const isMobile = {
  Android: () => navigator.userAgent.match(/Android/i),
  iOS: () => navigator.userAgent.match(/iPhone|iPad|iPod/i),
  any: () => navigator.userAgent.match(/Android|iPhone|iPad|iPod/i)
};

function escapeHtml(text) {
  return text
    .replace(/&/g, "&")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&#039;")
    .replace(/\n/g, "<br>");
}

function escapeAttr(text) {
  return text
    .replace(/&/g, "&amp;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&#039;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;");
}

const SAFE_URI_SCHEME = /^(https?:|simplex:|mailto:|tel:)/i;

function safeHref(uri) {
  if (SAFE_URI_SCHEME.test(uri)) return escapeAttr(uri);
  return escapeAttr(`javascript:void(alert('Potentially malicious link blocked:\\n'+${JSON.stringify(uri)}))`);
}

function getSimplexLinkDescr(linkType) {
  switch (linkType) {
    case 'contact': return 'SimpleX contact address';
    case 'invitation': return 'SimpleX one-time invitation';
    case 'group': return 'SimpleX group link';
    case 'channel': return 'SimpleX channel link';
    case 'relay': return 'SimpleX relay link';
    default: return 'SimpleX link';
  }
}

function viaHost(smpHosts) {
  const first = smpHosts[0] ?? '?';
  return `via ${first}`;
}

function isCurrentSite(uri) {
  return uri.startsWith("https://simplex.chat") || uri.startsWith("https://www.simplex.chat")
}

function targetBlank(uri) {
  return isCurrentSite(uri) ? '' : ' target="_blank" rel="noopener"'
}

const MAX_LIST_DEPTH = 7;

const MAX_TABLE_CELLS = 1000;

const COPY_BUTTON =
  '<button type="button" class="md-copy" aria-label="Copy">' +
  '<svg class="md-icon-copy" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><rect x="9" y="9" width="11" height="11" rx="2.5"></rect><path d="M15 9V6.5A2.5 2.5 0 0 0 12.5 4h-6A2.5 2.5 0 0 0 4 6.5v6A2.5 2.5 0 0 0 6.5 15H9"></path></svg>' +
  '<svg class="md-icon-done" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M5 12.5l4.5 4.5L19 7.5"></path></svg>' +
  '</button>';

// navigator.clipboard is undefined outside secure contexts; fall back to execCommand
function copyToClipboard(text) {
  if (navigator.clipboard && navigator.clipboard.writeText) {
    return navigator.clipboard.writeText(text);
  }
  return new Promise(function(resolve, reject) {
    const ta = document.createElement('textarea');
    ta.value = text;
    ta.style.position = 'fixed';
    ta.style.top = '-9999px';
    document.body.appendChild(ta);
    ta.select();
    let ok = false;
    try { ok = document.execCommand('copy'); } catch (e) {}
    document.body.removeChild(ta);
    ok ? resolve() : reject(new Error('copy failed'));
  });
}

function handleCodeClick(e) {
  const card = e.target.closest('.md-code');
  if (!card) return;
  const button = e.target.closest('.md-copy');
  if (!button) {
    card.classList.toggle('tapped');
    return;
  }
  const pre = card.querySelector('pre');
  if (!pre) return;
  copyToClipboard(pre.innerText).then(() => {
    button.classList.add('copied');
    setTimeout(() => button.classList.remove('copied'), 1500);
  }).catch(() => {});
}

function validBlocks(fts, blocks) {
  let pos = 0;
  const range = (r) => {
    const valid = !!r && Number.isInteger(r.from) && Number.isInteger(r.to) && pos <= r.from && r.from <= r.to && r.to <= fts.length;
    if (valid) pos = r.to;
    return valid;
  };
  const entries = (items, depth) =>
    Array.isArray(items) && (items.length === 0 || depth <= MAX_LIST_DEPTH) && items.every((e) => !!e && range(e.content) && entries(e.items, depth + 1));
  const rows = (rs) => Array.isArray(rs) && rs.every((row) => Array.isArray(row) && row.every(range));
  return Array.isArray(blocks) && blocks.every((b) => {
    switch (b && b.type) {
      case 'paragraph':
      case 'heading':
      case 'codeBlock':
      case 'quote':
        return range(b.content);
      case 'list':
        return entries(b.items, 1);
      case 'table':
        return Array.isArray(b.columns) && rows([b.header]) && rows(b.rows);
      case 'rule':
        return range(b.mark);
      default:
        return false;
    }
  });
}

function renderBlocks(fts, blocks) {
  let html = '';
  let pos = 0;
  const segments = (r) => renderSegments(fts.slice(r.from, r.to), true);
  const isParagraphBreak = (ft) => ft.format && ft.format.type === 'markup' && ft.format.token && ft.format.token.type === 'paragraphBreak';
  const gap = (to) => {
    if (html && fts.slice(pos, to).some(isParagraphBreak)) html += '<div class="md-gap"></div>';
    pos = Math.max(pos, to);
  };
  const block = (r, open, close) => {
    gap(r.from);
    html += open + segments(r) + close;
    pos = r.to;
  };
  const entry = (e, level) => {
    html += `<div class="md-entry" style="padding-left: ${1.25 * Math.min(level, 6)}em;"><span class="md-mark">${escapeHtml(String(e.number ?? '•'))}</span><span class="md-text">${segments(e.content)}</span></div>`;
    pos = e.content.to;
    e.items.forEach((item) => entry(item, level + 1));
  };
  const table = (b) => {
    const rows = [b.header].concat(b.rows);
    const width = b.columns.length * rows.length <= MAX_TABLE_CELLS ? b.columns.length : 0;
    const align = (c) => (b.columns[c] === 'center' || b.columns[c] === 'right' ? b.columns[c] : 'left');
    const cell = (tag, c, r) => `<${tag} style="text-align: ${align(c)};">${r ? segments(r) : ''}</${tag}>`;
    const row = (cells, tag) =>
      '<tr>' + cells.map((r, c) => cell(tag, c, r)).join('') + Array.from({ length: Math.max(0, width - cells.length) }, (_, k) => cell(tag, cells.length + k, null)).join('') + '</tr>';
    gap(b.header.length > 0 ? b.header[0].from : pos);
    html += '<div class="md-table"><div class="md-frame"><table>' + row(b.header, 'th') + b.rows.map((r) => row(r, 'td')).join('') + '</table></div></div>';
    const last = rows[rows.length - 1];
    pos = last.length > 0 ? last[last.length - 1].to : pos;
  };
  for (const b of blocks) {
    switch (b.type) {
      case 'paragraph':
        block(b.content, '<div>', '</div>');
        break;
      case 'heading':
        block(b.content, `<div class="md-h${b.level === 1 || b.level === 2 || b.level === 3 ? b.level : 4}">`, '</div>');
        break;
      case 'codeBlock':
        block(b.content, '<div class="md-code"><pre>', '</pre>' + COPY_BUTTON + '</div>');
        break;
      case 'quote':
        block(b.content, '<div class="md-quote"><span class="md-bar"></span><div class="md-text">', '</div></div>');
        break;
      case 'list':
        if (b.items.length > 0) gap(b.items[0].content.from);
        b.items.forEach((item) => entry(item, 0));
        break;
      case 'table':
        table(b);
        break;
      case 'rule':
        block(b.mark, '<hr class="md-rule">', '');
        break;
    }
  }
  return html;
}

function markupHtml(token) {
  switch (token && token.type) {
    case 'softBreak':
      return ' ';
    case 'lineBreak':
    case 'hardBreak':
      return '<br>';
    default:
      return '';
  }
}

function renderMarkdown(fts, blocks) {
  return validBlocks(fts, blocks) ? renderBlocks(fts, blocks) : renderSegments(fts, false);
}

function renderSegments(fts, withBlocks) {
  let html = '';
  for (const ft of fts) {
    const { format, text } = ft;
    if (!format) {
      html += escapeHtml(text);
      continue;
    }
    try {
      switch (format.type) {
        case 'bold':
          html += withBlocks && format.singleStar ? `<em>${escapeHtml(text)}</em>` : `<strong>${escapeHtml(text)}</strong>`;
          break;
        case 'italic':
          html += `<em>${escapeHtml(text)}</em>`;
          break;
        case 'strikeThrough':
          html += `<s>${escapeHtml(text)}</s>`;
          break;
        case 'snippet':
          html += `<span style="font-family: monospace;">${escapeHtml(text)}</span>`;
          break;
        case 'secret':
          html += `<span class="secret">${escapeHtml(text)}</span>`;
          break;
        case 'small':
          html += `<span class="small-text">${escapeHtml(text)}</span>`;
          break;
        case 'colored':
          html += `<span class="${(format.color || '').replace(/[^a-zA-Z0-9_-]/g, '')}">${escapeHtml(text)}</span>`;
          break;
        case 'uri': {
          let href = text.startsWith('http://') || text.startsWith('https://') || text.startsWith('simplex:/') ? text : 'https://' + text;
          html += `<a href="${safeHref(href)}"${targetBlank(href)}>${escapeHtml(text)}</a>`;
          break;
        }
        case 'hyperLink': {
          const { showText, linkUri } = format;
          html += `<a href="${safeHref(linkUri)}"${targetBlank(linkUri)}>${escapeHtml(showText ?? linkUri)}</a>`;
          break;
        }
        case 'simplexLink': {
          const { showText, linkType, simplexUri, smpHosts } = format;
          const linkText = showText ? escapeHtml(showText) : getSimplexLinkDescr(linkType);
          html += `<a href="${safeHref(platformSimplexUri(simplexUri))}" target="_blank" rel="noopener">${linkText} <em>(${escapeHtml(viaHost(smpHosts))})</em></a>`;
          break;
        }
        case 'command':
          html += `<span style="font-family: monospace;">${escapeHtml(text)}</span>`;
          break;
        case 'mention':
          html += `<strong>${escapeHtml(text)}</strong>`;
          break;
        case 'email':
          html += `<a href="mailto:${escapeAttr(text)}">${escapeHtml(text)}</a>`;
          break;
        case 'phone':
          html += `<a href="tel:${escapeAttr(text)}">${escapeHtml(text)}</a>`;
          break;
        case 'escape':
          break;
        case 'markup':
          html += withBlocks ? markupHtml(format.token) : escapeHtml(text);
          break;
        case 'unknown':
          html += escapeHtml(text);
          break;
        default:
          html += escapeHtml(text);
      }
    } catch(e) {
      console.log(e);
      html += escapeHtml(text);
    }
  }
  return html;
}

const simplexAddressRegexp = /^simplex:\/([a-z]+)#(.+)/i;

const simplexShortLinkTypes = ["a", "c", "g", "i", "r"];

function platformSimplexUri(uri) {
  if (isMobile.any()) return uri;
  const res = uri.match(simplexAddressRegexp);
  if (!res || !Array.isArray(res) || res.length < 3) return uri;
  const linkType = res[1];
  const fragment = res[2];
  if (simplexShortLinkTypes.includes(linkType)) {
    const queryIndex = fragment.indexOf('?');
    if (queryIndex === -1) return uri;
    const hashPart = fragment.substring(0, queryIndex);
    const queryStr = fragment.substring(queryIndex + 1);
    const params = new URLSearchParams(queryStr);
    const host = params.get('h');
    if (!host) return uri;
    params.delete('h');
    let newFragment = hashPart;
    const remainingParams = params.toString();
    if (remainingParams) newFragment += '?' + remainingParams;
    return `https://${host}:/${linkType}#${newFragment}`;
  } else {
    return `https://simplex.chat/${linkType}#${fragment}`;
  }
}