import 'dart:convert';
import 'dart:typed_data';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_functions/cloud_functions.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../core/firebase/firebase_providers.dart';
import '../../household/data/household_providers.dart';

/// Ergebnis der KI-Krankheits-Diagnose (Cloud Function diagnosePlant).
class DiagnosisResult {
  const DiagnosisResult({
    required this.healthy,
    required this.matchesSpecies,
    required this.summary,
    required this.details,
    required this.treatment,
    required this.prevention,
  });

  final bool healthy;

  /// false, wenn das Foto laut KI eindeutig eine andere Pflanzenart zeigt
  /// als die im Profil hinterlegte (z. B. versehentlich falsches Foto).
  final bool matchesSpecies;

  final String summary;
  final String details;
  final String treatment;
  final String prevention;
}

/// Ein gespeicherter Eintrag der Untersuchungshistorie
/// (households/{id}/plants/{id}/diagnoses).
class PlantDiagnosisEntry {
  const PlantDiagnosisEntry({
    required this.id,
    required this.createdAt,
    required this.result,
  });

  final String id;

  /// null, solange der Server-Zeitstempel noch nicht bestätigt ist.
  final DateTime? createdAt;

  final DiagnosisResult result;
}

class PlantDiagnosisService {
  PlantDiagnosisService(
    this._functionsGetter,
    this._firestore,
    this._householdIdGetter,
  );

  // Lazy, damit Widget-Tests ohne initialisiertes Firebase auskommen —
  // FirebaseFunctions.instanceFor wirft sonst schon beim Erzeugen.
  final FirebaseFunctions Function() _functionsGetter;
  final FirebaseFirestore _firestore;
  final String? Function() _householdIdGetter;

  CollectionReference<Map<String, dynamic>> _diagnosesRef(
    String householdId,
    String plantId,
  ) {
    return _firestore
        .collection('households')
        .doc(householdId)
        .collection('plants')
        .doc(plantId)
        .collection('diagnoses');
  }

  /// Schickt das Foto an die Cloud Function (Claude) – dauert einige Sekunden.
  /// [speciesHint] ist die bekannte Art der Pflanze und hilft der Diagnose.
  Future<DiagnosisResult> diagnose(
    Uint8List imageBytes, {
    String? speciesHint,
  }) async {
    final callable = _functionsGetter().httpsCallable('diagnosePlant');
    final response = await callable.call<Map<String, dynamic>>({
      'imageBase64': base64Encode(imageBytes),
      if (speciesHint != null && speciesHint.trim().isNotEmpty)
        'speciesHint': speciesHint.trim(),
    });
    final data = response.data;
    return DiagnosisResult(
      healthy: data['healthy'] as bool? ?? false,
      matchesSpecies: data['matchesSpecies'] as bool? ?? true,
      summary: data['summary'] as String? ?? '',
      details: data['details'] as String? ?? '',
      treatment: data['treatment'] as String? ?? '',
      prevention: data['prevention'] as String? ?? '',
    );
  }

  /// Legt einen Eintrag in der Untersuchungshistorie der Pflanze an.
  Future<void> saveDiagnosis(String plantId, DiagnosisResult result) async {
    final householdId = _householdIdGetter();
    if (householdId == null) return;
    await _diagnosesRef(householdId, plantId).add({
      'healthy': result.healthy,
      'matchesSpecies': result.matchesSpecies,
      'summary': result.summary,
      'details': result.details,
      'treatment': result.treatment,
      'prevention': result.prevention,
      'createdAt': FieldValue.serverTimestamp(),
    });
  }

  /// Entfernt einen Eintrag aus der Historie (nur volle Mitglieder).
  Future<void> deleteDiagnosis(String plantId, String diagnosisId) async {
    final householdId = _householdIdGetter();
    if (householdId == null) return;
    await _diagnosesRef(householdId, plantId).doc(diagnosisId).delete();
  }
}

final plantDiagnosisServiceProvider = Provider<PlantDiagnosisService>((ref) {
  return PlantDiagnosisService(
    () => FirebaseFunctions.instanceFor(region: 'europe-west3'),
    ref.watch(firestoreProvider),
    () => ref.read(householdIdProvider).value,
  );
});

/// Untersuchungshistorie einer Pflanze, neueste zuerst, live aus Firestore.
final plantDiagnosesProvider =
    StreamProvider.family<List<PlantDiagnosisEntry>, String>((ref, plantId) {
  final householdId = ref.watch(householdIdProvider).value;
  if (householdId == null) return Stream.value(const []);

  return ref
      .watch(firestoreProvider)
      .collection('households')
      .doc(householdId)
      .collection('plants')
      .doc(plantId)
      .collection('diagnoses')
      .orderBy('createdAt', descending: true)
      .snapshots()
      .map((snapshot) => [
            for (final doc in snapshot.docs)
              PlantDiagnosisEntry(
                id: doc.id,
                createdAt: (doc.data()['createdAt'] as Timestamp?)?.toDate(),
                result: DiagnosisResult(
                  healthy: doc.data()['healthy'] as bool? ?? false,
                  matchesSpecies:
                      doc.data()['matchesSpecies'] as bool? ?? true,
                  summary: doc.data()['summary'] as String? ?? '',
                  details: doc.data()['details'] as String? ?? '',
                  treatment: doc.data()['treatment'] as String? ?? '',
                  prevention: doc.data()['prevention'] as String? ?? '',
                ),
              ),
          ]);
});