import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../services/ocr_service.dart';
import '../services/pdf_text_indexer.dart';
import '../services/pdfrx_page_text_source.dart';

enum OcrStatus { none, processing, done, failed }

final ocrServiceProvider = Provider<OcrService>((ref) => OcrService());

/// The import-time PDF document-body indexer, wired to the pdfrx-backed embedded
/// text + page-render OCR sources (see [PdfrxPageTextSource]). The import flow
/// fires [PdfTextIndexer.indexPdf] (fire-and-forget) so a scanned PDF's text
/// becomes searchable in the background without blocking the editor opening.
final pdfTextIndexerProvider = Provider<PdfTextIndexer>(
  (ref) => PdfTextIndexer(
    loadEmbeddedText: PdfrxPageTextSource.loadEmbeddedText,
    ocrPages: PdfrxPageTextSource.ocrPages,
  ),
);

/// Tracks local OCR processing status per note ID.
///
/// This map only ever holds an entry per note that has had OCR triggered in
/// the current session. To keep it from growing without bound over a long
/// session, prune terminal/stale entries via [OcrStatusX] (e.g. remove an
/// entry once its result has been surfaced, or call [OcrStatusX.pruneOcr]
/// after a sweep). Kept as a [StateProvider] so existing call sites that
/// assign `ocrStatusProvider.notifier.state` continue to work.
final ocrStatusProvider = StateProvider<Map<String, OcrStatus>>((ref) => {});

/// Pruning helpers for [ocrStatusProvider] that keep its backing map bounded.
extension OcrStatusX on Ref {
  /// Removes the tracked status for [noteId] (e.g. when its note is deleted
  /// or its result has been consumed by the UI).
  void clearOcr(String noteId) {
    final current = read(ocrStatusProvider);
    if (!current.containsKey(noteId)) return;
    read(ocrStatusProvider.notifier).state = Map<String, OcrStatus>.from(
      current,
    )..remove(noteId);
  }

  /// Drops all completed/failed entries, keeping only in-flight work so the
  /// map stays bounded.
  void pruneOcr() {
    final current = read(ocrStatusProvider);
    final next = <String, OcrStatus>{
      for (final entry in current.entries)
        if (entry.value == OcrStatus.processing) entry.key: entry.value,
    };
    if (next.length != current.length) {
      read(ocrStatusProvider.notifier).state = next;
    }
  }
}