// ESM module: shared printable HTML builder
// Note: callers must sanitize any HTML fields (e.g., summary) before passing.

function escapeText(str) {
  if (str == null) return '';
  return String(str)
    .replace(/&/g, '&')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/\"/g, '&quot;')
    .replace(/'/g, '&#39;');
}

export function buildPrintableHtml(cv, templateId) {
  const { personal = {}, summary = '', work = [], education = [], skills = [], languages = [], certifications = [], templateId: cvTemplateId } = cv || {};
  const tid = templateId || cvTemplateId || 'ats';

  const baseStyles = `
    @page { size: A4; margin: 20mm; }
    body { font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, Noto Sans; color: #1f2937; }
    .page { width: 210mm; min-height: 297mm; margin: 0 auto; background: white; }
    h1 { font-size: 24px; margin: 0 0 6px 0; }
    h2 { font-size: 16px; margin: 16px 0 8px 0; padding-bottom: 4px; border-bottom: 1px solid #e5e7eb; color: #374151; }
    h3 { font-size: 14px; margin: 0; }
    .header { border-bottom: 1px solid #e5e7eb; padding-bottom: 12px; margin-bottom: 16px; }
    .meta { display: flex; flex-wrap: wrap; gap: 8px; font-size: 12px; color: #6b7280; }
    .section { margin-bottom: 16px; }
    .job, .edu { margin-bottom: 12px; }
    .row { display: flex; justify-content: space-between; align-items: flex-start; }
    .small { font-size: 12px; color: #6b7280; }
    ul { padding-left: 20px; }
    li { margin: 4px 0; }
    .chips { display: flex; flex-wrap: wrap; gap: 6px; }
    .chip { background: #f3f4f6; color: #1f2937; padding: 2px 8px; border-radius: 12px; font-size: 12px; }
  `;

  const classicStyles = `
    @page { size: A4; margin: 22mm; }
    body { font-family: Georgia, Cambria, 'Times New Roman', Times, serif; color: #111827; }
    h1 { font-size: 26px; }
    h2 { font-size: 16px; margin: 18px 0 6px 0; padding-bottom: 0; border-bottom: none; color: #374151; letter-spacing: 0.2px; }
    .header { border-bottom: none; padding-bottom: 0; margin-bottom: 10px; }
    .chip { background: #f9fafb; color: #111827; }
  `;

  const modernStyles = `
    @page { size: A4; margin: 18mm; }
    body { font-family: Inter, ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, Noto Sans; color: #0f172a; }
    .accent { height: 6px; background: #0ea5e9; margin-bottom: 12px; }
    h1 { font-weight: 700; letter-spacing: 0.3px; }
    h2 { color: #0ea5e9; border-color: #bae6fd; }
    .header { border-left: 6px solid #0ea5e9; padding-left: 12px; }
    .chip { background: #e0f2fe; color: #0c4a6e; }
  `;

  const minimalStyles = `
    @page { size: A4; margin: 25mm; }
    body { font-family: 'Source Serif Pro', Georgia, Cambria, 'Times New Roman', Times, serif; color: #1f2937; }
    h1 { font-size: 24px; font-weight: 600; }
    h2 { font-size: 15px; margin: 22px 0 6px 0; border-bottom: none; color: #374151; }
    .header { border-bottom: none; margin-bottom: 8px; }
    .section { margin-bottom: 22px; }
    .chip { background: #f3f4f6; color: #374151; }
  `;

  const timelineStyles = `
    @page { size: A4; margin: 18mm; }
    body { font-family: Inter, ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, Noto Sans; color: #0f172a; }
    .grid { display: grid; grid-template-columns: 1fr 2fr; gap: 18px; }
    .sidebar h2 { font-size: 12px; text-transform: uppercase; letter-spacing: 1.2px; color: #111827; margin: 0; }
    .divider { border-top: 1px solid #e5e7eb; margin: 4px 0 8px; }
    .contact-list { font-size: 12px; color: #111827; }
    .timeline { position: relative; }
    .tl-row { display: grid; grid-template-columns: 24px 1fr; gap: 12px; margin-bottom: 16px; }
    .tl-dot { width: 10px; height: 10px; background: #2563eb; border-radius: 50%; margin-top: 3px; }
    .tl-line { position: absolute; left: 4px; top: 0; bottom: 0; width: 2px; background: #e5e7eb; }
    .small { font-size: 12px; color: #6b7280; }
  `;

  const stylesVariant = tid === 'classic' ? classicStyles : tid === 'modern' ? modernStyles : tid === 'minimal' ? minimalStyles : tid === 'timeline' ? timelineStyles : '';
  const styles = `
    <style>
      ${baseStyles}
      ${stylesVariant}
    </style>
  `;

  const headerLinks = (personal.links || [])
    .map(l => `<a href="${escapeText(l.url)}" target="_blank" rel="noopener noreferrer">${escapeText(l.label || l.url)}</a>`)
    .join(' · ');

  const safePhotoUrl = typeof personal.photoUrl === 'string' && /^(https?:\/\/)/i.test(personal.photoUrl) ? personal.photoUrl : '';
  const headerPhoto = tid === 'modern' && safePhotoUrl ? `<img src="${escapeText(safePhotoUrl)}" alt="${escapeText((personal.firstName || '') + ' ' + (personal.lastName || ''))} photo" style="width:64px;height:64px;border-radius:50%;object-fit:cover;border:2px solid rgba(255,255,255,0.7);margin-right:12px;" referrerpolicy="no-referrer" />` : '';
  const headline = Array.isArray(personal.extras) && personal.extras.length ? personal.extras[0] : '';
  const headerHtml = tid === 'timeline'
    ? `
      <div class="header">
        <h1>${escapeText(personal.firstName || '')} ${escapeText(personal.lastName || '')}</h1>
        ${headline ? `<div class="small" style="text-transform:uppercase;margin-top:4px;color:#374151;">${escapeText(headline)}</div>` : ''}
      </div>
    `
    : `
      <div class="header" style="display:flex;align-items:center;gap:12px;">
        ${headerPhoto}
        <div>
          <h1>${escapeText(personal.firstName || '')} ${escapeText(personal.lastName || '')}</h1>
          <div class="meta">
            ${personal.email ? `<span>${escapeText(personal.email)}</span>` : ''}
            ${personal.phone ? `<span>${escapeText(personal.phone)}</span>` : ''}
            ${(personal.city || personal.country) ? `<span>${personal.city ? escapeText(personal.city) : ''}${personal.city && personal.country ? ', ' : ''}${personal.country ? escapeText(personal.country) : ''}</span>` : ''}
            ${headerLinks ? `<span>${headerLinks}</span>` : ''}
          </div>
        </div>
      </div>
    `;

  const summarySection = summary ? `
    <div class="section">
      <h2>Professional Summary</h2>
      <div>${summary}</div>
    </div>
  ` : '';

  const workSection = (work && work.length) ? (
    tid === 'timeline'
      ? `
        <div class="section">
          <h2>Work Experience</h2>
          <div class="timeline">
            <div class="tl-line"></div>
            ${work.map(job => `
              <div class="tl-row">
                <div class="tl-dot"></div>
                <div>
                  <div class="row" style="justify-content:space-between;">
                    <div>
                      <h3>${escapeText(job.title)}</h3>
                      <div class="small">${escapeText(job.company)}</div>
                    </div>
                    <div class="small">
                      ${escapeText(job.startDate || '')} - ${escapeText(job.endDate || 'Present')}
                      ${job.location ? `<div>${escapeText(job.location)}</div>` : ''}
                    </div>
                  </div>
                  ${(job.bullets && job.bullets.length) ? `
                    <ul>
                      ${job.bullets.map(b => `<li>${escapeText(b)}</li>`).join('')}
                    </ul>
                  ` : ''}
                </div>
              </div>
            `).join('')}
          </div>
        </div>
      `
      : `
        <div class="section">
          <h2>Work Experience</h2>
          ${work.map(job => `
            <div class="job">
              <div class="row">
                <div>
                  <h3>${escapeText(job.title)}</h3>
                  <div class="small">${escapeText(job.company)}</div>
                </div>
                <div class="small">
                  ${escapeText(job.startDate || '')} - ${escapeText(job.endDate || 'Present')}
                  ${job.location ? `<div>${escapeText(job.location)}</div>` : ''}
                </div>
              </div>
              ${(job.bullets && job.bullets.length) ? `
                <ul>
                  ${job.bullets.map(b => `<li>${escapeText(b)}</li>`).join('')}
                </ul>
              ` : ''}
            </div>
          `).join('')}
        </div>
      `
  ) : '';

  const eduSection = (education && education.length) ? `
    <div class="section">
      <h2>Education</h2>
      ${education.map(ed => `
        <div class="edu">
          <div class="row">
            <div>
              <h3>${escapeText(ed.degree)}</h3>
              <div class="small">${escapeText(ed.school)}</div>
            </div>
            <div class="small">
              ${escapeText(ed.startDate || '')} - ${escapeText(ed.endDate || '')}
            </div>
          </div>
          ${ed.gpa ? `<div class="small">GPA: ${escapeText(ed.gpa)}</div>` : ''}
        </div>
      `).join('')}
    </div>
  ` : '';

  const skillsSection = (skills && skills.length) ? `
    <div class="section">
      <h2>Skills</h2>
      <div class="chips">
        ${skills.map(s => `<span class="chip">${escapeText(s.name)}${s.level ? ` — ${escapeText(s.level)}` : ''}</span>`).join('')}
      </div>
    </div>
  ` : '';

  const languagesSection = (languages && languages.length) ? `
    <div class="section">
      <h2>Languages</h2>
      <div class="chips">
        ${languages.map(l => `<span class="chip">${escapeText(l.name)}${l.level ? ` — ${escapeText(l.level)}` : ''}</span>`).join('')}
      </div>
    </div>
  ` : '';

  const certsSection = (certifications && certifications.length) ? `
    <div class="section">
      <h2>Certifications</h2>
      <ul>
        ${certifications.map(c => `<li>${escapeText(c.name)}${c.issuer ? ` - ${escapeText(c.issuer)}` : ''}${c.date ? ` (${escapeText(c.date)})` : ''}</li>`).join('')}
      </ul>
    </div>
  ` : '';

  const accentTop = tid === 'modern' ? '<div class="accent"></div>' : '';

  // Sidebar for timeline theme: contact + skills/languages + references
  const referenceLines = (Array.isArray(personal.extras) ? personal.extras.slice(1) : []).filter(Boolean);
  const sidebar = tid === 'timeline' ? `
    <aside class="sidebar">
      <section>
        <h2>Contact</h2>
        <div class="divider"></div>
        <div class="contact-list">
          ${personal.phone ? `<div>${escapeText(personal.phone)}</div>` : ''}
          ${personal.email ? `<div>${escapeText(personal.email)}</div>` : ''}
          ${(personal.street || personal.city || personal.country || personal.postcode) ? `<div>${escapeText([personal.street, personal.city, personal.country, personal.postcode].filter(Boolean).join(', '))}</div>` : ''}
          ${headerLinks ? `<div>${headerLinks}</div>` : ''}
        </div>
      </section>
      ${(skills && skills.length) ? `
        <section>
          <h2>Skills</h2>
          <div class="divider"></div>
          <div class="chips">${skills.map(s => `<span class="chip">${escapeText(s.name)}${s.level ? ` — ${escapeText(s.level)}` : ''}</span>`).join('')}</div>
        </section>
      ` : ''}
      ${(languages && languages.length) ? `
        <section>
          <h2>Languages</h2>
          <div class="divider"></div>
          <div class="chips">${languages.map(l => `<span class="chip">${escapeText(l.name)}${l.level ? ` — ${escapeText(l.level)}` : ''}</span>`).join('')}</div>
        </section>
      ` : ''}
      ${(referenceLines && referenceLines.length) ? `
        <section>
          <h2>Reference</h2>
          <div class="divider"></div>
          <div class="small">${referenceLines.map(r => `<div>${escapeText(r)}</div>`).join('')}</div>
        </section>
      ` : ''}
    </aside>
  ` : '';
  const bodyContent = tid === 'timeline'
    ? `
      ${accentTop}
      ${headerHtml}
      <div class="grid">
        ${sidebar}
        <main>
          ${summarySection}
          ${workSection}
          ${eduSection}
          ${certsSection}
        </main>
      </div>
    `
    : `
      ${accentTop}
      ${headerHtml}
      ${summarySection}
      ${workSection}
      ${eduSection}
      ${skillsSection}
      ${languagesSection}
      ${certsSection}
    `;

  return `<!doctype html>
  <html lang="en">
    <head>
      <meta charset="UTF-8" />
      <meta name="viewport" content="width=device-width, initial-scale=1.0" />
      <title>Printable CV</title>
      ${styles}
    </head>
    <body>
      <div class="page">
        ${bodyContent}
      </div>
    </body>
  </html>`;
}