {
		return m.GetResultFunc(ctx, id)
	}
	return nil, errors.New("not implemented")
}

func (m *MockResultService) UpdateResult(ctx context.Context, result *domain.Result) (*domain.Result, error) {
	if m.UpdateResultFunc != nil {
		return m.UpdateResultFunc(ctx, result)
	}
	return nil, errors.New("not implemented")
}

func (m *MockResultService) DeleteResult(ctx context.Context, id uuid.UUID) error {
	if m.DeleteResultFunc != nil {
		return m.DeleteResultFunc(ctx, id)
	}
	return errors.New("not implemented")
}

func (m *MockResultService) ListResults(ctx context.Context, pageSize int32, pageToken int32, competitionID *uuid.UUID, userID *uuid.UUID, status *domain.ResultStatus, minScore *float64, maxScore *float64) (results []domain.Result, totalCount int32, nextPageToken int32, err error) {
	if m.ListResultsFunc != nil {
		return m.ListResultsFunc(ctx, pageSize, pageToken, competitionID, userID, status, minScore, maxScore)
	}
	return nil, 0, 0, errors.New("not implemented")
}

func (m *MockResultService) GetByCompetitionAndUser(ctx context.Context, competitionID uuid.UUID, userID uuid.UUID) (*domain.Result, error) {
	if m.GetByCompetitionAndUserFunc != nil {
		return m.GetByCompetitionAndUserFunc(ctx, competitionID, userID)
	}
	return nil, errors.New("not implemented")
}

func (m *MockResultService) GetLeaderboard(ctx context.Context, competitionID uuid.UUID, limit int32, offset int32) ([]domain.Result, int32, error) {
	if m.GetLeaderboardFunc != nil {
		return m.GetLeaderboardFunc(ctx, competitionID, limit, offset)
	}
	return nil, 0, errors.New("not implemented")
}

func (m *MockResultService) UpdateStatus(ctx context.Context, id uuid.UUID, status domain.ResultStatus) (*domain.Result, error) {
	if m.UpdateStatusFunc != nil {
		return m.UpdateStatusFunc(ctx, id, status)
	}
	return nil, errors.New("not implemented")
}

func (m *MockResultService) RecalculateRanks(ctx context.Context, competitionID uuid.UUID) error {
	if m.RecalculateRanksFunc != nil {
		return m.RecalculateRanksFunc(ctx, competitionID)
	}
	return errors.New("not implemented")
}

func TestNewResultsHandler(t *testing.T) {
	mockService := &MockResultService{}
	handler := NewResultsHandler(mockService, "localhost:50051", "localhost:50055", "localhost:50056")

	if handler == nil {
		t.Fatal("Expected handler to be created, got nil")
	}

	if handler.service == nil {
		t.Error("Expected service to be set")
	}

	if handler.userServiceAddr != "localhost:50051" {
		t.Errorf("Expected userServiceAddr to be localhost:50051, got %s", handler.userServiceAddr)
	}

	if handler.submissionServiceAddr != "localhost:50055" {
		t.Errorf("Expected submissionServiceAddr to be localhost:50055, got %s", handler.submissionServiceAddr)
	}

	if handler.taskServiceAddr != "localhost:50056" {
		t.Errorf("Expected taskServiceAddr to be localhost:50056, got %s", handler.taskServiceAddr)
	}
}

func TestGetCompetitionResults_InvalidCompetitionID(t *testing.T) {
	mockService := &MockResultService{}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.GetCompetitionResultsRequest{
		CompetitionId: "invalid-uuid",
		PageSize:      10,
		PageToken:     0,
	}

	resp, err := handler.GetCompetitionResults(context.Background(), req)

	if err == nil {
		t.Fatal("Expected error for invalid competition ID, got nil")
	}

	if resp != nil {
		t.Error("Expected nil response for invalid competition ID")
	}

	st, ok := status.FromError(err)
	if !ok {
		t.Fatal("Expected gRPC status error")
	}

	if st.Code() != codes.InvalidArgument {
		t.Errorf("Expected code InvalidArgument, got %v", st.Code())
	}
}

func TestGetCompetitionResults_ServiceError(t *testing.T) {
	mockService := &MockResultService{
		GetLeaderboardFunc: func(ctx context.Context, competitionID uuid.UUID, limit int32, offset int32) ([]domain.Result, int32, error) {
			return nil, 0, errors.New("database error")
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	competitionID := uuid.New()
	req := &pb.GetCompetitionResultsRequest{
		CompetitionId: competitionID.String(),
		PageSize:      10,
		PageToken:     0,
	}

	resp, err := handler.GetCompetitionResults(context.Background(), req)

	if err == nil {
		t.Fatal("Expected error from service, got nil")
	}

	if resp != nil {
		t.Error("Expected nil response on service error")
	}

	st, ok := status.FromError(err)
	if !ok {
		t.Fatal("Expected gRPC status error")
	}

	if st.Code() != codes.Internal {
		t.Errorf("Expected code Internal, got %v", st.Code())
	}
}

func TestGetCompetitionResults_EmptyLeaderboard(t *testing.T) {
	mockService := &MockResultService{
		GetLeaderboardFunc: func(ctx context.Context, competitionID uuid.UUID, limit int32, offset int32) ([]domain.Result, int32, error) {
			return []domain.Result{}, 0, nil
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	competitionID := uuid.New()
	req := &pb.GetCompetitionResultsRequest{
		CompetitionId: competitionID.String(),
		PageSize:      10,
		PageToken:     0,
	}

	resp, err := handler.GetCompetitionResults(context.Background(), req)

	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	if resp == nil {
		t.Fatal("Expected response, got nil")
	}

	if len(resp.Results) != 0 {
		t.Errorf("Expected 0 results, got %d", len(resp.Results))
	}

	if resp.TotalCount != 0 {
		t.Errorf("Expected total count 0, got %d", resp.TotalCount)
	}

	if resp.NextPageToken != 0 {
		t.Errorf("Expected next page token 0, got %d", resp.NextPageToken)
	}
}

func TestGetUserCompetitionResults_InvalidCompetitionID(t *testing.T) {
	mockService := &MockResultService{}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.GetUserCompetitionResultsRequest{
		CompetitionId: "invalid-uuid",
		UserId:        uuid.New().String(),
	}

	resp, err := handler.GetUserCompetitionResults(context.Background(), req)

	if err == nil {
		t.Fatal("Expected error for invalid competition ID, got nil")
	}

	if resp != nil {
		t.Error("Expected nil response for invalid competition ID")
	}

	st, ok := status.FromError(err)
	if !ok {
		t.Fatal("Expected gRPC status error")
	}

	if st.Code() != codes.InvalidArgument {
		t.Errorf("Expected code InvalidArgument, got %v", st.Code())
	}
}

func TestGetUserCompetitionResults_InvalidUserID(t *testing.T) {
	mockService := &MockResultService{}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.GetUserCompetitionResultsRequest{
		CompetitionId: uuid.New().String(),
		UserId:        "invalid-uuid",
	}

	resp, err := handler.GetUserCompetitionResults(context.Background(), req)

	if err == nil {
		t.Fatal("Expected error for invalid user ID, got nil")
	}

	if resp != nil {
		t.Error("Expected nil response for invalid user ID")
	}

	st, ok := status.FromError(err)
	if !ok {
		t.Fatal("Expected gRPC status error")
	}

	if st.Code() != codes.InvalidArgument {
		t.Errorf("Expected code InvalidArgument, got %v", st.Code())
	}
}

func TestGetUserCompetitionResults_NotFound(t *testing.T) {
	mockService := &MockResultService{
		GetByCompetitionAndUserFunc: func(ctx context.Context, competitionID uuid.UUID, userID uuid.UUID) (*domain.Result, error) {
			return nil, domain.ErrResultNotFound
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.GetUserCompetitionResultsRequest{
		CompetitionId: uuid.New().String(),
		UserId:        uuid.New().String(),
	}

	resp, err := handler.GetUserCompetitionResults(context.Background(), req)

	if err == nil {
		t.Fatal("Expected error for not found result, got nil")
	}

	if resp != nil {
		t.Error("Expected nil response for not found result")
	}

	st, ok := status.FromError(err)
	if !ok {
		t.Fatal("Expected gRPC status error")
	}

	if st.Code() != codes.NotFound {
		t.Errorf("Expected code NotFound, got %v", st.Code())
	}
}

func TestGetUserCompetitionResults_Success(t *testing.T) {
	rank := 1
	competitionID := uuid.New()
	userID := uuid.New()

	mockService := &MockResultService{
		GetByCompetitionAndUserFunc: func(ctx context.Context, compID uuid.UUID, uID uuid.UUID) (*domain.Result, error) {
			return &domain.Result{
				ID:            uuid.New(),
				CompetitionID: compID,
				UserID:        uID,
				Score:         95.5,
				Rank:          &rank,
				Status:        domain.ResultStatusCompleted,
			}, nil
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.GetUserCompetitionResultsRequest{
		CompetitionId: competitionID.String(),
		UserId:        userID.String(),
	}

	resp, err := handler.GetUserCompetitionResults(context.Background(), req)

	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	if resp == nil {
		t.Fatal("Expected response, got nil")
	}

	if resp.Result == nil {
		t.Fatal("Expected result, got nil")
	}

	if resp.Result.UserId != userID.String() {
		t.Errorf("Expected user ID %s, got %s", userID.String(), resp.Result.UserId)
	}

	if resp.Result.TotalScore != 95 {
		t.Errorf("Expected total score 95, got %d", resp.Result.TotalScore)
	}

	if resp.Result.OverallPosition != 1 {
		t.Errorf("Expected overall position 1, got %d", resp.Result.OverallPosition)
	}
}

func TestRecalculateResults_InvalidCompetitionID(t *testing.T) {
	mockService := &MockResultService{}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.RecalculateResultsRequest{
		CompetitionId: "invalid-uuid",
	}

	resp, err := handler.RecalculateResults(context.Background(), req)

	if err == nil {
		t.Fatal("Expected error for invalid competition ID, got nil")
	}

	if resp != nil {
		t.Error("Expected nil response for invalid competition ID")
	}

	st, ok := status.FromError(err)
	if !ok {
		t.Fatal("Expected gRPC status error")
	}

	if st.Code() != codes.InvalidArgument {
		t.Errorf("Expected code InvalidArgument, got %v", st.Code())
	}
}

func TestRecalculateResults_ServiceError(t *testing.T) {
	mockService := &MockResultService{
		RecalculateRanksFunc: func(ctx context.Context, competitionID uuid.UUID) error {
			return errors.New("recalculation failed")
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.RecalculateResultsRequest{
		CompetitionId: uuid.New().String(),
	}

	resp, err := handler.RecalculateResults(context.Background(), req)

	if err == nil {
		t.Fatal("Expected error from service, got nil")
	}

	if resp != nil {
		t.Error("Expected nil response on service error")
	}

	st, ok := status.FromError(err)
	if !ok {
		t.Fatal("Expected gRPC status error")
	}

	if st.Code() != codes.Internal {
		t.Errorf("Expected code Internal, got %v", st.Code())
	}
}

func TestRecalculateResults_Success(t *testing.T) {
	mockService := &MockResultService{
		RecalculateRanksFunc: func(ctx context.Context, competitionID uuid.UUID) error {
			return nil
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	req := &pb.RecalculateResultsRequest{
		CompetitionId: uuid.New().String(),
	}

	resp, err := handler.RecalculateResults(context.Background(), req)

	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	if resp == nil {
		t.Fatal("Expected response, got nil")
	}
}

func TestFetchUsername(t *testing.T) {
	handler := &ResultsHandler{
		userServiceAddr: "invalid-address",
	}

	// Test with invalid address - should return empty string
	username := handler.fetchUsername(context.Background(), uuid.New().String())

	if username != "" {
		t.Errorf("Expected empty username on error, got %s", username)
	}
}

func TestFetchTaskStatuses(t *testing.T) {
	handler := &ResultsHandler{
		submissionServiceAddr: "invalid-address",
	}

	// Test with invalid address - should return empty slice
	statuses := handler.fetchTaskStatuses(context.Background(), uuid.New().String(), uuid.New().String())

	if statuses == nil {
		t.Fatal("Expected empty slice, got nil")
	}

	if len(statuses) != 0 {
		t.Errorf("Expected 0 statuses on error, got %d", len(statuses))
	}
}

func TestEnrichUserResult(t *testing.T) {
	rank := 1
	result := &domain.Result{
		ID:            uuid.New(),
		CompetitionID: uuid.New(),
		UserID:        uuid.New(),
		Score:         95.5,
		Rank:          &rank,
		Status:        domain.ResultStatusCompleted,
	}

	handler := &ResultsHandler{
		userServiceAddr:       "invalid-address",
		submissionServiceAddr: "invalid-address",
		taskServiceAddr:       "invalid-address",
	}

	competitionID := uuid.New().String()
	pbResult := handler.enrichUserResult(context.Background(), result, competitionID)

	if pbResult == nil {
		t.Fatal("Expected result, got nil")
	}

	if pbResult.UserId != result.UserID.String() {
		t.Errorf("Expected user ID %s, got %s", result.UserID.String(), pbResult.UserId)
	}

	if pbResult.TotalScore != int32(result.Score) {
		t.Errorf("Expected total score %d, got %d", int32(result.Score), pbResult.TotalScore)
	}

	if pbResult.OverallPosition != int32(*result.Rank) {
		t.Errorf("Expected position %d, got %d", *result.Rank, pbResult.OverallPosition)
	}

	if pbResult.Username != "" {
		t.Errorf("Expected empty username, got %s", pbResult.Username)
	}

	if len(pbResult.TaskStatuses) != 0 {
		t.Errorf("Expected 0 task statuses, got %d", len(pbResult.TaskStatuses))
	}
}

func TestEnrichUserResult_WithoutRank(t *testing.T) {
	result := &domain.Result{
		ID:            uuid.New(),
		CompetitionID: uuid.New(),
		UserID:        uuid.New(),
		Score:         95.5,
		Rank:          nil,
		Status:        domain.ResultStatusCompleted,
	}

	handler := &ResultsHandler{
		userServiceAddr:       "invalid-address",
		submissionServiceAddr: "invalid-address",
		taskServiceAddr:       "invalid-address",
	}

	competitionID := uuid.New().String()
	pbResult := handler.enrichUserResult(context.Background(), result, competitionID)

	if pbResult == nil {
		t.Fatal("Expected result, got nil")
	}

	if pbResult.OverallPosition != 0 {
		t.Errorf("Expected position 0 for nil rank, got %d", pbResult.OverallPosition)
	}
}

func TestGetCompetitionResults_Pagination(t *testing.T) {
	rank1, rank2, rank3 := 1, 2, 3
	results := []domain.Result{
		{
			ID:            uuid.New(),
			CompetitionID: uuid.New(),
			UserID:        uuid.New(),
			Score:         100.0,
			Rank:          &rank1,
			Status:        domain.ResultStatusCompleted,
		},
		{
			ID:            uuid.New(),
			CompetitionID: uuid.New(),
			UserID:        uuid.New(),
			Score:         95.0,
			Rank:          &rank2,
			Status:        domain.ResultStatusCompleted,
		},
		{
			ID:            uuid.New(),
			CompetitionID: uuid.New(),
			UserID:        uuid.New(),
			Score:         90.0,
			Rank:          &rank3,
			Status:        domain.ResultStatusCompleted,
		},
	}

	mockService := &MockResultService{
		GetLeaderboardFunc: func(ctx context.Context, competitionID uuid.UUID, limit int32, offset int32) ([]domain.Result, int32, error) {
			return results, 25, nil
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	competitionID := uuid.New()
	req := &pb.GetCompetitionResultsRequest{
		CompetitionId: competitionID.String(),
		PageSize:      10,
		PageToken:     0,
	}

	resp, err := handler.GetCompetitionResults(context.Background(), req)

	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	if resp == nil {
		t.Fatal("Expected response, got nil")
	}

	if len(resp.Results) != 3 {
		t.Errorf("Expected 3 results, got %d", len(resp.Results))
	}

	if resp.TotalCount != 25 {
		t.Errorf("Expected total count 25, got %d", resp.TotalCount)
	}

	if resp.NextPageToken != 1 {
		t.Errorf("Expected next page token 1, got %d", resp.NextPageToken)
	}
}

func TestGetCompetitionResults_LastPage(t *testing.T) {
	rank1 := 1
	results := []domain.Result{
		{
			ID:            uuid.New(),
			CompetitionID: uuid.New(),
			UserID:        uuid.New(),
			Score:         100.0,
			Rank:          &rank1,
			Status:        domain.ResultStatusCompleted,
		},
	}

	mockService := &MockResultService{
		GetLeaderboardFunc: func(ctx context.Context, competitionID uuid.UUID, limit int32, offset int32) ([]domain.Result, int32, error) {
			return results, 1, nil
		},
	}
	handler := NewResultsHandler(mockService, "", "", "")

	competitionID := uuid.New()
	req := &pb.GetCompetitionResultsRequest{
		CompetitionId: competitionID.String(),
		PageSize:      10,
		PageToken:     0,
	}

	resp, err := handler.GetCompetitionResults(context.Background(), req)

	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	if resp == nil {
		t.Fatal("Expected response, got nil")
	}

	if resp.NextPageToken != 0 {
		t.Errorf("Expected next page token 0 on last page, got %d", resp.NextPageToken)
	}
}