/// Transactions tab: recent bank movements from the ingtrak API.
library;

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

import '../models/bank.dart';
import '../providers/bank_provider.dart';
import '../utils/connect_bank.dart';
import '../utils/helpers.dart';
import '../widgets/empty_state.dart';
import '../widgets/loading_view.dart';
import '../widgets/responsive_body.dart';

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

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

    return Scaffold(
      appBar: AppBar(
        title: const Text('Transactions'),
        actions: [
          IconButton(
            tooltip: 'Refresh',
            onPressed: bank.isLoading ? null : bank.refresh,
            icon: const Icon(Icons.refresh),
          ),
        ],
      ),
      body: RefreshIndicator(
        onRefresh: bank.refresh,
        child: ResponsiveBody(
          child: _TransactionsBody(bank: bank),
        ),
      ),
    );
  }
}

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

  final BankController bank;

  @override
  Widget build(BuildContext context) {
    if (bank.isLoading && bank.transactions.isEmpty) {
      return const LoadingView(message: 'Loading transactions…');
    }

    if (!bank.isLinked) {
      return ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        children: [
          EmptyState(
            icon: Icons.receipt_long_outlined,
            title: 'No transactions yet',
            message: bank.error ??
                'Link your bank on the Balance tab to load recent activity.',
            actionLabel: bank.isConnecting ? 'Opening…' : 'Connect bank',
            onAction: () => runConnectBank(context, bank),
          ),
        ],
      );
    }

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

    if (bank.transactions.isEmpty) {
      return ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        children: const [
          EmptyState(
            icon: Icons.inbox_outlined,
            title: 'No recent activity',
            message: 'The backend returned an empty transaction list.',
          ),
        ],
      );
    }

    return ListView.separated(
      physics: const AlwaysScrollableScrollPhysics(),
      padding: const EdgeInsets.only(top: 8, bottom: 32),
      itemCount: bank.transactions.length,
      separatorBuilder: (_, _) => const SizedBox(height: 8),
      itemBuilder: (context, index) {
        return _TransactionTile(tx: bank.transactions[index]);
      },
    );
  }
}

class _TransactionTile extends StatelessWidget {
  const _TransactionTile({required this.tx});

  final BankTransaction tx;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colors = theme.colorScheme;
    final isCredit = tx.amount >= 0;
    final amountColor = isCredit ? colors.primary : colors.error;

    return Card(
      child: ListTile(
        title: Text(
          tx.description,
          maxLines: 2,
          overflow: TextOverflow.ellipsis,
        ),
        subtitle: Text(
          [
            formatIsoDate(tx.date),
            if (tx.pending) 'Pending',
          ].where((part) => part.isNotEmpty).join(' · '),
        ),
        trailing: Text(
          formatMoney(tx.amount, tx.currency),
          style: theme.textTheme.titleMedium?.copyWith(color: amountColor),
        ),
      ),
    );
  }
}