import React, { useState } from "react";
import {
  Box,
  Button,
  FormControl,
  FormLabel,
  Input,
  VStack,
  Heading,
  Text,
  Link,
  useColorMode,
  InputGroup,
  InputRightElement,
  IconButton,
  Spinner,
} from "@chakra-ui/react";
import { ViewIcon, ViewOffIcon } from "@chakra-ui/icons";
import { useNavigate } from "react-router-dom";
import { useAuth } from "../../../contexts/AuthContext";

export default function SignInCentered() {
  const { colorMode } = useColorMode();
  const navigate = useNavigate();
  const { login, isLoading } = useAuth();

  // 表单状态
  const [formData, setFormData] = useState({
    email: "",
    password: "",
  });

  // UI状态
  const [showPassword, setShowPassword] = useState(false);
  const [errors, setErrors] = useState({});

  // 处理输入变化
  const handleInputChange = (e) => {
    const { name, value } = e.target;
    setFormData(prev => ({
      ...prev,
      [name]: value
    }));
    // 清除对应字段的错误
    if (errors[name]) {
      setErrors(prev => ({
        ...prev,
        [name]: ""
      }));
    }
  };

  // 表单验证
  const validateForm = () => {
    const newErrors = {};

    if (!formData.email) {
      newErrors.email = "邮箱是必填项";
    } else if (!/\S+@\S+\.\S+/.test(formData.email)) {
      newErrors.email = "请输入有效的邮箱地址";
    }

    if (!formData.password) {
      newErrors.password = "密码是必填项";
    } else if (formData.password.length < 6) {
      newErrors.password = "密码至少需要6个字符";
    }

    setErrors(newErrors);
    return Object.keys(newErrors).length === 0;
  };

  // 处理表单提交
  const handleSubmit = async (e) => {
    e.preventDefault();
    
    if (!validateForm()) {
      return;
    }

    const result = await login(formData.email, formData.password);
    
    if (result.success) {
      // 登录成功，跳转到首页
      navigate("/home");
    }
  };

  return (
    <Box
      minH="100vh"
      display="flex"
      alignItems="center"
      justifyContent="center"
      bg={colorMode === "dark" ? "gray.800" : "gray.50"}
      p={4}
    >
      <Box
        w="full"
        maxW="md"
        p={8}
        bg={colorMode === "dark" ? "gray.700" : "white"}
        borderRadius="lg"
        shadow="xl"
      >
        <VStack spacing={6}>
          <Box textAlign="center">
            <Heading size="lg" mb={2}>欢迎回来1</Heading>
            <Text color="gray.500">请输入您的凭据登录</Text>
          </Box>
          
          <form onSubmit={handleSubmit} style={{ width: "100%" }}>
            <VStack spacing={4}>
              <FormControl isInvalid={!!errors.email}>
                <FormLabel>邮箱地址</FormLabel>
                <Input
                  name="email"
                  type="email"
                  placeholder="your@email.com"
                  value={formData.email}
                  onChange={handleInputChange}
                  size="lg"
                />
                {errors.email && (
                  <Text color="red.500" fontSize="sm" mt={1}>
                    {errors.email}
                  </Text>
                )}
              </FormControl>
              
              <FormControl isInvalid={!!errors.password}>
                <FormLabel>密码</FormLabel>
                <InputGroup size="lg">
                  <Input
                    name="password"
                    type={showPassword ? "text" : "password"}
                    placeholder="********"
                    value={formData.password}
                    onChange={handleInputChange}
                  />
                  <InputRightElement>
                    <IconButton
                      aria-label={showPassword ? "隐藏密码" : "显示密码"}
                      icon={showPassword ? <ViewOffIcon /> : <ViewIcon />}
                      variant="ghost"
                      onClick={() => setShowPassword(!showPassword)}
                    />
                  </InputRightElement>
                </InputGroup>
                {errors.password && (
                  <Text color="red.500" fontSize="sm" mt={1}>
                    {errors.password}
                  </Text>
                )}
              </FormControl>
              
              <Button
                type="submit"
                colorScheme="blue"
                w="full"
                size="lg"
                isLoading={isLoading}
                loadingText="登录中..."
              >
                {isLoading ? <Spinner size="sm" /> : "登录"}
              </Button>
            </VStack>
          </form>
          
          <VStack spacing={3}>
            <Text fontSize="sm" textAlign="center">
              还没有账户？{" "}
              <Link 
                color="blue.500" 
                onClick={() => navigate("/auth/signup")}
                _hover={{ textDecoration: "underline" }}
              >
                立即注册
              </Link>
            </Text>
            
            <Box textAlign="center">
              <Link 
                color="gray.500" 
                fontSize="sm"
                _hover={{ color: "blue.500" }}
              >
                忘记密码？
              </Link>
              <Text color="gray.500" fontSize="sm" mt={2}>
                还没有账户？{" "}
                <Link 
                  color="blue.500" 
                  fontWeight="medium"
                  _hover={{ textDecoration: "underline" }}
                  onClick={() => navigate('/auth/sign-up')}
                >
                  立即注册
                </Link>
              </Text>
            </Box>
          </VStack>
        </VStack>
      </Box>
    </Box>
  );
}