import 'dart:convert';
import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:latlong2/latlong.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

import '../models/field_property.dart';

class GeoJsonImportResult {
  final int imported;
  final List<String> skipped;
  const GeoJsonImportResult({required this.imported, required this.skipped});
}

/// Ingatlan-parcellák geometriája (GeoJSON-import + térképi lekérdezés).
///
/// SZÁNDÉKOSAN tisztán online, nincs helyi tükör-tábla. A tábla
/// PROJEKT-FÜGGETLEN, közös katalógus — egy fizikai telek geometriája
/// nem egyetlen projekthez tartozik.
class ParcelGeometryService extends GetxService {
  static ParcelGeometryService get to => Get.find();

  SupabaseClient get _client => Supabase.instance.client;

  // ═════════════════════════════════════════════════════════════════
  // Normalizálás — PONTOSAN a levél-pipeline szabálya (ellenőrzött
  // minta alapján): minden "/"-lel elválasztott számjegy-szegmensről
  // levágja a vezető nullákat.
  //   "0173/4" → "173/4", "0620" → "620", "011/9" → "11/9"
  // ═════════════════════════════════════════════════════════════════

  static String normalizeParcelNumber(String raw) {
    final trimmed = raw.trim();
    final parts = trimmed.split('/');
    final normalized = parts.map((p) {
      final stripped = p.replaceFirst(RegExp(r'^0+(?=\d)'), '');
      return stripped.isEmpty ? '0' : stripped;
    }).join('/');
    return normalized;
  }

  // ═════════════════════════════════════════════════════════════════
  // Import
  // ═════════════════════════════════════════════════════════════════

  static const _settlementKeys = ['telepules', 'település', 'settlement'];
  static const _parcelKeys = [
    'hrsz',
    'helyrajziszam',
    'helyrajzi_szam',
    'parcel_number',
  ];

  static String? _extractByKeys(Map<String, dynamic> props, List<String> keys) {
    final lower = {for (final e in props.entries) e.key.toLowerCase(): e.value};
    for (final k in keys) {
      final v = lower[k];
      if (v != null && v.toString().trim().isNotEmpty)
        return v.toString().trim();
    }
    return null;
  }

  /// A GeoJSON tartalmának importja — Feature-önként upsert, egy hibás
  /// elem nem akasztja meg a többit.
  Future<GeoJsonImportResult> importGeoJson(String content,
      {required String projectId, String? sourceFileName}) async {
    final dynamic json = jsonDecode(content);
    final features = (json is Map && json['features'] is List)
        ? json['features'] as List
        : <dynamic>[];

    var imported = 0;
    final skipped = <String>[];

    for (final f in features) {
      try {
        if (f is! Map) {
          skipped.add('érvénytelen elem');
          continue;
        }
        final geometry = f['geometry'];
        if (geometry is! Map) {
          skipped.add('geometria nélküli elem');
          continue;
        }

        final geomType = geometry['type'] as String?;
        List coords;
        if (geomType == 'MultiPolygon') {
          coords = geometry['coordinates'] as List;
        } else if (geomType == 'Polygon') {
          // Egységesítjük MultiPolygon-alakúra tároláshoz, hogy a
          // megjelenítés mindig ugyanazt a szerkezetet olvassa.
          coords = [geometry['coordinates']];
        } else {
          skipped.add('nem támogatott geometria-típus: $geomType');
          continue;
        }

        final props = (f['properties'] as Map?)?.cast<String, dynamic>() ?? {};
        final settlement = _extractByKeys(props, _settlementKeys);
        final rawParcel = _extractByKeys(props, _parcelKeys);

        if (settlement == null || rawParcel == null) {
          skipped.add(
              'hiányzó település/helyrajzi szám (talált kulcsok: ${props.keys.join(", ")})');
          continue;
        }

        final normalized = normalizeParcelNumber(rawParcel);
        final bbox = _computeBbox(coords);

        await _client.from('terepi_seged_field_parcel_geometries').upsert({
          'project_id': projectId,
          'settlement': settlement,
          'normalized_parcel_number': normalized,
          'parcel_number_raw': rawParcel,
          'geometry': {'type': 'MultiPolygon', 'coordinates': coords},
          'bbox_min_lat': bbox.minLat,
          'bbox_max_lat': bbox.maxLat,
          'bbox_min_lon': bbox.minLon,
          'bbox_max_lon': bbox.maxLon,
          'source_file': sourceFileName,
        }, onConflict: 'project_id,settlement,normalized_parcel_number');

        imported++;
      } catch (e) {
        skipped.add('hiba: $e');
      }
    }

    return GeoJsonImportResult(imported: imported, skipped: skipped);
  }

  _Bbox _computeBbox(List multiPolygonCoords) {
    double minLat = double.infinity, maxLat = -double.infinity;
    double minLon = double.infinity, maxLon = -double.infinity;
    for (final polygon in multiPolygonCoords) {
      for (final ring in polygon as List) {
        for (final point in ring as List) {
          final lon = (point[0] as num).toDouble();
          final lat = (point[1] as num).toDouble();
          if (lat < minLat) minLat = lat;
          if (lat > maxLat) maxLat = lat;
          if (lon < minLon) minLon = lon;
          if (lon > maxLon) maxLon = lon;
        }
      }
    }
    return _Bbox(
        minLat: minLat, maxLat: maxLat, minLon: minLon, maxLon: maxLon);
  }

  // ═════════════════════════════════════════════════════════════════
  // Lekérdezés a térképi megjelenítéshez
  // ═════════════════════════════════════════════════════════════════

  /// Egy vagy több ingatlan geometriája (settlement + normalized_parcel_number
  /// párok alapján) — a property-lista bármely részhalmazára hívható.
  Future<List<Map<String, dynamic>>> fetchGeometriesFor(
      List<FieldProperty> properties) async {
    if (properties.isEmpty) return [];

    // Minden átadott property ugyanahhoz az (aktív) projekthez tartozik —
    // a geometria is erre a projektre szűkül.
    final projectId = properties.first.projectId;

    final bySettlement = <String, Set<String>>{};
    for (final p in properties) {
      bySettlement
          .putIfAbsent(p.settlement, () => {})
          .add(p.normalizedParcelNumber);
    }

    final result = <Map<String, dynamic>>[];
    for (final entry in bySettlement.entries) {
      final rows = await _client
          .from('terepi_seged_field_parcel_geometries')
          .select()
          .eq('project_id', projectId)
          .eq('settlement', entry.key)
          .inFilter('normalized_parcel_number', entry.value.toList());
      result.addAll(List<Map<String, dynamic>>.from(rows));
    }
    return result;
  }

  // ═════════════════════════════════════════════════════════════════
  // flutter_map segédek
  // ═════════════════════════════════════════════════════════════════

  List<Polygon> parsePolygons(List<Map<String, dynamic>> rows,
      {Color color = Colors.deepOrange}) {
    final polygons = <Polygon>[];
    for (final row in rows) {
      final geom = row['geometry'] as Map;
      final coords = geom['coordinates'] as List; // MultiPolygon
      for (final polygon in coords) {
        final outerRing = (polygon as List).first as List;
        final points = outerRing
            .map((p) =>
                LatLng((p[1] as num).toDouble(), (p[0] as num).toDouble()))
            .toList();
        polygons.add(Polygon(
          points: points,
          color: color.withOpacity(0.35),
          borderColor: color,
          borderStrokeWidth: 2,
        ));
      }
    }
    return polygons;
  }

  LatLngBounds? computeBounds(List<Map<String, dynamic>> rows) {
    if (rows.isEmpty) return null;
    double minLat = double.infinity, maxLat = -double.infinity;
    double minLon = double.infinity, maxLon = -double.infinity;
    for (final row in rows) {
      minLat = math.min(minLat, (row['bbox_min_lat'] as num).toDouble());
      maxLat = math.max(maxLat, (row['bbox_max_lat'] as num).toDouble());
      minLon = math.min(minLon, (row['bbox_min_lon'] as num).toDouble());
      maxLon = math.max(maxLon, (row['bbox_max_lon'] as num).toDouble());
    }
    return LatLngBounds(LatLng(minLat, minLon), LatLng(maxLat, maxLon));
  }
}

class _Bbox {
  final double minLat, maxLat, minLon, maxLon;
  const _Bbox({
    required this.minLat,
    required this.maxLat,
    required this.minLon,
    required this.maxLon,
  });
}