//! Accent- and case-insensitive text matching.

/// Lowercase `s` and strip accents ("Lim-Dûl's Cohort" → "lim-dul's cohort"),
/// so typed text matches card names however they're accented. Uses the same
/// per-character table as the fuzzy name search's own normalization, so both
/// search paths agree on what counts as a match.
pub fn fold(s: &str) -> String {
    s.chars()
        .map(|c| nucleo::chars::normalize(nucleo::chars::to_lower_case(c)))
        .collect()
}

/// Register [`fold`] as the SQL function `fold(text)` on `conn`, so queries
/// can compare `fold(oc.name)` against a folded pattern.
pub(crate) fn register_sql_fold(conn: &rusqlite::Connection) -> rusqlite::Result<()> {
    use rusqlite::functions::FunctionFlags;
    conn.create_scalar_function(
        "fold",
        1,
        FunctionFlags::SQLITE_UTF8 | FunctionFlags::SQLITE_DETERMINISTIC,
        |ctx| {
            Ok(match ctx.get::<Option<String>>(0)? {
                Some(s) => Some(fold(&s)),
                None => None,
            })
        },
    )
}

#[cfg(test)]
mod tests {
    use super::fold;

    #[test]
    fn folds_case_and_accents_and_leaves_ascii_alone() {
        assert_eq!(fold("Lim-Dûl's Cohort"), "lim-dul's cohort");
        assert_eq!(fold("Éowyn, Lady of Rohan"), "eowyn, lady of rohan");
        assert_eq!(fold("Hamato Ninpō"), "hamato ninpo");
        assert_eq!(fold("Jakub Šlemr"), "jakub slemr");
        assert_eq!(fold("Lightning Bolt"), "lightning bolt");
    }
}