import { Client } from "ldapts";
import { IAuthenticationHandler } from "./index.js";
import { TotpChecker } from "./totpChecker.js";

export interface LdapAuthenticationConfiguration {
    ldapUrl: string;
    bindDnField: string;
    bindBase: string;
    usernameField: string;
    totpField?: string|null;
}

interface AccountInformations {
    username: string;
    totp: string|null;
}

export class LdapAuthenticationHandler implements IAuthenticationHandler {
    private configuration: LdapAuthenticationConfiguration;

    public constructor(configuration: LdapAuthenticationConfiguration) {
        this.configuration = configuration;
    }

    private async tryBind(username: string, password: string): Promise<AccountInformations|null> {
        if (!username || !password)
            return null;
        const client = new Client({
            url: this.configuration.ldapUrl,
            timeout: 0,
            connectTimeout: 0,
            tlsOptions: {
                minVersion: 'TLSv1.2',
            },
            strictDN: true,
        });
        const bindDn = `${this.configuration.bindDnField}=${username},${this.configuration.bindBase}`;
        let totp: string|null = null;

        try {
            await client.bind(bindDn, password);
            if (this.configuration.totpField) {
                const data = await client.search(bindDn);
                let totpData = data.searchEntries[0]?.[this.configuration.totpField];
                if (typeof totpData === "string")
                    totp = totpData;
                if (Array.isArray(totpData))
                    totp = totpData.join("");
                else
                    totp = totpData.toString("utf8");
            }
        }
        catch (ex) {
            console.error(ex);
            return null;
        }
        finally {
            client.unbind();
        }
        return <AccountInformations> {
            username: username,
            totp: totp
        };
    }

    public async tryLogin(username: string, password: string, totp?: string): Promise<boolean | null> {
        const account = await this.tryBind(username, password);
        if (!account)
            return null;
        return TotpChecker.ValidateTotp(account.totp, totp);
    }
    public async needTotp(username: string, password: string): Promise<boolean | null> {
        const account = await this.tryBind(username, password);
        if (!account)
            return null;
        return !!account.totp;
    }
}