// error
#[derive(thiserror::Error)]
// the rest
#[derive(Debug)]
pub enum Error {
    #[error("Unique constraint on primary key")]
    UniqueConstraintPrimaryKey,

    #[error("Unique constraint on key {0}")]
    UniqueConstraint(String),

    #[error("{0}")]
    Database(#[from] sqlx::Error),
}

fn parse_unique_constraint(msg: &str) -> Option<String> {
    // Format will be "table.column"
    let mut constraint = msg.strip_prefix("UNIQUE constraint failed: ")?.split('.');

    // Extract "column" (which is the second value)
    let _table = constraint.next()?;
    let column = constraint.next()?;

    Some(column.to_string())
}

pub fn handle_error(e: sqlx::Error) -> Error {
    match e.as_database_error() {
        Some(database_error) => match database_error.code() {
            // List of all codes: https://www.sqlite.org/rescode.html
            Some(code) => match code.as_ref() {
                "1555" => Error::UniqueConstraintPrimaryKey,

                // Attempt to extract unique constraint column
                "2067" => match parse_unique_constraint(database_error.message()) {
                    Some(column) => Error::UniqueConstraint(column),
                    None => Error::Database(e),
                },
                _ => Error::Database(e),
            },
            None => Error::Database(e),
        },
        None => Error::Database(e),
    }
}