const TASK_ROUTING_HINT_RE = /^【TKMind 路由提示】[\s\S]*?\n\n/;
const MEMIND_TASK_ORCHESTRATION_RE = /^【Memind 任务编排】[\s\S]*?(?:用户任务：|用户任务:)\s*/u;
const MINDSPACE_CONTEXT_RE = /^\[MindSpace 上下文\][\s\S]*?\n\n/;
const USER_IDENTITY_BLOCK_RE = /^\[用户身份\][\s\S]*?\n\n/;
const IMAGE_URL_LINES_RE = /\n*\[图片\d+]: [^\n]+/g;
const FILE_ATTACHMENT_LINES_RE = /\n*\[文件\d+: [^\]]+\]: [^\n]+/g;
const ASSISTANT_DELIVERABLE_RE =
  /\[[^\]]+\]\(https?:\/\/[^)]+\)|https?:\/\/(?:m\.)?[^/\s]*tkmind\.(?:cn|ai)\/(?:MindSpace|u)\/|\bpublic\/[A-Za-z0-9._-]+\.html\b/i;
const INTERNAL_ASSISTANT_MARKERS = [
  /data-mindspace-page-tag/i,
  /mindspace-cover/i,
  /\bload_skill\b/i,
  /static-page-publish/i,
  /\.agents\/skills/i,
  /SKILL\.md/i,
  /注意到技能/u,
  /技能更新/u,
  /页脚要用.*platform-brand/u,
];
const URL_PATTERN =
  /https?:\/\/[^\s<>"')\]]+\/(?:MindSpace|temp)\/([0-9a-f-]{36}|[a-z0-9._-]+)\/([^\s<>"')\]]+\.html)/gi;
const PUBLICATION_URL_PATTERN =
  /https?:\/\/[^\s<>"')\]]+\/u\/([a-z0-9._-]+)\/pages\/([^\s<>"')\]]+)/gi;
const MARKDOWN_LINK_RE = /\[([^\]]+)\]\((https?:\/\/[^)]+)\)/g;
const COMBINED_LINK_RE =
  /\[([^\]]+)\]\((https?:\/\/[^)]+)\)|(https?:\/\/[^\s<>"')\]]+)|`?(public\/[A-Za-z0-9._-]+\.html)`?|(\/?MindSpace\/([0-9a-f-]{36}|[a-z0-9._-]+)\/(public\/[A-Za-z0-9._-]+\.html))/gi;
const RELATIVE_PUBLIC_HTML_RE = /\b(public\/[A-Za-z0-9._-]+\.html)\b/gi;

function stripImageUrlLines(text) {
  return String(text ?? '')
    .replace(IMAGE_URL_LINES_RE, '')
    .replace(FILE_ATTACHMENT_LINES_RE, '')
    .trim();
}

function stripUserFacingPrefixes(text) {
  let next = String(text ?? '');
  next = next.replace(USER_IDENTITY_BLOCK_RE, '').trimStart();
  next = next.replace(TASK_ROUTING_HINT_RE, '').trimStart();
  next = next.replace(MEMIND_TASK_ORCHESTRATION_RE, '').trimStart();
  while (MINDSPACE_CONTEXT_RE.test(next)) {
    next = next.replace(MINDSPACE_CONTEXT_RE, '').trimStart();
  }
  return next.trim();
}

function deriveAssistantFacingText(text) {
  const trimmed = String(text ?? '').trim();
  if (!trimmed) return '';
  if (ASSISTANT_DELIVERABLE_RE.test(trimmed)) return trimmed;
  if (INTERNAL_ASSISTANT_MARKERS.some((pattern) => pattern.test(trimmed))) return '';
  return trimmed;
}

function decodeSegment(segment) {
  try {
    return decodeURIComponent(segment);
  } catch {
    return segment;
  }
}

function normalizeWorkspaceRelativePath(relativePath) {
  const parts = String(relativePath ?? '')
    .replace(/^\/+/, '')
    .split('/')
    .filter((part) => part && part !== '.' && part !== '..');
  if (parts.length === 0) return '';
  if (parts[0]?.toLowerCase() === 'public') return parts.join('/');
  if (parts.length === 1 && parts[0].toLowerCase().endsWith('.html')) return `public/${parts[0]}`;
  return parts.join('/');
}

function resolveWorkspacePublicUrl(relativePath, publishKey, apiBaseUrl) {
  const normalized = normalizeWorkspaceRelativePath(relativePath);
  if (!publishKey || !normalized.startsWith('public/') || !/\.html$/i.test(normalized)) {
    return null;
  }
  const base = String(apiBaseUrl || '').replace(/\/$/, '');
  if (!base) return null;
  const encodedPath = normalized.split('/').map((part) => encodeURIComponent(part)).join('/');
  return `${base}/MindSpace/${encodeURIComponent(publishKey)}/${encodedPath}`;
}

function buildPageLinkFromRelativePath(relativePath, publishKey, apiBaseUrl) {
  const normalized = normalizeWorkspaceRelativePath(relativePath);
  const publicUrl = resolveWorkspacePublicUrl(normalized, publishKey, apiBaseUrl);
  if (!publicUrl) return null;
  const filename = normalized.split('/').pop() || normalized;
  return {
    publicUrl,
    filename,
    title: filename.replace(/\.html$/i, '').replace(/[-_]+/g, ' '),
    relativePath: normalized,
  };
}

function extractRelativePublicPageLinks(content, publishKey, apiBaseUrl) {
  if (!publishKey || !apiBaseUrl) return [];
  const links = [];
  const seen = new Set();
  for (const match of String(content ?? '').matchAll(RELATIVE_PUBLIC_HTML_RE)) {
    const link = buildPageLinkFromRelativePath(match[1], publishKey, apiBaseUrl);
    if (!link || seen.has(link.publicUrl)) continue;
    seen.add(link.publicUrl);
    links.push(link);
  }
  return links;
}

function mergePageLinks(...groups) {
  const links = [];
  const seen = new Set();
  for (const group of groups) {
    for (const link of group || []) {
      if (!link?.publicUrl || seen.has(link.publicUrl)) continue;
      seen.add(link.publicUrl);
      links.push(link);
    }
  }
  return links;
}

function normalizeStaticHtmlRelativePath(relativePath) {
  const parts = String(relativePath ?? '')
    .replace(/^\/+/, '')
    .split('/')
    .filter((part) => part && part !== '.' && part !== '..');
  if (parts.length === 0) return '';
  if (parts[0]?.toLowerCase() === 'public') return ['public', ...parts.slice(1)].join('/');
  if (parts.length === 1 && parts[0].toLowerCase().endsWith('.html')) return `public/${parts[0]}`;
  return parts.join('/');
}

function escapeRegExp(value) {
  return value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

function encodeUrlPath(relativePath) {
  return relativePath
    .split('/')
    .filter(Boolean)
    .map((part) => encodeURIComponent(part))
    .join('/');
}

function canonicalizeStaticPageUrl(publicUrl, originalRelativePath) {
  const canonicalRelativePath = normalizeStaticHtmlRelativePath(originalRelativePath);
  const originalClean = originalRelativePath.replace(/^\/+/, '');
  if (!canonicalRelativePath || canonicalRelativePath === originalClean) return publicUrl;
  const suffix = escapeRegExp(encodeUrlPath(originalClean));
  return publicUrl.replace(new RegExp(`${suffix}$`), encodeUrlPath(canonicalRelativePath));
}

function extractStaticPageLinks(content) {
  const links = [];
  const seen = new Set();
  const source = String(content ?? '');
  for (const match of source.matchAll(URL_PATTERN)) {
    const relativePath = decodeSegment(match[2]);
    const filename = relativePath.split('/').pop() || relativePath;
    const publicUrl = canonicalizeStaticPageUrl(match[0], relativePath);
    if (seen.has(publicUrl)) continue;
    seen.add(publicUrl);
    links.push({
      publicUrl,
      filename,
      title: filename.replace(/\.html$/i, '').replace(/[-_]+/g, ' '),
    });
  }
  for (const match of source.matchAll(PUBLICATION_URL_PATTERN)) {
    const slug = decodeSegment(match[2]).replace(/\/$/, '');
    const publicUrl = match[0].replace(/\/$/, '');
    if (seen.has(publicUrl)) continue;
    seen.add(publicUrl);
    const filename = slug.split('/').pop() || slug;
    links.push({
      publicUrl,
      filename,
      title: filename.replace(/\.html$/i, '').replace(/[-_]+/g, ' '),
    });
  }
  return links;
}

function normalizeUrlForMatch(url) {
  return String(url ?? '').replace(/\/$/, '').trim();
}

function cleanupOrphanMarkdownDecorations(text) {
  return String(text ?? '')
    .replace(/(?:\*\*){1,}/g, '')
    .replace(/^[👉🔗\s\-•*：:]+$/gm, '')
    .replace(/\n{3,}/g, '\n\n')
    .trim();
}

function stripPageDeliverableLinks(text, pageLinks) {
  if (!pageLinks?.length) return String(text ?? '').trim();
  const urlSet = new Set(pageLinks.map((link) => normalizeUrlForMatch(link.publicUrl)));
  let next = String(text ?? '');
  const markdownWithDecorationRe =
    /[👉🔗\s]*(?:\*\*)?\[([^\]]+)\]\((https?:\/\/[^)]+)\)(?:\*\*)?/g;
  next = next.replace(markdownWithDecorationRe, (full, _label, url) =>
    urlSet.has(normalizeUrlForMatch(url)) ? '' : full,
  );
  for (const url of urlSet) {
    next = next.replace(new RegExp(escapeRegExp(url) + '\\/?', 'gi'), '');
  }
  return cleanupOrphanMarkdownDecorations(next);
}

function parseMessageParts(text, options = {}) {
  const { publishKey = '', apiBaseUrl = '' } = options;
  const input = String(text ?? '');
  if (!input) return [];
  const parts = [];
  let lastIndex = 0;
  let match;
  COMBINED_LINK_RE.lastIndex = 0;
  while ((match = COMBINED_LINK_RE.exec(input)) !== null) {
    if (match.index > lastIndex) {
      parts.push({ type: 'text', text: input.slice(lastIndex, match.index) });
    }
    if (match[1] && match[2]) {
      parts.push({ type: 'link', text: match[1], url: match[2] });
    } else if (match[3]) {
      parts.push({ type: 'link', text: match[3], url: match[3] });
    } else if (match[4]) {
      const relativePath = match[4].replace(/`/g, '');
      const link = buildPageLinkFromRelativePath(relativePath, publishKey, apiBaseUrl);
      parts.push({
        type: 'link',
        text: link?.title || relativePath,
        url: link?.publicUrl || relativePath,
      });
    } else if (match[5] && match[6]) {
      const encodedPath = match[5].replace(/^\/+/, '');
      const publicUrl = resolveWorkspacePublicUrl(
        encodedPath.slice(encodedPath.indexOf('public/')),
        match[6],
        apiBaseUrl,
      ) || (apiBaseUrl ? `${String(apiBaseUrl).replace(/\/$/, '')}/${encodedPath}` : match[5]);
      parts.push({
        type: 'link',
        text: buildPageLinkFromRelativePath(
          encodedPath.slice(encodedPath.indexOf('public/')),
          match[6],
          apiBaseUrl,
        )?.title || encodedPath.split('/').pop(),
        url: publicUrl,
      });
    }
    lastIndex = match.index + match[0].length;
  }
  if (lastIndex < input.length) {
    parts.push({ type: 'text', text: input.slice(lastIndex) });
  }
  return parts.length ? parts : [{ type: 'text', text: input }];
}

function getRawMessageText(message) {
  if (!message) return '';
  if (typeof message.text === 'string') return message.text;
  if (Array.isArray(message.content)) {
    return message.content
      .filter((part) => part && part.type === 'text')
      .map((part) => part.text || '')
      .join('\n');
  }
  return '';
}

function getDisplayText(message) {
  const rawText = getRawMessageText(message);
  if (message?.role === 'user') {
    if (message.metadata?.displayText != null) {
      return stripImageUrlLines(message.metadata.displayText);
    }
    return stripImageUrlLines(stripUserFacingPrefixes(rawText));
  }
  if (message?.metadata?.displayText != null) {
    return stripImageUrlLines(deriveAssistantFacingText(message.metadata.displayText));
  }
  return stripImageUrlLines(deriveAssistantFacingText(rawText));
}

function buildMessageView(message, options = {}) {
  const { publishKey = '', apiBaseUrl = '' } = options;
  const rawText = getRawMessageText(message);
  const displayText = getDisplayText(message);
  const sourceText = displayText || rawText;
  const pageLinks = mergePageLinks(
    extractStaticPageLinks(sourceText),
    extractRelativePublicPageLinks(sourceText, publishKey, apiBaseUrl),
  );
  let text = displayText;
  if (!text && pageLinks.length > 0) {
    text = '页面已生成，可点击下方链接查看。';
  }
  if (!text.trim()) return null;

  const markdownTitleByUrl = {};
  for (const match of String(sourceText).matchAll(MARKDOWN_LINK_RE)) {
    markdownTitleByUrl[match[2]] = match[1];
  }
  const enrichedPageLinks = pageLinks.map((link) => ({
    ...link,
    title: markdownTitleByUrl[link.publicUrl] || link.title,
  }));
  const renderText = stripPageDeliverableLinks(text, enrichedPageLinks);
  const pageLinkUrls = new Set(enrichedPageLinks.map((link) => normalizeUrlForMatch(link.publicUrl)));
  const parts = parseMessageParts(renderText, { publishKey, apiBaseUrl }).filter(
    (part) =>
      part.type !== 'link' || !pageLinkUrls.has(normalizeUrlForMatch(part.url)),
  );

  return {
    id: message.id || `${message.role}_${message.created || Date.now()}`,
    role: message.role || 'assistant',
    text: renderText,
    copyText: renderText,
    parts,
    pageLinks: enrichedPageLinks,
    created: message.created || 0,
  };
}

module.exports = {
  buildMessageView,
  extractStaticPageLinks,
  extractRelativePublicPageLinks,
  getDisplayText,
  parseMessageParts,
  resolveWorkspacePublicUrl,
};