import 'dart:async';

import 'package:flutter/material.dart';

import '../app_scope.dart';
import '../config.dart';
import '../format.dart';
import '../inbox.dart';
import '../polling.dart';
import 'thread_screen.dart';

class InboxScreen extends StatefulWidget {
  const InboxScreen({super.key});

  @override
  State<InboxScreen> createState() => _InboxScreenState();
}

class _InboxScreenState extends State<InboxScreen> {
  var _started = false;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    if (_started) {
      return;
    }
    _started = true;
    unawaited(AppScope.of(context).inbox.refreshList(showLoading: true));
  }

  Future<void> _logout() async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: const Text('Log out?'),
          content: const Text(
            'This device will stop receiving support notifications.',
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context, false),
              child: const Text('Cancel'),
            ),
            FilledButton(
              onPressed: () => Navigator.pop(context, true),
              child: const Text('Log out'),
            ),
          ],
        );
      },
    );
    if (confirmed != true || !mounted) {
      return;
    }
    final session = AppScope.of(context).session;
    await session.signOut();
  }

  @override
  Widget build(BuildContext context) {
    final inbox = AppScope.of(context).inbox;
    return ForegroundPoll(
      onPoll: () => inbox.refreshList(),
      child: Scaffold(
        appBar: AppBar(
          title: const Text('Inbox'),
          actions: [
            IconButton(
              tooltip: 'Log out',
              onPressed: _logout,
              icon: const Icon(Icons.logout),
            ),
          ],
        ),
        body: Column(
          children: [
            _Filters(inbox: inbox),
            const Divider(height: 1),
            Expanded(
              child: ListenableBuilder(
                listenable: inbox,
                builder: (context, _) {
                  return RefreshIndicator(
                    onRefresh: () => inbox.refreshList(),
                    child: _TicketList(inbox: inbox),
                  );
                },
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _Filters extends StatelessWidget {
  const _Filters({required this.inbox});

  final InboxController inbox;

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: inbox,
      builder: (context, _) {
        return Padding(
          padding: const EdgeInsets.fromLTRB(16, 12, 16, 12),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              SegmentedButton<TicketStatusFilter>(
                segments: const [
                  ButtonSegment(
                    value: TicketStatusFilter.open,
                    label: Text('Open'),
                  ),
                  ButtonSegment(
                    value: TicketStatusFilter.closed,
                    label: Text('Closed'),
                  ),
                  ButtonSegment(
                    value: TicketStatusFilter.all,
                    label: Text('All'),
                  ),
                ],
                selected: {inbox.statusFilter},
                onSelectionChanged: (selection) {
                  inbox.setStatusFilter(selection.first);
                },
              ),
              const SizedBox(height: 12),
              DropdownButton<String?>(
                isExpanded: true,
                value: inbox.category,
                items: [
                  const DropdownMenuItem<String?>(
                    value: null,
                    child: Text('All categories'),
                  ),
                  for (final entry in supportCategoryLabels.entries)
                    DropdownMenuItem<String?>(
                      value: entry.key,
                      child: Text(entry.value),
                    ),
                ],
                onChanged: inbox.setCategory,
              ),
            ],
          ),
        );
      },
    );
  }
}

class _TicketList extends StatelessWidget {
  const _TicketList({required this.inbox});

  final InboxController inbox;

  @override
  Widget build(BuildContext context) {
    if (inbox.loading && inbox.tickets.isEmpty) {
      return const Center(child: CircularProgressIndicator());
    }
    if (inbox.error != null && inbox.tickets.isEmpty) {
      return ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        children: [
          Padding(
            padding: const EdgeInsets.all(24),
            child: Column(
              children: [
                Text(inbox.error!, textAlign: TextAlign.center),
                const SizedBox(height: 12),
                OutlinedButton(
                  onPressed: () => inbox.refreshList(showLoading: true),
                  child: const Text('Try again'),
                ),
              ],
            ),
          ),
        ],
      );
    }
    if (inbox.tickets.isEmpty) {
      return ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        children: const [
          Padding(
            padding: EdgeInsets.all(24),
            child: Text('No tickets', textAlign: TextAlign.center),
          ),
        ],
      );
    }
    return ListView.separated(
      physics: const AlwaysScrollableScrollPhysics(),
      padding: const EdgeInsets.symmetric(vertical: 8),
      itemCount: inbox.tickets.length,
      separatorBuilder: (context, index) => const Divider(height: 1),
      itemBuilder: (context, index) {
        final ticket = inbox.tickets[index];
        return ListTile(
          title: Text(ticket.displayCategory),
          subtitle: Text(
            '${ticket.username}\n${ticket.lastMessagePreview}',
            maxLines: 3,
            overflow: TextOverflow.ellipsis,
          ),
          isThreeLine: true,
          trailing: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.end,
            children: [
              _StatusChip(closed: ticket.isClosed, label: ticket.statusLabel),
              const SizedBox(height: 6),
              Text(
                formatTimestamp(ticket.lastMessageAt),
                style: Theme.of(context).textTheme.labelSmall,
              ),
            ],
          ),
          onTap: () {
            Navigator.of(context).push(
              MaterialPageRoute<void>(
                builder: (_) => ThreadScreen(ticketId: ticket.id),
              ),
            );
          },
        );
      },
    );
  }
}

class _StatusChip extends StatelessWidget {
  const _StatusChip({required this.closed, required this.label});

  final bool closed;
  final String label;

  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    return DecoratedBox(
      decoration: BoxDecoration(
        color: closed
            ? scheme.surfaceContainerHighest
            : scheme.primaryContainer,
        borderRadius: BorderRadius.circular(999),
      ),
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
        child: Text(label, style: Theme.of(context).textTheme.labelSmall),
      ),
    );
  }
}