import 'dart:async';
import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
import '../models/sms_message.dart';
import '../main.dart';

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

  @override
  State<SmsListScreen> createState() => _SmsListScreenState();
}

class _SmsListScreenState extends State<SmsListScreen> {
  List<SmsMessage> _messages = [];
  final _selected = <int>{};
  Set<String> _uploadedKeys = {};
  bool _loading = false;
  bool _hasSmsPermission = false;
  StreamSubscription<SmsMessage>? _smsSub;

  static String _dedupKey(SmsMessage m) => '${m.phoneNumber}|${m.content}|${m.smsDate}';

  @override
  void initState() {
    super.initState();
    _uploadedKeys = settings.getUploadedKeys();
    _requestPermission();
  }

  Future<void> _requestPermission() async {
    final status = await Permission.sms.request();
    if (mounted) {
      setState(() => _hasSmsPermission = status.isGranted);
      if (status.isGranted) _loadSms();
    }
  }

  Future<void> _loadSms() async {
    setState(() => _loading = true);
    try {
      _messages = await smsReaderService.queryAllSms();
    } catch (e) { /* ignore */ }
    setState(() => _loading = false);
  }

  bool _isUploaded(SmsMessage m) => _uploadedKeys.contains(_dedupKey(m));

  Future<void> _uploadSelected() async {
    if (_selected.isEmpty) return;
    final toUpload = _messages
        .asMap()
        .entries
        .where((e) => _selected.contains(e.key) && !_isUploaded(e.value))
        .map((e) => e.value)
        .toList();
    if (toUpload.isEmpty) return;
    try {
      await apiService.uploadSms(toUpload);
      final newKeys = toUpload.map(_dedupKey).toList();
      settings.addUploadedKeys(newKeys);
      _uploadedKeys = settings.getUploadedKeys();
      _selected.clear();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Uploaded ${toUpload.length} messages')),
        );
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Upload failed: $e')),
        );
      }
    }
  }

  Future<void> _uploadAll() async {
    final toUpload = _messages.where((m) => !_isUploaded(m)).toList();
    if (toUpload.isEmpty) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('No new messages to upload')),
        );
      }
      return;
    }
    try {
      final count = await apiService.uploadSms(toUpload);
      final newKeys = toUpload.map(_dedupKey).toList();
      settings.addUploadedKeys(newKeys);
      _uploadedKeys = settings.getUploadedKeys();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Uploaded $count messages')),
        );
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Upload failed: $e')),
        );
      }
    }
  }

  void _toggleAutoUpload() {
    final newVal = !settings.autoUpload;
    settings.setAutoUpload(newVal);
    if (newVal) {
      _startAutoUpload();
    } else {
      _smsSub?.cancel();
      _smsSub = null;
    }
    setState(() {});
  }

  void _startAutoUpload() {
    _smsSub = smsReaderService.listenToIncoming().listen((sms) async {
      try {
        await apiService.uploadSms([sms]);
        settings.addUploadedKey(_dedupKey(sms));
        _uploadedKeys = settings.getUploadedKeys();
        _messages.insert(0, sms);
        if (mounted) setState(() {});
      } catch (_) {}
    });
  }

  @override
  void dispose() {
    _smsSub?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final colors = Theme.of(context).colorScheme;

    return Scaffold(
      appBar: AppBar(
        title: const Text('Messages'),
        actions: [
          if (_selected.isNotEmpty)
            IconButton(icon: const Icon(Icons.cloud_upload), onPressed: _uploadSelected, tooltip: 'Upload selected'),
          IconButton(icon: const Icon(Icons.refresh), onPressed: _hasSmsPermission ? _loadSms : _requestPermission),
        ],
      ),
      body: _hasSmsPermission == false
          ? Center(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                children: [
                  const Text('SMS permission required'),
                  const SizedBox(height: 12),
                  FilledButton(onPressed: _requestPermission, child: const Text('Grant')),
                ],
              ),
            )
          : _loading
              ? const Center(child: CircularProgressIndicator())
              : _messages.isEmpty
                  ? const Center(child: Text('No messages'))
                  : RefreshIndicator(
                      onRefresh: _loadSms,
                      child: ListView.builder(
                        itemCount: _messages.length,
                        itemBuilder: (_, i) {
                          final m = _messages[i];
                          final sel = _selected.contains(i);
                          final uploaded = _isUploaded(m);
                          return ListTile(
                            selected: sel,
                            leading: CircleAvatar(
                              backgroundColor: sel ? colors.primaryContainer : colors.surfaceContainerHighest,
                              child: Icon(
                                uploaded ? Icons.cloud_done : (m.type == 'received' ? Icons.arrow_downward : Icons.arrow_upward),
                                size: 18,
                              ),
                            ),
                            title: Text(
                              m.contactName ?? m.phoneNumber,
                              maxLines: 1,
                              overflow: TextOverflow.ellipsis,
                            ),
                            subtitle: Text(m.content, maxLines: 1, overflow: TextOverflow.ellipsis),
                            trailing: uploaded
                                ? Icon(Icons.cloud_done, color: colors.primary, size: 20)
                                : IconButton(
                                    icon: Icon(sel ? Icons.check_circle : Icons.circle_outlined),
                                    onPressed: () {
                                      setState(() {
                                        sel ? _selected.remove(i) : _selected.add(i);
                                      });
                                    },
                                  ),
                            onTap: uploaded
                                ? null
                                : () {
                                    setState(() {
                                      sel ? _selected.remove(i) : _selected.add(i);
                                    });
                                  },
                          );
                        },
                      ),
                    ),
      floatingActionButton: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          FloatingActionButton.small(
            heroTag: 'auto',
            onPressed: _toggleAutoUpload,
            backgroundColor: settings.autoUpload ? colors.errorContainer : colors.surfaceContainerHighest,
            child: Icon(settings.autoUpload ? Icons.sync_disabled : Icons.sync, color: colors.onPrimaryContainer),
          ),
          const SizedBox(height: 8),
          FloatingActionButton(
            heroTag: 'upload',
            onPressed: _uploadAll,
            tooltip: 'Upload all',
            child: const Icon(Icons.cloud_upload),
          ),
        ],
      ),
    );
  }
}