//! Fallible row decoding shared by connection and transaction queries.

use rusqlite::{Connection, OptionalExtension, Params, Row};

use crate::error::{Error, Result};

// Read explicitly indexed fields in declaration order; Rust infers their types.
macro_rules! sql_row {
    ($row:ident => $kind:ident { $($field:ident: $index:literal),+ $(,)? }) => {
        $kind { $($field: $row.get($index)?),+ }
    };
}
pub(crate) use sql_row;

pub(crate) fn constraint_conflict(error: rusqlite::Error, message: &str) -> Error {
    if error.sqlite_error_code() == Some(rusqlite::ErrorCode::ConstraintViolation) {
        Error::Conflict(message.to_owned())
    } else {
        Error::Database(error)
    }
}

pub(crate) fn query<T>(
    connection: &Connection,
    sql: &str,
    params: impl Params,
    decode: impl FnMut(&Row<'_>) -> Result<T>,
) -> Result<Vec<T>> {
    connection
        .prepare(sql)?
        .query_and_then(params, decode)?
        .collect()
}

pub(crate) fn query_optional<T>(
    connection: &Connection,
    sql: &str,
    params: impl Params,
    decode: impl FnOnce(&Row<'_>) -> Result<T>,
) -> Result<Option<T>> {
    connection
        .query_row(sql, params, |row| Ok(decode(row)))
        .optional()?
        .transpose()
}

#[cfg(test)]
mod tests;