import React, { useState, useEffect } from 'react';
import {
  StyleSheet,
  Text,
  View,
  TextInput,
  TouchableOpacity,
  Alert,
  ActivityIndicator,
  ScrollView,
} from 'react-native';
import { AppSettings } from '../types/config';
import {
  getSettings,
  saveSettings,
  downloadConfig,
  getConfig,
  clearCachedConfig,
} from '../services/configService';
import { useTasks } from '../context/TasksContext';

export default function SettingsScreen() {
  const { refreshConfig } = useTasks();
  const [settings, setSettings] = useState<AppSettings>({
    configFileName: '',
    serverUrl: '',
  });
  const [loading, setLoading] = useState(false);
  const [configStatus, setConfigStatus] = useState<string>('未加载');

  // 组件加载时获取设置
  useEffect(() => {
    loadSettings();
    checkConfigStatus();
  }, []);

  const loadSettings = async () => {
    try {
      const currentSettings = await getSettings();
      setSettings(currentSettings);
    } catch (error) {
      Alert.alert('错误', '加载设置失败');
    }
  };

  const checkConfigStatus = async () => {
    const config = await getConfig();
    if (config) {
      setConfigStatus(
        `已加载 (版本: ${config.version}, 任务数: ${
          config.tasks?.length || 0
        })`,
      );
    } else {
      setConfigStatus('未加载');
    }
  };

  const handleSaveSettings = async () => {
    if (!settings.configFileName.trim()) {
      Alert.alert('错误', '请输入配置文件名');
      return;
    }
    if (!settings.serverUrl.trim()) {
      Alert.alert('错误', '请输入服务器地址');
      return;
    }

    try {
      await saveSettings(settings);
      Alert.alert('成功', '设置已保存');
    } catch (error) {
      Alert.alert('错误', '保存设置失败');
    }
  };

  const handleRefreshLocalConfig = async () => {
    setLoading(true);
    try {
      // 清除缓存并重新加载本地配置
      await clearCachedConfig();
      await refreshConfig();
      await checkConfigStatus();

      Alert.alert('成功', '本地配置已刷新！');
    } catch (error) {
      console.error('刷新本地配置失败:', error);
      Alert.alert('错误', '刷新本地配置失败');
    } finally {
      setLoading(false);
    }
  };

  const handleDownloadConfig = async () => {
    if (!settings.configFileName.trim()) {
      Alert.alert('错误', '请先输入配置文件名');
      return;
    }
    if (!settings.serverUrl.trim()) {
      Alert.alert('错误', '请先输入服务器地址');
      return;
    }

    setLoading(true);
    try {
      // 先保存设置
      await saveSettings(settings);

      // 下载配置文件
      const config = await downloadConfig(
        settings.serverUrl,
        settings.configFileName,
      );

      Alert.alert(
        '成功',
        `配置文件下载成功！\n版本: ${config.version}\n任务数量: ${
          config.tasks?.length || 0
        }`,
        [
          {
            text: '确定',
            onPress: async () => {
              await refreshConfig();
              checkConfigStatus();
            },
          },
        ],
      );
    } catch (error) {
      Alert.alert(
        '下载失败',
        error instanceof Error ? error.message : '未知错误',
      );
    } finally {
      setLoading(false);
    }
  };

  const handleClearCache = async () => {
    Alert.alert(
      '确认清除',
      '确定要清除缓存的配置文件吗？系统将重新加载本地 config.json 文件。',
      [
        { text: '取消', style: 'cancel' },
        {
          text: '确定',
          onPress: async () => {
            setLoading(true);
            try {
              await clearCachedConfig();
              await refreshConfig();
              checkConfigStatus();
              Alert.alert('成功', '缓存已清除，已重新加载配置');
            } catch (error) {
              Alert.alert('错误', '清除缓存失败');
            } finally {
              setLoading(false);
            }
          },
        },
      ],
    );
  };

  const handleTestConnection = async () => {
    if (!settings.serverUrl.trim()) {
      Alert.alert('错误', '请先输入服务器地址');
      return;
    }

    setLoading(true);
    try {
      const controller = new AbortController();
      const timeoutId = setTimeout(() => controller.abort(), 5000);

      const response = await fetch(`${settings.serverUrl}/health`, {
        method: 'GET',
        signal: controller.signal,
      });

      clearTimeout(timeoutId);

      if (response.ok) {
        Alert.alert('连接成功', '服务器连接正常');
      } else {
        Alert.alert('连接失败', `HTTP ${response.status}`);
      }
    } catch (error) {
      Alert.alert('连接失败', '无法连接到服务器');
    } finally {
      setLoading(false);
    }
  };

  return (
    <ScrollView style={styles.container}>
      <View style={styles.content}>
        {loading && (
          <View style={styles.loadingOverlay}>
            <ActivityIndicator size="large" color="#007AFF" />
            <Text style={styles.loadingText}>处理中...</Text>
          </View>
        )}

        {/* 配置状态 */}
        <View style={styles.section}>
          <Text style={styles.sectionTitle}>配置状态</Text>
          <Text style={styles.statusText}>{configStatus}</Text>
        </View>

        {/* 配置文件设置 */}
        <View style={styles.section}>
          <Text style={styles.sectionTitle}>配置文件</Text>

          <View style={styles.inputGroup}>
            <Text style={styles.label}>配置文件名：</Text>
            <TextInput
              style={styles.textInput}
              value={settings.configFileName}
              onChangeText={text =>
                setSettings(prev => ({ ...prev, configFileName: text }))
              }
              placeholder="config"
              placeholderTextColor="#999"
              autoCapitalize="none"
            />
          </View>

          <View style={styles.buttonRow}>
            <TouchableOpacity
              style={[styles.button, styles.downloadButton]}
              onPress={handleDownloadConfig}
              disabled={loading}
            >
              <Text style={styles.buttonText}>下载配置文件</Text>
            </TouchableOpacity>

            <TouchableOpacity
              style={[styles.button, styles.refreshButton]}
              onPress={handleRefreshLocalConfig}
              disabled={loading}
            >
              <Text style={styles.buttonText}>刷新本地配置</Text>
            </TouchableOpacity>
          </View>

          <View style={styles.buttonRow}>
            <TouchableOpacity
              style={[styles.button, styles.clearButton]}
              onPress={handleClearCache}
              disabled={loading}
            >
              <Text style={styles.buttonText}>清除缓存</Text>
            </TouchableOpacity>
          </View>
        </View>

        {/* 服务器设置 */}
        <View style={styles.section}>
          <Text style={styles.sectionTitle}>服务器设置</Text>

          <View style={styles.inputGroup}>
            <Text style={styles.label}>服务器地址：</Text>
            <TextInput
              style={styles.textInput}
              value={settings.serverUrl}
              onChangeText={text =>
                setSettings(prev => ({ ...prev, serverUrl: text }))
              }
              placeholder="http://localhost:3000/api"
              placeholderTextColor="#999"
              autoCapitalize="none"
              keyboardType="url"
            />
          </View>

          <View style={styles.buttonRow}>
            <TouchableOpacity
              style={[styles.button, styles.testButton]}
              onPress={handleTestConnection}
              disabled={loading}
            >
              <Text style={styles.buttonText}>测试连接</Text>
            </TouchableOpacity>

            <TouchableOpacity
              style={[styles.button, styles.saveButton]}
              onPress={handleSaveSettings}
              disabled={loading}
            >
              <Text style={styles.buttonText}>保存设置</Text>
            </TouchableOpacity>
          </View>
        </View>

        {/* 说明信息 */}
        <View style={styles.infoSection}>
          <Text style={styles.infoTitle}>使用说明</Text>
          <Text style={styles.infoText}>配置文件加载优先级：</Text>
          <Text style={styles.infoText}>
            1. 缓存的服务器配置（从服务器下载的配置）
          </Text>
          <Text style={styles.infoText}>2. 本地 config.json 文件</Text>
          <Text style={styles.infoText}>3. 空数据（如果都没有找到）</Text>
          <Text style={styles.infoText}>
            • 点击"下载配置文件"从服务器获取最新配置
          </Text>
          <Text style={styles.infoText}>
            • 点击"清除缓存"强制重新加载本地配置文件
          </Text>
        </View>
      </View>
    </ScrollView>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#f5f5f5',
  },
  content: {
    padding: 20,
  },
  title: {
    fontSize: 24,
    fontWeight: 'bold',
    textAlign: 'center',
    marginBottom: 30,
    color: '#333',
  },
  section: {
    backgroundColor: 'white',
    borderRadius: 10,
    padding: 20,
    marginBottom: 20,
    shadowColor: '#000',
    shadowOffset: {
      width: 0,
      height: 2,
    },
    shadowOpacity: 0.1,
    shadowRadius: 3.84,
    elevation: 5,
  },
  sectionTitle: {
    fontSize: 18,
    fontWeight: 'bold',
    marginBottom: 15,
    color: '#333',
  },
  inputGroup: {
    marginBottom: 15,
  },
  label: {
    fontSize: 16,
    marginBottom: 8,
    color: '#333',
    fontWeight: '500',
  },
  inputRow: {
    flexDirection: 'row',
    alignItems: 'center',
  },
  textInput: {
    flex: 1,
    borderWidth: 1,
    borderColor: '#ddd',
    borderRadius: 8,
    padding: 12,
    fontSize: 16,
    backgroundColor: '#fafafa',
  },
  extension: {
    marginLeft: 8,
    fontSize: 16,
    color: '#666',
    fontWeight: '500',
  },
  statusRow: {
    flexDirection: 'row',
    alignItems: 'center',
    marginBottom: 15,
  },
  statusLabel: {
    fontSize: 16,
    color: '#333',
    fontWeight: '500',
  },
  statusText: {
    fontSize: 16,
    color: '#007AFF',
    marginLeft: 8,
  },
  button: {
    borderRadius: 8,
    padding: 12,
    alignItems: 'center',
    minHeight: 48,
    justifyContent: 'center',
  },
  downloadButton: {
    backgroundColor: '#007AFF',
    flex: 1,
    marginRight: 10,
  },
  refreshButton: {
    backgroundColor: '#32D74B',
    flex: 1,
  },
  testButton: {
    backgroundColor: '#34C759',
    flex: 1,
    marginRight: 10,
  },
  saveButton: {
    backgroundColor: '#FF9500',
    flex: 1,
  },
  buttonText: {
    color: 'white',
    fontSize: 16,
    fontWeight: '600',
  },
  buttonRow: {
    flexDirection: 'row',
    marginTop: 10,
  },
  infoSection: {
    backgroundColor: 'white',
    borderRadius: 10,
    padding: 20,
    marginBottom: 20,
  },
  infoTitle: {
    fontSize: 18,
    fontWeight: 'bold',
    marginBottom: 15,
    color: '#333',
  },
  infoText: {
    fontSize: 14,
    lineHeight: 20,
    color: '#666',
    marginBottom: 5,
  },
  loadingOverlay: {
    position: 'absolute',
    top: 0,
    left: 0,
    right: 0,
    bottom: 0,
    backgroundColor: 'rgba(255, 255, 255, 0.8)',
    justifyContent: 'center',
    alignItems: 'center',
    zIndex: 1,
  },
  loadingText: {
    marginTop: 10,
    fontSize: 16,
    color: '#007AFF',
  },
  clearButton: {
    backgroundColor: '#FF3B30',
  },
});