import fs from 'node:fs';
import path from 'node:path';
import { injectBeforeDocumentClosingHead } from '../../html-document-injection.mjs';
import { normalizeCoverMetaSuggestion, upsertMindspaceCoverMeta } from '../../mindspace-cover-meta.mjs';
import { preparePublishedPlatformBrand } from '../../mindspace-page-tag.mjs';
import { scheduleWorkspaceHtmlThumbnailSidecars } from '../../mindspace-workspace-thumbnails.mjs';
import {
  artifactFileExists,
  resolveArtifactLocalPath,
  verifyPageArtifactContent,
} from './page-artifact.mjs';
import {
  hasMindspaceCoverMeta,
  hasPlatformBrandMarker,
  hasShareDescription,
  verifyArtifactSharePreview,
  verifySharePreviewMeta,
} from './share-preview.mjs';

function escapeMetaAttribute(value) {
  return String(value ?? '')
    .replaceAll('&', '&')
    .replaceAll('"', '"')
    .replaceAll('<', '&lt;');
}

export { resolveArtifactLocalPath } from './page-artifact.mjs';

export function extractPageTitle(html) {
  const match = String(html ?? '').match(/<title[^>]*>([\s\S]*?)<\/title>/i);
  return match?.[1]?.replace(/<[^>]+>/g, '').trim() ?? '';
}

export function inferCoverMeta({ title = '', topic = '' } = {}) {
  const source = `${title} ${topic}`.trim();
  let tag = '报告';
  let emoji = '📄';
  let accent = '#667eea';
  let accent2 = '#764ba2';
  if (/攻略|旅行|游记|半日|地图|景点|路线/.test(source)) {
    tag = '旅行';
    emoji = '🏞️';
    accent = '#2e7d32';
    accent2 = '#1565c0';
  } else if (/新闻|早报|热点|资讯|日报/.test(source)) {
    tag = '资讯';
    emoji = '📰';
    accent = '#2563eb';
    accent2 = '#0f172a';
  } else if (/诗|诗词|散文|文学/.test(source)) {
    tag = '文艺';
    emoji = '🌿';
    accent = '#2d5016';
    accent2 = '#1a2a3a';
  }
  const subtitle = (title || topic || 'MindSpace 页面').trim().slice(0, 80);
  return normalizeCoverMetaSuggestion({ tag, emoji, accent, accent2, subtitle, cover: '' });
}

export function repairSharePreviewHtml(html, { title = '', topic = '' } = {}) {
  let next = String(html ?? '');
  const resolvedTitle = String(title || extractPageTitle(next) || '').trim();
  const summary = (topic || resolvedTitle || 'MindSpace 页面').trim().slice(0, 160);

  if (!hasShareDescription(next)) {
    const meta = `<meta name="description" content="${escapeMetaAttribute(summary)}">`;
    next = injectBeforeDocumentClosingHead(next, `${meta}\n`);
  }

  if (!hasMindspaceCoverMeta(next)) {
    next = upsertMindspaceCoverMeta(next, inferCoverMeta({ title: resolvedTitle, topic }));
  }

  if (!hasPlatformBrandMarker(next)) {
    next = preparePublishedPlatformBrand(next);
  }

  return next;
}

function syncArtifactSharePreview(artifact, localPath) {
  if (!artifact || !localPath) return artifact;
  try {
    const content = fs.readFileSync(localPath, 'utf8');
    artifact.sharePreview = verifySharePreviewMeta(content);
    artifact.exists = true;
    artifact.isHtmlDocument = /<(?:html|body|main|article)\b/i.test(content);
  } catch {
    // Keep the caller's existing artifact metadata when disk read fails.
  }
  return artifact;
}

export function repairArtifactSharePreview(artifact, { topic = '', publishDir = '' } = {}) {
  const localPath = resolveArtifactLocalPath(artifact, publishDir);
  const resolvedArtifact = localPath ? { ...artifact, localPath } : artifact;
  if (!artifactFileExists(resolvedArtifact)) {
    return { ok: false, reason: 'missing_file', changes: [] };
  }
  if (!verifyPageArtifactContent(resolvedArtifact).ok) {
    return { ok: false, reason: 'not_repairable_artifact', changes: [] };
  }
  if (!localPath) {
    return { ok: false, reason: 'missing_local_path', changes: [] };
  }

  const before = fs.readFileSync(localPath, 'utf8');
  if (verifySharePreviewMeta(before).ok) {
    syncArtifactSharePreview(artifact, localPath);
    return { ok: true, reason: null, changes: [], alreadyReady: true };
  }

  const title = extractPageTitle(before);
  const after = repairSharePreviewHtml(before, { title, topic });
  if (after === before) {
    return { ok: false, reason: 'repair_noop', changes: [] };
  }

  const changes = [];
  if (!hasShareDescription(before) && hasShareDescription(after)) changes.push('description');
  if (!hasMindspaceCoverMeta(before) && hasMindspaceCoverMeta(after)) changes.push('mindspace_cover');
  if (!hasPlatformBrandMarker(before) && hasPlatformBrandMarker(after)) changes.push('platform_brand');

  fs.writeFileSync(localPath, after, 'utf8');
  syncArtifactSharePreview(artifact, localPath);
  const verified = verifyArtifactSharePreview(artifact, { publishDir });
  if (!verified.ok) {
    return { ok: false, reason: verified.reason ?? 'repair_incomplete', changes };
  }
  if (publishDir && artifact?.relativePath) {
    scheduleWorkspaceHtmlThumbnailSidecars(
      publishDir,
      String(artifact.relativePath).replace(/\\/g, '/'),
    );
  }
  return { ok: true, reason: null, changes };
}

export function ensureArtifactsSharePreviewReady(
  artifacts = [],
  { topic = '', publishDir = '' } = {},
) {
  const next = [];
  for (const artifact of artifacts) {
    if (!artifact) continue;
    if (artifact.auxiliary || artifact.isStub) {
      next.push(artifact);
      continue;
    }
    if (artifact.sharePreview?.ok === true) {
      next.push(artifact);
      continue;
    }
    repairArtifactSharePreview(artifact, { topic, publishDir });
    next.push(artifact);
  }
  return next;
}