/**
 * progress.js
 * -----------
 * Progress section DOM management: per-file bars, overall bar, and
 * the final results summary.
 *
 * These functions are called by both stream.js (live SSE updates) and
 * session.js (snapshot restore on reconnect / page reload).
 *
 * Exports
 * -------
 *   setupProgressSection(files)
 *   setOverallProgress(pct)
 *   updateFileProgress(idx, pct, statusClass, statusText, detail, detailClass)
 *   showStreamLost()
 *   hideStreamLost()
 *   showResults(finalStatus)
 */

import { state, els, announce } from './state.js';
import { esc } from './utils.js';

// ─── Progress section setup ───────────────────────────────────────────────────

/**
 * Render the initial per-file progress items and reset counters.
 * Called when a new compression job starts or when the DOM needs to be
 * rebuilt after a full page reload.
 * @param {Array} files  — file objects from the job (name, path, …)
 */
export function setupProgressSection(files) {
  els.progTotal.textContent  = files.length;
  els.progDone.textContent   = '0';
  els.progStatus.textContent = 'Running';
  setOverallProgress(0);

  let html = '';
  files.forEach((f, idx) => {
    html += `
      <div class="file-progress-item" id="fpi-${idx}" role="listitem"
           aria-label="File ${idx + 1} of ${files.length}: ${esc(f.name)}">
        <div class="fp-header">
          <span class="fp-name">${esc(f.name)}</span>
          <span class="fp-status waiting" id="fps-${idx}"
                aria-live="polite">Waiting</span>
        </div>
        <div class="fp-bar-wrap" aria-label="Progress for ${esc(f.name)}">
          <div class="fp-bar" role="progressbar"
               aria-valuenow="0" aria-valuemin="0" aria-valuemax="100"
               id="fpbar-${idx}">
            <div class="fp-bar-fill" id="fpfill-${idx}" style="width:0%"></div>
          </div>
          <span class="fp-pct" id="fppct-${idx}" aria-hidden="true">0%</span>
        </div>
        <div class="fp-detail" id="fpdetail-${idx}"></div>
      </div>`;
  });
  els.fileProgressList.innerHTML = html;
}

// ─── Bar helpers ─────────────────────────────────────────────────────────────

/**
 * Update the overall progress bar.
 * @param {number} pct  0–100
 */
export function setOverallProgress(pct) {
  const p = Math.min(100, Math.round(pct));
  els.overallBarFill.style.width = `${p}%`;
  els.overallBar.setAttribute('aria-valuenow', p);
  els.overallPct.textContent = `${p}%`;
}

/**
 * Update a single file's progress bar, status badge, and detail text.
 *
 * @param {number} idx          — file index (0-based)
 * @param {number} pct          — 0–100
 * @param {string} statusClass  — 'waiting' | 'running' | 'done' | 'error'
 * @param {string} statusText   — visible badge text
 * @param {string} [detail]     — optional sub-text (elapsed time, size saved…)
 * @param {string} [detailClass]— optional class applied to the detail element
 */
export function updateFileProgress(idx, pct, statusClass, statusText, detail, detailClass) {
  const fill   = document.getElementById(`fpfill-${idx}`);
  const bar    = document.getElementById(`fpbar-${idx}`);
  const pctEl  = document.getElementById(`fppct-${idx}`);
  const status = document.getElementById(`fps-${idx}`);
  const item   = document.getElementById(`fpi-${idx}`);
  const det    = document.getElementById(`fpdetail-${idx}`);
  if (!fill) return;

  const p = Math.min(100, Math.round(pct));
  fill.style.width = `${p}%`;
  bar.setAttribute('aria-valuenow', p);
  pctEl.textContent  = `${p}%`;
  status.className   = `fp-status ${statusClass}`;
  status.textContent = statusText;
  item.className     = `file-progress-item ${statusClass}`;
  fill.classList.toggle('active', statusClass === 'running');

  if (detail !== undefined) {
    det.textContent = detail;
    det.className   = `fp-detail ${detailClass || ''}`;
  }
}

// ─── Stream-lost banner ───────────────────────────────────────────────────────

/** Show the disconnection warning banner and reveal the Reconnect button. */
export function showStreamLost() {
  els.streamLostBanner.hidden = false;
  els.reconnectBtn.hidden     = false;
  els.progStatus.textContent  = 'Disconnected';
  announce('Live progress stream disconnected. Use Reconnect to resume.');
}

/** Hide the disconnection warning banner and Reconnect button. */
export function hideStreamLost() {
  els.streamLostBanner.hidden = true;
  els.reconnectBtn.hidden     = true;
}

// ─── Results summary ─────────────────────────────────────────────────────────

/**
 * Render the Step 4 results card and scroll it into view.
 * @param {'done'|'cancelled'} finalStatus
 */
export function showResults(finalStatus) {
  const results = state.compressionResults;
  let html = '';

  if (finalStatus === 'cancelled') {
    html += `<p style="color:var(--text-muted);margin-bottom:var(--space-md)">
      Compression was cancelled. Completed files are listed below.</p>`;
  }

  if (!results.length && finalStatus === 'cancelled') {
    html += '<p style="color:var(--text-muted)">No files were completed before cancellation.</p>';
  }

  results.forEach(r => {
    if (r.status === 'done') {
      html += `
        <div class="result-row">
          <span class="result-icon">✅</span>
          <div class="result-info">
            <div class="result-name">${esc(r.filename)}</div>
            <div class="result-meta">→ ${esc(r.output || '')}</div>
          </div>
          <span class="result-reduction">-${r.reduction_pct}%</span>
        </div>`;
    } else if (r.status === 'error') {
      html += `
        <div class="result-row">
          <span class="result-icon">❌</span>
          <div class="result-info">
            <div class="result-name">${esc(r.filename)}</div>
            <div class="result-meta" style="color:var(--text-danger)">
              ${esc(r.message)}
            </div>
          </div>
        </div>`;
    }
  });

  if (!html) html = '<p style="color:var(--text-muted)">No results to display.</p>';
  els.resultsContent.innerHTML = html;
  els.sectionResults.hidden    = false;
  els.sectionResults.scrollIntoView({ behavior: 'smooth', block: 'start' });
}