import 'package:flutter/material.dart';
import '../../../../app/theme/app_colors.dart';
import '../../../../app/i18n/app_localizations.dart';
import '../../../../core/services/issuer_credit_service.dart';

/// 信用评级页面
///
/// 四因子信用评分：核销率35% + (1-Breakage率)25% + 市场存续20% + 用户满意度20%
/// AI建议列表：信用提升建议
class CreditPage extends StatefulWidget {
  const CreditPage({super.key});

  @override
  State<CreditPage> createState() => _CreditPageState();
}

class _CreditPageState extends State<CreditPage> {
  final _creditService = IssuerCreditService();

  bool _isLoading = true;
  String? _error;
  CreditModel? _credit;

  @override
  void initState() {
    super.initState();
    _loadCredit();
  }

  Future<void> _loadCredit() async {
    setState(() {
      _isLoading = true;
      _error = null;
    });

    try {
      final credit = await _creditService.getCredit();
      if (!mounted) return;
      setState(() {
        _credit = credit;
        _isLoading = false;
      });
    } catch (e) {
      debugPrint('[CreditPage] loadCredit error: $e');
      if (!mounted) return;
      setState(() {
        _isLoading = false;
        _error = e.toString();
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(context.t('credit_title'))),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : _error != null
              ? Center(
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      const Icon(Icons.error_outline, size: 48, color: AppColors.textTertiary),
                      const SizedBox(height: 16),
                      Text(_error!, style: const TextStyle(color: AppColors.textSecondary)),
                      const SizedBox(height: 16),
                      ElevatedButton(onPressed: _loadCredit, child: Text(context.t('retry'))),
                    ],
                  ),
                )
              : RefreshIndicator(
                  onRefresh: _loadCredit,
                  child: SingleChildScrollView(
                    physics: const AlwaysScrollableScrollPhysics(),
                    padding: const EdgeInsets.all(20),
                    child: Column(
                      children: [
                        // Score Gauge
                        _buildScoreGauge(context),
                        const SizedBox(height: 24),

                        // Four Factors
                        _buildFactorsCard(context),
                        const SizedBox(height: 20),

                        // Tier Progress
                        _buildTierProgress(context),
                        const SizedBox(height: 20),

                        // AI Suggestions
                        _buildAiSuggestions(context),
                        const SizedBox(height: 20),

                        // Credit History
                        _buildCreditHistory(context),
                      ],
                    ),
                  ),
                ),
    );
  }

  Widget _buildScoreGauge(BuildContext context) {
    final credit = _credit!;
    return Container(
      padding: const EdgeInsets.all(24),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: AppColors.borderLight),
      ),
      child: Column(
        children: [
          Container(
            width: 120,
            height: 120,
            decoration: BoxDecoration(
              shape: BoxShape.circle,
              gradient: LinearGradient(
                begin: Alignment.topCenter,
                end: Alignment.bottomCenter,
                colors: [AppColors.creditAA, AppColors.creditAA.withValues(alpha: 0.3)],
              ),
            ),
            child: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Text(credit.grade, style: const TextStyle(fontSize: 32, fontWeight: FontWeight.w700, color: Colors.white)),
                  Text('${credit.score}${context.t('credit_score_unit')}', style: const TextStyle(fontSize: 14, color: Colors.white70)),
                ],
              ),
            ),
          ),
          const SizedBox(height: 16),
          Text(context.t('credit_score_label'), style: const TextStyle(fontSize: 18, fontWeight: FontWeight.w600)),
          const SizedBox(height: 4),
          Text(context.t('credit_gap_label'), style: const TextStyle(fontSize: 13, color: AppColors.textSecondary)),
        ],
      ),
    );
  }

  Widget _buildFactorsCard(BuildContext context) {
    final factors = _credit!.factors;
    final factorColors = [AppColors.success, AppColors.info, AppColors.primary, AppColors.warning];

    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: AppColors.borderLight),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(context.t('credit_factors'), style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
          const SizedBox(height: 16),
          ...factors.asMap().entries.map((entry) {
            final f = entry.value;
            final color = factorColors[entry.key % factorColors.length];
            final score = f.score / 100;
            return Padding(
              padding: const EdgeInsets.only(bottom: 16),
              child: Column(
                children: [
                  Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Text(f.name, style: const TextStyle(fontSize: 13)),
                      Text(
                        '${f.score.toInt()}${context.t('credit_score_unit')} (${(f.weight * 100).toInt()}%)',
                        style: const TextStyle(fontSize: 12, color: AppColors.textSecondary),
                      ),
                    ],
                  ),
                  const SizedBox(height: 6),
                  ClipRRect(
                    borderRadius: BorderRadius.circular(4),
                    child: LinearProgressIndicator(
                      value: score.clamp(0.0, 1.0),
                      backgroundColor: AppColors.gray100,
                      valueColor: AlwaysStoppedAnimation(color),
                      minHeight: 8,
                    ),
                  ),
                ],
              ),
            );
          }),
          if (factors.isEmpty)
            const Padding(
              padding: EdgeInsets.all(16),
              child: Center(child: Text(context.t('credit_no_factors'), style: const TextStyle(color: AppColors.textTertiary))),
            ),
        ],
      ),
    );
  }

  Widget _buildTierProgress(BuildContext context) {
    final credit = _credit!;
    final tierColors = [AppColors.tierSilver, AppColors.tierGold, AppColors.tierPlatinum, AppColors.tierDiamond];
    final tiers = credit.tiers;

    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: AppColors.borderLight),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(context.t('credit_tier_title'), style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
          const SizedBox(height: 16),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceAround,
            children: tiers.asMap().entries.map((entry) {
              final index = entry.key;
              final name = entry.value;
              final isReached = index <= credit.currentTierIndex;
              final color = tierColors[index % tierColors.length];
              return Column(
                children: [
                  Container(
                    width: 44,
                    height: 44,
                    decoration: BoxDecoration(
                      color: isReached ? color.withValues(alpha: 0.15) : AppColors.gray100,
                      shape: BoxShape.circle,
                      border: isReached ? Border.all(color: color, width: 2) : null,
                    ),
                    child: Icon(
                      Icons.star_rounded,
                      color: isReached ? color : AppColors.textTertiary,
                      size: 22,
                    ),
                  ),
                  const SizedBox(height: 6),
                  Text(
                    name,
                    style: TextStyle(
                      fontSize: 12,
                      color: isReached ? color : AppColors.textTertiary,
                      fontWeight: isReached ? FontWeight.w600 : FontWeight.w400,
                    ),
                  ),
                ],
              );
            }).toList(),
          ),
          const SizedBox(height: 12),
          Text(
            context.t('credit_tier_progress'),
            style: const TextStyle(fontSize: 12, color: AppColors.textSecondary),
          ),
        ],
      ),
    );
  }

  Widget _buildAiSuggestions(BuildContext context) {
    final suggestions = _credit!.suggestions;
    final icons = [Icons.trending_up_rounded, Icons.notification_important_rounded, Icons.rate_review_rounded];

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Row(
          children: [
            const Icon(Icons.auto_awesome_rounded, color: AppColors.primary, size: 20),
            const SizedBox(width: 8),
            Text(context.t('credit_ai_title'), style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
          ],
        ),
        const SizedBox(height: 12),
        if (suggestions.isEmpty)
          Container(
            padding: const EdgeInsets.all(14),
            decoration: BoxDecoration(
              color: AppColors.primarySurface,
              borderRadius: BorderRadius.circular(10),
            ),
            child: Center(
              child: Text(context.t('credit_no_suggestions'), style: const TextStyle(color: AppColors.textSecondary)),
            ),
          )
        else
          ...suggestions.asMap().entries.map((entry) {
            final icon = icons[entry.key % icons.length];
            final text = entry.value;
            return Container(
              margin: const EdgeInsets.only(bottom: 10),
              padding: const EdgeInsets.all(14),
              decoration: BoxDecoration(
                color: AppColors.primarySurface,
                borderRadius: BorderRadius.circular(10),
              ),
              child: Row(
                children: [
                  Icon(icon, color: AppColors.primary, size: 20),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Text(text, style: const TextStyle(fontSize: 13, color: AppColors.textSecondary)),
                  ),
                ],
              ),
            );
          }),
      ],
    );
  }

  Widget _buildCreditHistory(BuildContext context) {
    // Credit history not yet provided by API, keeping placeholder
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: AppColors.borderLight),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(context.t('credit_history_title'), style: const TextStyle(fontSize: 15, fontWeight: FontWeight.w600)),
          const SizedBox(height: 12),
          const Padding(
            padding: EdgeInsets.all(16),
            child: Center(child: Text('--', style: TextStyle(color: AppColors.textTertiary))),
          ),
        ],
      ),
    );
  }
}