'use client';
import './NexusAuth.css';
import { useState, useEffect } from 'react';
import NexusAuthApi from '@lib/Nexus_Auth_API';
import SplashScreen from '@components/SplashScreen';
import { useToast } from '@lib/ToastContext';
import { CheckCircleIcon } from '@heroicons/react/20/solid';

const SignupForm = ({ onSignup }) => {
    const [username, setUsername] = useState('');
    const [password, setPassword] = useState('');
    const [confirmPassword, setConfirmPassword] = useState('');
    const [email, setEmail] = useState('');
    const [usernameAvailable, setUsernameAvailable] = useState(null); // null for initial state
    const [doesUsernameContainInvalidChars, setDoesUsernameContainInvalidChars] = useState(false);
    const [doesUsernameExceedMinLength, setDoesUsernameExceedMinLength] = useState(false);
    const [passwordValid, setPasswordValid] = useState(false); // Initially invalid
    const [formValid, setFormValid] = useState(false);
    const [debounceTimeout, setDebounceTimeout] = useState(null); // Store timeout ID

    const minUsernameLength = 3;

    const validatePassword = (password) => {
        return password.length >= 8;
    };

    const handleUsernameChange = (e) => {
        const newUsername = e.target.value;
        setUsername(newUsername);

        // Reset username availability while typing
        setUsernameAvailable(null);

        // Clear any existing debounce timeout
        if (debounceTimeout) {
            clearTimeout(debounceTimeout);
        }

        // Check for invalid characters
        const invalidChars = /[^a-zA-Z0-9_]/g;
        if (invalidChars.test(newUsername)) {
            setDoesUsernameContainInvalidChars(true);
            setTimeout(() => {
                setDoesUsernameContainInvalidChars(false);
            }, 2000); // Show error for 2 seconds
        }

        // Basic sanitization to prevent SQL injection
        const sanitizedUsername = newUsername.replace(invalidChars, '');

        if (sanitizedUsername.length < minUsernameLength) {
            setDoesUsernameExceedMinLength(false);
            return;
        } else {
            setDoesUsernameExceedMinLength(true);}

        if (sanitizedUsername.trim().length > 0) {
            // Set a new timeout to check availability
            const newTimeout = setTimeout(async () => {
                try {
                    const response = await NexusAuthApi.isUsernameAvailable(sanitizedUsername);
                    setUsernameAvailable(response?.is_available === true);
                } catch (error) {
                    console.error('Error checking username availability:', error);
                    setUsernameAvailable(null); // Fallback state
                }
            }, 1000); // 1-second debounce delay

            setDebounceTimeout(newTimeout);
        } else {
            setUsernameAvailable(null); // Reset availability check when input is empty
        }

        // Set sanitized username
        setUsername(sanitizedUsername);
    };

    const handlePasswordChange = (e) => {
        const newPassword = e.target.value;
        setPassword(newPassword);
        setPasswordValid(validatePassword(newPassword));
    };

    const handleConfirmPasswordChange = (e) => {
        setConfirmPassword(e.target.value);
    };

    const handleSubmit = (e) => {
        e.preventDefault();

        // Set email to null if it's empty
        const emailValue = email.trim() === '' ? null : email;

        if (password === confirmPassword && passwordValid) {
            onSignup({ username, password, email: emailValue });
        }
    };

    useEffect(() => {
        setFormValid(
            usernameAvailable === true &&
            password === confirmPassword &&
            passwordValid &&
            username.length >= minUsernameLength &&
            !doesUsernameContainInvalidChars
        );
    }, [username, password, confirmPassword, usernameAvailable, passwordValid]);

    return (
        <form onSubmit={handleSubmit} className="nexus-auth-form">
            <h2>Signup</h2>
            <div className="form-group">
                <label>Username:</label>
                <input
                    type="text"
                    value={username}
                    onChange={handleUsernameChange}
                    required
                    className={usernameAvailable === false ? 'error' : ''} />
                {usernameAvailable === true && username.length > 0 && (
                    <CheckCircleIcon className="h-5 w-5 text-green-500" />
                )}
                {doesUsernameExceedMinLength === false && (
                    <p className="error-message text-red-500">Username must have more than {minUsernameLength} characters.</p>
                )}
                {doesUsernameContainInvalidChars === true && (
                    <p className="error-message text-red-500">Username cannot contain invalid characters.</p>
                )}
                {usernameAvailable === false && (
                    <p className="error-message text-red-500">Username is already taken</p>
                )}
                {usernameAvailable === null && username.length > 0 && (
                    <p className="typing-message text-green-500">Checking username availability...</p>
                )}
            </div>
            <div className="form-group">
                <label>Password:</label>
                <input
                    type="password"
                    value={password}
                    onChange={handlePasswordChange}
                    required
                    className={passwordValid ? '' : 'error'} />
                {passwordValid && (
                    <CheckCircleIcon className="h-5 w-5 text-green-500" />
                )}
                {!passwordValid && (
                    <p className="error-message text-yellow-500">Password must be at least 8 characters long</p>
                )}
            </div>
            <div className="form-group">
                <label>Confirm Password:</label>
                <input
                    type="password"
                    value={confirmPassword}
                    onChange={handleConfirmPasswordChange}
                    required
                    className={password === confirmPassword ? '' : 'error'} />
                {password === confirmPassword && confirmPassword.length > 0 && (
                    <CheckCircleIcon className="h-5 w-5 text-green-500" />
                )}
                {password !== confirmPassword && confirmPassword.length > 0 && (
                    <p className="error-message text-red-500">Passwords do not match</p>
                )}
            </div>
            <div className="form-group">
                <label>Email (optional):</label>
                <input
                    type="email"
                    value={email}
                    onChange={(e) => setEmail(e.target.value)} />
            </div>
            <button type="submit" className="submit-button" disabled={!formValid}>
                Signup
            </button>
        </form>
    );
};

const LoginForm = ({ onLogin }) => {
    const [username, setUsername] = useState('');
    const [password, setPassword] = useState('');

    const handleSubmit = (e) => {
        e.preventDefault();
        onLogin({ username, password });
    };

    return (
        <form onSubmit={handleSubmit} className="nexus-auth-form">
            <h2>Login</h2>
            <div className="form-group">
                <label>Username:</label>
                <input
                    type="text"
                    value={username}
                    onChange={(e) => setUsername(e.target.value)}
                    required />
            </div>
            <div className="form-group">
                <label>Password:</label>
                <input
                    type="password"
                    value={password}
                    onChange={(e) => setPassword(e.target.value)}
                    required />
            </div>
            <button type="submit" className="submit-button">
                Login
            </button>
        </form>
    );
};

export const NexusAuthWrapper = ({ children }) => {
    const [isLoggedIn, setIsLoggedIn] = useState(false);
    const [isSignup, setIsSignup] = useState(false);
    const [isLoading, setIsLoading] = useState(true);
    const toast = useToast();

    useEffect(() => {
        const validateUserSession = async () => {
            const storedUsername = localStorage.getItem("me");
            const storedToken = localStorage.getItem("s_tkn");
            const storedUserID = localStorage.getItem("u_id");

            if (storedUsername && storedToken && storedUserID) {
                try {
                    // Validate the token with the NexusAuthApi
                    const response = await NexusAuthApi.validateToken(storedUserID, storedToken);

                    if (response.data && response.data.user_id) {
                        // Token is valid; response contains user details
                        console.log("User is already logged in.");
                        toast.info("Welcome back, " + response.data.username + "!");
                        setIsLoggedIn(true);

                        // Optionally, update localStorage with new details if needed
                        localStorage.setItem("me", response.data.username);
                        localStorage.setItem("s_tkn", response.data.access_token);
                        localStorage.setItem("u_id", response.data.user_id);
                        localStorage.setItem("a_l", response.data.access_level);
                    } else if (response.status === 401) {
                        // Token is invalid; clear local storage
                        console.info("Token validation failed with status 401:");
                        clearLocalStorage();
                    } else {
                        // Handle other errors (e.g., network issues)
                        console.debug("Token validation failed due to an unexpected error:", response.data);
                        toast.error("Unable to validate token. Please check your connection.");
                    }
                } catch (error) {
                    // Handle other errors (e.g., network issues)
                    console.debug("Token validation failed due to an unexpected error:", error);
                    toast.error("Unable to validate token. Please check your connection.");

                }
            }
            setIsLoading(false);

        };

        const clearLocalStorage = () => {
            localStorage.removeItem("me");
            localStorage.removeItem("s_tkn");
            localStorage.removeItem("u_id");
            localStorage.removeItem("a_l");
            setIsLoggedIn(false);
            toast.error("Session expired. Please login again.");
        };

        validateUserSession();
    }, []);

    const handleSignup = async (data) => {
        setIsLoading(true);
        try {
            const response = await NexusAuthApi.signup(data.username, data.password, data.email);
            console.log("Signup successful:", response);
            setIsLoading(false);
            toast.success('Signup successful. Please login to continue');
            setIsSignup(false);
        } catch (error) {
            setIsLoading(false);
            console.debug("Signup failed:", error);
            toast.error("Signup failed");
        }
    };

    const handleLogin = async (data) => {
        setIsLoading(true);
        try {
            const response = await NexusAuthApi.login(data.username, data.password);
            console.log("Login successful:", response);
            toast.success('Login successful.');
            // Save username and token to localStorage
            localStorage.setItem("me", response.username);
            localStorage.setItem("s_tkn", response.access_token);
            localStorage.setItem("u_id", response.user_id);
            localStorage.setItem("a_l", response.access_level);

            setIsLoggedIn(true);
            setIsLoading(false);
        } catch (error) {
            setIsLoading(false);
            console.debug("Login failed:", error);
            toast.error("Login failed");
        }
    };

    if (isLoading) {
        return <SplashScreen />;
    }

    return (
        <div>
            {isLoggedIn ? (
                children
            ) : (
                <div className="nexus-auth-signup-login">
                    <h1>Nexus Accounts</h1>
                    <button onClick={() => setIsSignup(!isSignup)}>
                        {isSignup ? "Already have an Account? Login" : "Don't have an Account? Signup"}
                    </button>
                    {isSignup ? (
                        <SignupForm onSignup={handleSignup} />
                    ) : (
                        <LoginForm onLogin={handleLogin} />
                    )}
                </div>
            )}
        </div>
    );
};