/**
 * compress.js
 * -----------
 * Compression job lifecycle: start, notification opt-in, cancel, and restart.
 *
 * Exports
 * -------
 *   initCompress()  — attach all event listeners; call once at startup
 */

import { state, els, announce } from './state.js';
import { setupProgressSection, showResults } from './progress.js';
import { startProgressStream } from './stream.js';
import { smtpIsConfigured } from './settings.js';

// ─── Public init ─────────────────────────────────────────────────────────────

/**
 * Attach event listeners for:
 *   - Notification checkbox toggle
 *   - "Compress Selected Files" button
 *   - "Cancel Compression" button
 *   - "Start New Session" (restart) button
 *
 * Call once during app initialisation.
 */
export function initCompress() {
  _initNotifyToggle();
  _initCompressButton();
  _initCancelButton();
  _initRestartButton();
}

// ─── Notification opt-in ─────────────────────────────────────────────────────

function _initNotifyToggle() {
  els.notifyChk.addEventListener('change', () => {
    const show = els.notifyChk.checked;
    els.notifyEmailRow.hidden = !show;
    els.notifyEmail.setAttribute('aria-required', show ? 'true' : 'false');
    const warn = document.getElementById('smtp-not-configured-warn');
    if (show) {
      els.notifyEmail.focus();
      if (warn) warn.hidden = smtpIsConfigured();
    } else {
      els.notifyEmail.value = '';
      if (warn) warn.hidden = true;
    }
  });
}

// ─── Start compression ────────────────────────────────────────────────────────

function _initCompressButton() {
  els.compressBtn.addEventListener('click', async () => {
    const selectedFiles = state.scannedFiles.filter(
      f => state.selectedPaths.has(f.path),
    );
    if (!selectedFiles.length) return;

    const suffix      = els.suffixInput.value.trim() || '_new';
    const notifyEmail = els.notifyChk.checked ? els.notifyEmail.value.trim() : '';

    // Client-side email validation
    if (els.notifyChk.checked) {
      if (!notifyEmail) {
        els.notifyEmail.setCustomValidity('Please enter your email address.');
        els.notifyEmail.reportValidity();
        return;
      }
      if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(notifyEmail)) {
        els.notifyEmail.setCustomValidity('Please enter a valid email address.');
        els.notifyEmail.reportValidity();
        return;
      }
      els.notifyEmail.setCustomValidity('');
    }

    els.compressBtn.disabled    = true;
    els.compressBtn.textContent = 'Starting…';

    try {
      const resp = await fetch('/api/compress/start', {
        method:  'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          files: selectedFiles.map(f => ({
            path:                f.path,
            size_bytes:          f.size_bytes,
            target_bit_rate_bps: f.target_bit_rate_bps || 1_000_000,
            codec:               f.codec || 'unknown',
          })),
          suffix,
          notify_email: notifyEmail,
        }),
      });
      const data = await resp.json();

      if (!resp.ok) {
        alert(`Failed to start compression: ${data.error}`);
        _resetCompressBtn();
        return;
      }

      state.currentJobId       = data.job_id;
      state.seenEventCount     = 0;
      state.compressionResults = [];
      sessionStorage.setItem('vp-job-id', data.job_id);

      setupProgressSection(selectedFiles);
      els.sectionProgress.hidden = false;
      els.sectionProgress.scrollIntoView({ behavior: 'smooth', block: 'start' });
      announce(`Compression started for ${selectedFiles.length} file(s).`);
      startProgressStream(data.job_id, selectedFiles);

    } catch (err) {
      alert(`Error: ${err.message}`);
      _resetCompressBtn();
    }
  });
}

function _resetCompressBtn() {
  els.compressBtn.disabled  = false;
  els.compressBtn.innerHTML =
    '<span class="btn-icon-prefix" aria-hidden="true">⚡</span> Compress Selected Files';
}

// ─── Cancel ───────────────────────────────────────────────────────────────────

function _initCancelButton() {
  els.cancelBtn.addEventListener('click', async () => {
    if (!state.currentJobId) return;
    if (!confirm(
      'Cancel all compression operations? ' +
      'Any file currently being processed will be deleted.',
    )) return;

    els.cancelBtn.disabled    = true;
    els.cancelBtn.textContent = 'Cancelling…';

    try {
      await fetch(`/api/compress/cancel/${state.currentJobId}`, { method: 'POST' });
      announce('Cancellation requested.');
    } catch (err) {
      console.error('Cancel error:', err);
    }
  });
}

// ─── Restart (new session) ────────────────────────────────────────────────────

function _initRestartButton() {
  els.restartBtn.addEventListener('click', () => {
    // Clear state
    state.scannedFiles       = [];
    state.selectedPaths.clear();
    state.currentJobId       = null;
    state.compressionResults = [];
    state.seenEventCount     = 0;

    if (state.eventSource) {
      state.eventSource.close();
      state.eventSource = null;
    }
    if (state.reconnectTimer) {
      clearTimeout(state.reconnectTimer);
      state.reconnectTimer = null;
    }
    sessionStorage.removeItem('vp-job-id');

    // Reset UI
    els.sectionFiles.hidden        = true;
    els.sectionProgress.hidden     = true;
    els.sectionResults.hidden      = true;
    els.fileTbody.innerHTML        = '';
    els.fileProgressList.innerHTML = '';
    els.scanStatus.textContent     = '';
    els.notifyChk.checked          = false;
    els.notifyEmailRow.hidden      = true;
    els.notifyEmail.value          = '';
    els.notifyStatus.hidden        = true;
    els.notifyStatus.textContent   = '';
    els.streamLostBanner.hidden    = true;
    els.reconnectBtn.hidden        = true;
    els.cancelBtn.disabled         = false;
    els.cancelBtn.textContent      = '✕ Cancel Compression';
    _resetCompressBtn();

    document.getElementById('section-config')
      .scrollIntoView({ behavior: 'smooth' });
    els.dirInput.focus();
    announce('Session reset. Ready to scan again.');
  });
}