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 lessonToDomain(l dbgen.Lesson) domain.Lesson {
	out := domain.Lesson{
		ID:       l.ID,
		ModuleID: l.ModuleID,
		Title:    l.Title,
	}
	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) CreateLesson(ctx context.Context, moduleID int64, input domain.CreateLessonInput) (domain.Lesson, error) {
	l, err := s.queries.CreateLesson(ctx, dbgen.CreateLessonParams{
		ModuleID:    moduleID,
		Title:       input.Title,
		VideoUrl:    toPgText(input.VideoURL),
		Thumbnail:   toPgText(input.Thumbnail),
		Description: toPgText(input.Description),
	})
	if err != nil {
		return domain.Lesson{}, err
	}
	return lessonToDomain(l), nil
}

func (s *Store) GetLessonByID(ctx context.Context, id int64) (domain.Lesson, error) {
	l, err := s.queries.GetLessonByID(ctx, id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.Lesson{}, pgx.ErrNoRows
		}
		return domain.Lesson{}, err
	}
	return lessonToDomain(l), nil
}

func (s *Store) ListLessonsByModuleID(ctx context.Context, moduleID int64, limit, offset int32) ([]domain.Lesson, int64, error) {
	rows, err := s.queries.ListLessonsByModuleID(ctx, dbgen.ListLessonsByModuleIDParams{
		ModuleID: moduleID,
		Limit:    limit,
		Offset:   offset,
	})
	if err != nil {
		return nil, 0, err
	}
	if len(rows) == 0 {
		return []domain.Lesson{}, 0, nil
	}
	var total int64
	out := make([]domain.Lesson, 0, len(rows))
	for i, r := range rows {
		if i == 0 {
			total = r.TotalCount
		}
		out = append(out, lessonToDomain(dbgen.Lesson{
			ID:          r.ID,
			ModuleID:    r.ModuleID,
			Title:       r.Title,
			VideoUrl:    r.VideoUrl,
			Thumbnail:   r.Thumbnail,
			Description: r.Description,
			CreatedAt:   r.CreatedAt,
			UpdatedAt:   r.UpdatedAt,
		}))
	}
	return out, total, nil
}

func (s *Store) UpdateLesson(ctx context.Context, id int64, input domain.UpdateLessonInput) (domain.Lesson, 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.UpdateLesson(ctx, dbgen.UpdateLessonParams{
		ID:          id,
		Title:       titleText,
		VideoUrl:    optionalTextUpdate(input.VideoURL),
		Thumbnail:   optionalTextUpdate(input.Thumbnail),
		Description: optionalTextUpdate(input.Description),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.Lesson{}, pgx.ErrNoRows
		}
		return domain.Lesson{}, err
	}
	return lessonToDomain(l), nil
}

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