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 examPrepModuleToDomain(m dbgen.ExamPrepUnitModule) domain.ExamPrepModule {
	out := domain.ExamPrepModule{
		ID:        m.ID,
		UnitID:    m.UnitID,
		Name:      m.Name,
		SortOrder: int(m.SortOrder),
	}
	out.Description = fromPgText(m.Description)
	out.Thumbnail = fromPgText(m.Thumbnail)
	out.Icon = fromPgText(m.Icon)
	out.CreatedAt = m.CreatedAt.Time
	if m.UpdatedAt.Valid {
		t := m.UpdatedAt.Time
		out.UpdatedAt = &t
	}
	return out
}

func (s *Store) CreateExamPrepUnitModule(ctx context.Context, unitID int64, input domain.CreateExamPrepModuleInput) (domain.ExamPrepModule, error) {
	m, err := s.queries.ExamPrepCreateUnitModule(ctx, dbgen.ExamPrepCreateUnitModuleParams{
		UnitID:      unitID,
		Name:        input.Name,
		Description: toPgText(input.Description),
		Thumbnail:   toPgText(input.Thumbnail),
		Icon:        toPgText(input.Icon),
	})
	if err != nil {
		return domain.ExamPrepModule{}, err
	}
	return examPrepModuleToDomain(m), nil
}

func (s *Store) GetExamPrepUnitModuleByID(ctx context.Context, id int64) (domain.ExamPrepModule, error) {
	m, err := s.queries.ExamPrepGetUnitModuleByID(ctx, id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.ExamPrepModule{}, pgx.ErrNoRows
		}
		return domain.ExamPrepModule{}, err
	}
	return examPrepModuleToDomain(m), nil
}

func (s *Store) ListExamPrepUnitModulesByUnit(ctx context.Context, unitID int64, limit, offset int32) ([]domain.ExamPrepModule, int64, error) {
	rows, err := s.queries.ExamPrepListUnitModulesByUnit(ctx, dbgen.ExamPrepListUnitModulesByUnitParams{
		UnitID: unitID,
		Limit:  limit,
		Offset: offset,
	})
	if err != nil {
		return nil, 0, err
	}
	if len(rows) == 0 {
		return []domain.ExamPrepModule{}, 0, nil
	}
	var total int64
	out := make([]domain.ExamPrepModule, 0, len(rows))
	for i, r := range rows {
		if i == 0 {
			total = r.TotalCount
		}
		item := examPrepModuleToDomain(dbgen.ExamPrepUnitModule{
			ID:          r.ID,
			UnitID:      r.UnitID,
			Name:        r.Name,
			Description: r.Description,
			Thumbnail:   r.Thumbnail,
			Icon:        r.Icon,
			SortOrder:   r.SortOrder,
			CreatedAt:   r.CreatedAt,
			UpdatedAt:   r.UpdatedAt,
		})
		item.LessonsCount = &r.LessonsCount
		item.PracticesCount = &r.PracticesCount
		out = append(out, item)
	}
	return out, total, nil
}

func (s *Store) ListExamPrepUnitModuleIDsByUnit(ctx context.Context, unitID int64) ([]int64, error) {
	return s.queries.ExamPrepListUnitModuleIDsByUnit(ctx, unitID)
}

func (s *Store) UpdateExamPrepUnitModule(ctx context.Context, id int64, input domain.UpdateExamPrepModuleInput) (domain.ExamPrepModule, error) {
	var nameText pgtype.Text
	if input.Name != nil {
		nameText = pgtype.Text{String: *input.Name, Valid: true}
	} else {
		nameText = pgtype.Text{Valid: false}
	}
	m, err := s.queries.ExamPrepUpdateUnitModule(ctx, dbgen.ExamPrepUpdateUnitModuleParams{
		ID:          id,
		Name:        nameText,
		Description: optionalTextUpdate(input.Description),
		Thumbnail:   optionalTextUpdate(input.Thumbnail),
		Icon:        optionalTextUpdate(input.Icon),
		SortOrder:   optionalInt4Update(input.SortOrder),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.ExamPrepModule{}, pgx.ErrNoRows
		}
		return domain.ExamPrepModule{}, err
	}
	return examPrepModuleToDomain(m), nil
}

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