-- name: CreateLesson :one
INSERT INTO lessons (module_id, title, video_url, thumbnail, description, sort_order)
SELECT
    $1,
    $2,
    $3,
    $4,
    $5,
    coalesce((
        SELECT
            max(l.sort_order)
        FROM lessons l
        WHERE
            l.module_id = $1), 0) + 1
RETURNING
    *;

-- name: GetLessonByID :one
SELECT *
FROM lessons
WHERE id = $1;

-- name: ListLessonsByModuleID :many
SELECT
    COUNT(*) OVER () AS total_count,
    l.id,
    l.module_id,
    l.title,
    l.video_url,
    l.thumbnail,
    l.description,
    l.sort_order,
    l.created_at,
    l.updated_at
FROM
    lessons l
WHERE
    l.module_id = $1
ORDER BY
    l.sort_order ASC,
    l.id ASC
LIMIT $2
OFFSET $3;

-- name: UpdateLesson :one
UPDATE lessons
SET
    title = COALESCE(sqlc.narg('title')::varchar, title),
    video_url = COALESCE(sqlc.narg('video_url')::text, video_url),
    thumbnail = COALESCE(sqlc.narg('thumbnail')::text, thumbnail),
    description = COALESCE(sqlc.narg('description')::text, description),
    sort_order = coalesce(sqlc.narg('sort_order')::int, sort_order),
    updated_at = CURRENT_TIMESTAMP
WHERE
    id = sqlc.arg('id')
RETURNING
    *;

-- name: DeleteLesson :exec
DELETE FROM lessons
WHERE id = $1;