import { useEffect, useRef, useState } from 'react';

import { clearAuthState, storeAuthState } from '../../auth-session.js';
import { initializeTelemetry } from '../../telemetry.js';
import {
    LOGIN_ERROR_MESSAGES,
    requestLogin,
    validateLogin
} from './login-service.js';
import { FormAlert } from '../shared/ui/FormAlert.jsx';

void initializeTelemetry();

const EMPTY_CREDENTIALS = Object.freeze({ password: '', username: '' });

function BrandIcon() {
    return (
        <svg width="40" height="40" viewBox="0 0 40 40" fill="none" xmlns="http://www.w3.org/2000/svg" aria-hidden="true">
            <rect width="40" height="40" rx="12" fill="url(#logo-gradient)" />
            <path d="M12 20L18 26L28 14" stroke="white" strokeWidth="3" strokeLinecap="round" strokeLinejoin="round" />
            <defs>
                <linearGradient id="logo-gradient" x1="0" y1="0" x2="40" y2="40">
                    <stop stopColor="#6366f1" />
                    <stop offset="1" stopColor="#8b5cf6" />
                </linearGradient>
            </defs>
        </svg>
    );
}

function UserIcon() {
    return (
        <svg className="input-icon" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
            <path d="M20 21v-2a4 4 0 0 0-4-4H8a4 4 0 0 0-4 4v2" />
            <circle cx="12" cy="7" r="4" />
        </svg>
    );
}

function LockIcon() {
    return (
        <svg className="input-icon" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
            <rect x="3" y="11" width="18" height="11" rx="2" ry="2" />
            <path d="M7 11V7a5 5 0 0 1 10 0v4" />
        </svg>
    );
}

function EyeIcon() {
    return (
        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden="true">
            <path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z" />
            <circle cx="12" cy="12" r="3" />
        </svg>
    );
}

function Spinner() {
    return (
        <svg className="spinner" width="20" height="20" viewBox="0 0 24 24" aria-hidden="true">
            <circle cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="3" fill="none" strokeDasharray="31.4 31.4" strokeLinecap="round" />
        </svg>
    );
}

export function LoginApp() {
    const [credentials, setCredentials] = useState(EMPTY_CREDENTIALS);
    const [errors, setErrors] = useState({});
    const [alert, setAlert] = useState(null);
    const [loading, setLoading] = useState(false);
    const [passwordVisible, setPasswordVisible] = useState(false);
    const [rippleVisible, setRippleVisible] = useState(false);
    const redirectTimer = useRef(null);

    useEffect(() => () => {
        if (redirectTimer.current) {
            window.clearTimeout(redirectTimer.current);
        }
    }, []);

    const updateField = event => {
        const { name, value } = event.target;
        setCredentials(current => ({ ...current, [name]: value }));
        setErrors(current => ({ ...current, [name]: undefined }));
    };

    const submit = async event => {
        event.preventDefault();
        const nextErrors = validateLogin(credentials);
        setErrors(nextErrors);
        setAlert(null);

        if (Object.keys(nextErrors).length > 0) {
            return;
        }

        setLoading(true);
        try {
            const result = await requestLogin(credentials);
            if (!result.ok) {
                setAlert({ message: result.message, type: 'error' });
                return;
            }

            clearAuthState();
            const session = storeAuthState(result.data);
            if (!session) {
                setAlert({ message: LOGIN_ERROR_MESSAGES.invalidResponse, type: 'error' });
                return;
            }

            setAlert({ message: 'Вход выполнен успешно!', type: 'success' });
            redirectTimer.current = window.setTimeout(() => {
                window.location.assign(session.redirect || '/');
            }, 400);
        } catch (error) {
            setAlert({ message: LOGIN_ERROR_MESSAGES.connection, type: 'error' });
        } finally {
            setLoading(false);
        }
    };

    const showRipple = () => {
        setRippleVisible(false);
        window.requestAnimationFrame(() => setRippleVisible(true));
    };

    return (
        <>
            <div className="background" aria-hidden="true">
                <div className="shape shape-1" />
                <div className="shape shape-2" />
                <div className="shape shape-3" />
            </div>

            <main className="login-container">
                <div className="login-card">
                    <header className="login-header">
                        <div className="logo"><BrandIcon /></div>
                        <h1>Добро пожаловать</h1>
                        <p className="subtitle">Войдите в свой аккаунт</p>
                    </header>

                    <form id="login-form" noValidate onSubmit={submit}>
                        <div className={`form-group stagger-1${errors.username ? ' has-error shake' : ''}`}>
                            <label htmlFor="username">Имя пользователя</label>
                            <div className="input-wrapper">
                                <UserIcon />
                                <input
                                    type="text"
                                    id="username"
                                    name="username"
                                    value={credentials.username}
                                    onChange={updateField}
                                    placeholder="Введите имя пользователя"
                                    autoComplete="username"
                                    aria-invalid={Boolean(errors.username)}
                                    aria-describedby="username-error"
                                    required
                                />
                            </div>
                            <span className="error-message" id="username-error">{errors.username || ''}</span>
                        </div>

                        <div className={`form-group stagger-2${errors.password ? ' has-error shake' : ''}`}>
                            <label htmlFor="password">Пароль</label>
                            <div className="input-wrapper">
                                <LockIcon />
                                <input
                                    type={passwordVisible ? 'text' : 'password'}
                                    id="password"
                                    name="password"
                                    value={credentials.password}
                                    onChange={updateField}
                                    placeholder="Введите пароль"
                                    autoComplete="current-password"
                                    aria-invalid={Boolean(errors.password)}
                                    aria-describedby="password-error"
                                    required
                                />
                                <button
                                    type="button"
                                    className="btn btn-icon-md btn-secondary toggle-password"
                                    id="toggle-password"
                                    aria-label={passwordVisible ? 'Скрыть пароль' : 'Показать пароль'}
                                    aria-pressed={passwordVisible}
                                    onClick={() => setPasswordVisible(visible => !visible)}
                                >
                                    <EyeIcon />
                                </button>
                            </div>
                            <span className="error-message" id="password-error">{errors.password || ''}</span>
                        </div>

                        <FormAlert alert={alert} className="stagger-3" id="form-alert" />

                        <button
                            type="submit"
                            className="btn btn-lg btn-primary btn-submit stagger-4"
                            id="btn-submit"
                            disabled={loading}
                            onPointerDown={showRipple}
                        >
                            {loading ? <Spinner /> : <span className="btn-text">Войти</span>}
                            {rippleVisible && <span className="ripple" onAnimationEnd={() => setRippleVisible(false)} />}
                        </button>
                    </form>
                </div>
            </main>
        </>
    );
}