import 'package:flutter/material.dart';

import '../models/question_source_preference.dart';
import '../repositories/question_source_config_repository.dart';
import '../routes/app_routes.dart';
import '../services/questions_hub_service.dart';
import '../theme/app_theme.dart';

/// Configure which question API sources are active and their relative mix.
class QuestionSourceSettingsSheet extends StatefulWidget {
  const QuestionSourceSettingsSheet({
    super.key,
    required this.initialPreferences,
  });

  final List<QuestionSourcePreference> initialPreferences;

  static Future<void> show(BuildContext context) {
    return showDialog<void>(
      context: context,
      builder: (BuildContext context) {
        return Dialog(
          key: const Key('question-source-settings-dialog'),
          insetPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 24),
          child: ConstrainedBox(
            constraints: const BoxConstraints(maxWidth: 520),
            child: QuestionSourceSettingsSheet(
              initialPreferences:
                  QuestionSourceConfigRepository.instance.current,
            ),
          ),
        );
      },
    );
  }

  @override
  State<QuestionSourceSettingsSheet> createState() =>
      _QuestionSourceSettingsSheetState();
}

class _QuestionSourceSettingsSheetState extends State<QuestionSourceSettingsSheet> {
  late List<QuestionSourcePreference> _draft;
  String? _validationMessage;
  bool _saving = false;
  bool _resettingSpelling = false;

  @override
  void initState() {
    super.initState();
    _draft = QuestionSourceConfigRepository.mergeWithDefaults(
      widget.initialPreferences,
    ).map((QuestionSourcePreference source) => source.copyWith()).toList();
  }

  void _updateSource(int index, QuestionSourcePreference next) {
    setState(() {
      _draft[index] = next;
      _validationMessage = null;
    });
  }

  void _openSpellingWordList(BuildContext context) {
    Navigator.of(context).pushNamed(AppRoutes.spellingWordList);
  }

  Future<void> _confirmResetSpellingProgress() async {
    final bool? confirmed = await showDialog<bool>(
      context: context,
      builder: (BuildContext dialogContext) {
        return AlertDialog(
          key: const Key('spelling-progress-reset-confirm-dialog'),
          title: const Text('Reset spelling progress?'),
          content: const Text(
            'This deletes your spelling question links and familiarity scores '
            'and returns spelling to its initial state. You cannot undo this.',
          ),
          actions: <Widget>[
            TextButton(
              onPressed: () => Navigator.of(dialogContext).pop(false),
              child: const Text('Cancel'),
            ),
            TextButton(
              key: const Key('spelling-progress-reset-confirm-button'),
              onPressed: () => Navigator.of(dialogContext).pop(true),
              child: const Text('Reset'),
            ),
          ],
        );
      },
    );
    if (confirmed != true || !mounted) {
      return;
    }

    setState(() {
      _resettingSpelling = true;
      _validationMessage = null;
    });

    final bool ok =
        await QuestionsHubService.instance.resetSpellingProgress();
    if (!mounted) {
      return;
    }
    setState(() {
      _resettingSpelling = false;
      if (!ok) {
        _validationMessage = 'Could not reset spelling progress.';
      }
    });
  }

  Future<void> _save() async {
    final bool hasEnabled =
        _draft.any((QuestionSourcePreference source) => source.enabled);
    if (!hasEnabled) {
      setState(() {
        _validationMessage = 'Enable at least one question source.';
      });
      return;
    }

    setState(() {
      _saving = true;
      _validationMessage = null;
    });

    try {
      final List<QuestionSourcePreference> normalized =
          QuestionSourceConfigRepository.mergeWithDefaults(_draft);
      await QuestionSourceConfigRepository.instance.saveAll(normalized);
      if (mounted) {
        Navigator.of(context).pop();
      }
    } catch (_) {
      if (!mounted) {
        return;
      }
      setState(() {
        _saving = false;
        _validationMessage = 'Could not save question sources.';
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final Map<String, int> mix =
        QuestionSourceConfigRepository.effectiveMix(_draft);
    final int enabledCount =
        _draft.where((QuestionSourcePreference s) => s.enabled).length;

    return Stack(
      children: <Widget>[
        Padding(
      padding: const EdgeInsets.fromLTRB(16, 12, 8, 16),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: <Widget>[
          Row(
            children: <Widget>[
              const Icon(Icons.settings, color: AppColors.accent, size: 22),
              const SizedBox(width: 8),
              const Expanded(
                child: Text(
                  'Question sources',
                  style: TextStyle(
                    fontSize: 18,
                    fontWeight: FontWeight.w700,
                    color: AppColors.textPrimary,
                  ),
                ),
              ),
              IconButton(
                key: const Key('question-source-settings-close'),
                tooltip: 'Close',
                onPressed: _resettingSpelling || _saving
                    ? null
                    : () => Navigator.of(context).pop(),
                icon: const Icon(Icons.close),
              ),
            ],
          ),
          Text(
            'Choose which pipelines may deliver questions and set their relative mix.',
            style: Theme.of(context).textTheme.bodyLarge,
          ),
          const SizedBox(height: 12),
          Flexible(
            child: SingleChildScrollView(
              child: Column(
                children: <Widget>[
                  for (int index = 0; index < _draft.length; index++)
                    _QuestionSourceRow(
                      key: Key('question-source-row-${_draft[index].id}'),
                      source: _draft[index],
                      effectivePercent: mix[_draft[index].id],
                      onChanged: (QuestionSourcePreference next) =>
                          _updateSource(index, next),
                      onEditSpelling: _draft[index].id == 'spelling'
                          ? () => _openSpellingWordList(context)
                          : null,
                      onResetSpelling: _draft[index].id == 'spelling'
                          ? _confirmResetSpellingProgress
                          : null,
                      resetSpellingBusy: _resettingSpelling,
                    ),
                ],
              ),
            ),
          ),
          const SizedBox(height: 8),
          Text(
            enabledCount == 0
                ? 'No sources enabled.'
                : 'Effective mix: ${mix.entries.map((MapEntry<String, int> entry) {
                    final QuestionSourcePreference source = _draft.firstWhere(
                      (QuestionSourcePreference s) => s.id == entry.key,
                    );
                    return '${source.label} ${entry.value}%';
                  }).join(', ')}',
            style: Theme.of(context).textTheme.bodyLarge?.copyWith(
                  color: AppColors.accent,
                  fontWeight: FontWeight.w600,
                ),
          ),
          if (_validationMessage != null) ...<Widget>[
            const SizedBox(height: 8),
            Text(
              _validationMessage!,
              style: const TextStyle(color: Colors.redAccent),
            ),
          ],
          const SizedBox(height: 12),
          Row(
            mainAxisAlignment: MainAxisAlignment.end,
            children: <Widget>[
              TextButton(
                onPressed: _resettingSpelling || _saving
                    ? null
                    : () => Navigator.of(context).pop(),
                child: const Text('Cancel'),
              ),
              const SizedBox(width: 8),
              FilledButton(
                key: const Key('question-source-settings-save'),
                onPressed: _saving || _resettingSpelling ? null : _save,
                child: _saving
                    ? const SizedBox(
                        width: 18,
                        height: 18,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      )
                    : const Text('Save'),
              ),
            ],
          ),
        ],
      ),
    ),
        if (_resettingSpelling)
          Positioned.fill(
            child: ColoredBox(
              color: Colors.black.withValues(alpha: 0.45),
              child: const Center(
                child: SizedBox(
                  width: 32,
                  height: 32,
                  child: CircularProgressIndicator(
                    strokeWidth: 2,
                    color: AppColors.accent,
                  ),
                ),
              ),
            ),
          ),
      ],
    );
  }
}

class _QuestionSourceRow extends StatelessWidget {
  const _QuestionSourceRow({
    super.key,
    required this.source,
    required this.effectivePercent,
    required this.onChanged,
    this.onEditSpelling,
    this.onResetSpelling,
    this.resetSpellingBusy = false,
  });

  final QuestionSourcePreference source;
  final int? effectivePercent;
  final ValueChanged<QuestionSourcePreference> onChanged;
  final VoidCallback? onEditSpelling;
  final VoidCallback? onResetSpelling;
  final bool resetSpellingBusy;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 8),
      child: DecoratedBox(
        decoration: BoxDecoration(
          color: AppColors.surfaceElevated,
          borderRadius: BorderRadius.circular(12),
          border: Border.all(color: AppColors.accent.withValues(alpha: 0.15)),
        ),
        child: Padding(
          padding: const EdgeInsets.fromLTRB(12, 8, 12, 12),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: <Widget>[
              Row(
                children: <Widget>[
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: <Widget>[
                        Row(
                          children: <Widget>[
                            Flexible(
                              child: Text(
                                source.label,
                                style: Theme.of(context).textTheme.titleLarge,
                              ),
                            ),
                            if (source.comingSoon) ...<Widget>[
                              const SizedBox(width: 8),
                              DecoratedBox(
                                decoration: BoxDecoration(
                                  color: AppColors.accent.withValues(alpha: 0.12),
                                  borderRadius: BorderRadius.circular(6),
                                ),
                                child: Padding(
                                  padding: const EdgeInsets.symmetric(
                                    horizontal: 8,
                                    vertical: 2,
                                  ),
                                  child: Text(
                                    'Coming soon',
                                    style: Theme.of(context)
                                        .textTheme
                                        .bodyLarge
                                        ?.copyWith(
                                          color: AppColors.accent,
                                          fontWeight: FontWeight.w600,
                                          fontSize: 12,
                                        ),
                                  ),
                                ),
                              ),
                            ],
                          ],
                        ),
                        const SizedBox(height: 2),
                        Text(
                          source.description,
                          style: Theme.of(context).textTheme.bodyLarge,
                        ),
                      ],
                    ),
                  ),
                  if (onEditSpelling != null)
                    IconButton(
                      key: const Key('question-source-edit-spelling'),
                      tooltip: 'Edit spelling word list',
                      onPressed: resetSpellingBusy ? null : onEditSpelling,
                      icon: const Icon(Icons.edit, size: 20),
                    ),
                  if (onResetSpelling != null)
                    IconButton(
                      key: const Key('question-source-reset-spelling'),
                      tooltip: 'Reset spelling progress',
                      onPressed: resetSpellingBusy ? null : onResetSpelling,
                      icon: const Icon(Icons.restart_alt, size: 20),
                    ),
                  Switch(
                    key: Key('question-source-enabled-${source.id}'),
                    value: source.enabled,
                    onChanged: source.comingSoon
                        ? null
                        : (bool enabled) =>
                            onChanged(source.copyWith(enabled: enabled)),
                  ),
                ],
              ),
              if (source.enabled && !source.comingSoon) ...<Widget>[
                Row(
                  children: <Widget>[
                    const Text('Weight'),
                    const Spacer(),
                    Text(
                      effectivePercent == null
                          ? '${source.ratio}'
                          : '${source.ratio} (${effectivePercent}%)',
                      style: const TextStyle(
                        color: AppColors.accent,
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ],
                ),
                Slider(
                  key: Key('question-source-ratio-${source.id}'),
                  value: source.ratio.toDouble(),
                  min: 0,
                  max: 100,
                  divisions: 20,
                  label: '${source.ratio}',
                  onChanged: (double value) =>
                      onChanged(source.copyWith(ratio: value.round())),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}