import 'package:flutter/material.dart';

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

String aiProviderLabel(AiProviderType provider) => switch (provider) {
  AiProviderType.mock => '内置练习模式',
  AiProviderType.openAi => 'OpenAI API',
  AiProviderType.gemini => 'Gemini API',
  AiProviderType.compatible => 'OpenAI 兼容',
};

/// AI 服务：服务类型、接口地址、模型与 API Key。
class AiServiceView extends StatefulWidget {
  const AiServiceView({super.key, required this.state});
  final AppState state;

  @override
  State<AiServiceView> createState() => _AiServiceViewState();
}

class _AiServiceViewState extends State<AiServiceView> {
  late final endpoint = TextEditingController(text: widget.state.aiEndpoint);
  late final model = TextEditingController(text: widget.state.aiModel);
  final apiKey = TextEditingController();
  bool testingConnection = false;

  @override
  void dispose() {
    endpoint.dispose();
    model.dispose();
    apiKey.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) => SpacedColumn(
    children: [
      Text(
        '订阅版 ChatGPT / Gemini 不能直接作为 App API 使用。请使用自己的 API Key，或填写兼容 OpenAI 接口的 CLIProxyAPI 地址。AI 只提供建议，不会直接决定你的掌握程度。',
        style: TextStyle(fontSize: 12, color: AppColors.muted),
      ),
      DropdownButtonFormField<AiProviderType>(
        initialValue: widget.state.aiProvider,
        decoration: const InputDecoration(
          labelText: '服务类型',
          border: OutlineInputBorder(),
        ),
        items: const [
          DropdownMenuItem(
            value: AiProviderType.mock,
            child: Text('内置练习模式（无需网络）'),
          ),
          DropdownMenuItem(
            value: AiProviderType.openAi,
            child: Text('OpenAI API'),
          ),
          DropdownMenuItem(
            value: AiProviderType.gemini,
            child: Text('Gemini API'),
          ),
          DropdownMenuItem(
            value: AiProviderType.compatible,
            child: Text('OpenAI 兼容 / CLIProxyAPI'),
          ),
        ],
        onChanged: _changeProvider,
      ),
      TextField(
        controller: endpoint,
        keyboardType: TextInputType.url,
        decoration: const InputDecoration(
          labelText: 'Base URL（可选）',
          hintText:
              'OpenAI / 兼容： https://…/v1；Gemini： https://generativelanguage.googleapis.com/v1beta',
          border: OutlineInputBorder(),
        ),
      ),
      TextField(
        controller: model,
        decoration: const InputDecoration(
          labelText: '模型名称（可选）',
          hintText: '例如 gpt-4.1-mini',
          border: OutlineInputBorder(),
        ),
      ),
      TextField(
        controller: apiKey,
        obscureText: true,
        decoration: const InputDecoration(
          labelText: 'API Key（仅保存到设备安全存储）',
          border: OutlineInputBorder(),
        ),
      ),
      PrimaryButton(label: '保存服务设置', onPressed: _save),
      SecondaryButton(
        label: testingConnection ? '正在测试连接...' : '测试连接',
        onPressed: testingConnection ? null : _testConnection,
      ),
      SecondaryButton(
        label: '从配置文件重载 (ai_config.json)',
        onPressed: _reloadFromAsset,
      ),
    ],
  );

  void _changeProvider(AiProviderType? value) {
    if (value == null) return;
    setState(() {
      widget.state.setAiProvider(value);
      if (value == AiProviderType.gemini && endpoint.text.trim().isEmpty) {
        endpoint.text = 'https://generativelanguage.googleapis.com/v1beta';
        if (model.text.trim().isEmpty) model.text = 'gemini-2.5-flash';
      }
    });
  }

  Future<void> _save() async {
    final messenger = ScaffoldMessenger.of(context);
    widget.state.saveAiConfiguration(
      endpoint: endpoint.text,
      model: model.text,
    );
    if (apiKey.text.trim().isNotEmpty) {
      await AiService.instance.saveApiKey(apiKey.text);
    }
    messenger.showSnackBar(const SnackBar(content: Text('服务设置已保存。')));
  }

  Future<void> _testConnection() async {
    final messenger = ScaffoldMessenger.of(context);
    setState(() => testingConnection = true);
    final result = await AiService.instance.testConnection(
      provider: widget.state.aiProvider,
      endpoint: endpoint.text,
      model: model.text,
      explicitApiKey: apiKey.text,
    );
    if (!mounted) return;
    setState(() => testingConnection = false);
    messenger.showSnackBar(
      SnackBar(
        content: Text(result.message),
        backgroundColor: result.ok ? AppColors.green : Colors.redAccent,
        duration: const Duration(seconds: 4),
      ),
    );
  }

  Future<void> _reloadFromAsset() async {
    final messenger = ScaffoldMessenger.of(context);
    final ok = await widget.state.reloadAiConfigFromAsset();
    if (!mounted) return;
    if (ok) {
      setState(() {
        endpoint.text = widget.state.aiEndpoint;
        model.text = widget.state.aiModel;
      });
    }
    messenger.showSnackBar(
      SnackBar(
        content: Text(
          ok ? '已从 assets/config/ai_config.json 载入配置。' : '未找到配置文件或解析失败。',
        ),
      ),
    );
  }
}