import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:go_router/go_router.dart';
import 'package:url_launcher/url_launcher.dart';

import 'package:social_app/core/l10n/l10n.dart';
import 'package:social_app/core/ui_schema/navigation/ui_schema_navigation.dart';
import 'package:social_app/core/theme/design_tokens.dart';
import 'package:social_app/shared/widgets/toast/toast.dart';
import 'package:social_app/shared/widgets/toast/toast_type.dart';

const _titleFontSize = AppSpacing.lg + 1;
const _bodyFontSize = AppSpacing.md;
const _captionFontSize = AppSpacing.sm + AppSpacing.xs / 2;
const _codeFontSize = AppSpacing.sm + AppSpacing.xs;
const _buttonFontSize = AppSpacing.sm + AppSpacing.xs;
const _statusLabelTokenPrefix = 'ui.status.';

class UiSchemaRenderer {
  final BuildContext context;
  final ColorScheme colorScheme;

  UiSchemaRenderer(this.context, this.colorScheme);

  Widget renderSchema(Map<String, dynamic>? schema) {
    if (schema == null || schema.isEmpty) {
      return const SizedBox.shrink();
    }
    final root = _asMap(schema['root']);
    if (root == null) {
      return _fallback(L10n.current.uiSchemaInvalid);
    }
    return _renderLayoutNode(root);
  }

  Widget _renderLayoutNode(Map<String, dynamic> node) {
    final type = _asString(node['type']);
    return switch (type) {
      'stack' => _renderStack(node),
      'grid' => _renderGrid(node),
      _ => _fallback(L10n.current.uiSchemaUnsupportedLayout(type)),
    };
  }

  Widget _renderNode(Map<String, dynamic> node) {
    final type = _asString(node['type']);
    if (node['visible'] == false) {
      return const SizedBox.shrink();
    }
    return switch (type) {
      'text' => _renderText(node),
      'icon' => _renderIcon(node),
      'badge' => _renderBadge(node),
      'button' => _renderButton(node),
      'kv' => _renderKv(node),
      'divider' => _renderDivider(node),
      'stack' => _renderStack(node),
      'grid' => _renderGrid(node),
      _ => _fallback(L10n.current.uiSchemaUnknownNode(type)),
    };
  }

  Widget _renderStack(Map<String, dynamic> node) {
    final children = _asList(
      node['children'],
    ).whereType<Map<String, dynamic>>().map(_renderNode).toList();
    final gap = _asDouble(node['gap'], fallback: AppSpacing.sm);
    final direction = _asString(node['direction'], fallback: 'vertical');

    Widget content;
    if (direction == 'horizontal') {
      content = Wrap(
        direction: Axis.horizontal,
        spacing: gap,
        runSpacing: gap,
        crossAxisAlignment: WrapCrossAlignment.center,
        children: children,
      );
    } else {
      content = Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: _withGap(children, gap),
      );
    }
    return _wrapSurface(node, content);
  }

  Widget _renderGrid(Map<String, dynamic> node) {
    final children = _asList(
      node['children'],
    ).whereType<Map<String, dynamic>>().map(_renderNode).toList();
    final columns = _asInt(node['columns'], fallback: 2).clamp(1, 3);
    final gap = _asDouble(node['gap'], fallback: AppSpacing.sm);
    return _wrapSurface(
      node,
      GridView.count(
        crossAxisCount: columns,
        crossAxisSpacing: gap,
        mainAxisSpacing: gap,
        childAspectRatio: 1.6,
        physics: const NeverScrollableScrollPhysics(),
        shrinkWrap: true,
        children: children,
      ),
    );
  }

  Widget _renderText(Map<String, dynamic> node) {
    final role = _asString(node['role'], fallback: 'body');
    final status = _asString(node['status']);
    final style = switch (role) {
      'title' => TextStyle(
        fontSize: _titleFontSize,
        fontWeight: FontWeight.w600,
        color: colorScheme.onSurface,
        height: 1.25,
      ),
      'subtitle' => TextStyle(
        fontSize: AppSpacing.md,
        fontWeight: FontWeight.w600,
        color: colorScheme.onSurface,
      ),
      'caption' => TextStyle(
        fontSize: _captionFontSize,
        color: colorScheme.onSurfaceVariant,
        height: 1.4,
      ),
      'code' => TextStyle(
        fontSize: _codeFontSize,
        color: colorScheme.onSurfaceVariant,
        fontFamily: 'monospace',
      ),
      _ => TextStyle(
        fontSize: _bodyFontSize,
        color: colorScheme.onSurfaceVariant,
        height: 1.4,
      ),
    };
    return Text(
      _asString(node['content']),
      maxLines: _asIntOrNull(node['maxLines']),
      overflow: TextOverflow.ellipsis,
      style: style.copyWith(color: _statusTextColor(status, style.color)),
    );
  }

  Widget _renderIcon(Map<String, dynamic> node) {
    final value = _asString(node['value']);
    if (_asString(node['source']) == 'emoji' && value.isNotEmpty) {
      return Text(value, style: const TextStyle(fontSize: 18));
    }
    return Icon(Icons.bubble_chart_rounded, color: _statusTextColor('', null));
  }

  Widget _renderBadge(Map<String, dynamic> node) {
    final status = _asString(node['status']);
    final resolvedLabel = _resolveStatusLabel(
      rawLabel: _asString(node['label']),
      status: status,
    );
    final statusDotColor = _statusBorder(status);
    return Padding(
      padding: const EdgeInsets.only(left: AppSpacing.xs / 2),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          Container(
            width: AppSpacing.xs,
            height: AppSpacing.xs,
            decoration: BoxDecoration(
              color: statusDotColor,
              shape: BoxShape.circle,
            ),
          ),
          const SizedBox(width: AppSpacing.xs),
          Text(
            resolvedLabel,
            style: TextStyle(
              fontSize: _captionFontSize,
              fontWeight: FontWeight.w600,
              color: colorScheme.onSurfaceVariant,
            ),
          ),
        ],
      ),
    );
  }

  Widget _renderButton(Map<String, dynamic> node) {
    final style = _asString(node['style'], fallback: 'secondary');
    final action = _asMap(node['action']);
    final disabled = node['disabled'] == true;
    final isPrimary = style == 'primary';
    final isGhost = style == 'ghost';
    final isDanger = style == 'danger';
    final backgroundColor = isPrimary
        ? colorScheme.primaryContainer
        : isGhost
        ? colorScheme.surface
        : isDanger
        ? colorScheme.errorContainer
        : colorScheme.surfaceContainerLow;
    final foregroundColor = isPrimary
        ? colorScheme.onPrimaryContainer
        : isDanger
        ? colorScheme.onErrorContainer
        : isGhost
        ? colorScheme.onSurfaceVariant
        : colorScheme.onSurfaceVariant;
    final borderColor = isPrimary
        ? colorScheme.primary.withValues(alpha: 0.3)
        : isGhost
        ? colorScheme.outlineVariant.withValues(alpha: 0.4)
        : isDanger
        ? colorScheme.error.withValues(alpha: 0.35)
        : colorScheme.outlineVariant.withValues(alpha: 0.4);
    return ElevatedButton(
      onPressed: disabled
          ? null
          : () async {
              await _handleAction(action);
            },
      style: ElevatedButton.styleFrom(
        elevation: 0,
        padding: const EdgeInsets.symmetric(
          horizontal: AppSpacing.md + AppSpacing.xs,
          vertical: AppSpacing.sm,
        ),
        minimumSize: const Size(0, AppSpacing.xxl + AppSpacing.xs),
        backgroundColor: backgroundColor,
        foregroundColor: foregroundColor,
        shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(AppRadius.full),
          side: BorderSide(color: borderColor),
        ),
      ),
      child: Text(
        _asString(node['label'], fallback: L10n.current.uiSchemaActionFallback),
        style: TextStyle(
          fontSize: _buttonFontSize,
          fontWeight: isPrimary ? FontWeight.w700 : FontWeight.w600,
        ),
      ),
    );
  }

  Future<void> _handleAction(Map<String, dynamic>? action) async {
    if (action == null || action.isEmpty) {
      Toast.show(
        context,
        L10n.current.uiSchemaActionNotImplemented,
        type: ToastType.warning,
      );
      return;
    }

    final type = _asString(action['type']);
    switch (type) {
      case 'navigation':
        _handleNavigationAction(action);
        return;
      case 'url':
        await _handleUrlAction(action);
        return;
      case 'copy':
        _handleCopyAction(action);
        return;
      case 'event':
      case 'tool':
      case 'payload':
      default:
        Toast.show(
          context,
          L10n.current.uiSchemaActionNotImplemented,
          type: ToastType.info,
        );
    }
  }

  Future<void> _handleUrlAction(Map<String, dynamic> action) async {
    final rawUrl = _asString(action['url']).trim();
    if (!_isValidExternalUrl(rawUrl)) {
      Toast.show(
        context,
        L10n.current.uiSchemaUrlInvalid,
        type: ToastType.error,
      );
      return;
    }

    final uri = Uri.tryParse(rawUrl);
    if (uri == null) {
      Toast.show(
        context,
        L10n.current.uiSchemaUrlInvalid,
        type: ToastType.error,
      );
      return;
    }

    final target = _asString(action['target'], fallback: '_blank');
    final mode = target == '_self'
        ? LaunchMode.platformDefault
        : LaunchMode.externalApplication;

    try {
      final launched = await launchUrl(uri, mode: mode);
      if (!context.mounted) {
        return;
      }
      if (!launched) {
        debugPrint('UiSchemaRenderer: failed to launch URL: $rawUrl');
        Toast.show(
          context,
          L10n.current.uiSchemaUrlOpenFailed,
          type: ToastType.error,
        );
      }
    } catch (error) {
      debugPrint('UiSchemaRenderer: URL launch error for $rawUrl: $error');
      if (!context.mounted) {
        return;
      }
      Toast.show(
        context,
        L10n.current.uiSchemaUrlOpenFailed,
        type: ToastType.error,
      );
    }
  }

  void _handleNavigationAction(Map<String, dynamic> action) {
    final path = _asString(action['path']).trim();
    if (!isValidInternalNavigationPath(path)) {
      Toast.show(
        context,
        L10n.current.uiSchemaNavigationInvalidPath,
        type: ToastType.error,
      );
      return;
    }

    final params = _asMap(action['params']);
    if (params != null && !_areScalarNavigationParams(params)) {
      Toast.show(
        context,
        L10n.current.uiSchemaNavigationInvalidParams,
        type: ToastType.error,
      );
      return;
    }

    final target = buildUiSchemaNavigationTarget(path: path, params: params);

    try {
      context.push(target);
    } catch (error) {
      debugPrint('UiSchemaRenderer: navigation failed for $target: $error');
      Toast.show(
        context,
        L10n.current.uiSchemaNavigationInvalidPath,
        type: ToastType.error,
      );
    }
  }

  void _handleCopyAction(Map<String, dynamic> action) {
    final content = _asString(action['content']);
    if (content.isEmpty) {
      Toast.show(
        context,
        L10n.current.uiSchemaActionNotImplemented,
        type: ToastType.warning,
      );
      return;
    }

    Clipboard.setData(ClipboardData(text: content));
    final successMessage = _asString(
      action['successMessage'],
      fallback: L10n.current.commonCopySuccess,
    );
    Toast.show(context, successMessage, type: ToastType.success);
  }

  static bool _isValidExternalUrl(String url) {
    if (url.isEmpty) return false;
    final uri = Uri.tryParse(url);
    if (uri == null || !uri.hasScheme) return false;
    final scheme = uri.scheme.toLowerCase();
    if (scheme == 'http' || scheme == 'https') {
      if (uri.host.isEmpty || uri.userInfo.isNotEmpty) {
        return false;
      }
      if (_isLocalOrPrivateHost(uri.host)) {
        return false;
      }
      return true;
    }
    return scheme == 'mailto' || scheme == 'tel' || scheme == 'sms';
  }

  static bool _areScalarNavigationParams(Map<String, dynamic> params) {
    for (final value in params.values) {
      if (value is String || value is num || value is bool) {
        continue;
      }
      return false;
    }
    return true;
  }

  static bool _isLocalOrPrivateHost(String host) {
    final normalizedHost = host.toLowerCase();
    if (normalizedHost.contains(':')) {
      return true;
    }
    if (int.tryParse(normalizedHost) != null) {
      return true;
    }
    if (normalizedHost == 'localhost' ||
        normalizedHost == '127.0.0.1' ||
        normalizedHost == '::1') {
      return true;
    }

    final ipv4 = normalizedHost.split('.');
    if (ipv4.length != 4) {
      return false;
    }
    final octets = <int>[];
    for (final part in ipv4) {
      final parsed = int.tryParse(part);
      if (parsed == null || parsed < 0 || parsed > 255) {
        return false;
      }
      octets.add(parsed);
    }

    final first = octets[0];
    final second = octets[1];
    if (first == 10 || first == 127 || first == 0) {
      return true;
    }
    if (first == 169 && second == 254) {
      return true;
    }
    if (first == 192 && second == 168) {
      return true;
    }
    if (first == 172 && second >= 16 && second <= 31) {
      return true;
    }
    return false;
  }

  Widget _renderKv(Map<String, dynamic> node) {
    final items = _asList(
      node['items'],
    ).whereType<Map<String, dynamic>>().toList();
    if (items.isEmpty) {
      return const SizedBox.shrink();
    }
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: _withGap(
        items.map((item) {
          final label = _asString(
            item['label'],
            fallback: _asString(item['key']),
          );
          final value = item['value']?.toString() ?? '-';
          return Container(
            width: double.infinity,
            padding: const EdgeInsets.symmetric(vertical: AppSpacing.xs),
            decoration: BoxDecoration(
              border: Border(
                bottom: BorderSide(
                  color: colorScheme.outlineVariant.withValues(alpha: 0.2),
                ),
              ),
            ),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Expanded(
                  flex: 3,
                  child: Text(
                    label,
                    style: TextStyle(
                      fontSize: _captionFontSize,
                      color: colorScheme.onSurfaceVariant.withValues(
                        alpha: 0.72,
                      ),
                    ),
                  ),
                ),
                const SizedBox(width: AppSpacing.sm),
                Expanded(
                  flex: 5,
                  child: Text(
                    value,
                    style: TextStyle(
                      fontSize: _bodyFontSize,
                      color: colorScheme.onSurface,
                      fontWeight: FontWeight.w400,
                    ),
                  ),
                ),
              ],
            ),
          );
        }).toList(),
        AppSpacing.xs,
      ),
    );
  }

  Widget _renderDivider(Map<String, dynamic> node) {
    final inset = _asDouble(node['inset'], fallback: 0);
    return Padding(
      padding: EdgeInsets.symmetric(horizontal: inset),
      child: Divider(height: 1, color: colorScheme.outlineVariant),
    );
  }

  Widget _wrapSurface(Map<String, dynamic> node, Widget child) {
    final appearance = _asString(node['appearance'], fallback: 'plain');
    final status = _asString(node['status']);
    if (appearance == 'plain') {
      return child;
    }
    final bg = switch (appearance) {
      'section' => colorScheme.surfaceContainerLow,
      'card' =>
        status == 'success'
            ? colorScheme.primaryContainer.withValues(alpha: 0.05)
            : colorScheme.surfaceContainerLow.withValues(alpha: 0.5),
      _ => _statusBackground(status),
    };
    final borderColor = switch (status) {
      'success' => colorScheme.primary.withValues(alpha: 0.1),
      'warning' => colorScheme.outlineVariant,
      'error' => colorScheme.error.withValues(alpha: 0.22),
      _ => colorScheme.outlineVariant,
    };
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(AppSpacing.md),
      decoration: BoxDecoration(
        color: bg,
        borderRadius: BorderRadius.circular(AppRadius.xl),
        border: Border.all(color: borderColor.withValues(alpha: 0.4)),
      ),
      child: child,
    );
  }

  Widget _fallback(String text) {
    return Container(
      padding: const EdgeInsets.all(AppSpacing.md),
      decoration: BoxDecoration(
        color: colorScheme.secondaryContainer,
        border: Border.all(color: colorScheme.secondary),
        borderRadius: BorderRadius.circular(AppRadius.md),
      ),
      child: Text(
        text,
        style: TextStyle(
          fontSize: _buttonFontSize,
          color: colorScheme.onSecondaryContainer,
        ),
      ),
    );
  }

  List<Widget> _withGap(List<Widget> widgets, double gap) {
    if (widgets.isEmpty) return const [];
    return [
      widgets.first,
      for (int i = 1; i < widgets.length; i++) ...[
        SizedBox(height: gap),
        widgets[i],
      ],
    ];
  }

  Color _statusBackground(String status) {
    return switch (status) {
      'success' => colorScheme.primaryContainer.withValues(alpha: 0.3),
      'warning' => colorScheme.secondaryContainer,
      'error' => colorScheme.errorContainer,
      'pending' => colorScheme.primaryContainer,
      _ => colorScheme.surfaceContainerHighest,
    };
  }

  Color _statusBorder(String status) {
    return switch (status) {
      'success' => colorScheme.primary,
      'warning' => colorScheme.secondary,
      'error' => colorScheme.error,
      'pending' => colorScheme.primary,
      _ => colorScheme.outlineVariant,
    };
  }

  Color? _statusTextColor(String status, Color? fallback) {
    return switch (status) {
      'success' => colorScheme.onSurfaceVariant,
      'warning' => colorScheme.onSecondaryContainer,
      'error' => colorScheme.onErrorContainer,
      'pending' => colorScheme.onPrimaryContainer,
      _ => fallback,
    };
  }

  String _resolveStatusLabel({
    required String rawLabel,
    required String status,
  }) {
    final normalizedStatus = status.trim().toLowerCase();
    final normalizedLabel = rawLabel.trim().toLowerCase();
    final bareLabel = normalizedLabel.startsWith(_statusLabelTokenPrefix)
        ? normalizedLabel.substring(_statusLabelTokenPrefix.length)
        : normalizedLabel;

    final isTokenLabel = normalizedLabel.startsWith(_statusLabelTokenPrefix);
    final isLegacyStatusLabel = bareLabel == normalizedStatus;

    if (isTokenLabel || isLegacyStatusLabel) {
      return _tryLocalizedStatusLabel(bareLabel) ?? rawLabel;
    }
    return rawLabel;
  }

  String? _tryLocalizedStatusLabel(String status) {
    final l10n = L10n.current;
    return switch (status) {
      'success' => l10n.uiSchemaStatusSuccess,
      'warning' => l10n.uiSchemaStatusWarning,
      'error' => l10n.uiSchemaStatusError,
      'pending' => l10n.uiSchemaStatusPending,
      'info' => l10n.uiSchemaStatusInfo,
      _ => null,
    };
  }

  static Map<String, dynamic>? _asMap(Object? value) {
    if (value is Map<String, dynamic>) {
      return value;
    }
    if (value is Map) {
      return Map<String, dynamic>.from(value);
    }
    return null;
  }

  static List<dynamic> _asList(Object? value) {
    return value is List ? value : const [];
  }

  static String _asString(Object? value, {String fallback = ''}) {
    return value is String ? value : fallback;
  }

  static int _asInt(Object? value, {int fallback = 0}) {
    if (value is int) {
      return value;
    }
    if (value is double) {
      return value.toInt();
    }
    if (value is String) {
      return int.tryParse(value) ?? fallback;
    }
    return fallback;
  }

  static int? _asIntOrNull(Object? value) {
    if (value == null) {
      return null;
    }
    return _asInt(value);
  }

  static double _asDouble(Object? value, {double fallback = 0}) {
    if (value is double) {
      return value;
    }
    if (value is int) {
      return value.toDouble();
    }
    if (value is String) {
      return double.tryParse(value) ?? fallback;
    }
    return fallback;
  }
}