/**
 * 公众号草稿统一 layout：阅读原文 + 底部关注区。
 * 标准定义见 wechat-draft-publication-standard.mjs 与 docs/wechat-draft-publication-standard.md
 */
import fs from 'node:fs';
import path from 'node:path';
import { fetch as undiciFetch } from 'undici';
import { PLATFORM_BRAND_ICON_PATH } from './mindspace-og-tags.mjs';
import {
  resolveMpFollowQrcodePath,
  uploadWechatArticleContentImage,
} from './wechat-news-morning-draft.mjs';
import { WECHAT_DRAFT_PUBLICATION_STANDARD } from './wechat-draft-publication-standard.mjs';

const WECHAT_DRAFT_CONTENT_CHAR_LIMIT =
  WECHAT_DRAFT_PUBLICATION_STANDARD.limits.maxContentChars;

export function clipWechatDraftBodyToFitFooter(
  body,
  footer,
  limit = WECHAT_DRAFT_CONTENT_CHAR_LIMIT,
) {
  const source = String(body ?? '');
  const suffix = String(footer ?? '');
  const separator = source && suffix ? '\n' : '';
  const maxBody = Math.max(0, Number(limit) - suffix.length - separator.length);
  if (source.length <= maxBody) return source;
  let clipped = source.slice(0, maxBody);
  const lastLt = clipped.lastIndexOf('<');
  const lastGt = clipped.lastIndexOf('>');
  if (lastLt > lastGt) clipped = clipped.slice(0, lastLt);
  return clipped.trimEnd();
}

export function renderReadOriginalLink(publicUrl) {
  if (!publicUrl) return '';
  return [
    '<p style="margin:18px 0 10px;text-align:center;line-height:1.6;">',
    `<a href="${publicUrl}" style="display:inline-block;padding:5px 14px;border:1px solid #e2e8f0;border-radius:999px;color:#576b95;font-size:12px;text-decoration:none;background:#fafafa;">📖 阅读原文</a>`,
    '</p>',
  ].join('');
}

/** @deprecated 保留别名，避免外部引用断裂 */
export const renderReadOriginalTop = renderReadOriginalLink;

export function renderFollowTkMindSection({
  qrcodeImageUrl = '',
} = {}) {
  const qrcodeBlock = qrcodeImageUrl
    ? `<img src="${qrcodeImageUrl}" alt="TKMind 服务号二维码" style="width:168px;height:168px;display:block;margin:14px auto 0;border-radius:10px;border:1px solid #eee;" />`
    : '';
  return [
    '<section style="text-align:center;padding:22px 16px 18px;margin:18px 0 8px;background:linear-gradient(180deg,#fff8f8,#fff);border:1px solid #ffcdd2;border-radius:12px;">',
    '<p style="margin:0 0 6px;font-size:16px;font-weight:700;color:#b71c1c;line-height:1.5;">欢迎关注 TKMind 智趣</p>',
    qrcodeBlock,
    qrcodeImageUrl
      ? '<p style="margin:12px 0 0;font-size:12px;color:#a0aec0;">长按扫描关注</p>'
      : '<p style="margin:12px 0 0;font-size:12px;color:#a0aec0;">关注 TKMind 服务号</p>',
    '</section>',
  ].filter(Boolean).join('');
}

export function applyWechatDraftArticleLayout(
  content,
  { publicUrl = '', qrcodeImageUrl = '' } = {},
) {
  const footerParts = [];
  if (publicUrl) {
    footerParts.push(renderReadOriginalLink(publicUrl));
  }
  footerParts.push(renderFollowTkMindSection({ qrcodeImageUrl }));
  const footer = footerParts.filter(Boolean).join('\n');
  const body = clipWechatDraftBodyToFitFooter(String(content ?? '').trim(), footer);
  return [body, footer].filter(Boolean).join(body && footer ? '\n' : '');
}

export function resolveTkMindBrandIconPath(memindLibRoot = process.cwd()) {
  const candidates = [
    path.join(memindLibRoot, 'public', PLATFORM_BRAND_ICON_PATH.replace(/^\//, '')),
    path.join(memindLibRoot, 'dist', PLATFORM_BRAND_ICON_PATH.replace(/^\//, '')),
    path.join(process.cwd(), 'public', PLATFORM_BRAND_ICON_PATH.replace(/^\//, '')),
  ];
  return candidates.find((candidate) => fs.existsSync(candidate)) ?? null;
}

export async function uploadWechatDraftBrandAssets({
  accessToken,
  wechatFetch = undiciFetch,
  memindLibRoot = process.cwd(),
} = {}) {
  let qrcodeImageUrl = '';
  if (!accessToken) {
    return { qrcodeImageUrl };
  }

  const qrcodePath = resolveMpFollowQrcodePath(memindLibRoot);
  if (qrcodePath) {
    qrcodeImageUrl = await uploadWechatArticleContentImage(
      accessToken,
      fs.readFileSync(qrcodePath),
      { wechatFetch, filename: 'mp-follow-qrcode.png' },
    );
  }

  return { qrcodeImageUrl };
}

export async function finalizeWechatDraftArticleForPush({
  content,
  publicUrl = '',
  accessToken = null,
  wechatFetch = undiciFetch,
  memindLibRoot = process.cwd(),
} = {}) {
  const brandAssets = await uploadWechatDraftBrandAssets({
    accessToken,
    wechatFetch,
    memindLibRoot,
  });
  return {
    content: applyWechatDraftArticleLayout(content, {
      publicUrl,
      ...brandAssets,
    }),
    ...brandAssets,
  };
}