/// Home: balance overview; tap balance to open transactions.
library;

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

import '../providers/bank_provider.dart';
import '../providers/tx_meta_provider.dart';
import '../utils/app_theme.dart';
import '../utils/connect_bank.dart';
import '../utils/helpers.dart';
import '../utils/navigation.dart';
import '../widgets/empty_state.dart';
import '../widgets/loading_view.dart';
import '../widgets/responsive_body.dart';
import '../widgets/skip_build_when_covered.dart';
import 'transaction_detail_screen.dart';
import 'transactions_screen.dart';

class HomeScreen extends StatelessWidget {
  const HomeScreen({super.key});

  @override
  Widget build(BuildContext context) {
    final bank = context.watch<BankController>();

    return Scaffold(
      appBar: AppBar(
        title: const Text('Home'),
        actions: bankAppBarActions(
          context: context,
          onRefresh: bank.refresh,
          refreshing: bank.isLoading,
        ),
      ),
      body: RefreshIndicator(
        onRefresh: bank.refresh,
        child: ResponsiveBody(
          child: _HomeBody(bank: bank),
        ),
      ),
    );
  }
}

class _HomeBody extends StatelessWidget {
  const _HomeBody({required this.bank});

  final BankController bank;

  void _openTransactions(BuildContext context) {
    Navigator.of(context).push(
      MaterialPageRoute<void>(builder: (_) => const TransactionsScreen()),
    );
  }

  @override
  Widget build(BuildContext context) {
    // Stay subscribed, but skip heavy scans while covered by another route
    // (e.g. transaction detail applying labels to many similar txs).
    context.watch<TxMetaController>();

    if (bank.isLoading && bank.balance == null && !bank.hasData) {
      return const LoadingView(message: 'Checking bank link…');
    }

    if (!bank.isLinked && !bank.hasData) {
      return ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        children: [
          EmptyState(
            icon: Icons.account_balance_outlined,
            title: 'Bank not linked',
            message: bank.error ??
                'Connect your bank to see balance and categorize spending.',
            actionLabel: bank.isConnecting ? 'Opening…' : 'Connect bank',
            onAction: () => runConnectBank(context, bank),
          ),
        ],
      );
    }

    if (bank.error != null && bank.balance == null && !bank.hasData) {
      return ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        children: [
          EmptyState(
            icon: Icons.error_outline,
            title: 'Could not load balance',
            message: bank.error!,
            actionLabel: 'Retry',
            onAction: bank.refresh,
          ),
        ],
      );
    }

    return SkipBuildWhenCovered(
      builder: (context) {
          final balance = bank.balance;
          final theme = Theme.of(context);
          final colors = theme.colorScheme;
          final meta = context.watch<TxMetaController>();
          final recent = bank.transactions.take(5).toList(growable: false);
          final categorized =
              meta.labeledTransactionCount(bank.transactions);

          return ListView(
      physics: const AlwaysScrollableScrollPhysics(),
      padding: const EdgeInsets.only(top: 8, bottom: 32),
      children: [
        Material(
          color: Colors.transparent,
          child: InkWell(
            borderRadius: BorderRadius.circular(20),
            onTap: () => _openTransactions(context),
            child: Ink(
              width: double.infinity,
              padding: const EdgeInsets.all(24),
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(20),
                gradient: LinearGradient(
                  colors: [colors.primary, colors.tertiary],
                ),
                boxShadow: [
                  BoxShadow(
                    color: colors.primary.withValues(alpha: 0.28),
                    blurRadius: 20,
                    offset: const Offset(0, 10),
                  ),
                ],
              ),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    'Current balance',
                    style: theme.textTheme.labelMedium?.copyWith(
                      color: colors.onPrimary.withValues(alpha: 0.8),
                    ),
                  ),
                  const SizedBox(height: 8),
                  Text(
                    balance == null
                        ? '—'
                        : formatMoney(balance.amount, balance.currency),
                    style: theme.textTheme.headlineMedium?.copyWith(
                      color: colors.onPrimary,
                    ),
                  ),
                  const SizedBox(height: 12),
                  Row(
                    children: [
                      Icon(
                        Icons.receipt_long,
                        size: 16,
                        color: colors.onPrimary.withValues(alpha: 0.9),
                      ),
                      const SizedBox(width: 6),
                      Expanded(
                        child: Text(
                          'Tap to view transactions',
                          style: theme.textTheme.labelMedium?.copyWith(
                            color: colors.onPrimary.withValues(alpha: 0.9),
                          ),
                        ),
                      ),
                      Icon(
                        Icons.chevron_right,
                        color: colors.onPrimary.withValues(alpha: 0.9),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ),
        ),
        const SizedBox(height: 20),
        Row(
          children: [
            Expanded(
              child: _StatChip(
                label: 'Transactions',
                value: '${bank.transactions.length}',
                icon: Icons.list_alt,
              ),
            ),
            const SizedBox(width: 10),
            Expanded(
              child: _StatChip(
                label: 'Categorized',
                value: '$categorized',
                icon: Icons.label_outline,
              ),
            ),
          ],
        ),
        if (recent.isNotEmpty) ...[
          const SizedBox(height: 24),
          Row(
            children: [
              Text('Recent', style: theme.textTheme.titleMedium),
              const Spacer(),
              TextButton(
                onPressed: () => _openTransactions(context),
                child: const Text('See all'),
              ),
            ],
          ),
          const SizedBox(height: 4),
          for (final tx in recent)
            ListTile(
              contentPadding: EdgeInsets.zero,
              dense: true,
                leading: Builder(
                  builder: (context) {
                    final labels =
                        meta.leafLabelsFor(meta.metaFor(tx));
                    final label = labels.isEmpty ? null : labels.first;
                    return Icon(
                      label?.icon ?? Icons.receipt_long_outlined,
                      color: label?.color,
                    );
                  },
                ),
              title: Text(
                tx.description,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
              ),
              subtitle: Text(formatIsoDate(tx.date)),
              trailing: Text(
                formatMoney(tx.amount, tx.currency),
                style: theme.textTheme.titleSmall?.copyWith(
                  color: tx.amount >= 0 ? AppTheme.accent : AppTheme.expense,
                ),
              ),
              onTap: () {
                Navigator.of(context).push(
                  MaterialPageRoute<void>(
                    builder: (_) => TransactionDetailScreen(tx: tx),
                  ),
                );
              },
            ),
        ],
        if (bank.error != null) ...[
          const SizedBox(height: 12),
          Text(
            bank.error!,
            style: theme.textTheme.bodyMedium?.copyWith(color: colors.error),
          ),
        ],
      ],
    );
      },
    );
  }
}

class _StatChip extends StatelessWidget {
  const _StatChip({
    required this.label,
    required this.value,
    required this.icon,
  });

  final String label;
  final String value;
  final IconData icon;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colors = theme.colorScheme;
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 12),
      decoration: BoxDecoration(
        color: colors.surfaceContainerLow,
        borderRadius: BorderRadius.circular(14),
      ),
      child: Row(
        children: [
          Icon(icon, size: 18, color: colors.primary),
          const SizedBox(width: 10),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(value, style: theme.textTheme.titleMedium),
                Text(label, style: theme.textTheme.labelMedium),
              ],
            ),
          ),
        ],
      ),
    );
  }
}