import { useRouter } from 'expo-router';
import React, { useEffect, useRef, useState } from 'react';
import {
    Alert,
    ImageBackground,
    KeyboardAvoidingView,
    Platform,
    ScrollView,
    StatusBar,
    StyleSheet,
    Text,
    TextInput,
    TouchableOpacity,
    View,
} from 'react-native';
import { useSafeAreaInsets } from 'react-native-safe-area-context';

import { Images } from '@/constants/images';
import { login, sendVerifyCode } from '@/services/user';

export default function LoginScreen() {
  const router = useRouter();
  const insets = useSafeAreaInsets();

  const [phone, setPhone] = useState('');
  const [verifyCode, setVerifyCode] = useState('');
  const [agreeFlag, setAgreeFlag] = useState(false);
  const [countdown, setCountdown] = useState(0);
  const [disabled, setDisabled] = useState(false);
  const [loading, setLoading] = useState(false);
  const [tips, setTips] = useState('获取验证码');

  const timerRef = useRef<ReturnType<typeof setInterval> | null>(null);

  useEffect(() => {
    return () => {
      if (timerRef.current) {
        clearInterval(timerRef.current);
      }
    };
  }, []);

  // 验证手机号
  const isChinesePhoneNumber = (phoneNumber: string) => {
    const phoneNumberPattern = /^1[3-9]\d{9}$/;
    return phoneNumberPattern.test(phoneNumber);
  };

  // 开始倒计时
  const startCountdown = () => {
    setDisabled(true);
    let count = 60;
    setTips(`${count}s后重新获取`);
    
    timerRef.current = setInterval(() => {
      count--;
      if (count > 0) {
        setTips(`${count}s后重新获取`);
      } else {
        resetCountdown();
      }
    }, 1000);
  };

  // 重置倒计时
  const resetCountdown = () => {
    setDisabled(false);
    setTips('获取验证码');
    if (timerRef.current) {
      clearInterval(timerRef.current);
      timerRef.current = null;
    }
  };

  // 获取验证码
  const handleGetVerifyCode = async () => {
    if (disabled) return;
    
    if (phone && isChinesePhoneNumber(phone)) {
      try {
        const res = await sendVerifyCode(phone, 'LOGIN');
        if (res) {
          Alert.alert('提示', '验证码已发送');
          startCountdown();
        }
      } catch (error) {
        Alert.alert('错误', '获取验证码失败，请重试');
      }
    } else {
      Alert.alert('提示', '请输入正确的手机号');
    }
  };

  // 登录
  const handleLogin = async () => {
    if (!agreeFlag) {
      Alert.alert('提示', '请您先阅读并同意用户协议和隐私政策');
      return;
    }
    
    if (phone && isChinesePhoneNumber(phone) && verifyCode) {
      setLoading(true);
      try {
        const result = await login({
          loginWay: 'MOBILE',
          mobile: phone,
          verifycode: verifyCode,
        });
        
        if (result.success) {
          // TODO: 如果 needInfo 为 true，跳转到完善信息页面
          // if (result.needInfo) {
          //   router.replace('/user-info');
          //   return;
          // }
          router.back();
        } else {
          Alert.alert('错误', '登录失败，请检查验证码');
        }
      } catch (error) {
        Alert.alert('错误', '登录失败');
      }
      setLoading(false);
    } else {
      Alert.alert('提示', '请输入手机号和验证码');
    }
  };

  const goBack = () => {
    router.back();
  };

  return (
    <View style={styles.container}>
      <StatusBar barStyle="light-content" />
      <ImageBackground
        source={{ uri: Images.common.loginBg }}
        style={styles.background}
        resizeMode="cover"
      >
        <KeyboardAvoidingView
          style={styles.keyboardView}
          behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
        >
          <ScrollView
            contentContainerStyle={styles.scrollContent}
            keyboardShouldPersistTaps="handled"
            showsVerticalScrollIndicator={false}
          >
            {/* 底部表单区域 */}
            <View style={[styles.bottom, { paddingBottom: insets.bottom + 70 }]}>
              {/* 表单 */}
              <View style={styles.form}>
                {/* 手机号输入 */}
                <View style={styles.formItem}>
                  <Text style={styles.label}>手机号</Text>
                  <TextInput
                    style={styles.input}
                    value={phone}
                    onChangeText={setPhone}
                    placeholder="手机号"
                    placeholderTextColor="rgba(255,255,255,0.5)"
                    keyboardType="phone-pad"
                    maxLength={11}
                  />
                </View>
                <View style={styles.divider} />

                {/* 验证码输入 */}
                <View style={styles.formItem}>
                  <Text style={styles.label}>验证码</Text>
                  <TextInput
                    style={[styles.input, styles.codeInput]}
                    value={verifyCode}
                    onChangeText={setVerifyCode}
                    placeholder="请填写验证码"
                    placeholderTextColor="rgba(255,255,255,0.5)"
                    keyboardType="number-pad"
                    maxLength={6}
                  />
                  <TouchableOpacity
                    style={[styles.verifyBtn, disabled && styles.verifyBtnDisabled]}
                    onPress={handleGetVerifyCode}
                    disabled={disabled}
                  >
                    <Text style={[styles.verifyBtnText, disabled && styles.verifyBtnTextDisabled]}>
                      {tips}
                    </Text>
                  </TouchableOpacity>
                </View>
                <View style={styles.divider} />
              </View>

              {/* 协议勾选 */}
              <TouchableOpacity
                style={styles.agree}
                onPress={() => setAgreeFlag(!agreeFlag)}
              >
                <View style={[styles.radio, agreeFlag && styles.radioChecked]}>
                  {agreeFlag && <View style={styles.radioInner} />}
                </View>
                <Text style={styles.agreeText}>
                  我已阅读并同意
                  <Text style={styles.linkText}>《用户协议》</Text>
                  跟
                  <Text style={styles.linkText}>《隐私政策》</Text>
                </Text>
              </TouchableOpacity>

              {/* 按钮区域 */}
              <View style={styles.btnArea}>
                <TouchableOpacity
                  style={[styles.btn, loading && styles.btnDisabled]}
                  onPress={handleLogin}
                  disabled={loading}
                  activeOpacity={0.8}
                >
                  <ImageBackground
                    source={{ uri: Images.common.loginBtn }}
                    style={styles.loginBtnBg}
                    resizeMode="stretch"
                  >
                    <Text style={styles.btnText}>
                      {loading ? '登录中...' : '登录'}
                    </Text>
                  </ImageBackground>
                </TouchableOpacity>

                <TouchableOpacity style={styles.btnBack} onPress={goBack}>
                  <Text style={styles.btnBackText}>返回</Text>
                </TouchableOpacity>
              </View>
            </View>
          </ScrollView>
        </KeyboardAvoidingView>
      </ImageBackground>
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#1a1a2e',
  },
  background: {
    flex: 1,
  },
  keyboardView: {
    flex: 1,
  },
  scrollContent: {
    flexGrow: 1,
    justifyContent: 'flex-end',
  },
  bottom: {
    width: '100%',
  },
  form: {
    paddingHorizontal: 25,
  },
  formItem: {
    flexDirection: 'row',
    alignItems: 'center',
    paddingVertical: 12,
  },
  label: {
    color: '#fff',
    fontSize: 14,
    width: 50,
  },
  input: {
    flex: 1,
    color: '#fff',
    fontSize: 14,
    paddingVertical: 8,
    outlineStyle: 'none',
  } as any,
  codeInput: {
    flex: 1,
  },
  divider: {
    height: 1,
    backgroundColor: 'rgba(255,255,255,0.2)',
  },
  verifyBtn: {
    backgroundColor: '#000',
    borderRadius: 4,
    paddingHorizontal: 10,
    paddingVertical: 5,
    minWidth: 80,
    alignItems: 'center',
  },
  verifyBtnDisabled: {
    backgroundColor: '#ccc',
  },
  verifyBtnText: {
    color: '#fff',
    fontSize: 12,
  },
  verifyBtnTextDisabled: {
    color: '#666',
  },
  agree: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'center',
    marginTop: 25,
    paddingHorizontal: 25,
  },
  radio: {
    width: 16,
    height: 16,
    borderRadius: 8,
    borderWidth: 1,
    borderColor: 'rgba(255,255,255,0.5)',
    marginRight: 6,
    justifyContent: 'center',
    alignItems: 'center',
  },
  radioChecked: {
    borderColor: '#8b3dff',
    backgroundColor: '#8b3dff',
  },
  radioInner: {
    width: 6,
    height: 6,
    borderRadius: 3,
    backgroundColor: '#fff',
  },
  agreeText: {
    color: '#fff',
    fontSize: 12,
  },
  linkText: {
    color: '#8b3dff',
  },
  btnArea: {
    paddingTop: 15,
    alignItems: 'center',
  },
  btn: {
    width: 234,
    height: 45,
    overflow: 'hidden',
  },
  loginBtnBg: {
    width: '100%',
    height: '100%',
    justifyContent: 'center',
    alignItems: 'center',
  },
  btnDisabled: {
    opacity: 0.6,
  },
  btnText: {
    color: '#fff',
    fontSize: 14,
    fontWeight: '600',
  },
  btnBack: {
    width: 234,
    height: 35,
    backgroundColor: '#fff',
    borderRadius: 25,
    justifyContent: 'center',
    alignItems: 'center',
    marginTop: 10,
    borderWidth: 1,
    borderColor: '#fff',
  },
  btnBackText: {
    color: '#888',
    fontSize: 12,
  },
});