package repository

import (
	"context"
	"errors"

	dbgen "Yimaru-Backend/gen/db"
	"Yimaru-Backend/internal/domain"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgtype"
)

func examPrepLessonToDomain(l dbgen.ExamPrepUnitModuleLesson) domain.ExamPrepLesson {
	out := domain.ExamPrepLesson{
		ID:           l.ID,
		UnitModuleID: l.UnitModuleID,
		Title:        l.Title,
		SortOrder:    int(l.SortOrder),
	}
	out.VideoURL = fromPgText(l.VideoUrl)
	out.Thumbnail = fromPgText(l.Thumbnail)
	out.Description = fromPgText(l.Description)
	out.CreatedAt = l.CreatedAt.Time
	if l.UpdatedAt.Valid {
		t := l.UpdatedAt.Time
		out.UpdatedAt = &t
	}
	return out
}

func (s *Store) CreateExamPrepUnitModuleLesson(ctx context.Context, unitModuleID int64, input domain.CreateExamPrepLessonInput) (domain.ExamPrepLesson, error) {
	l, err := s.queries.ExamPrepCreateUnitModuleLesson(ctx, dbgen.ExamPrepCreateUnitModuleLessonParams{
		UnitModuleID: unitModuleID,
		Title:        input.Title,
		VideoUrl:     toPgText(input.VideoURL),
		Thumbnail:    toPgText(input.Thumbnail),
		Description:  toPgText(input.Description),
	})
	if err != nil {
		return domain.ExamPrepLesson{}, err
	}
	return examPrepLessonToDomain(l), nil
}

func (s *Store) GetExamPrepUnitModuleLessonByID(ctx context.Context, id int64) (domain.ExamPrepLesson, error) {
	l, err := s.queries.ExamPrepGetUnitModuleLessonByID(ctx, id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.ExamPrepLesson{}, pgx.ErrNoRows
		}
		return domain.ExamPrepLesson{}, err
	}
	out := examPrepLessonToDomain(dbgen.ExamPrepUnitModuleLesson{
		ID:           l.ID,
		UnitModuleID: l.UnitModuleID,
		Title:        l.Title,
		VideoUrl:     l.VideoUrl,
		Thumbnail:    l.Thumbnail,
		Description:  l.Description,
		SortOrder:    l.SortOrder,
		CreatedAt:    l.CreatedAt,
		UpdatedAt:    l.UpdatedAt,
	})
	out.HasPractice = l.HasPractice
	return out, nil
}

func (s *Store) ListExamPrepUnitModuleLessonsByUnitModuleID(ctx context.Context, unitModuleID int64, limit, offset int32) ([]domain.ExamPrepLesson, int64, error) {
	rows, err := s.queries.ExamPrepListUnitModuleLessonsByUnitModuleID(ctx, dbgen.ExamPrepListUnitModuleLessonsByUnitModuleIDParams{
		UnitModuleID: unitModuleID,
		Limit:        limit,
		Offset:       offset,
	})
	if err != nil {
		return nil, 0, err
	}
	if len(rows) == 0 {
		return []domain.ExamPrepLesson{}, 0, nil
	}
	var total int64
	out := make([]domain.ExamPrepLesson, 0, len(rows))
	for i, r := range rows {
		if i == 0 {
			total = r.TotalCount
		}
		item := examPrepLessonToDomain(dbgen.ExamPrepUnitModuleLesson{
			ID:           r.ID,
			UnitModuleID: r.UnitModuleID,
			Title:        r.Title,
			VideoUrl:     r.VideoUrl,
			Thumbnail:    r.Thumbnail,
			Description:  r.Description,
			SortOrder:    r.SortOrder,
			CreatedAt:    r.CreatedAt,
			UpdatedAt:    r.UpdatedAt,
		})
		item.HasPractice = r.HasPractice
		out = append(out, item)
	}
	return out, total, nil
}

func (s *Store) ListExamPrepUnitModuleLessonIDsByUnitModule(ctx context.Context, unitModuleID int64) ([]int64, error) {
	return s.queries.ExamPrepListUnitModuleLessonIDsByUnitModule(ctx, unitModuleID)
}

func (s *Store) UpdateExamPrepUnitModuleLesson(ctx context.Context, id int64, input domain.UpdateExamPrepLessonInput) (domain.ExamPrepLesson, error) {
	var titleText pgtype.Text
	if input.Title != nil {
		titleText = pgtype.Text{String: *input.Title, Valid: true}
	} else {
		titleText = pgtype.Text{Valid: false}
	}
	l, err := s.queries.ExamPrepUpdateUnitModuleLesson(ctx, dbgen.ExamPrepUpdateUnitModuleLessonParams{
		ID:           id,
		Title:        titleText,
		VideoUrl:     optionalTextUpdate(input.VideoURL),
		Thumbnail:    optionalTextUpdate(input.Thumbnail),
		Description:  optionalTextUpdate(input.Description),
		SortOrder:    optionalInt4Update(input.SortOrder),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.ExamPrepLesson{}, pgx.ErrNoRows
		}
		return domain.ExamPrepLesson{}, err
	}
	return examPrepLessonToDomain(l), nil
}

func (s *Store) DeleteExamPrepUnitModuleLesson(ctx context.Context, id int64) error {
	return s.queries.ExamPrepDeleteUnitModuleLesson(ctx, id)
}