// Author: fruit.com.cn

import 'dart:async';
import 'dart:math' as math;

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

import '../../../core/data/models/comment.dart';
import '../../../core/data/services/auth_controller.dart';
import '../../../core/data/services/comment_controller.dart';
import '../../../core/platform/haptics.dart';
import '../../../core/platform/keyboard_inset.dart';
import '../../../core/theme/app_colors.dart';
import '../../../core/widgets/auth_gate.dart';
import '../../../l10n/app_localizations.dart';

const double _sheetRadius = 20;
const double _inputRadius = 12;
const double _postButtonHeight = 32;
const int _maxCommentLength = 300;

/// 独立评论输入弹窗，复用原评论控制器的发布与列表更新能力。
class CommentComposerSheet extends StatefulWidget {
  const CommentComposerSheet({
    super.key,
    required this.controller,
    this.replyTo,
  });

  final CommentController controller;
  final DramaComment? replyTo;

  @override
  State<CommentComposerSheet> createState() => _CommentComposerSheetState();
}

class _CommentComposerSheetState extends State<CommentComposerSheet>
    with WidgetsBindingObserver {
  final _input = TextEditingController();
  final _inputFocus = FocusNode();
  final _keyboardInset = KeyboardInsetNotifier.instance;
  bool _keyboardWasVisible = false;
  bool _hadFocus = false;
  bool _closing = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _input.addListener(_onInputChanged);
    _inputFocus.addListener(_onFocusChanged);
    _keyboardInset.addListener(_onKeyboardInsetChanged);
    widget.controller.addListener(_onControllerChanged);
    unawaited(_keyboardInset.start());
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    _input.removeListener(_onInputChanged);
    _inputFocus.removeListener(_onFocusChanged);
    _keyboardInset.removeListener(_onKeyboardInsetChanged);
    widget.controller.removeListener(_onControllerChanged);
    _input.dispose();
    _inputFocus.dispose();
    super.dispose();
  }

  void _onInputChanged() {
    if (mounted) setState(() {});
  }

  void _onControllerChanged() {
    if (mounted) setState(() {});
  }

  void _onFocusChanged() {
    if (!mounted) return;
    final hasFocus = _inputFocus.hasFocus;
    if (_hadFocus && !hasFocus) {
      _closeSheet();
    }
    _hadFocus = hasFocus;
    setState(() {});
  }

  void _onKeyboardInsetChanged() {
    if (!mounted) return;
    setState(() {});
    _syncKeyboardVisibility(_keyboardHeight(context));
  }

  @override
  void didChangeMetrics() {
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (!mounted) return;
      _syncKeyboardVisibility(_keyboardHeight(context));
    });
  }

  void _syncKeyboardVisibility(double keyboardHeight) {
    if (keyboardHeight > 0) {
      _keyboardWasVisible = true;
      return;
    }
    if (_keyboardWasVisible) _closeSheet();
  }

  double _keyboardHeight(BuildContext context) => math.max(
    MediaQuery.viewInsetsOf(context).bottom,
    _keyboardInset.value / MediaQuery.devicePixelRatioOf(context),
  );

  void _closeSheet() {
    if (_closing || !mounted) return;
    _closing = true;
    Navigator.pop(context);
  }

  Future<void> _submit() async {
    if (widget.controller.submitting) return;
    final text = _input.text.trim();
    if (text.isEmpty) return;
    unawaited(context.read<Haptics>().lightImpact());
    final result = await widget.controller.publish(
      text,
      replyTo: widget.replyTo,
    );
    if (!mounted) return;
    if (result.isSuccess) {
      _closing = true;
      Navigator.pop(context, true);
      return;
    }
    final l10n = AppLocalizations.of(context)!;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(result.errorMessage ?? l10n.commentPostFailed)),
    );
  }

  Future<void> _authenticate() async {
    await ensureSignedIn(context);
    if (!mounted || !context.read<AuthController>().isSignedIn) return;
    _inputFocus.requestFocus();
  }

  @override
  Widget build(BuildContext context) {
    final screenHeight = MediaQuery.sizeOf(context).height;
    final halfHeight = (screenHeight * 0.5).roundToDouble();
    final maxHeight = math.max(
      0.0,
      screenHeight - MediaQuery.paddingOf(context).top,
    );
    final sheetHeight = math.min(halfHeight, maxHeight);
    final keyboardHeight = _keyboardHeight(context);
    final l10n = AppLocalizations.of(context)!;
    final signedIn = context.watch<AuthController>().isSignedIn;
    final hasContent = _input.text.trim().isNotEmpty;
    final canPost = signedIn && hasContent && !widget.controller.submitting;
    final multiline = _input.text.contains('\n');

    return AnimatedPadding(
      duration: const Duration(milliseconds: 200),
      curve: Curves.easeOut,
      padding: EdgeInsets.only(bottom: keyboardHeight),
      child: SizedBox(
        key: const Key('comment-composer-sheet'),
        height: sheetHeight,
        child: Material(
          color: AppColors.card,
          clipBehavior: Clip.antiAlias,
          borderRadius: const BorderRadius.vertical(
            top: Radius.circular(_sheetRadius),
          ),
          child: SafeArea(
            top: false,
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 16, 16, 12),
              child: TextFieldTapRegion(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    if (widget.replyTo != null)
                      Padding(
                        padding: const EdgeInsets.only(bottom: 8),
                        child: Text(
                          l10n.replyingTo(
                            widget.replyTo!.nickname.isEmpty
                                ? l10n.anonymousUser
                                : widget.replyTo!.nickname,
                          ),
                          style: const TextStyle(
                            color: AppColors.muted,
                            fontSize: 12,
                          ),
                        ),
                      ),
                    Expanded(
                      child: Align(
                        alignment: Alignment.topCenter,
                        child: Container(
                          decoration: BoxDecoration(
                            color: AppColors.commentInput,
                            borderRadius: BorderRadius.circular(_inputRadius),
                          ),
                          child: TextField(
                            key: const Key('comment-composer-input'),
                            autofocus: true,
                            controller: _input,
                            focusNode: _inputFocus,
                            readOnly: !signedIn,
                            canRequestFocus: signedIn,
                            minLines: 1,
                            maxLines: 4,
                            maxLength: _maxCommentLength,
                            textAlignVertical: multiline
                                ? TextAlignVertical.top
                                : TextAlignVertical.center,
                            style: TextStyle(
                              color: AppColors.cream,
                              fontSize: 15,
                              height: multiline ? 1.4 : null,
                            ),
                            cursorColor: AppColors.blue,
                            decoration: InputDecoration(
                              hintText: signedIn
                                  ? l10n.writeComment
                                  : l10n.commentLoginHint,
                              hintStyle: const TextStyle(
                                color: AppColors.muted,
                                fontSize: 14,
                              ),
                              counterText: '',
                              contentPadding: const EdgeInsets.symmetric(
                                horizontal: 16,
                                vertical: 12,
                              ),
                              border: InputBorder.none,
                              enabledBorder: InputBorder.none,
                              focusedBorder: InputBorder.none,
                            ),
                            onTap: signedIn ? null : _authenticate,
                            onTapOutside: (_) {
                              _inputFocus.unfocus();
                              _closeSheet();
                            },
                          ),
                        ),
                      ),
                    ),
                    const SizedBox(height: 12),
                    Align(
                      alignment: Alignment.centerRight,
                      child: SizedBox(
                        height: _postButtonHeight,
                        child: TextButton(
                          key: const Key('comment-composer-post'),
                          onPressed: canPost ? _submit : null,
                          style: TextButton.styleFrom(
                            minimumSize: const Size(0, _postButtonHeight),
                            padding: const EdgeInsets.symmetric(horizontal: 16),
                            tapTargetSize: MaterialTapTargetSize.shrinkWrap,
                            backgroundColor: hasContent
                                ? AppColors.blue.withValues(alpha: 0.12)
                                : AppColors.raised,
                            foregroundColor: AppColors.blue,
                            disabledForegroundColor: AppColors.muted,
                            disabledBackgroundColor: AppColors.raised,
                            shape: RoundedRectangleBorder(
                              borderRadius: BorderRadius.circular(8),
                            ),
                          ),
                          child: Text(
                            l10n.postComment,
                            style: const TextStyle(
                              fontSize: 14,
                              fontWeight: FontWeight.w600,
                            ),
                          ),
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}