import 'dart:async';

import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:image_picker/image_picker.dart';
import 'package:matrix/matrix.dart';

import '../matrix/client.dart';
import '../theme.dart';
import 'message_extras.dart';

/// Where a message goes: the room's main timeline, or a thread in it.
class SendTarget {
  const SendTarget({this.threadRootId, this.threadLastEventId});

  /// The thread's root, when sending into a thread.
  final String? threadRootId;

  /// The newest event in the thread: what a client that doesn't know
  /// threads shows the message as a reply to.
  final String? Function()? threadLastEventId;
}

/// The message box: text, attachments, typing notifications, and the
/// message being replied to, shown above it until sent or dismissed.
class Composer extends StatefulWidget {
  const Composer({
    super.key,
    required this.room,
    this.target = const SendTarget(),
    this.replyTo,
    this.onCancelReply,
    this.focus,
  });

  final Room room;
  final SendTarget target;

  /// The message being answered, or null.
  final Event? replyTo;
  final VoidCallback? onCancelReply;
  final FocusNode? focus;

  @override
  State<Composer> createState() => _ComposerState();
}

class _ComposerState extends State<Composer> {
  final _controller = TextEditingController();
  late final FocusNode _focus = widget.focus ?? FocusNode();
  Timer? _typingTimer;
  bool _typing = false;

  Room get _room => widget.room;

  @override
  void initState() {
    super.initState();
    _controller.addListener(_onChanged);
  }

  @override
  void didUpdateWidget(Composer old) {
    super.didUpdateWidget(old);
    // Choosing a message to reply to puts the cursor in the box.
    if (widget.replyTo != null && widget.replyTo != old.replyTo) {
      _focus.requestFocus();
    }
  }

  @override
  void dispose() {
    _typingTimer?.cancel();
    if (_typing) _room.setTyping(false).catchError((_) {});
    _controller.dispose();
    if (widget.focus == null) _focus.dispose();
    super.dispose();
  }

  void _onChanged() {
    final hasText = _controller.text.trim().isNotEmpty;
    if (hasText && !_typing) {
      _typing = true;
      _room.setTyping(true, timeout: 30000).catchError((_) {});
    }
    _typingTimer?.cancel();
    if (hasText) {
      _typingTimer = Timer(const Duration(seconds: 5), _stopTyping);
    } else {
      _stopTyping();
    }
    setState(() {});
  }

  void _stopTyping() {
    if (!_typing) return;
    _typing = false;
    _room.setTyping(false).catchError((_) {});
  }

  Future<void> _send() async {
    final text = _controller.text.trim();
    if (text.isEmpty) return;
    final replyTo = widget.replyTo;
    _controller.clear();
    _stopTyping();
    widget.onCancelReply?.call();
    try {
      // The pending message shows at once as "Sending"; a failure leaves it
      // in the timeline with Retry and Delete.
      await _room.sendTextEvent(
        text,
        inReplyTo: replyTo,
        threadRootEventId: widget.target.threadRootId,
        threadLastEventId: widget.target.threadLastEventId?.call(),
      );
    } catch (e) {
      _snack(describeError(e));
    }
  }

  Future<void> _sendFile(MatrixFile file, Event? replyTo) async {
    try {
      await _room.sendFileEvent(
        file,
        inReplyTo: replyTo,
        threadRootEventId: widget.target.threadRootId,
        threadLastEventId: widget.target.threadLastEventId?.call(),
        shrinkImageMaxDimension: 1600,
        extraContent: {'body': file.name},
      );
    } catch (e) {
      _snack(describeError(e));
    }
  }

  Future<void> _attach() async {
    final choice = await showModalBottomSheet<String>(
      context: context,
      builder: (sheet) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.photo_library_outlined),
              title: const Text('Photo or video'),
              onTap: () => Navigator.pop(sheet, 'gallery'),
            ),
            ListTile(
              leading: const Icon(Icons.photo_camera_outlined),
              title: const Text('Take a photo'),
              onTap: () => Navigator.pop(sheet, 'camera'),
            ),
            ListTile(
              leading: const Icon(Icons.insert_drive_file_outlined),
              title: const Text('File'),
              onTap: () => Navigator.pop(sheet, 'file'),
            ),
            const SizedBox(height: 8),
          ],
        ),
      ),
    );
    if (choice == null) return;
    final replyTo = widget.replyTo;
    widget.onCancelReply?.call();
    try {
      if (choice == 'file') {
        for (final f in await FilePicker.pickFiles()) {
          final bytes = await f.xFile.readAsBytes();
          await _sendFile(
            MatrixFile.fromMimeType(bytes: bytes, name: f.name),
            replyTo,
          );
        }
        return;
      }
      final picker = ImagePicker();
      final picked = choice == 'camera'
          ? [
              ?await picker.pickImage(
                source: ImageSource.camera,
                imageQuality: 90,
              ),
            ]
          : await picker.pickMultipleMedia(imageQuality: 90);
      for (final x in picked) {
        final bytes = await x.readAsBytes();
        await _sendFile(
          MatrixFile.fromMimeType(
            bytes: bytes,
            name: x.name,
            mimeType: x.mimeType,
          ),
          replyTo,
        );
      }
    } on PlatformException catch (e) {
      _snack(e.message ?? "Couldn't open that.");
    }
  }

  void _snack(String text) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(text)));
  }

  @override
  Widget build(BuildContext context) {
    final c = context.warp;
    final canSend = _controller.text.trim().isNotEmpty;
    final replyTo = widget.replyTo;
    final inThread = widget.target.threadRootId != null;
    final hint = inThread
        ? 'Reply in thread'
        : _room.encrypted
        ? 'Encrypted message'
        : 'Message';
    return Container(
      decoration: BoxDecoration(
        color: c.surface,
        border: Border(top: BorderSide(color: c.line)),
      ),
      child: SafeArea(
        top: false,
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            if (replyTo != null)
              Padding(
                padding: const EdgeInsets.fromLTRB(16, 8, 4, 0),
                child: Row(
                  children: [
                    Icon(Icons.reply, size: 18, color: c.tealText),
                    const SizedBox(width: 8),
                    Expanded(
                      child: QuoteBlock(
                        sender:
                            'Replying to ${replyTo.senderFromMemoryOrFallback.calcDisplayname()}',
                        text: quoteText(replyTo),
                      ),
                    ),
                    IconButton(
                      tooltip: 'Cancel reply',
                      icon: const Icon(Icons.close),
                      onPressed: widget.onCancelReply,
                    ),
                  ],
                ),
              ),
            Padding(
              padding: const EdgeInsets.fromLTRB(4, 6, 8, 6),
              child: Row(
                crossAxisAlignment: CrossAxisAlignment.end,
                children: [
                  IconButton(
                    tooltip: 'Attach',
                    icon: const Icon(Icons.add_circle_outline),
                    color: c.inkMuted,
                    onPressed: _attach,
                  ),
                  Expanded(
                    child: TextField(
                      controller: _controller,
                      focusNode: _focus,
                      minLines: 1,
                      maxLines: 6,
                      textCapitalization: TextCapitalization.sentences,
                      keyboardType: TextInputType.multiline,
                      decoration: InputDecoration(
                        hintText: hint,
                        isDense: true,
                        contentPadding: const EdgeInsets.symmetric(
                          horizontal: 16,
                          vertical: 10,
                        ),
                        border: OutlineInputBorder(
                          borderRadius: BorderRadius.circular(22),
                          borderSide: BorderSide.none,
                        ),
                        enabledBorder: OutlineInputBorder(
                          borderRadius: BorderRadius.circular(22),
                          borderSide: BorderSide.none,
                        ),
                        focusedBorder: OutlineInputBorder(
                          borderRadius: BorderRadius.circular(22),
                          borderSide: BorderSide(color: c.tealStrong),
                        ),
                      ),
                    ),
                  ),
                  const SizedBox(width: 6),
                  IconButton.filled(
                    tooltip: 'Send',
                    onPressed: canSend ? _send : null,
                    icon: const Icon(Icons.send_rounded),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}