import 'package:flutter/material.dart';

import '../../core/app_state.dart';
import '../../core/app_theme.dart';
import '../../core/models.dart';
import '../../widgets/app_widgets.dart';

class WelcomePage extends StatefulWidget {
  const WelcomePage({super.key, required this.state, required this.onContinue});

  final AppState state;
  final VoidCallback onContinue;

  @override
  State<WelcomePage> createState() => _WelcomePageState();
}

class _WelcomePageState extends State<WelcomePage> {
  late LearningGoal selectedGoal;
  late int selectedMinutes;

  @override
  void initState() {
    super.initState();
    selectedGoal = widget.state.goal;
    selectedMinutes = widget.state.dailyMinutes;
  }

  @override
  Widget build(BuildContext context) {
    return AppPage(
      child: SpacedColumn(
        spacing: 20,
        children: [
          Row(
            children: [
              ClipRRect(
                borderRadius: BorderRadius.circular(12),
                child: Image.asset(
                  'assets/branding/logo_512.png',
                  width: 44,
                  height: 44,
                ),
              ),
              const SizedBox(width: 12),
              const Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    '芽说英语',
                    style: TextStyle(
                      fontSize: 18,
                      fontWeight: FontWeight.bold,
                      color: AppColors.ink,
                    ),
                  ),
                  Text(
                    'SpeakSprout',
                    style: TextStyle(
                      fontSize: 12,
                      color: AppColors.green,
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                ],
              ),
            ],
          ),
          const Eyebrow('欢迎'),
          Text(
            '每天 20 分钟，\n说出能用的英语。',
            style: Theme.of(context).textTheme.headlineMedium,
          ),
          const Text('从真实生活场景开始，先做到听得懂、说得清。'),
          _ChoiceGroup<LearningGoal>(
            title: '你的主要目标',
            value: selectedGoal,
            options: const {
              LearningGoal.dailyLife: '日常生活',
              LearningGoal.travel: '旅行',
              LearningGoal.workStarter: '工作起步',
            },
            onChanged: (value) => setState(() => selectedGoal = value),
          ),
          _ChoiceGroup<int>(
            title: '每天学习多久？',
            value: selectedMinutes,
            options: const {10: '10 分钟', 20: '20 分钟', 30: '30 分钟'},
            onChanged: (value) => setState(() => selectedMinutes = value),
          ),
          PrimaryButton(
            label: '继续',
            onPressed: () {
              widget.state
                ..setGoal(selectedGoal)
                ..setDailyMinutes(selectedMinutes);
              widget.onContinue();
            },
          ),
        ],
      ),
    );
  }
}

class PlacementPage extends StatefulWidget {
  const PlacementPage({
    super.key,
    required this.state,
    required this.onStart,
    this.onBack,
  });

  final AppState state;
  final VoidCallback onStart;
  final VoidCallback? onBack;

  @override
  State<PlacementPage> createState() => _PlacementPageState();
}

class _PlacementPageState extends State<PlacementPage> {
  late PlacementLevel selected;

  @override
  void initState() {
    super.initState();
    selected = widget.state.placement;
  }

  @override
  Widget build(BuildContext context) {
    const labels = {
      PlacementLevel.beginner: ('完全零基础', '从你好、自我介绍开始'),
      PlacementLevel.someBasics: ('能说一点', '认识常见单词或短句'),
      PlacementLevel.simpleConversation: ('能简单对话', '想说得更自然、更有信心'),
    };
    return AppPage(
      appBar: widget.onBack != null
          ? AppBar(
              leading: IconButton(
                icon: const Icon(Icons.arrow_back),
                tooltip: "返回",
                onPressed: widget.onBack,
              ),
              title: const Text("基础定位"),
            )
          : null,
      child: SpacedColumn(
        spacing: 14,
        children: [
          const Eyebrow('第一步 · 约 3 分钟'),
          Text('从哪里开始？', style: Theme.of(context).textTheme.headlineMedium),
          const Text('选择最接近的状态，之后随时能调整。'),
          for (final option in PlacementLevel.values)
            _PlacementChoice(
              option: option,
              labels: labels[option]!,
              isSelected: selected == option,
              onTap: () => setState(() => selected = option),
            ),
          PrimaryButton(
            label: '开始 3 分钟定位',
            onPressed: () {
              widget.state.setPlacement(selected);
              widget.onStart();
            },
          ),
          Center(
            child: TextButton(
              onPressed: widget.onStart,
              child: const Text('直接从第一课开始'),
            ),
          ),
        ],
      ),
    );
  }
}

class _PlacementChoice extends StatelessWidget {
  const _PlacementChoice({
    required this.option,
    required this.labels,
    required this.isSelected,
    required this.onTap,
  });

  final PlacementLevel option;
  final (String, String) labels;
  final bool isSelected;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) => SectionCard(
    tint: isSelected ? AppColors.softGreen : null,
    onTap: onTap,
    child: Row(
      children: [
        Icon(
          isSelected ? Icons.radio_button_checked : Icons.radio_button_off,
          color: isSelected ? AppColors.green : AppColors.muted,
        ),
        const SizedBox(width: 10),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                labels.$1,
                style: const TextStyle(fontWeight: FontWeight.w600),
              ),
              const SizedBox(height: 3),
              Text(labels.$2, style: Theme.of(context).textTheme.bodyMedium),
            ],
          ),
        ),
      ],
    ),
  );
}

class _ChoiceGroup<T> extends StatelessWidget {
  const _ChoiceGroup({
    required this.title,
    required this.value,
    required this.options,
    required this.onChanged,
  });

  final String title;
  final T value;
  final Map<T, String> options;
  final ValueChanged<T> onChanged;

  @override
  Widget build(BuildContext context) {
    return SectionCard(
      child: SpacedColumn(
        spacing: 10,
        children: [
          Text(title, style: const TextStyle(fontWeight: FontWeight.w600)),
          Wrap(
            spacing: 8,
            runSpacing: 8,
            children: options.entries
                .map(
                  (entry) => ChoiceChip(
                    label: Text(entry.value),
                    selected: value == entry.key,
                    selectedColor: AppColors.softGreen,
                    onSelected: (_) => onChanged(entry.key),
                  ),
                )
                .toList(),
          ),
        ],
      ),
    );
  }
}