// Vestibule admin wizard — production implementation.
//
// Two-phase UI:
//   Phase A (auth gate):
//     - No admin password set → setup view (first run)
//     - Admin password set → enter view (returning)
//   Phase B (wizard):
//     - Six steps, navigated with prev/next
//     - Final step shows JSON review and save button
//
// Credential split (two passwords, two surfaces):
//   Admin password — gates this wizard. PBKDF2-SHA-256, 100k
//   iterations, 16-byte salt, in-browser via Web Crypto.
//   Kiosk unlock password — releases the session. Argon2id in
//   usher, file storage at 0600 (see helper/src/crypto.rs).

const PBKDF2_ITERATIONS = 100_000;
const PBKDF2_HASH = "SHA-256";
const PBKDF2_KEYLEN_BITS = 256;
const SALT_BYTES = 16;
const MIN_PASSWORD_LENGTH = 8;
const TOTAL_STEPS = 6;

// URL policy engine — shared with the background script. Loaded via
// <script src="url-policy.js"> in admin.html; the wizard uses it for
// entry normalization and the homepage-on-safelist validation so the
// rule the operator configures is the rule the engine enforces.
const UrlPolicy = globalThis.VestibuleUrlPolicy;

// ─── Crypto utilities ─────────────────────────────────────────────────

const bytesToBase64 = (bytes) => btoa(String.fromCharCode(...bytes));
const base64ToBytes = (b64) => Uint8Array.from(atob(b64), (c) => c.charCodeAt(0));

const generateSalt = () => crypto.getRandomValues(new Uint8Array(SALT_BYTES));

async function hashPassword(password, saltBytes) {
  const enc = new TextEncoder();
  const keyMaterial = await crypto.subtle.importKey(
    "raw",
    enc.encode(password),
    "PBKDF2",
    false,
    ["deriveBits"]
  );
  const bits = await crypto.subtle.deriveBits(
    { name: "PBKDF2", salt: saltBytes, iterations: PBKDF2_ITERATIONS, hash: PBKDF2_HASH },
    keyMaterial,
    PBKDF2_KEYLEN_BITS
  );
  return new Uint8Array(bits);
}

async function verifyPassword(password, storedHashB64, storedSaltB64) {
  const hash = await hashPassword(password, base64ToBytes(storedSaltB64));
  const stored = base64ToBytes(storedHashB64);
  if (hash.length !== stored.length) return false;
  // SEI CERT MSC06-C: XOR-accumulate every byte. Array.prototype.every
  // short-circuits on the first mismatch and leaks timing; reduce does not.
  return hash.reduce((acc, b, i) => acc | (b ^ stored[i]), 0) === 0;
}

// ─── View helpers (step-down, no nested conditionals) ─────────────────

const ALL_VIEWS = () =>
  document.querySelectorAll(".auth-view, #view-wizard");

function showView(id) {
  ALL_VIEWS().forEach((v) => (v.hidden = true));
  const el = document.getElementById(id);
  if (el) el.hidden = false;
}

function showStep(n) {
  document.querySelectorAll(".step").forEach((s) => {
    s.hidden = true;
    s.classList.remove("active");
  });
  const target = document.querySelector(`.step[data-step="${n}"]`);
  if (target) {
    target.hidden = false;
    target.classList.add("active");
  }

  document.querySelectorAll("#step-list li").forEach((li) => {
    li.classList.remove("active", "completed");
    const step = parseInt(li.dataset.step, 10);
    if (step === n) li.classList.add("active");
    else if (step < n) li.classList.add("completed");
  });

  document.getElementById("wizard-progress").textContent = `Step ${n} of ${TOTAL_STEPS}`;
  document.getElementById("btn-prev").disabled = n === 1;

  const nextBtn = document.getElementById("btn-next");
  nextBtn.hidden = n === TOTAL_STEPS;

  if (n === TOTAL_STEPS) updateReview();
}

const getRadio = (name) => {
  const el = document.querySelector(`input[name="${name}"]:checked`);
  return el ? el.value : null;
};

const setRadio = (name, value) => {
  const el = document.querySelector(`input[name="${name}"][value="${value}"]`);
  if (el) el.checked = true;
};

const textareaLines = (id) =>
  document
    .getElementById(id)
    .value.split("\n")
    .map((s) => s.trim())
    .filter((s) => s.length > 0);

// Safelist entries as they will be saved: hostnames only, normalized,
// deduplicated, order preserved.
const safelistFromTextarea = () => {
  const seen = new Set();
  const entries = [];
  textareaLines("cfg-url-entries").forEach((line) => {
    const entry = UrlPolicy.normalizeDomainEntry(line);
    if (entry === null || seen.has(entry)) return;
    seen.add(entry);
    entries.push(entry);
  });
  return entries;
};

// ─── Config gather / fill (table-driven field maps) ───────────────────

const FIELD_MAP = [
  { key: "kioskName",        el: "cfg-kiosk-name",           get: (el) => el.value.trim() || "Vestibule Kiosk" },
  { key: "homeUrl",          el: "cfg-home-url",             get: (el) => el.value.trim() || "about:blank" },
  { key: "attractUrl",       el: "cfg-attract-url",          get: (el) => el.value.trim() },
];

const RADIO_MAP = [
  { cfg: "urlPolicy.mode",         radio: "url-mode",       default: "safelist" },
  { cfg: "session.onReset",        radio: "on-reset",        default: "both" },
  { cfg: "power.mode",             radio: "power-mode",      default: "aware" },
  { cfg: "power.onWake",           radio: "on-wake",         default: "both" },
  { cfg: "unlock.method",          radio: "unlock-method",   default: "password" },
];

// Help text per URL mode — the entries textarea means something
// different in each. One row per mode, shown under the textarea.
const ENTRIES_HELP = {
  safelist: "Domains, one per line. An entry grants the domain and every subdomain; pasted URLs are normalized to their hostname. Include the domains of third-party resources (CDNs, SSO, analytics) the kiosk content needs — they are blocked too.",
  open: "No entries apply in open mode; every URL is allowed.",
  blocklist: "Substrings, one per line. Any URL containing a listed string is blocked. Case-insensitive.",
  allowlist: "Substrings, one per line. Only URLs containing a listed string are allowed. An empty list allows everything — prefer safelist mode.",
};

function getNested(obj, path, fallback) {
  const result = path.split(".").reduce((acc, key) => (acc ? acc[key] : undefined), obj);
  return result !== undefined ? result : fallback;
}

function setNested(obj, path, value) {
  const keys = path.split(".");
  const last = keys.pop();
  const target = keys.reduce((acc, key) => (acc[key] = acc[key] || {}), obj);
  target[last] = value;
}

function gatherConfig() {
  const cfg = {
    version: 1,
    urlPolicy: { safelist: [], allowlist: [], blocklist: [] },
    session: { dataPersistenceAllowlist: [] },
    power: {},
    unlock: {},
    presence: {
      enabled: false,
      awayThresholdS: 10,
      faceMatchThreshold: 0.6,
      privacyMode: true,
    },
    _meta: { savedAt: new Date().toISOString(), schemaVersion: 1 },
  };

  FIELD_MAP.forEach(({ key, el, get }) => setNested(cfg, key, get(document.getElementById(el))));

  RADIO_MAP.forEach(({ cfg: cfgPath, radio, default: def }) => {
    setNested(cfg, cfgPath, getRadio(radio) || def);
  });

  // Entries feed the list the selected mode consumes. Safelist mode
  // normalizes to hostnames; the substring modes keep raw lines.
  const urlEntries = textareaLines("cfg-url-entries");
  if (cfg.urlPolicy.mode === "safelist") cfg.urlPolicy.safelist = safelistFromTextarea();
  else if (cfg.urlPolicy.mode === "allowlist") cfg.urlPolicy.allowlist = urlEntries;
  else cfg.urlPolicy.blocklist = urlEntries;

  cfg.session.idleTimeoutS = parseInt(document.getElementById("cfg-idle-timeout").value, 10) || 300;
  cfg.session.dataPersistenceAllowlist = textareaLines("cfg-persistence-allowlist");

  return cfg;
}

function fillConfig(cfg) {
  if (!cfg) return;
  FIELD_MAP.forEach(({ key, el }) => {
    const val = getNested(cfg, key, "");
    if (val) document.getElementById(el).value = val;
  });
  RADIO_MAP.forEach(({ cfg: cfgPath, radio, default: def }) => {
    setRadio(radio, getNested(cfg, cfgPath, def));
  });
  if (cfg.session) {
    document.getElementById("cfg-idle-timeout").value = cfg.session.idleTimeoutS || 300;
    document.getElementById("cfg-persistence-allowlist").value =
      (cfg.session.dataPersistenceAllowlist || []).join("\n");
  }
  if (cfg.urlPolicy) {
    const mode = cfg.urlPolicy.mode;
    const entries =
      mode === "safelist" ? cfg.urlPolicy.safelist :
      mode === "allowlist" ? cfg.urlPolicy.allowlist :
      cfg.urlPolicy.blocklist;
    document.getElementById("cfg-url-entries").value = (entries || []).join("\n");
  }
}

// ─── Review and save ──────────────────────────────────────────────────

function updateReview() {
  const cfg = gatherConfig();
  const display = { ...cfg, unlock: { method: cfg.unlock.method, password: "(sent to usher for Argon2id hashing)" } };
  document.getElementById("review-output").textContent = JSON.stringify(display, null, 2);
}

async function saveConfig() {
  const resultEl = document.getElementById("save-result");
  resultEl.hidden = true;
  resultEl.className = "save-result";

  const unlockPwd = document.getElementById("cfg-unlock-password").value;
  const unlockPwdConfirm = document.getElementById("cfg-unlock-password-confirm").value;

  if (unlockPwd && unlockPwd !== unlockPwdConfirm) {
    return showSaveError(resultEl, "Unlock passwords do not match.");
  }

  const cfg = gatherConfig();

  // Safelist mode: the kiosk must be able to reach its own home page
  // (and attract URL when set) — a domain not on the list refuses the
  // save instead of shipping a configuration that blocks the kiosk's
  // front door.
  const missing = missingSafelistDomains(cfg);
  if (missing.length > 0) {
    return showSaveError(resultEl,
      `Safelist check failed: ${missing.map((d) => `'${d}'`).join(", ")} ` +
      `${missing.length === 1 ? "is" : "are"} not on the safelist (step 2). ` +
      "Add the domain there, or set the home URL to an internal page (about:blank).");
  }

  // Persist config to browser storage (adminConfig + policy mirror)
  await persistConfig(cfg, resultEl);

  // If a new unlock password was entered, send it to usher for Argon2id
  // hashing and file storage. usher stores the PHC string at
  // ~/.config/vestibule/unlock.hash (0600). The hash never touches
  // browser storage.
  if (unlockPwd) {
    await sendUnlockPasswordToUsher(unlockPwd, resultEl);
  }
}

// URLs the kiosk navigates to on its own (home, attract) that the
// current safelist does not cover. The decision is delegated to the
// engine — the same function the background script calls — so the
// wizard can never disagree with runtime enforcement.
function missingSafelistDomains(cfg) {
  if (cfg.urlPolicy.mode !== "safelist") return [];
  const safelist = cfg.urlPolicy.safelist;
  return [cfg.homeUrl, cfg.attractUrl]
    .filter((url) => url && url.length > 0)
    .filter((url) =>
      UrlPolicy.shouldBlockRequest(url, { mode: "safelist", safelist }, { mainFrame: true }))
    .map((url) => UrlPolicy.homeHostnameOf(url) || url);
}

function sendUnlockPasswordToUsher(password, resultEl) {
  return new Promise((resolve) => {
    const timeoutId = setTimeout(() => {
      showSaveError(resultEl, "Unlock password storage timed out. Is usher running?");
      browser.runtime.onMessage.removeListener(handler);
      resolve();
    }, 10_000);

    const handler = (msg) => {
      if (msg.type !== "unlock-set-result") return;
      clearTimeout(timeoutId);
      browser.runtime.onMessage.removeListener(handler);

      if (msg.ok) {
        console.log("[vestibule-admin] unlock hash stored by usher");
      } else {
        showSaveError(resultEl, `Unlock password storage failed: ${msg.error || "unknown"}`);
      }
      resolve();
    };

    browser.runtime.onMessage.addListener(handler);
    browser.runtime.sendMessage({ type: "set-unlock-password", password }).catch(() => {
      clearTimeout(timeoutId);
      browser.runtime.onMessage.removeListener(handler);
      showSaveError(resultEl, "Cannot reach usher. Is the native host installed?");
      resolve();
    });
  });
}

async function persistConfig(cfg, resultEl) {
  try {
    await browser.storage.local.set({
      adminConfig: cfg,
      policy: {
        mode: cfg.urlPolicy.mode,
        safelist: cfg.urlPolicy.safelist,
        allowlist: cfg.urlPolicy.allowlist,
        blocklist: cfg.urlPolicy.blocklist,
        homeUrl: cfg.homeUrl,
        idleTimeoutS: cfg.session.idleTimeoutS,
        onReset: cfg.session.onReset,
        dataPersistenceAllowlist: cfg.session.dataPersistenceAllowlist,
        onWake: cfg.power.onWake,
      },
    });
    resultEl.textContent = "Configuration saved. The kiosk will use these settings immediately.";
    resultEl.classList.add("success");
    resultEl.hidden = false;
    console.log("[vestibule-admin] config saved:", cfg);
  } catch (e) {
    showSaveError(resultEl, `Save failed: ${e.message}`);
    console.error("[vestibule-admin] save failed:", e);
  }
}

function showSaveError(el, message) {
  el.textContent = message;
  el.classList.add("error");
  el.hidden = false;
}

// ─── Auth gate ────────────────────────────────────────────────────────

async function initAuthGate() {
  const stored = await browser.storage.local.get("adminAuth");
  return stored.adminAuth ? initReturningUser(stored.adminAuth) : initFirstRun();
}

function initFirstRun() {
  showView("view-auth-setup");
  document.getElementById("setup-submit").addEventListener("click", handleSetupSubmit);
  document.getElementById("setup-password-confirm").addEventListener("keydown", (e) => {
    if (e.key === "Enter") document.getElementById("setup-submit").click();
  });
}

async function handleSetupSubmit() {
  const pwd = document.getElementById("setup-password").value;
  const pwdConfirm = document.getElementById("setup-password-confirm").value;

  if (!pwd) return alert("Password cannot be empty.");
  if (pwd.length < MIN_PASSWORD_LENGTH) return alert(`Password must be at least ${MIN_PASSWORD_LENGTH} characters.`);
  if (pwd !== pwdConfirm) return alert("Passwords do not match.");

  const salt = await generateSalt();
  const hash = await hashPassword(pwd, salt);
  await browser.storage.local.set({
    adminAuth: {
      salt: bytesToBase64(salt),
      hash: bytesToBase64(hash),
      iterations: PBKDF2_ITERATIONS,
      algorithm: "PBKDF2-SHA-256",
      createdAt: new Date().toISOString(),
    },
  });
  console.log("[vestibule-admin] admin password set");
  enterWizard();
}

function initReturningUser(auth) {
  showView("view-auth-enter");
  const submit = document.getElementById("enter-submit");
  const passwordInput = document.getElementById("enter-password");
  const errEl = document.getElementById("enter-error");

  submit.addEventListener("click", async () => {
    errEl.hidden = true;
    const ok = await verifyPassword(passwordInput.value, auth.hash, auth.salt);
    if (ok) return enterWizard();
    errEl.textContent = "Invalid password.";
    errEl.hidden = false;
    passwordInput.value = "";
    passwordInput.focus();
  });

  passwordInput.addEventListener("keydown", (e) => {
    if (e.key === "Enter") submit.click();
  });
}

// ─── Homepage × safelist live check (step 1 ↔ step 2) ────────────────
//
// Safelist mode only: the home URL's domain must be on the list.
// The status line under the Home URL field answers in the operator's
// terms — which domain was read, whether it is listed — and offers
// the one-click fix. The same rule refuses the save (see
// missingSafelistDomains) and is guaranteed at runtime by the
// background script's home-origin exemption.

function updateUrlEntriesHelp() {
  const mode = getRadio("url-mode") || "safelist";
  document.getElementById("url-entries-help").textContent = ENTRIES_HELP[mode];
}

function updateHomeDomainStatus() {
  const statusEl = document.getElementById("home-domain-status");
  const textEl = document.getElementById("home-domain-text");
  const btnEl = document.getElementById("btn-add-home-domain");

  const mode = getRadio("url-mode") || "safelist";
  const homeUrl = document.getElementById("cfg-home-url").value.trim();

  // The check is a safelist-mode concern; other modes do not gate
  // the home page this way and the status line stays out of the way.
  if (mode !== "safelist" || !homeUrl) {
    statusEl.hidden = true;
    btnEl.hidden = true;
    return;
  }

  const hostname = UrlPolicy.homeHostnameOf(homeUrl);
  if (!hostname) {
    textEl.textContent = "Internal page — always permitted.";
    statusEl.classList.remove("warn");
    statusEl.classList.add("ok");
    btnEl.hidden = true;
    statusEl.hidden = false;
    return;
  }

  const blocked = UrlPolicy.shouldBlockRequest(
    homeUrl, { mode: "safelist", safelist: safelistFromTextarea() }, { mainFrame: true });

  if (!blocked) {
    textEl.textContent = `${hostname} — on the safelist.`;
    statusEl.classList.remove("warn");
    statusEl.classList.add("ok");
    btnEl.hidden = true;
  } else {
    textEl.textContent = `${hostname} is not on the safelist — the save will be refused until it is added.`;
    statusEl.classList.remove("ok");
    statusEl.classList.add("warn");
    btnEl.hidden = false;
  }
  statusEl.hidden = false;
}

function addHomeDomainToSafelist() {
  const hostname = UrlPolicy.homeHostnameOf(
    document.getElementById("cfg-home-url").value.trim());
  if (!hostname) return;

  if (!safelistFromTextarea().some((entry) =>
    hostname === entry || hostname.endsWith("." + entry))) {
    const textarea = document.getElementById("cfg-url-entries");
    textarea.value = textarea.value.trim();
    if (textarea.value) textarea.value += "\n";
    textarea.value += hostname;
  }
  updateHomeDomainStatus();
}

function wireUrlPolicyLiveChecks() {
  document.getElementById("cfg-home-url").addEventListener("input", updateHomeDomainStatus);
  document.getElementById("cfg-url-entries").addEventListener("input", updateHomeDomainStatus);
  document.querySelectorAll("input[name='url-mode']").forEach((radio) =>
    radio.addEventListener("change", () => {
      updateUrlEntriesHelp();
      updateHomeDomainStatus();
    }));
  document.getElementById("btn-add-home-domain").addEventListener(
    "click", addHomeDomainToSafelist);
  updateUrlEntriesHelp();
  updateHomeDomainStatus();
}

// ─── Wizard entry ─────────────────────────────────────────────────────

async function enterWizard() {
  showView("view-wizard");

  const stored = await browser.storage.local.get("adminConfig");
  if (stored.adminConfig) fillConfig(stored.adminConfig);
  else applyDefaults();

  let currentStep = 1;
  showStep(currentStep);

  document.getElementById("btn-prev").addEventListener("click", () => {
    if (currentStep > 1) showStep(--currentStep);
  });
  document.getElementById("btn-next").addEventListener("click", () => {
    if (currentStep < TOTAL_STEPS) showStep(++currentStep);
  });

  document.querySelectorAll("#step-list li").forEach((li) => {
    li.addEventListener("click", () => {
      const target = parseInt(li.dataset.step, 10);
      if (target <= currentStep || target === currentStep + 1) showStep((currentStep = target));
    });
  });

  document.getElementById("btn-save").addEventListener("click", saveConfig);
  document.getElementById("btn-cancel").addEventListener("click", () => {
    if (confirm("Discard changes and close?")) window.close();
  });

  wireUrlPolicyLiveChecks();
}

function applyDefaults() {
  setRadio("url-mode", "safelist");
  setRadio("on-reset", "both");
  setRadio("power-mode", "aware");
  setRadio("on-wake", "both");
  setRadio("unlock-method", "password");
  document.getElementById("cfg-idle-timeout").value = "300";
}

// ─── Boot ─────────────────────────────────────────────────────────────

document.addEventListener("DOMContentLoaded", initAuthGate);
console.log("[vestibule-admin] wizard loaded");