// Author: fruit.com.cn

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

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

import '../../../core/data/models/comment.dart';
import '../../../core/data/models/drama.dart';
import '../../../core/data/repositories/comment_repository.dart';
import '../../../core/data/repositories/interaction_repository.dart';
import '../../../core/data/services/comment_controller.dart';
import '../../../core/formatting/error_text.dart';
import '../../../core/theme/app_colors.dart';
import '../../../core/widgets/app_glow_panel.dart';
import '../../../core/widgets/empty_state.dart';
import '../../../l10n/app_localizations.dart';
import 'comment_composer_sheet.dart';
import 'comment_thread.dart';
import 'comment_tile.dart';

const double _composerRadius = 22;
const double _composerHeight = 44;
const double _sendButtonSize = 38;
const double _sheetRadius = 20;
const double _headerHeight = 44;
const double _composerTopGap = 8;

/// 服务端评论底部弹窗：匿名列表、游标翻页、回复与设备身份发布。
class DramaCommentsSheet extends StatefulWidget {
  const DramaCommentsSheet({super.key, required this.drama, this.episodeId});

  final Drama drama;
  final String? episodeId;

  @override
  State<DramaCommentsSheet> createState() => _DramaCommentsSheetState();
}

class _DramaCommentsSheetState extends State<DramaCommentsSheet> {
  late final CommentRepository _comments;
  late final CommentController _controller;
  OverlayEntry? _composerOverlay;
  OverlayEntry? _successOverlay;
  Timer? _successOverlayTimer;
  int? _serverCount;
  int _countRequest = 0;

  @override
  void initState() {
    super.initState();
    _comments = context.read<CommentRepository>();
    _controller = CommentController(
      comments: _comments,
      interactions: context.read<InteractionRepository>(),
      dramaId: widget.drama.id,
      episodeId: widget.episodeId,
    );
    unawaited(_controller.load());
    unawaited(_refreshCount());
  }

  @override
  void dispose() {
    _removeComposerOverlay();
    _successOverlayTimer?.cancel();
    _successOverlay?.remove();
    _controller.dispose();
    super.dispose();
  }

  void _beginReply(DramaComment comment) {
    unawaited(_openComposer(replyTo: comment));
  }

  Future<void> _refreshCount() async {
    final request = ++_countRequest;
    try {
      final count = await _comments.count(
        widget.drama.id,
        episodeId: widget.episodeId,
      );
      if (!mounted || request != _countRequest) return;
      setState(() => _serverCount = count);
    } catch (_) {
      if (!mounted || request != _countRequest) return;
      setState(() => _serverCount = null);
    }
  }

  Future<void> _openComposer({DramaComment? replyTo}) async {
    if (!mounted) return;
    _removeComposerOverlay();
    final entry = OverlayEntry(
      builder: (_) => CommentComposerSheet(
        controller: _controller,
        replyTo: replyTo,
        onDismiss: _closeComposer,
        onPosted: _handleComposerPosted,
      ),
    );
    setState(() => _composerOverlay = entry);
    Overlay.of(context, rootOverlay: true).insert(entry);
  }

  void _handleComposerPosted() {
    _closeComposer();
    _showPostSuccess();
    unawaited(_refreshCount());
  }

  void _closeComposer() {
    if (!mounted) {
      _removeComposerOverlay();
      return;
    }
    setState(_removeComposerOverlay);
  }

  void _removeComposerOverlay() {
    final entry = _composerOverlay;
    _composerOverlay = null;
    if (entry?.mounted ?? false) entry!.remove();
    FocusManager.instance.primaryFocus?.unfocus();
  }

  void _handleDismissLayerTap() {
    Navigator.pop(context);
  }

  void _showPostSuccess() {
    _successOverlayTimer?.cancel();
    _successOverlay?.remove();
    final l10n = AppLocalizations.of(context)!;
    final entry = OverlayEntry(
      builder: (_) =>
          _CommentPostSuccessOverlay(message: l10n.commentPostSuccess),
    );
    _successOverlay = entry;
    Overlay.of(context, rootOverlay: true).insert(entry);
    _successOverlayTimer = Timer(const Duration(milliseconds: 1200), () {
      if (entry.mounted) entry.remove();
      if (identical(_successOverlay, entry)) _successOverlay = null;
    });
  }

  double _sheetHeight(BuildContext context) {
    final screenHeight = MediaQuery.sizeOf(context).height;
    final topSafeArea = MediaQuery.paddingOf(context).top;
    final halfHeight = (screenHeight * 0.5).roundToDouble();
    final maxHeight = math.max(0.0, screenHeight - topSafeArea);
    return math.min(halfHeight, maxHeight);
  }

  @override
  Widget build(BuildContext context) {
    final sheetHeight = _sheetHeight(context);
    final content = Stack(
      fit: StackFit.expand,
      children: [
        Positioned.fill(
          child: GestureDetector(
            key: const Key('player-comments-dismiss-layer'),
            behavior: HitTestBehavior.opaque,
            onTap: _handleDismissLayerTap,
          ),
        ),
        Align(
          alignment: Alignment.bottomCenter,
          child: GestureDetector(
            behavior: HitTestBehavior.opaque,
            onTap: () {},
            child: KeyedSubtree(
              key: const Key('player-comments-sheet'),
              child: SizedBox(
                key: const Key('comment-sheet-constraints'),
                height: sheetHeight,
                child: AppGlowPanel(
                  borderRadius: const BorderRadius.vertical(
                    top: Radius.circular(_sheetRadius),
                  ),
                  border: false,
                  child: Container(
                    decoration: const BoxDecoration(color: AppColors.transparent),
                    child: SafeArea(
                    top: false,
                    child: ListenableBuilder(
                      listenable: _controller,
                      builder: (context, _) {
                        return Padding(
                          padding: const EdgeInsets.symmetric(horizontal: 16),
                          child: _content(context),
                        );
                      },
                      ),
                    ),
                  ),
                ),
              ),
            ),
          ),
        ),
      ],
    );
    return PopScope(
      canPop: _composerOverlay == null,
      onPopInvokedWithResult: (didPop, _) {
        if (!didPop && _composerOverlay != null) {
          FocusManager.instance.primaryFocus?.unfocus();
          unawaited(
            SystemChannels.textInput.invokeMethod<void>('TextInput.hide'),
          );
        }
      },
      child: content,
    );
  }

  Widget _content(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final count = _serverCount ?? _controller.exactCount;
    final composerReserve = _composerHeight + _composerTopGap;
    return Column(
      key: const Key('comment-sheet-content'),
      mainAxisSize: MainAxisSize.min,
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        SizedBox(
          height: _headerHeight,
          width: double.infinity,
          child: Stack(
            alignment: Alignment.center,
            children: [
              Text(
                count == null ? l10n.comments : l10n.commentsWithCount(count),
                key: const Key('comment-count-label'),
                textAlign: TextAlign.center,
                style: const TextStyle(
                  color: AppColors.onSurface,
                  fontSize: 16,
                  fontWeight: FontWeight.w400,
                ),
              ),
              Positioned(
                left: 0,
                child: SizedBox.square(
                  dimension: 44,
                  child: IconButton(
                    key: const Key('player-comments-close'),
                    tooltip: l10n.close,
                    padding: EdgeInsets.zero,
                    onPressed: () => Navigator.pop(context),
                    icon: const Icon(
                      Icons.keyboard_arrow_down_rounded,
                      size: 24,
                      color: AppColors.cream,
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
        Expanded(child: _list(l10n, composerReserve: composerReserve)),
        Padding(
          key: const Key('comment-composer-area'),
          padding: const EdgeInsets.only(top: _composerTopGap),
          child: _fakeComposer(l10n),
        ),
      ],
    );
  }

  Widget _list(AppLocalizations l10n, {required double composerReserve}) {
    if (_controller.loading && _controller.comments.isEmpty) {
      return const Padding(
        padding: EdgeInsets.only(top: 4),
        child: Center(
          child: CircularProgressIndicator(key: Key('comment-list-loading')),
        ),
      );
    }
    if (_controller.error != null && _controller.comments.isEmpty) {
      return Padding(
        padding: const EdgeInsets.only(top: 4),
        child: EmptyState(
          key: const Key('comment-list-error'),
          icon: Icons.cloud_off_rounded,
          title: errorText(l10n, _controller.error, l10n.commentsLoadFailed),
          actionLabel: l10n.retry,
          actionKey: const Key('comment-list-retry'),
          onAction: _controller.load,
          compact: true,
        ),
      );
    }
    if (_controller.comments.isEmpty) {
      return Padding(
        padding: const EdgeInsets.only(top: 4),
        child: EmptyState(
          key: const Key('comment-list-empty'),
          icon: Icons.chat_bubble_outline_rounded,
          title: l10n.noComments,
          compact: true,
        ),
      );
    }
    return ListView.builder(
      key: const Key('comment-list'),
      padding: EdgeInsets.only(top: 4, bottom: composerReserve),
      itemCount: _controller.comments.length + 1,
      itemBuilder: (context, index) {
        if (index == _controller.comments.length) return _footer(l10n);
        return CommentThread(
          comment: _controller.comments[index],
          controller: _controller,
          handlers: CommentInteractionHandlers(onReply: _beginReply),
        );
      },
    );
  }

  Widget _footer(AppLocalizations l10n) {
    if (_controller.loadingMore) {
      return const Padding(
        padding: EdgeInsets.symmetric(vertical: 12),
        child: Center(child: CircularProgressIndicator()),
      );
    }
    if (_controller.hasMore) {
      return TextButton(
        key: const Key('comment-list-load-more'),
        onPressed: _controller.loadMore,
        child: Text(l10n.loadMore),
      );
    }
    if (_controller.comments.isNotEmpty) {
      return Padding(
        key: const Key('paged-list-no-more'),
        padding: const EdgeInsets.symmetric(vertical: 12),
        child: Text(
          l10n.noMoreItems,
          textAlign: TextAlign.center,
          style: const TextStyle(color: AppColors.textHint, fontSize: 12),
        ),
      );
    }
    return const SizedBox(height: 8);
  }

  Widget _fakeComposer(AppLocalizations l10n) {
    return GestureDetector(
      behavior: HitTestBehavior.opaque,
      onTap: _openComposer,
      child: Container(
        key: const Key('comment-input-placeholder'),
        height: _composerHeight,
        padding: const EdgeInsets.only(right: 6),
        decoration: BoxDecoration(
          color: AppColors.commentInput,
          borderRadius: BorderRadius.circular(_composerRadius),
        ),
        child: Row(
          children: [
            Expanded(
              child: Align(
                alignment: Alignment.centerLeft,
                child: Padding(
                  padding: const EdgeInsets.only(left: 16),
                  child: Text(
                    l10n.writeComment,
                    key: const Key('comment-input-placeholder-label'),
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                    style: const TextStyle(
                      color: AppColors.muted,
                      fontSize: 14,
                      height: 1,
                    ),
                  ),
                ),
              ),
            ),
            SizedBox.square(
              dimension: _sendButtonSize,
              child: IconButton.filled(
                key: const Key('comment-post'),
                tooltip: l10n.postComment,
                padding: EdgeInsets.zero,
                iconSize: 18,
                onPressed: _openComposer,
                icon: const Icon(Icons.send_rounded),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _CommentPostSuccessOverlay extends StatelessWidget {
  const _CommentPostSuccessOverlay({required this.message});

  final String message;

  @override
  Widget build(BuildContext context) {
    return Positioned.fill(
      child: IgnorePointer(
        child: Align(
          alignment: const Alignment(0, -0.4),
          child: Semantics(
            liveRegion: true,
            child: Material(
              type: MaterialType.transparency,
              child: Container(
                key: const Key('comment-post-success-snackbar'),
                padding: const EdgeInsets.symmetric(
                  horizontal: 16,
                  vertical: 10,
                ),
                decoration: BoxDecoration(
                  color: AppColors.mediaBlack.withValues(alpha: 0.82),
                  borderRadius: BorderRadius.circular(8),
                ),
                child: Text(
                  message,
                  textAlign: TextAlign.center,
                  style: const TextStyle(
                    color: AppColors.onPrimary,
                    fontSize: 14,
                    decoration: TextDecoration.none,
                    decorationColor: AppColors.transparent,
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}