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

import 'package:timetrack/features/projects/domain/projects_provider.dart';
import 'package:timetrack/features/reports/domain/report_data.dart';
import 'package:timetrack/features/reports/domain/reports_provider.dart';
import 'package:timetrack/features/reports/presentation/widgets/duration_bar_chart.dart';
import 'package:timetrack/features/reports/presentation/widgets/period_navigator.dart';
import 'package:timetrack/features/reports/presentation/widgets/project_breakdown_list.dart';
import 'package:timetrack/features/reports/presentation/widgets/summary_header.dart';

class ReportsScreen extends ConsumerWidget {
  const ReportsScreen({super.key});

  static const _weekLabels = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'];
  static const _dayLabels = [
    '0', '2', '4', '6', '8', '10', '12', '14', '16', '18', '20', '22',
  ];

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final notifier = ref.read(reportsNotifierProvider.notifier);
    final reportAsync = ref.watch(reportsNotifierProvider);
    final projectsAsync = ref.watch(allProjectsProvider);

    return Scaffold(
      appBar: AppBar(
        title: const Text('Reports'),
        bottom: PreferredSize(
          preferredSize: const Size.fromHeight(48),
          child: _PeriodTabs(
            current: notifier.period,
            onChanged: notifier.selectPeriod,
          ),
        ),
      ),
      body: reportAsync.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (e, _) => Center(child: Text('Error: $e')),
        data: (report) => _buildBody(context, ref, report, projectsAsync, notifier),
      ),
    );
  }

  Widget _buildBody(
    BuildContext context,
    WidgetRef ref,
    ReportData report,
    AsyncValue projectsAsync,
    ReportsNotifier notifier,
  ) {
    final chartLabels = _labelsFor(notifier.period, report.chartValues.length);

    return ListView(
      children: [
        PeriodNavigator(
          period: notifier.period,
          periodStart: report.periodStart,
          periodEnd: report.periodEnd,
          onPrevious: notifier.goToPrevious,
          onNext: notifier.goToNext,
        ),
        SummaryHeader(
          totalDuration: report.totalDuration,
          entryCount: report.durationByProject.length,
        ),
        Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
          child: SizedBox(
            height: 200,
            child: report.chartValues.isEmpty ||
                    report.chartValues.every((v) => v == 0)
                ? Center(
                    child: Text(
                      'No data for this period',
                      style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                            color: Theme.of(context).colorScheme.onSurfaceVariant,
                          ),
                    ),
                  )
                : DurationBarChart(
                    values: report.chartValues,
                    labels: chartLabels,
                  ),
          ),
        ),
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 8, 16, 4),
          child: Text(
            'By project',
            style: Theme.of(context).textTheme.labelLarge,
          ),
        ),
        projectsAsync.when(
          data: (projects) => ProjectBreakdownList(
            durationByProject: report.durationByProject,
            projects: projects,
            totalDuration: report.totalDuration,
          ),
          loading: () => const SizedBox.shrink(),
          error: (e, _) => const SizedBox.shrink(),
        ),
      ],
    );
  }

  List<String> _labelsFor(ReportPeriod period, int count) {
    switch (period) {
      case ReportPeriod.week:
        return _weekLabels;
      case ReportPeriod.day:
        return _dayLabels;
      case ReportPeriod.month:
        return List.generate(count, (i) => '${i + 1}');
    }
  }
}

class _PeriodTabs extends StatelessWidget {
  const _PeriodTabs({required this.current, required this.onChanged});

  final ReportPeriod current;
  final ValueChanged<ReportPeriod> onChanged;

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: ReportPeriod.values.map((p) {
        final label = p.name[0].toUpperCase() + p.name.substring(1);
        return Padding(
          padding: const EdgeInsets.symmetric(horizontal: 4),
          child: ChoiceChip(
            label: Text(label),
            selected: current == p,
            onSelected: (_) => onChanged(p),
          ),
        );
      }).toList(),
    );
  }
}