houhou/src-tauri/src/kanji.rs

use sqlx::{Row, SqlitePool};
use tauri::State;

pub struct KanjiDb(pub SqlitePool);

#[derive(Debug, Derivative, Serialize, Deserialize)]
#[derivative(Default)]
pub struct GetKanjiOptions {
  #[derivative(Default(value = "10"))]
  how_many: u32,
}

#[derive(Debug, Serialize, Deserialize)]
pub struct GetKanjiResult {
  count: u32,
  kanji: Vec<String>,
}

#[tauri::command]
pub async fn get_kanji(
  state: State<'_, KanjiDb>,
  options: Option<GetKanjiOptions>,
) -> Result<GetKanjiResult, ()> {
  let opts = options.unwrap_or_default();

  let result = sqlx::query(
    r#"SELECT * FROM KanjiSet 
    LEFT JOIN KanjiMeaningSet ON KanjiSet.ID = KanjiMeaningSet.Kanji_ID
    WHERE MostUsedRank IS NOT NULL
    ORDER BY MostUsedRank
    LIMIT ?"#,
  )
  .bind(opts.how_many)
  .fetch_all(&state.0)
  .await
  .map_err(|_| ())?;

  let kanji = result.into_iter().map(|row| row.get("Character")).collect();

  let count = sqlx::query("SELECT COUNT(*) FROM KanjiSet")
    .fetch_one(&state.0)
    .await
    .map_err(|_| ())?;
  let count = count.try_get(0).map_err(|_| ())?;

  Ok(GetKanjiResult { kanji, count })
}