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 moduleToDomain(m dbgen.Module) domain.Module {
	out := domain.Module{
		ID:        m.ID,
		ProgramID: m.ProgramID,
		CourseID:  m.CourseID,
		Name:      m.Name,
	}
	out.Description = fromPgText(m.Description)
	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) CreateModule(ctx context.Context, programID, courseID int64, input domain.CreateModuleInput) (domain.Module, error) {
	m, err := s.queries.CreateModule(ctx, dbgen.CreateModuleParams{
		ProgramID:   programID,
		CourseID:    courseID,
		Name:        input.Name,
		Description: toPgText(input.Description),
		Icon:        toPgText(input.Icon),
	})
	if err != nil {
		return domain.Module{}, err
	}
	return moduleToDomain(m), nil
}

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

func (s *Store) ListModulesByProgramAndCourse(ctx context.Context, programID, courseID int64, limit, offset int32) ([]domain.Module, int64, error) {
	rows, err := s.queries.ListModulesByProgramAndCourse(ctx, dbgen.ListModulesByProgramAndCourseParams{
		ProgramID: programID,
		CourseID:  courseID,
		Limit:     limit,
		Offset:    offset,
	})
	if err != nil {
		return nil, 0, err
	}
	if len(rows) == 0 {
		return []domain.Module{}, 0, nil
	}
	var total int64
	out := make([]domain.Module, 0, len(rows))
	for i, r := range rows {
		if i == 0 {
			total = r.TotalCount
		}
		out = append(out, moduleToDomain(dbgen.Module{
			ID:          r.ID,
			ProgramID:   r.ProgramID,
			CourseID:    r.CourseID,
			Name:        r.Name,
			Description: r.Description,
			Icon:        r.Icon,
			CreatedAt:   r.CreatedAt,
			UpdatedAt:   r.UpdatedAt,
		}))
	}
	return out, total, nil
}

func (s *Store) UpdateModule(ctx context.Context, id int64, input domain.UpdateModuleInput) (domain.Module, 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.UpdateModule(ctx, dbgen.UpdateModuleParams{
		ID:          id,
		Name:        nameText,
		Description: optionalTextUpdate(input.Description),
		Icon:        optionalTextUpdate(input.Icon),
	})
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return domain.Module{}, pgx.ErrNoRows
		}
		return domain.Module{}, err
	}
	return moduleToDomain(m), nil
}

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