use sea_orm_migration::prelude::*;

#[derive(DeriveMigrationName)]
pub struct Migration;

#[async_trait::async_trait]
impl MigrationTrait for Migration {
    async fn up(&self, manager: &SchemaManager) -> Result<(), DbErr> {
        let conn = manager.get_connection();
        conn.execute_unprepared(
            "DELETE FROM artists WHERE id NOT IN (
                SELECT DISTINCT artist_id FROM tracks WHERE artist_id IS NOT NULL
                UNION SELECT DISTINCT artist_id FROM wanted_items WHERE artist_id IS NOT NULL
                UNION SELECT DISTINCT artist_id FROM albums WHERE artist_id IS NOT NULL
            )",
        )
        .await?;
        Ok(())
    }

    async fn down(&self, _manager: &SchemaManager) -> Result<(), DbErr> {
        // Orphaned artists cannot be restored
        Ok(())
    }
}