//! App state: the open [`Catalog`] and fuzzy [`NameIndex`], plus the db paths.

use std::path::PathBuf;

use mtgc_core::{Catalog, NameIndex};

/// Managed application state, guarded by a `Mutex` in Tauri's state store.
pub struct AppState {
    pub library_path: PathBuf,
    pub reference_path: PathBuf,
    pub catalog: Option<Catalog>,
    pub index: Option<NameIndex>,
}

impl AppState {
    /// Initialize with default paths under the app data dir and open the catalog
    /// if a reference db already exists.
    pub fn new(data_dir: PathBuf) -> Self {
        let mut s = Self {
            library_path: data_dir.join("library.db"),
            reference_path: data_dir.join("reference.db"),
            catalog: None,
            index: None,
        };
        // Best-effort open; failures just leave the catalog unloaded.
        let _ = s.reopen();
        s
    }

    /// (Re)open the catalog + rebuild the name index. Only opens when a reference
    /// db exists — attaching a non-existent file would create an empty (tableless)
    /// db and make every query fail.
    pub fn reopen(&mut self) -> Result<(), String> {
        if self.reference_path.exists() {
            let catalog = Catalog::open(&self.library_path, &self.reference_path)
                .map_err(|e| e.to_string())?;
            let index = catalog.build_name_index().map_err(|e| e.to_string())?;
            self.index = Some(index);
            self.catalog = Some(catalog);
        } else {
            self.catalog = None;
            self.index = None;
        }
        Ok(())
    }

    pub fn catalog(&self) -> Result<&Catalog, String> {
        self.catalog
            .as_ref()
            .ok_or_else(|| "Card data not loaded yet — click 'Download card data'.".to_string())
    }

    pub fn index(&self) -> Result<&NameIndex, String> {
        self.index
            .as_ref()
            .ok_or_else(|| "Card data not loaded yet — click 'Download card data'.".to_string())
    }
}