"use strict";

const CLIENT_NAME_RE = /^[A-Za-z0-9._-]{1,64}$/;
const TOKEN_PREFIX = "fab_";

function nowIso() {
  return new Date().toISOString().replace(/\.\d{3}Z$/, "Z");
}

async function sha256Hex(text) {
  const buf = await crypto.subtle.digest("SHA-256", new TextEncoder().encode(text));
  return Array.from(new Uint8Array(buf), (b) => b.toString(16).padStart(2, "0")).join("");
}

function publicClient(row) {
  return {
    id: row.id,
    name: row.name,
    created: row.created,
    last_used: row.last_used || null,
  };
}

async function loadClients() {
  const data = await browser.storage.local.get("clients");
  return Array.isArray(data.clients) ? data.clients : [];
}

async function saveClients(clients) {
  await browser.storage.local.set({ clients });
}

async function listClients() {
  return (await loadClients()).map(publicClient);
}

async function createClient(name) {
  name = String(name || "").trim();
  if (!CLIENT_NAME_RE.test(name)) {
    throw new Error("Name must be 1–64 characters: A-Za-z0-9._-");
  }
  const clients = await loadClients();
  if (clients.some((row) => row.name === name)) {
    throw new Error("A client with that name already exists");
  }
  const raw = new Uint8Array(32);
  crypto.getRandomValues(raw);
  const token = TOKEN_PREFIX + Array.from(raw, (b) => b.toString(16).padStart(2, "0")).join("");
  const idBytes = new Uint8Array(16);
  crypto.getRandomValues(idBytes);
  const id = Array.from(idBytes, (b) => b.toString(16).padStart(2, "0")).join("");
  clients.push({
    id,
    name,
    token_hash: await sha256Hex(token),
    created: nowIso(),
    last_used: null,
  });
  await saveClients(clients);
  return { id, name, token };
}

async function revokeClient(id) {
  const clients = await loadClients();
  const next = clients.filter((row) => row.id !== id && row.name !== id);
  if (next.length === clients.length) {
    throw new Error("No such client");
  }
  await saveClients(next);
  return id;
}

async function findClientByTokenHash(tokenHash) {
  const clients = await loadClients();
  const row = clients.find((item) => item.token_hash === tokenHash);
  if (!row) {
    return null;
  }
  row.last_used = nowIso();
  await saveClients(clients);
  return publicClient(row);
}