import 'dart:convert';
import 'package:crypto/crypto.dart';
import 'package:drift/drift.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../database/app_database.dart';
import 'database_provider.dart';

// ── Insight type enum ─────────────────────────────────────────────────────────

enum InsightType { weekly, monthly, query }

// ── Cached insight lookup ─────────────────────────────────────────────────────

final cachedInsightProvider =
    FutureProvider.autoDispose.family<LlmInsight?, String>((ref, promptHash) {
  return ref.watch(insightDaoProvider).getCached(promptHash);
});

// ── Insight notifier — triggers generation and caches results ─────────────────

class InsightNotifier extends Notifier<AsyncValue<String?>> {
  @override
  AsyncValue<String?> build() => const AsyncData(null);

  String _hashPrompt(String prompt) =>
      sha256.convert(utf8.encode(prompt)).toString();

  Future<void> generateInsight({
    required String prompt,
    required InsightType type,
    DateTime? rangeStart,
    DateTime? rangeEnd,
  }) async {
    state = const AsyncLoading();

    final hash = _hashPrompt(prompt);
    final dao = ref.read(insightDaoProvider);

    final cached = await dao.getCached(hash);
    if (!ref.mounted) return;
    if (cached != null) {
      state = AsyncData(cached.responseText);
      return;
    }

    // Generation happens in LlmNotifier (see llm_provider.dart)
    state = const AsyncData(null);
  }

  Future<void> saveInsight({
    required String promptHash,
    required String responseText,
    required InsightType type,
    DateTime? rangeStart,
    DateTime? rangeEnd,
  }) async {
    await ref.read(insightDaoProvider).upsertInsight(
          LlmInsightsCompanion.insert(
            type: type.name,
            promptHash: promptHash,
            responseText: responseText,
            rangeStart: Value(rangeStart),
            rangeEnd: Value(rangeEnd),
          ),
        );
    if (!ref.mounted) return;
    state = AsyncData(responseText);
  }

  void clear() => state = const AsyncData(null);
}

final insightNotifierProvider =
    NotifierProvider.autoDispose<InsightNotifier, AsyncValue<String?>>(
        InsightNotifier.new);