import 'dart:convert';

import 'package:drift/drift.dart';
import 'package:http/http.dart' as http;

import '../database/app_database.dart';
import '../utils/app_config.dart';

abstract class ExportService {
  Future<void> uploadToServer();
}

class DefaultExportService implements ExportService {
  final AppDatabase database;

  DefaultExportService({required this.database});

  @override
  Future<void> uploadToServer() async {
    try {
      final closedTabs = await _getAllClosedTabs();
      final exportData = _buildExportPayload(closedTabs);

      final response = await http.post(
        Uri.parse(kExportServerUrl),
        headers: {'Content-Type': 'application/json'},
        body: jsonEncode(exportData),
      );

      if (response.statusCode != 200 && response.statusCode != 201) {
        // Should prob log this one tho
      }
    } catch (_) {
      // if this fails who cares
    }
  }

  Future<List<_ClosedTabExport>> _getAllClosedTabs() async {
    final tabQuery = database.select(database.closedTabs)
      ..orderBy([(tab) => OrderingTerm.desc(tab.closedAt)]);

    final tabRows = await tabQuery.get();

    final result = <_ClosedTabExport>[];

    for (final tabRow in tabRows) {
      final itemsQuery = database.select(database.closedTabItems)
        ..where((item) => item.closedTabId.equals(tabRow.id));

      final itemRows = await itemsQuery.get();

      result.add(
        _ClosedTabExport(
          id: tabRow.id,
          originalTabId: tabRow.originalTabId,
          customerName: tabRow.customerName,
          closedAt: tabRow.closedAt.toIso8601String(),
          paymentMethod: tabRow.paymentMethod,
          items: itemRows
              .map(
                (row) => _ClosedTabItemExport(
                  productId: row.productId,
                  productName: row.productName,
                  quantity: row.quantity,
                  unitPriceInCents: row.unitPriceInCents,
                  purchasedAt: row.purchasedAt?.toIso8601String(),
                  removedAt: row.removedAt?.toIso8601String(),
                ),
              )
              .toList(),
        ),
      );
    }

    return result;
  }

  Map<String, dynamic> _buildExportPayload(List<_ClosedTabExport> tabs) {
    return {
      'exportedAt': DateTime.now().toIso8601String(),
      'appVersion': '1.0.7',
      'closedTabs': tabs
          .map(
            (tab) => {
              'id': tab.id,
              'originalTabId': tab.originalTabId,
              'customerName': tab.customerName,
              'closedAt': tab.closedAt,
              'paymentMethod': tab.paymentMethod,
              'items': tab.items
                  .map(
                    (item) => {
                      'productId': item.productId,
                      'productName': item.productName,
                      'quantity': item.quantity,
                      'unitPriceInCents': item.unitPriceInCents,
                      'purchasedAt': item.purchasedAt,
                      'removedAt': item.removedAt,
                      'isRemoved': item.isRemoved,
                      'lineTotalInCents': item.lineTotalInCents,
                    },
                  )
                  .toList(),
              'itemCount': tab.items.fold(
                0,
                (sum, item) => sum + (item.isRemoved ? 0 : item.quantity),
              ),
              'totalInCents': tab.items.fold(
                0,
                (sum, item) => sum + item.lineTotalInCents,
              ),
            },
          )
          .toList(),
    };
  }
}

class _ClosedTabItemExport {
  final String productId;
  final String productName;
  final int quantity;
  final int unitPriceInCents;
  final String? purchasedAt;
  final String? removedAt;

  _ClosedTabItemExport({
    required this.productId,
    required this.productName,
    required this.quantity,
    required this.unitPriceInCents,
    required this.purchasedAt,
    required this.removedAt,
  });

  bool get isRemoved => removedAt != null;

  int get lineTotalInCents => isRemoved ? 0 : quantity * unitPriceInCents;
}

class _ClosedTabExport {
  final String id;
  final String originalTabId;
  final String customerName;
  final String closedAt;
  final String paymentMethod;
  final List<_ClosedTabItemExport> items;

  _ClosedTabExport({
    required this.id,
    required this.originalTabId,
    required this.customerName,
    required this.closedAt,
    required this.paymentMethod,
    required this.items,
  });
}