export default class LibreAuth {
    name: string;
    ownerId: string;
    version: string;
    apiUrl: string;
    sessionId: string | null = null;
    enckey: string | null = null;
    hash: string = '';

    constructor(name: string, ownerId: string, version: string, apiUrl: string) {
        this.name = name;
        this.ownerId = ownerId;
        this.version = version;
        this.apiUrl = apiUrl.replace(/\/$/, '') + '/';
    }

    async init(enckey?: string) {
        this.enckey = (enckey || this.randEnc()).substring(0, 35);
        const res = await this.req({ type: 'init', ver: this.version, enckey: this.enckey, hash: this.hash || '' });
        if (!res.success) throw new Error(res.message);
        this.sessionId = res.sessionid;
        return res;
    }

    randEnc() {
        const a = new Uint8Array(18);
        crypto.getRandomValues(a);
        return Array.from(a, b => b.toString(16).padStart(2, '0')).join('').substring(0, 35);
    }

    async login(user: string, pass: string, hwid = '') {
        return this.auth({ type: 'login', username: user, pass, hwid });
    }

    async license(key: string, hwid = '') {
        return this.auth({ type: 'license', key, hwid });
    }

    async register(user: string, pass: string, key: string, hwid = '') {
        return this.auth({ type: 'register', username: user, pass, key, hwid });
    }

    private async auth(extra: Record<string, string>) {
        const res = await this.req(extra);
        if (!res.success) throw new Error(res.message);
        return res.info ?? res;
    }

    private async req(extra: Record<string, string>) {
        const body = new URLSearchParams({
            name: this.name,
            ownerid: this.ownerId,
            ...extra,
        });
        if (this.sessionId) body.set('sessionid', this.sessionId);
        const res = await fetch(this.apiUrl, {
            method: 'POST',
            headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
            body: body.toString(),
        });
        if (res.status === 429) throw new Error('Rate limited');
        return res.json();
    }
}