import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
import 'package:intl/intl.dart';
import 'package:prasule/api/category.dart';
import 'package:prasule/api/wallet.dart';
import 'package:prasule/api/walletmanager.dart';
import 'package:prasule/main.dart';
import 'package:prasule/pw/platformbutton.dart';
import 'package:prasule/pw/platformroute.dart';
import 'package:prasule/util/drawer.dart';
import 'package:prasule/util/graphs.dart';
import 'package:prasule/views/settings/settings.dart';
import 'package:prasule/views/setup.dart';
import 'package:shared_preferences/shared_preferences.dart';

/// Shows data from a [Wallet] in graphs
class GraphView extends StatefulWidget {
  /// Shows data from a [Wallet] in graphs
  const GraphView({super.key});

  @override
  State<GraphView> createState() => _GraphViewState();
}

class _GraphViewState extends State<GraphView> {
  var _selectedDate = DateTime.now();
  Wallet? selectedWallet;
  List<Wallet> wallets = [];
  String? locale;
  Set<String> yearlyBtnSet = {"monthly"};
  Set<String> graphTypeSet = {"expense", "income"};
  bool get yearly => yearlyBtnSet.contains("yearly");

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    locale ??= Localizations.localeOf(context).languageCode;
  }

  List<double> generateChartData(EntryType type) {
    final data = List<double>.filled(
      yearly ? 12 : DateTime(_selectedDate.year, _selectedDate.month, 0).day,
      0,
    );
    if (selectedWallet == null) return [];
    for (var i = 0; i < data.length; i++) {
      final entriesForRange = selectedWallet!.entries.where(
        (element) =>
            ((!yearly)
                ? element.date.month == _selectedDate.month &&
                    element.date.year == _selectedDate.year &&
                    element.date.day == i + 1
                : element.date.month == i + 1 &&
                    element.date.year == _selectedDate.year) &&
            element.type == type,
      );
      var sum = 0.0;
      for (final e in entriesForRange) {
        sum += e.data.amount;
      }
      data[i] = sum;
    }
    return data;
  }

  Future<void> loadWallet() async {
    wallets = await WalletManager.listWallets();
    if (wallets.isEmpty && mounted) {
      unawaited(
        Navigator.of(context)
            .pushReplacement(platformRoute((c) => const SetupView())),
      );
      return;
    }
    selectedWallet = wallets.first;
    setState(() {});
  }

  int? chartType;
  @override
  void initState() {
    super.initState();
    loadWallet();
    SharedPreferences.getInstance().then((s) {
      chartType = s.getInt("monthlygraph") ?? 2;
      setState(() {});
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: DropdownButton<int>(
          value:
              (selectedWallet == null) ? -1 : wallets.indexOf(selectedWallet!),
          items: [
            ...wallets.map(
              (e) => DropdownMenuItem(
                value: wallets.indexOf(
                  e,
                ),
                child: Text(e.name),
              ),
            ),
            DropdownMenuItem(
              value: -1,
              child: Text(AppLocalizations.of(context).newWallet),
            ),
          ],
          onChanged: (v) async {
            if (v == null || v == -1) {
              await Navigator.of(context).push(
                platformRoute(
                  (c) => const SetupView(
                    newWallet: true,
                  ),
                ),
              );
              wallets = await WalletManager.listWallets();
              logger.i(wallets.length);
              selectedWallet = wallets.last;
              setState(() {});
              return;
            }
            selectedWallet = wallets[v];
            setState(() {});
          },
        ),
        actions: [
          PopupMenuButton(
            itemBuilder: (context) => [
              AppLocalizations.of(context).settings,
              AppLocalizations.of(context).about,
            ].map((e) => PopupMenuItem(value: e, child: Text(e))).toList(),
            onSelected: (value) {
              if (value == AppLocalizations.of(context).settings) {
                Navigator.of(context).push(
                  platformRoute(
                    (context) => const SettingsView(),
                  ),
                );
              } else if (value == AppLocalizations.of(context).about) {
                showAboutDialog(
                  context: context,
                  applicationLegalese: AppLocalizations.of(context).license,
                  applicationName: "Prašule",
                );
              }
            },
          ),
        ],
      ),
      drawer: makeDrawer(context, 2),
      body: SingleChildScrollView(
        child: Center(
          child: (selectedWallet == null)
              ? const CircularProgressIndicator(
                  strokeWidth: 5,
                )
              : SizedBox(
                  width: MediaQuery.of(context).size.width,
                  height: MediaQuery.of(context).size.height,
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      SegmentedButton<String>(
                        segments: [
                          ButtonSegment<String>(
                            value: "expense",
                            label: Text(AppLocalizations.of(context).expenses),
                          ),
                          ButtonSegment<String>(
                            value: "income",
                            label: Text(AppLocalizations.of(context).income),
                          ),
                        ],
                        selected: graphTypeSet,
                        multiSelectionEnabled: true,
                        onSelectionChanged: (selection) {
                          graphTypeSet = selection;
                          setState(() {});
                        },
                      ),
                      const SizedBox(
                        height: 5,
                      ),
                      SegmentedButton<String>(
                        segments: [
                          ButtonSegment<String>(
                            value: "yearly",
                            label: Text(AppLocalizations.of(context).yearly),
                          ),
                          ButtonSegment<String>(
                            value: "monthly",
                            label: Text(AppLocalizations.of(context).monthly),
                          ),
                        ],
                        selected: yearlyBtnSet,
                        onSelectionChanged: (selection) async {
                          yearlyBtnSet = selection;
                          final s = await SharedPreferences.getInstance();
                          chartType = yearly
                              ? (s.getInt("yearlygraph") ?? 1)
                              : (s.getInt("monthlygraph") ?? 2);
                          setState(() {});
                        },
                      ),
                      const SizedBox(height: 5),
                      Container(
                        decoration: BoxDecoration(
                          borderRadius: BorderRadius.circular(8),
                          color:
                              Theme.of(context).colorScheme.secondaryContainer,
                        ),
                        child: Padding(
                          padding: const EdgeInsets.all(8),
                          child: Column(
                            children: [
                              PlatformButton(
                                style: ButtonStyle(
                                  backgroundColor: MaterialStateProperty.all(
                                    Theme.of(context).colorScheme.primary,
                                  ),
                                  foregroundColor: MaterialStateProperty.all(
                                    Theme.of(context).colorScheme.onPrimary,
                                  ),
                                ),
                                text: yearly
                                    ? DateFormat.y(locale).format(_selectedDate)
                                    : DateFormat.yMMMM(locale)
                                        .format(_selectedDate),
                                onPressed: () async {
                                  final firstDate = (selectedWallet!.entries
                                        ..sort(
                                          (a, b) => a.date.compareTo(b.date),
                                        ))
                                      .first
                                      .date;
                                  final lastDate = (selectedWallet!.entries
                                        ..sort(
                                          (a, b) => b.date.compareTo(a.date),
                                        ))
                                      .first
                                      .date;
                                  final newDate = await showDatePicker(
                                    context: context,
                                    initialDate: DateTime(
                                      _selectedDate.year,
                                      _selectedDate.month,
                                    ),
                                    firstDate: firstDate,
                                    lastDate: lastDate,
                                    initialEntryMode: yearly
                                        ? DatePickerEntryMode.input
                                        : DatePickerEntryMode.calendar,
                                    initialDatePickerMode: yearly
                                        ? DatePickerMode.year
                                        : DatePickerMode.day,
                                  );
                                  if (newDate == null) return;
                                  _selectedDate = newDate;
                                  setState(() {});
                                },
                              ),
                              const SizedBox(
                                height: 5,
                              ),
                              SizedBox(
                                width: MediaQuery.of(context).size.width * 0.9,
                                height: 300,
                                child: (chartType == null)
                                    ? const CircularProgressIndicator()
                                    : (chartType == 1)
                                        ? ExpensesBarChart(
                                            currency: selectedWallet!.currency,
                                            date: _selectedDate,
                                            locale: locale ?? "en",
                                            yearly: yearly,
                                            expenseData: (graphTypeSet
                                                    .contains("expense"))
                                                ? generateChartData(
                                                    EntryType.expense,
                                                  )
                                                : [],
                                            incomeData: (graphTypeSet
                                                    .contains("income"))
                                                ? generateChartData(
                                                    EntryType.income,
                                                  )
                                                : [],
                                          )
                                        : ExpensesLineChart(
                                            currency: selectedWallet!.currency,
                                            date: _selectedDate,
                                            locale: locale ?? "en",
                                            yearly: yearly,
                                            expenseData: (graphTypeSet
                                                    .contains("expense"))
                                                ? generateChartData(
                                                    EntryType.expense,
                                                  )
                                                : [],
                                            incomeData: (graphTypeSet
                                                    .contains("income"))
                                                ? generateChartData(
                                                    EntryType.income,
                                                  )
                                                : [],
                                          ),
                              ),
                            ],
                          ),
                        ),
                      ),
                    ],
                  ),
                ),
        ),
      ),
    );
  }
}