// Steward web UI: router, layout and login.
import { h, mount, toast, errorBox } from "./ui.js";
import { wordmark, logo } from "./brand.js";
import { api, get, state, can, setUnauthorizedHandler } from "./api.js";
import * as dashboard from "./pages/dashboard.js";
import * as subnets from "./pages/subnets.js";
import * as subnet from "./pages/subnet.js";
import * as leases from "./pages/leases.js";
import * as reservations from "./pages/reservations.js";
import * as activity from "./pages/activity.js";
import * as settings from "./pages/settings.js";
import * as history from "./pages/history.js";
import * as audit from "./pages/audit.js";
import * as users from "./pages/users.js";
import * as account from "./pages/account.js";
import * as certificate from "./pages/certificate.js";

const routes = [
  { pattern: /^$/, page: dashboard, nav: "dashboard" },
  { pattern: /^subnets$/, page: subnets, nav: "subnets" },
  { pattern: /^subnets\/(\d+)(?:\/(\w+))?$/, page: subnet, nav: "subnets", params: ["id", "tab"] },
  { pattern: /^leases$/, page: leases, nav: "leases" },
  { pattern: /^reservations$/, page: reservations, nav: "reservations" },
  { pattern: /^activity$/, page: activity, nav: "activity" },
  { pattern: /^settings$/, page: settings, nav: "settings" },
  { pattern: /^history$/, page: history, nav: "history" },
  { pattern: /^history\/(\d+)$/, page: history, nav: "history", params: ["id"] },
  { pattern: /^audit$/, page: audit, nav: "audit" },
  { pattern: /^users$/, page: users, nav: "users" },
  { pattern: /^account$/, page: account, nav: "account" },
  { pattern: /^certificate$/, page: certificate, nav: "certificate" },
];

// The top bar. ["key", "#/href", "Label", permission?]
const navItems = [
  ["dashboard", "#/", "Dashboard"],
  ["subnets", "#/subnets", "Subnets", "config"],
  ["leases", "#/leases", "Leases", "leases"],
  ["reservations", "#/reservations", "Reservations", "config"],
  ["activity", "#/activity", "Activity", "leases"],
  ["history", "#/history", "History", "config"],
  { menu: "Server", items: [
    ["settings", "#/settings", "Settings and options", "config"],
    ["certificate", "#/certificate", "Certificate", "admin"],
    ["audit", "#/audit", "Audit log", "audit"],
  ] },
];

const app = document.getElementById("app");
let mainEl, navEl, current = { key: "" }, routeGen = 0;

function parseHash() {
  const raw = location.hash.replace(/^#\/?/, "");
  const [path, qs] = raw.split("?");
  return { path: path.replace(/\/$/, ""), query: new URLSearchParams(qs || "") };
}

function renderLogin(message) {
  const user = h("input", { name: "username", autocomplete: "username", placeholder: "Username", required: true });
  const pass = h("input", { name: "password", type: "password", autocomplete: "current-password", placeholder: "Password", required: true });
  const err = h("div");
  const form = h("form", { onsubmit: async (e) => {
    e.preventDefault();
    mount(err);
    try {
      const me = await api("POST", "/auth/login", { body: { username: user.value, password: pass.value } });
      await loggedIn(me);
    } catch (ex) {
      mount(err, errorBox(ex));
      pass.select();
    }
  } }, user, pass, h("button", { class: "primary", type: "submit" }, "Log in"), err);
  mount(app, h("div", { class: "login panel" },
    logo(104, "login-logo"),
    h("h1", null, wordmark()),
    h("div", { class: "tag" }, "Keeper of the hold's addresses"),
    message ? h("div", { class: "msg warn" }, message) : null,
    form));
  user.focus();
}

async function loggedIn(me) {
  state.me = me;
  state.csrf = me.csrf_token || "";
  layout();
  window.addEventListener("hashchange", route);
  await route();
}

function layout() {
  navEl = h("nav", { class: "main" });
  mainEl = h("main");
  const me = state.me;
  const header = h("header", { class: "top" },
    h("a", { class: "brand", href: "#/", title: "Dashboard" },
      logo(30),
      wordmark({ rule: false, height: 17, cls: "brand-name" })),
    navEl,
    h("div", { class: "header-right" },
      menu(h("span", { class: "user", title: (me.permissions || []).join("\n") }, me.user.username), [
        h("a", { href: "#/account" }, "Account"),
        me.admin ? h("a", { href: "#/users" }, "Users") : null,
        h("button", { type: "button", class: "menu-item", onclick: logout }, "Log out"),
      ], { right: true, active: ["account", "users"].includes(current.nav), label: "Account menu" })));
  mount(app, h("div", { class: "shell" }, header, mainEl, footer(me.build)));
  renderNav();
}

// footer names the build: the release, or the commit for other builds.
function footer(b) {
  if (!b) return null;
  let title = b.tag ? "Steward " + b.version + " (release " + b.tag + ")" : "Steward " + b.version;
  if (!b.tag && b.commit) {
    title = "Development build of commit " + b.commit + (b.modified ? " with uncommitted changes" : "");
    if (b.since) title += b.ahead ? ", " + b.ahead + (b.ahead === 1 ? " commit" : " commits") + " after " + b.since : ", at " + b.since;
  }
  return h("footer", { class: "site" }, "Powered by ",
    h("a", { href: b.url, target: "_blank", rel: "noopener", title }, "Steward " + (b.tag || b.commit ? b.label : b.version)));
}

function renderNav() {
  const allowed = (n) => !n[3] || (n[3] === "admin" ? state.me.admin : can(n[3], false));
  const link = ([key, href, label]) => h("a", { href, class: current.nav === key ? "active" : "" }, label);
  mount(navEl, navItems.map((n) => {
    if (!n.menu) return allowed(n) ? link(n) : null;
    const items = n.items.filter(allowed);
    if (!items.length) return null;
    return menu(n.menu, items.map(link), { active: items.some((i) => i[0] === current.nav), label: n.menu + " menu" });
  }));
}

// menu is a drop-down that closes when an item is picked, on a click
// elsewhere and on Escape.
function menu(label, items, opts = {}) {
  const d = h("details", { class: "menu" + (opts.right ? " right" : "") },
    h("summary", { class: opts.active ? "active" : "", "aria-label": opts.label || null }, label, h("span", { class: "caret", "aria-hidden": "true" }, "▾")),
    h("div", { class: "menu-list", role: "menu" }, items.filter(Boolean)));
  d.addEventListener("click", (e) => { if (e.target.closest(".menu-list a, .menu-list button")) d.open = false; });
  return d;
}

document.addEventListener("click", (e) => {
  for (const d of document.querySelectorAll("details.menu[open]")) if (!d.contains(e.target)) d.open = false;
});
document.addEventListener("keydown", (e) => {
  if (e.key !== "Escape") return;
  for (const d of document.querySelectorAll("details.menu[open]")) { d.open = false; d.querySelector("summary").focus(); }
});

async function logout() {
  try { await api("POST", "/auth/logout"); } catch { /* ignore */ }
  state.me = null;
  state.csrf = "";
  window.removeEventListener("hashchange", route);
  renderLogin("You have logged out.");
}

// stopTimers lets a page that refreshes itself stop when it is left.
let pageCleanup = null;
export function onLeave(fn) { pageCleanup = fn; }

async function route() {
  if (!state.me) return;
  if (pageCleanup) { pageCleanup(); pageCleanup = null; }
  const { path, query } = parseHash();
  for (const r of routes) {
    const m = path.match(r.pattern);
    if (!m) continue;
    const params = {};
    (r.params || []).forEach((p, i) => { params[p] = m[i + 1]; });
    current = { key: path, nav: r.nav, page: r.page, params, query };
    renderNav();
    const gen = ++routeGen;
    const old = mainEl.firstChild;
    const slow = setTimeout(() => { if (gen === routeGen && mainEl.firstChild === old) mount(mainEl, h("div", { class: "muted" }, "Loading…")); }, 300);
    try {
      await r.page.render(mainEl, params, query);
    } catch (e) {
      if (gen === routeGen) mount(mainEl, h("h1", null, "Something went wrong"), errorBox(e));
    } finally {
      clearTimeout(slow);
    }
    return;
  }
  mount(mainEl, h("h1", null, "Not found"), h("p", null, h("a", { href: "#/" }, "Back to the dashboard")));
}

// rerender draws the current page again (after a change).
export function rerender() {
  if (current.page) route();
}

setUnauthorizedHandler(() => {
  if (state.me) {
    state.me = null;
    window.removeEventListener("hashchange", route);
    renderLogin("Your session has expired. Please log in again.");
  }
});

(async function boot() {
  try {
    await loggedIn(await get("/auth/whoami"));
  } catch (e) {
    if (e.status === 401) renderLogin();
    else mount(app, h("div", { class: "login panel" }, h("h1", null, "Steward"), errorBox(e)));
  }
})();

window.addEventListener("unhandledrejection", (e) => {
  toast(e.reason && e.reason.message ? e.reason.message : String(e.reason), "err");
});