// Copyright 2019 The Flutter team. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';

import 'package:gallery/data/gallery_options.dart';
import 'package:gallery/l10n/gallery_localizations.dart';
import 'package:gallery/layout/adaptive.dart';
import 'package:gallery/layout/text_scale.dart';
import 'package:gallery/studies/rally/charts/line_chart.dart';
import 'package:gallery/studies/rally/charts/pie_chart.dart';
import 'package:gallery/studies/rally/charts/vertical_fraction_bar.dart';
import 'package:gallery/studies/rally/colors.dart';
import 'package:gallery/studies/rally/data.dart';
import 'package:gallery/studies/rally/formatters.dart';

class FinancialEntityView extends StatelessWidget {
  const FinancialEntityView({
    this.heroLabel,
    this.heroAmount,
    this.wholeAmount,
    this.segments,
    this.financialEntityCards,
  }) : assert(segments.length == financialEntityCards.length);

  /// The amounts to assign each item.
  final List<RallyPieChartSegment> segments;
  final String heroLabel;
  final double heroAmount;
  final double wholeAmount;
  final List<FinancialEntityCategoryView> financialEntityCards;

  @override
  Widget build(BuildContext context) {
    final maxWidth = pieChartMaxSize + (cappedTextScale(context) - 1.0) * 100.0;
    return LayoutBuilder(builder: (context, constraints) {
      return Column(
        children: [
          ConstrainedBox(
            constraints: BoxConstraints(
              // We decrease the max height to ensure the [RallyPieChart] does
              // not take up the full height when it is smaller than
              // [kPieChartMaxSize].
              maxHeight: math.min(
                constraints.biggest.shortestSide * 0.9,
                maxWidth,
              ),
            ),
            child: RallyPieChart(
              heroLabel: heroLabel,
              heroAmount: heroAmount,
              wholeAmount: wholeAmount,
              segments: segments,
            ),
          ),
          const SizedBox(height: 24),
          Container(
            height: 1,
            constraints: BoxConstraints(maxWidth: maxWidth),
            color: RallyColors.inputBackground,
          ),
          Container(
            constraints: BoxConstraints(maxWidth: maxWidth),
            color: RallyColors.cardBackground,
            child: Column(
              children: financialEntityCards,
            ),
          ),
        ],
      );
    });
  }
}

/// A reusable widget to show balance information of a single entity as a card.
class FinancialEntityCategoryView extends StatelessWidget {
  const FinancialEntityCategoryView({
    @required this.indicatorColor,
    @required this.indicatorFraction,
    @required this.title,
    @required this.subtitle,
    @required this.semanticsLabel,
    @required this.amount,
    @required this.suffix,
  });

  final Color indicatorColor;
  final double indicatorFraction;
  final String title;
  final String subtitle;
  final String semanticsLabel;
  final String amount;
  final Widget suffix;

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return Semantics.fromProperties(
      properties: SemanticsProperties(
        button: true,
        label: semanticsLabel,
      ),
      excludeSemantics: true,
      child: FlatButton(
        onPressed: () {
          Navigator.push(
            context,
            MaterialPageRoute<FinancialEntityCategoryDetailsPage>(
              builder: (context) => FinancialEntityCategoryDetailsPage(),
            ),
          );
        },
        child: Column(
          children: [
            Container(
              padding: EdgeInsets.symmetric(vertical: 16),
              child: Row(
                children: [
                  Container(
                    alignment: Alignment.center,
                    height: 32 + 60 * (cappedTextScale(context) - 1),
                    padding: const EdgeInsets.symmetric(horizontal: 12),
                    child: VerticalFractionBar(
                      color: indicatorColor,
                      fraction: indicatorFraction,
                    ),
                  ),
                  Expanded(
                    child: Wrap(
                      alignment: WrapAlignment.spaceBetween,
                      crossAxisAlignment: WrapCrossAlignment.center,
                      children: [
                        Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            Text(
                              title,
                              style: textTheme.body1.copyWith(fontSize: 16),
                            ),
                            Text(
                              subtitle,
                              style: textTheme.body1
                                  .copyWith(color: RallyColors.gray60),
                            ),
                          ],
                        ),
                        Text(
                          amount,
                          style: textTheme.body2.copyWith(
                            fontSize: 20,
                            color: RallyColors.gray,
                          ),
                        ),
                      ],
                    ),
                  ),
                  Container(
                    constraints: BoxConstraints(minWidth: 32),
                    padding: EdgeInsetsDirectional.only(start: 12),
                    child: suffix,
                  ),
                ],
              ),
            ),
            const Divider(
              height: 1,
              indent: 16,
              endIndent: 16,
              color: RallyColors.dividerColor,
            ),
          ],
        ),
      ),
    );
  }
}

/// Data model for [FinancialEntityCategoryView].
class FinancialEntityCategoryModel {
  const FinancialEntityCategoryModel(
    this.indicatorColor,
    this.indicatorFraction,
    this.title,
    this.subtitle,
    this.usdAmount,
    this.suffix,
  );

  final Color indicatorColor;
  final double indicatorFraction;
  final String title;
  final String subtitle;
  final double usdAmount;
  final Widget suffix;
}

FinancialEntityCategoryView buildFinancialEntityFromAccountData(
  AccountData model,
  int accountDataIndex,
  BuildContext context,
) {
  final amount = usdWithSignFormat(context).format(model.primaryAmount);
  final shortAccountNumber = model.accountNumber.substring(6);
  return FinancialEntityCategoryView(
    suffix: const Icon(Icons.chevron_right, color: Colors.grey),
    title: model.name,
    subtitle: '• • • • • • $shortAccountNumber',
    semanticsLabel: GalleryLocalizations.of(context).rallyAccountAmount(
      model.name,
      shortAccountNumber,
      amount,
    ),
    indicatorColor: RallyColors.accountColor(accountDataIndex),
    indicatorFraction: 1,
    amount: amount,
  );
}

FinancialEntityCategoryView buildFinancialEntityFromBillData(
  BillData model,
  int billDataIndex,
  BuildContext context,
) {
  final amount = usdWithSignFormat(context).format(model.primaryAmount);
  return FinancialEntityCategoryView(
    suffix: const Icon(Icons.chevron_right, color: Colors.grey),
    title: model.name,
    subtitle: model.dueDate,
    semanticsLabel: GalleryLocalizations.of(context).rallyBillAmount(
      model.name,
      model.dueDate,
      amount,
    ),
    indicatorColor: RallyColors.billColor(billDataIndex),
    indicatorFraction: 1,
    amount: amount,
  );
}

FinancialEntityCategoryView buildFinancialEntityFromBudgetData(
  BudgetData model,
  int budgetDataIndex,
  BuildContext context,
) {
  final amountUsed = usdWithSignFormat(context).format(model.amountUsed);
  final primaryAmount = usdWithSignFormat(context).format(model.primaryAmount);
  final amount =
      usdWithSignFormat(context).format(model.primaryAmount - model.amountUsed);

  return FinancialEntityCategoryView(
    suffix: Text(
      GalleryLocalizations.of(context).rallyFinanceLeft,
      style: Theme.of(context)
          .textTheme
          .body1
          .copyWith(color: RallyColors.gray60, fontSize: 10),
    ),
    title: model.name,
    subtitle: amountUsed + ' / ' + primaryAmount,
    semanticsLabel: GalleryLocalizations.of(context).rallyBudgetAmount(
      model.name,
      model.amountUsed,
      model.primaryAmount,
      amount,
    ),
    indicatorColor: RallyColors.budgetColor(budgetDataIndex),
    indicatorFraction: model.amountUsed / model.primaryAmount,
    amount: amount,
  );
}

List<FinancialEntityCategoryView> buildAccountDataListViews(
  List<AccountData> items,
  BuildContext context,
) {
  return List<FinancialEntityCategoryView>.generate(
    items.length,
    (i) => buildFinancialEntityFromAccountData(items[i], i, context),
  );
}

List<FinancialEntityCategoryView> buildBillDataListViews(
  List<BillData> items,
  BuildContext context,
) {
  return List<FinancialEntityCategoryView>.generate(
    items.length,
    (i) => buildFinancialEntityFromBillData(items[i], i, context),
  );
}

List<FinancialEntityCategoryView> buildBudgetDataListViews(
  List<BudgetData> items,
  BuildContext context,
) {
  return <FinancialEntityCategoryView>[
    for (int i = 0; i < items.length; i++)
      buildFinancialEntityFromBudgetData(items[i], i, context)
  ];
}

class FinancialEntityCategoryDetailsPage extends StatelessWidget {
  final List<DetailedEventData> items =
      DummyDataService.getDetailedEventItems();

  @override
  Widget build(BuildContext context) {
    final isDesktop = isDisplayDesktop(context);

    return ApplyTextOptions(
      child: Scaffold(
        appBar: AppBar(
          elevation: 0,
          centerTitle: true,
          title: Text(
            GalleryLocalizations.of(context).rallyAccountDataChecking,
            style: Theme.of(context).textTheme.body1.copyWith(fontSize: 18),
          ),
        ),
        body: Column(
          children: [
            SizedBox(
              height: 200,
              width: double.infinity,
              child: RallyLineChart(events: items),
            ),
            Expanded(
              child: Padding(
                padding: isDesktop ? EdgeInsets.all(40) : EdgeInsets.zero,
                child: ListView(
                  shrinkWrap: true,
                  children: [
                    for (DetailedEventData detailedEventData in items)
                      _DetailedEventCard(
                        title: detailedEventData.title,
                        date: detailedEventData.date,
                        amount: detailedEventData.amount,
                      ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _DetailedEventCard extends StatelessWidget {
  const _DetailedEventCard({
    @required this.title,
    @required this.date,
    @required this.amount,
  });

  final String title;
  final DateTime date;
  final double amount;

  @override
  Widget build(BuildContext context) {
    final isDesktop = isDisplayDesktop(context);
    return FlatButton(
      onPressed: () {},
      padding: EdgeInsets.symmetric(horizontal: 16),
      child: Column(
        children: [
          Container(
            padding: EdgeInsets.symmetric(vertical: 16),
            width: double.infinity,
            child: isDesktop
                ? Row(
                    children: [
                      Expanded(
                        flex: 1,
                        child: _EventTitle(title: title),
                      ),
                      _EventDate(date: date),
                      Expanded(
                        flex: 1,
                        child: Align(
                          alignment: AlignmentDirectional.centerEnd,
                          child: _EventAmount(amount: amount),
                        ),
                      ),
                    ],
                  )
                : Wrap(
                    alignment: WrapAlignment.spaceBetween,
                    children: [
                      Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          _EventTitle(title: title),
                          _EventDate(date: date),
                        ],
                      ),
                      _EventAmount(amount: amount),
                    ],
                  ),
          ),
          SizedBox(
            height: 1,
            child: Container(
              color: RallyColors.dividerColor,
            ),
          ),
        ],
      ),
    );
  }
}

class _EventAmount extends StatelessWidget {
  const _EventAmount({Key key, @required this.amount}) : super(key: key);

  final double amount;

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return Text(
      usdWithSignFormat(context).format(amount),
      style: textTheme.body2.copyWith(fontSize: 20, color: RallyColors.gray),
    );
  }
}

class _EventDate extends StatelessWidget {
  const _EventDate({Key key, @required this.date}) : super(key: key);

  final DateTime date;

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return Text(
      shortDateFormat(context).format(date),
      semanticsLabel: longDateFormat(context).format(date),
      style: textTheme.body1.copyWith(color: RallyColors.gray60),
    );
  }
}

class _EventTitle extends StatelessWidget {
  const _EventTitle({Key key, @required this.title}) : super(key: key);

  final String title;

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return Text(
      title,
      style: textTheme.body1.copyWith(fontSize: 16),
    );
  }
}