app-api/internal/repository/model.go

package repository

import (
	"context"
	"database/sql"
	"fmt"
	"strings"

	"github.com/luxsin/app-api/internal/model"
)

type ModelRepository struct {
	db *sql.DB
}

func NewModelRepository(db *sql.DB) *ModelRepository {
	return &ModelRepository{db: db}
}

func (r *ModelRepository) List(ctx context.Context, brandName, modelName string) ([]model.Model, error) {
	brandName = strings.TrimSpace(brandName)
	modelName = strings.TrimSpace(modelName)

	const baseQuery = `SELECT id, brand_name, name, form, rig, source, eq_key, create_at FROM model`

	var (
		query string
		args  []any
	)

	switch {
	case brandName != "":
		query = baseQuery + " WHERE brand_name = ? ORDER BY name ASC"
		args = []any{brandName}
	case modelName != "":
		query = baseQuery + " WHERE name LIKE ? ORDER BY name ASC"
		args = []any{"%" + modelName + "%"}
	default:
		return []model.Model{}, nil
	}

	rows, err := r.db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("query model: %w", err)
	}
	defer rows.Close()

	list := make([]model.Model, 0)
	for rows.Next() {
		m, err := scanModel(rows)
		if err != nil {
			return nil, err
		}
		list = append(list, m)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("iterate model: %w", err)
	}

	return list, nil
}

func scanModel(rows *sql.Rows) (model.Model, error) {
	var m model.Model
	var form, rig, source, eqKey sql.NullString

	if err := rows.Scan(
		&m.ID,
		&m.BrandName,
		&m.Name,
		&form,
		&rig,
		&source,
		&eqKey,
		&m.CreateAt,
	); err != nil {
		return model.Model{}, fmt.Errorf("scan model: %w", err)
	}

	m.Form = nullStringPtr(form)
	m.Rig = nullStringPtr(rig)
	m.Source = nullStringPtr(source)
	m.EqKey = nullStringPtr(eqKey)

	return m, nil
}

func nullStringPtr(ns sql.NullString) *string {
	if !ns.Valid {
		return nil
	}
	s := ns.String
	return &s
}