import express from 'express';
import jwt from 'jsonwebtoken';
import { fetch } from 'undici';
import { getPresignedUrl, getPublicUrlForKey, copyObject } from './storage/s3';

const router = express.Router();

function getGhostToken(): string {
  const apiUrl = process.env.GHOST_ADMIN_API_URL || '';
  const apiKey = process.env.GHOST_ADMIN_API_KEY || '';
  if (!apiUrl || !apiKey) {
    throw new Error('Missing GHOST_ADMIN_API_URL or GHOST_ADMIN_API_KEY');
  }
  const [keyId, secret] = apiKey.split(':');
  if (!keyId || !secret) throw new Error('Invalid GHOST_ADMIN_API_KEY format');

  const now = Math.floor(Date.now() / 1000);
  const token = jwt.sign(
    {
      iat: now,
      exp: now + 5 * 60,
      aud: '/admin/',
    },
    Buffer.from(secret, 'hex'),
    {
      keyid: keyId,
      algorithm: 'HS256',
      issuer: keyId,
    }
  );
  return token;
}

router.post('/post', async (req, res) => {
  try {
    const apiUrl = process.env.GHOST_ADMIN_API_URL || '';
    const token = getGhostToken();

    const {
      id,
      title,
      html,
      tags,
      feature_image,
      canonical_url,
      status,
    } = req.body as {
      id?: string;
      title: string;
      html: string;
      tags?: string[];
      feature_image?: string;
      canonical_url?: string;
      status?: 'draft' | 'published';
    };

    if (!title || !html) {
      return res.status(400).json({ error: 'title and html are required' });
    }

    const replacePairs: Array<{ from: string; to: string }> = [];

    async function rewriteInternalMediaUrl(src: string, bucketFallback: string): Promise<string> {
      try {
        if (!src) return src;
        // handle absolute or relative /api/media/obj URLs
        const isInternal = src.includes('/api/media/obj');
        if (!isInternal) return src;
        // parse query
        const base = 'http://local';
        const decoded = src.replace(/&amp;/g, '&');
        const u = new URL(decoded, base);
        const key = u.searchParams.get('key') || '';
        const bucket = u.searchParams.get('bucket') || bucketFallback;
        if (!key || !bucket) return src;
        // Prefer a public base if provided (and optionally copy), else presigned URL
        let out: string;
        const publicBase = process.env.PUBLIC_MEDIA_BASE_URL;
        if (publicBase) {
          const destBucket = process.env.PUBLIC_MEDIA_BUCKET || '';
          if (destBucket) {
            try {
              await copyObject({ srcBucket: bucket, srcKey: key, destBucket, destKey: key });
            } catch (e) {
              console.warn('[Ghost] Copy to public bucket failed, will still use public base URL', e);
            }
          }
          out = getPublicUrlForKey(key) as string;
        } else {
          out = await getPresignedUrl({ bucket, key, expiresInSeconds: 60 * 60 * 24 * 7 });
        }
        if (out !== src) {
          replacePairs.push({ from: src, to: out });
        }
        return out;
      } catch {
        return src;
      }
    }

    async function rewriteHtmlImagesToPublic(htmlIn: string, bucketFallback: string): Promise<string> {
      if (!htmlIn) return htmlIn;
      const re = /<img\b[^>]*src=["']([^"']+)["'][^>]*>/gi;
      const matches = [...htmlIn.matchAll(re)];
      if (matches.length === 0) return htmlIn;
      let out = '';
      let last = 0;
      for (const m of matches) {
        const idx = m.index || 0;
        const full = m[0];
        const src = m[1];
        const newSrc = await rewriteInternalMediaUrl(src, bucketFallback);
        out += htmlIn.slice(last, idx) + full.replace(src, newSrc);
        last = idx + full.length;
      }
      out += htmlIn.slice(last);
      return out;
    }

    // Inspect incoming HTML for <img> srcs before rewriting
    try {
      const re = /<img\b[^>]*src=["']([^"']+)["'][^>]*>/gi;
      const found = [...(html || '').matchAll(re)].map(m => m[1]);
      console.log('[Ghost] Incoming feature_image (raw):', feature_image || '(none)');
      console.log('[Ghost] Incoming <img> count:', found.length);
      console.log('[Ghost] Incoming <img> srcs (first 5):', found.slice(0, 5));
      console.log('[Ghost] HTML contains /api/media/obj:', (html || '').includes('/api/media/obj'));
    } catch {}

    const bucketDefault = process.env.S3_BUCKET || '';
    const rewrittenFeatureImage = await rewriteInternalMediaUrl(feature_image || '', bucketDefault);
    const rewrittenHtml = await rewriteHtmlImagesToPublic(html, bucketDefault);

    // Debug logs to trace rewriting
    try {
      const base = process.env.PUBLIC_MEDIA_BASE_URL || '(none)';
      console.log('[Ghost] PUBLIC_MEDIA_BASE_URL:', base);
      console.log('[Ghost] Replacements count:', replacePairs.length);
      if (rewrittenFeatureImage && rewrittenFeatureImage !== (feature_image || '')) {
        console.log('[Ghost] feature_image rewritten');
      }
      if (replacePairs.length > 0) {
        console.log('[Ghost] Sample replacements:', replacePairs.slice(0, 3));
      }
    } catch {}

    const payload = {
      posts: [
        {
          ...(id ? { id } : {}),
          title,
          html: rewrittenHtml,
          status: status || 'draft',
          tags: tags && Array.isArray(tags) ? tags : [],
          ...(rewrittenFeatureImage ? { feature_image: rewrittenFeatureImage } : {}),
          ...(canonical_url ? { canonical_url } : {}),
        },
      ],
    };

    const base = apiUrl.replace(/\/$/, '');
    const url = id ? `${base}/posts/${id}/?source=html` : `${base}/posts/?source=html`;

    const method = id ? 'PUT' : 'POST';

    const ghRes = await fetch(url, {
      method,
      headers: {
        'Content-Type': 'application/json',
        'Accept': 'application/json',
        'Accept-Version': 'v5.0',
        Authorization: `Ghost ${token}`,
      },
      body: JSON.stringify(payload),
    });

    const contentType = ghRes.headers.get('content-type') || '';
    if (!ghRes.ok) {
      const text = await ghRes.text();
      console.error('Ghost API error:', ghRes.status, text);
      return res.status(ghRes.status).json({ error: 'Ghost API error', detail: text });
    }
    if (!contentType.includes('application/json')) {
      const text = await ghRes.text();
      console.error('Ghost API non-JSON response (possible wrong GHOST_ADMIN_API_URL):', text.slice(0, 300));
      return res.status(500).json({ error: 'Ghost response not JSON', detail: text.slice(0, 500) });
    }

    const data: any = await ghRes.json();
    const post = data?.posts?.[0] || {};
    return res.json({ id: post.id, url: post.url, status: post.status });
  } catch (err: any) {
    console.error('Ghost publish failed:', err);
    return res.status(500).json({ error: 'Ghost publish failed', detail: err?.message || String(err) });
  }
});

// Preview endpoint: rewrite media URLs without copying, to render a faithful content preview
router.post('/preview', async (req, res) => {
  try {
    const { html, feature_image } = req.body as { html: string; feature_image?: string };

    const replacePairs: Array<{ from: string; to: string }> = [];
    const origin = `${req.protocol}://${req.get('host')}`;

    async function rewriteInternalMediaUrlPreview(src: string, _bucketFallback: string): Promise<string> {
      try {
        if (!src) return src;
        // If this references our media proxy, ensure it points to the API origin
        if (src.startsWith('/api/media/obj')) {
          const out = `${origin}${src}`;
          if (out !== src) replacePairs.push({ from: src, to: out });
          return out;
        }
        if (/^https?:\/\//i.test(src)) {
          try {
            const uAbs = new URL(src);
            if (uAbs.pathname === '/api/media/obj') {
              const out = `${origin}${uAbs.pathname}${uAbs.search}`;
              if (out !== src) replacePairs.push({ from: src, to: out });
              return out;
            }
            return src;
          } catch {
            return src;
          }
        }
        return src;
      } catch {
        return src;
      }
    }

    async function rewriteHtmlImagesToPublicPreview(htmlIn: string, bucketFallback: string): Promise<string> {
      if (!htmlIn) return htmlIn;
      const re = /<img\b[^>]*src=["']([^"']+)["'][^>]*>/gi;
      const matches = [...htmlIn.matchAll(re)];
      if (matches.length === 0) return htmlIn;
      let out = '';
      let last = 0;
      for (const m of matches) {
        const idx = m.index || 0;
        const full = m[0];
        const srcAttr = m[1];
        const newSrc = await rewriteInternalMediaUrlPreview(srcAttr, process.env.S3_BUCKET || '');
        out += htmlIn.slice(last, idx) + full.replace(srcAttr, newSrc);
        last = idx + full.length;
      }
      out += htmlIn.slice(last);
      return out;
    }

    const rewrittenFeatureImage = await rewriteInternalMediaUrlPreview(feature_image || '', '');
    const rewrittenHtml = await rewriteHtmlImagesToPublicPreview(html, '');

    return res.json({ html: rewrittenHtml, feature_image: rewrittenFeatureImage, replacements: replacePairs });
  } catch (err: any) {
    console.error('Ghost preview failed:', err);
    return res.status(500).json({ error: 'Ghost preview failed', detail: err?.message || String(err) });
  }
});

export default router;