use crate::database::Database;
use crate::error::Result;
use crate::metadata::DBMetadata;

pub trait Migration {
    fn up(&self, db: &Database) -> Result<()>;
    fn down(&self, db: &Database) -> Result<()>;
    fn version(&self) -> u64;
}

#[derive(Debug, Clone, Eq, PartialEq)]
pub enum Direction {
    Up,
    Down,
}

pub fn do_migration<T: Migration>(db: &Database, migration: T, direction: Direction) -> Result<()> {
    if direction == Direction::Up {
        migration.up(db)?;
    } else {
        migration.down(db)?;
    }

    let metadata = DBMetadata {
        id: None,
        version: migration.version(),
    };

    db.insert(metadata)?;

    Ok(())
}