Add basic client-side account handling toolkit

import { Base64 } from "/static/lib/base64-3.7.5/base64.mjs"

export function getKey() {

    return JSON.parse(localStorage.getItem("key"))

}

export function isExpired(key) {

    const now = new Date()

    return now > new Date(key.expiresAt)

}

export function isLoggedIn() {

    return getKey() !== null && !isExpired(getKey())

}

export async function login(username, password) {

    // We use a library to Base64 encode username and password to conform to RFC7671

    // (https://datatracker.ietf.org/doc/html/rfc7617#section-2.1) because the built-in

    // JavaScript function btoa cannot deal with Unicode characters properly.

    const encodedUsernamePassword = Base64.encode(`${username}:${password}`)

    const key = await m.request({

        method: "POST",

        url: "/api/v0/keys",

        headers: {

            Authorization: `Basic ${encodedUsernamePassword}`,

        },

    })

    localStorage.setItem("key", JSON.stringify(key))

}

export async function logout() {

    const key = getKey()

    // Remove the key from local storage. This way, the logout button will always reset the local session in the browser,

    // even if something weird happens immediately afterwards.

    localStorage.removeItem("key")

    if (!key) {

        throw new Error(`Tried to logout, but the key was falsy: key = ${key}`)

    }

    try {

        await m.request({

            method: "DELETE",

            url: `/api/v0/keys/${key.uuid}`,

            headers: {

                Authorization: `Bearer ${key.secret}`,

            },

        })

    } catch (e) {

        if (e.code === 401 && isExpired(key)) {

            // Expired keys are deleted automatically and are not authorized to do anything anymore,

            // so this error is expected. We do nothing in this case, but could show an info message.

        } else {

            // This should not happen, rethrow

            throw e

        }

    }

}