/**
 * options.js — ATS Resume Generator extension options page
 *
 * chrome.storage.local key contract (shared with background.js in Plan 04):
 *   resume_b64       {string}  Base64-encoded PDF bytes
 *   resume_sha256    {string}  Hex SHA-256 of the original PDF bytes
 *   resume_filename  {string}  Original filename for display
 *   api_url          {string}  HF Space base URL (e.g. https://user-space.hf.space)
 *   api_token        {string}  Bearer token sent as X-Api-Token header
 *
 * Background service worker (background.js) reads:
 *   chrome.storage.local.get(['resume_b64', 'api_token', 'api_url'])
 */

// ─── Version display ──────────────────────────────────────────────────────────
document.getElementById('ext_version').textContent = 'v' + chrome.runtime.getManifest().version;

// ─── Test Connection button ──────────────────────────────────────────────────
document.getElementById('test_conn_btn').addEventListener('click', async () => {
  const url = document.getElementById('api_url').value.trim();
  const token = document.getElementById('api_token').value.trim();
  const statusEl = document.getElementById('test_conn_status');
  if (!url) { statusEl.textContent = 'Enter API URL first.'; statusEl.style.color = '#dc2626'; return; }
  statusEl.textContent = 'Testing...'; statusEl.style.color = '#64748b';
  try {
    const r = await fetch(`${url.replace(/\/$/, '')}/api/health`, {
      headers: { 'X-Api-Token': token || '' }, signal: AbortSignal.timeout(10000),
    });
    if (r.ok) { statusEl.textContent = 'Connected!'; statusEl.style.color = '#16a34a'; }
    else if (r.status === 401) { statusEl.textContent = 'Auth failed — check token.'; statusEl.style.color = '#dc2626'; }
    else { statusEl.textContent = `Error (HTTP ${r.status})`; statusEl.style.color = '#dc2626'; }
  } catch (e) { statusEl.textContent = 'Cannot reach backend.'; statusEl.style.color = '#dc2626'; }
});

// ─── Load stored settings on page open ───────────────────────────────────────
chrome.storage.local.get(
  ['api_url', 'api_token', 'resume_filename', 'resume_sha256', 'resume_latex', 'gen_version_default', 'autofill_profile_json', 'default_cover_letter_latex'],
  (data) => {
    if (data.api_url) {
      document.getElementById('api_url').value = data.api_url;
    }
    if (data.api_token) {
      document.getElementById('api_token').value = data.api_token;
    }
    if (data.resume_filename) {
      const shortHash = (data.resume_sha256 || '').slice(0, 16);
      document.getElementById('resume_status').textContent =
        `Stored: ${data.resume_filename} (SHA-256: ${shortHash}...)`;
    }
    if (data.resume_latex && data.resume_latex.trim()) {
      document.getElementById('resume_latex').value = data.resume_latex;
      document.getElementById('latex_status').textContent =
        `LaTeX saved (${data.resume_latex.length.toLocaleString()} chars). Takes priority over the PDF.`;
    } else if (self.DEFAULT_RESUME_LATEX) {
      // R20: seed the built-in default resume so the extension works out-of-the-box.
      document.getElementById('resume_latex').value = self.DEFAULT_RESUME_LATEX;
      chrome.storage.local.set({ resume_latex: self.DEFAULT_RESUME_LATEX });
      document.getElementById('latex_status').textContent =
        `Default resume loaded (${self.DEFAULT_RESUME_LATEX.length.toLocaleString()} chars). Edit to use your own.`;
    }
    if (data.gen_version_default) {
      document.getElementById('gen_version_default').value = data.gen_version_default;
    }
    if (data.autofill_profile_json) {
      document.getElementById('autofill_profile_json').value = data.autofill_profile_json;
    }
    if (data.default_cover_letter_latex && data.default_cover_letter_latex.trim()) {
      document.getElementById('cover_letter_latex').value = data.default_cover_letter_latex;
      document.getElementById('cl_latex_status').textContent =
        `Custom template saved (${data.default_cover_letter_latex.length.toLocaleString()} chars).`;
    }
  }
);

// ─── SHA-256 helper via Web Crypto API (available in extension context) ───────
async function sha256Hex(buffer) {
  const hashBuffer = await crypto.subtle.digest('SHA-256', buffer);
  const hashArray = Array.from(new Uint8Array(hashBuffer));
  return hashArray.map((b) => b.toString(16).padStart(2, '0')).join('');
}

// ─── ArrayBuffer → base64 string ─────────────────────────────────────────────
function bufToBase64(buffer) {
  let binary = '';
  const bytes = new Uint8Array(buffer);
  for (let i = 0; i < bytes.byteLength; i++) {
    binary += String.fromCharCode(bytes[i]);
  }
  return btoa(binary);
}

// ─── Auto-evict generation caches to free quota for settings ─────────────────
// ponytail: settings always win over stale generation results
async function ensureQuota(needBytes) {
  const LIMIT = chrome.storage.local.QUOTA_BYTES || 10485760;
  const used = await new Promise(r => chrome.storage.local.getBytesInUse(null, r));
  if (used + needBytes < LIMIT * 0.85) return true;
  await new Promise(r => chrome.storage.local.remove(
    ['ats_results', 'ats_app_results', 'ats_bulk_history'], r));
  const after = await new Promise(r => chrome.storage.local.getBytesInUse(null, r));
  return after + needBytes < LIMIT * 0.95;
}

// ─── Save button handler ──────────────────────────────────────────────────────
document.getElementById('save_btn').addEventListener('click', async () => {
  const api_url = document.getElementById('api_url').value.trim();
  const api_token = document.getElementById('api_token').value.trim();
  const fileInput = document.getElementById('resume_file');
  const statusEl = document.getElementById('status_msg');

  // Validate required fields
  if (!api_url || !api_token) {
    statusEl.textContent = 'Error: API URL and token are required.';
    statusEl.style.color = '#dc2626';
    return;
  }

  const toStore = { api_url, api_token };

  // ─── LaTeX source (priority input) ─────────────────────────────────────────
  const latexSrc = document.getElementById('resume_latex').value.trim();
  toStore.resume_latex = latexSrc;  // store '' to allow clearing it
  toStore.gen_version_default = document.getElementById('gen_version_default').value;
  const autofillProfile = document.getElementById('autofill_profile_json').value.trim();
  if (autofillProfile) {
    try {
      JSON.parse(autofillProfile);
      toStore.autofill_profile_json = autofillProfile;
    } catch (_) {
      statusEl.textContent = 'Error: Autofill profile must be valid JSON.';
      statusEl.style.color = '#dc2626';
      return;
    }
  } else {
    toStore.autofill_profile_json = '';
  }
  document.getElementById('latex_status').textContent = latexSrc
    ? `LaTeX saved (${latexSrc.length.toLocaleString()} chars). Takes priority over the PDF.`
    : 'No LaTeX saved.';

  const clLatex = document.getElementById('cover_letter_latex').value.trim();
  toStore.default_cover_letter_latex = clLatex;
  document.getElementById('cl_latex_status').textContent = clLatex
    ? `Custom template saved (${clLatex.length.toLocaleString()} chars).`
    : 'No custom template — using built-in default.';

  // Handle optional resume upload
  if (fileInput.files.length > 0) {
    const file = fileInput.files[0];

    if (!file.name.toLowerCase().endsWith('.pdf')) {
      statusEl.textContent = 'Error: Please select a PDF file.';
      statusEl.style.color = '#dc2626';
      return;
    }

    const buffer = await file.arrayBuffer();
    const resume_b64 = bufToBase64(buffer);
    const resume_sha256 = await sha256Hex(buffer);
    const resume_filename = file.name;

    toStore.resume_b64 = resume_b64;
    toStore.resume_sha256 = resume_sha256;
    toStore.resume_filename = resume_filename;

    document.getElementById('resume_status').textContent =
      `Stored: ${resume_filename} (SHA-256: ${resume_sha256.slice(0, 16)}...)`;
  }

  // Auto-evict generation caches if storage is tight
  const payloadSize = JSON.stringify(toStore).length * 2;
  if (!(await ensureQuota(payloadSize))) {
    statusEl.textContent = 'Error: Storage full even after clearing caches. Remove the PDF resume or reduce LaTeX size.';
    statusEl.style.color = '#dc2626';
    return;
  }

  // Persist to chrome.storage.local
  chrome.storage.local.set(toStore, () => {
    if (chrome.runtime.lastError) {
      statusEl.textContent = 'Error saving: ' + chrome.runtime.lastError.message;
      statusEl.style.color = '#dc2626';
    } else {
      statusEl.textContent = 'Settings saved successfully.';
      statusEl.style.color = '#16a34a';
    }
  });
});