// Version: 1.0.0 | Created: 2026-04-01
// Message input bar. Text field + send button.

import 'package:flutter/material.dart';

class MessageInput extends StatefulWidget {
  const MessageInput({
    super.key,
    required this.onSend,
    required this.isSending,
  });

  final Future<void> Function(String text) onSend;
  final bool isSending;

  @override
  State<MessageInput> createState() => _MessageInputState();
}

class _MessageInputState extends State<MessageInput> {
  final _controller = TextEditingController();
  bool _hasText = false;

  @override
  void initState() {
    super.initState();
    _controller.addListener(() {
      final hasText = _controller.text.trim().isNotEmpty;
      if (hasText != _hasText) {
        setState(() => _hasText = hasText);
      }
    });
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  Future<void> _submit() async {
    final text = _controller.text.trim();
    if (text.isEmpty) return;
    _controller.clear();
    await widget.onSend(text);
  }

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

    return Container(
      padding: const EdgeInsets.fromLTRB(8, 8, 8, 12),
      decoration: BoxDecoration(
        color: theme.colorScheme.surface,
        border: Border(
          top: BorderSide(color: theme.colorScheme.outline.withAlpha(51)),
        ),
      ),
      child: SafeArea(
        top: false,
        child: Row(
          children: [
            IconButton(
              icon: const Icon(Icons.add),
              tooltip: 'Attach file (Phase 2)',
              onPressed: null, // Phase 2
              color: theme.colorScheme.onSurface.withAlpha(153),
            ),
            Expanded(
              child: TextField(
                controller: _controller,
                decoration: const InputDecoration(
                  hintText: 'Message',
                  contentPadding: EdgeInsets.symmetric(
                    horizontal: 16,
                    vertical: 10,
                  ),
                ),
                textInputAction: TextInputAction.send,
                onSubmitted: (_) => _submit(),
                maxLines: null,
                keyboardType: TextInputType.multiline,
              ),
            ),
            const SizedBox(width: 8),
            AnimatedSwitcher(
              duration: const Duration(milliseconds: 150),
              child: widget.isSending
                  ? const SizedBox(
                      width: 40,
                      height: 40,
                      child: Center(
                        child: SizedBox(
                          width: 20,
                          height: 20,
                          child: CircularProgressIndicator(strokeWidth: 2.5),
                        ),
                      ),
                    )
                  : IconButton(
                      icon: const Icon(Icons.send_rounded),
                      onPressed: _hasText ? _submit : null,
                      color: _hasText
                          ? theme.colorScheme.primary
                          : theme.colorScheme.onSurface.withAlpha(77),
                      tooltip: 'Send message',
                    ),
            ),
          ],
        ),
      ),
    );
  }
}