const express = require('express');
const db = require('../db');
const { authMiddleware, adminOnly } = require('../middleware/auth');

const router = express.Router();

router.use((req, res, next) => {
  res.setHeader('Cache-Control', 'no-store');
  next();
});

const PUBLIC_KEYS = ['site_name','site_description','site_url','primary_color',
  'recaptcha_site_key','turnstile_site_key',
  'theme_wallpaper','theme_wallpaper_scale','theme_wallpaper_enabled','nav_style','card_style',
  'glass_blur','glass_opacity','theme_force_dark',
  'captcha_type','captcha_login','captcha_register','captcha_forum',
  'rainid_enabled','rainid_register_redirect',
  'homepage_avatar','homepage_bio','homepage_content','blog_show_sidebar',
  'site_favicon','homepage_contacts','music_embed_enabled','music_embed_code','music_embed_position','music_embed_autohide','music_embed_idle_timeout',
  'footer_style','footer_copyright','footer_powered','footer_desc',
  'footer_columns',
  'show_uid_in_comments',
  'forum_guest_visible'];

const ALL_KEYS = ['site_name','site_description','site_url','primary_color','recaptcha_site_key','turnstile_site_key',
  'smtp_host','smtp_port','smtp_user','smtp_from_email','smtp_from_name',
  'theme_wallpaper','theme_wallpaper_scale','theme_wallpaper_enabled','nav_style','card_style','glass_blur','glass_opacity','theme_force_dark',
  'captcha_type','captcha_login','captcha_register','captcha_forum',
  'rainid_enabled','rainid_client_id','rainid_discovery_url','rainid_register_redirect',
  'homepage_avatar','homepage_bio','homepage_content','blog_show_sidebar',
  'site_favicon','homepage_contacts','music_embed_enabled','music_embed_code','music_embed_position','music_embed_autohide','music_embed_idle_timeout',
  'footer_style','footer_copyright','footer_powered','footer_desc',
  'footer_columns',
  'comment_moderate','comment_notify','show_uid_in_comments',
  'proxy_allowed_hosts',
  'forum_guest_visible',
  'feed_forum_enabled','feed_show_full','feed_max_items'];

const ALLOWED_SET = [...ALL_KEYS, 'recaptcha_secret_key', 'smtp_pass', 'turnstile_secret_key', 'rainid_client_secret'];

const THEME_RULES = {
  glass_blur: (value) => {
    const raw = String(value).trim();
    const number = Number(raw);
    return /^\d+$/.test(raw) && Number.isInteger(number) && number >= 5 && number <= 40;
  },
  glass_opacity: (value) => {
    const raw = String(value).trim();
    const number = Number(raw);
    return raw !== '' && Number.isFinite(number) && number >= 0.1 && number <= 0.95;
  },
  theme_force_dark: (value) => ['0', '1'].includes(String(value)),
  theme_wallpaper_scale: (value) => ['cover', 'contain', 'repeat', 'stretch'].includes(String(value)),
  nav_style: (value) => ['default', 'glass', 'capsule'].includes(String(value)),
  card_style: (value) => ['default', 'glass'].includes(String(value)),
};

function normalizePrimaryColor(value) {
  const raw = String(value).trim();
  if (/^#[0-9a-f]{3}$/i.test(raw)) {
    return '#' + raw.slice(1).split('').map((c) => c + c).join('').toLowerCase();
  }
  if (/^#[0-9a-f]{6}$/i.test(raw)) return raw.toLowerCase();
  return null;
}

function validateThemeSettings(body) {
  const validated = {};

  if (body.primary_color !== undefined) {
    const color = normalizePrimaryColor(body.primary_color);
    if (!color) return { error: '主色调格式无效：仅支持 #RGB 或 #RRGGBB' };
    validated.primary_color = color;
  }

  for (const [key, validate] of Object.entries(THEME_RULES)) {
    if (body[key] === undefined) continue;
    if (!validate(body[key])) return { error: `主题设置 ${key} 的值无效` };
    validated[key] = String(body[key]).trim();
  }

  return { validated };
}

// footer_columns JSON 校验：数组（最多 3 栏，并行展示上限）；每项 {title: string ≤20, links: [{label ≤50, url ≤200}]}。
// url 白名单：站内相对路径以 / 开头（排除 // 协议相对），或 http(s):// 外链；拒绝 javascript:/data:/vbscript: 等危险协议。
// 返回解析后的数组，非法返回 null。
function validateFooterColumns(raw) {
  let parsed;
  try { parsed = JSON.parse(raw); } catch { return null; }
  if (!Array.isArray(parsed) || parsed.length > 3) return null;
  for (const col of parsed) {
    if (!col || typeof col !== 'object') return null;
    if (typeof col.title !== 'string' || !col.title.trim() || col.title.trim().length > 20) return null;
    if (!Array.isArray(col.links) || col.links.length > 20) return null;
    for (const link of col.links) {
      if (!link || typeof link !== 'object') return null;
      if (typeof link.label !== 'string' || !link.label.trim() || link.label.trim().length > 50) return null;
      const url = String(link.url || '').trim();
      if (!url || url.length > 200) return null;
      // 站内相对路径：/ 开头且非 // 开头；外链：http(s):// 开头
      if (!(/^\/(?!\/)/.test(url) || /^https?:\/\//i.test(url))) return null;
      // 危险协议兜底（上方协议白名单已排除，双保险）
      if (/^(javascript|data|vbscript):/i.test(url)) return null;
    }
  }
  return parsed;
}

router.get('/public', (req, res) => {
  const settings = {};
  PUBLIC_KEYS.forEach(k => settings[k] = db.getSetting(k));
  res.json(settings);
});

router.get('/', authMiddleware, adminOnly, (req, res) => {
  const settings = {};
  ALL_KEYS.forEach(k => settings[k] = db.getSetting(k));
  res.json(settings);
});

router.put('/', authMiddleware, adminOnly, (req, res) => {
  const themeValidation = validateThemeSettings(req.body);
  if (themeValidation.error) return res.status(400).json({ error: themeValidation.error });

  // footer_columns 特判校验：非法 JSON/结构/危险协议 → 400 不落库（空串表示回退硬编码，放行）
  if (req.body.footer_columns !== undefined && String(req.body.footer_columns) !== '') {
    if (!validateFooterColumns(String(req.body.footer_columns))) {
      return res.status(400).json({
        error: '页脚栏目格式无效：需为 [{title, links:[{label,url}]}]，标题≤20字、链接标签≤50字、url 仅限站内路径(/开头)或 http(s) 链接'
      });
    }
  }
  const values = { ...req.body, ...themeValidation.validated };
  for (const [key, value] of Object.entries(req.body)) {
    if (ALLOWED_SET.includes(key)) db.setSetting(key, values[key] === undefined ? String(value) : values[key]);
  }
  res.json({ message: '设置已保存' });
});

module.exports = router;