export type SocialLinkIconInput = {
  label: string
  url: string
  icon?: string | null
}

/** 优先使用条目中的 icon；否则按域名与标题推断 */
export function socialLinkIconName(link: SocialLinkIconInput): string {
  const raw = link.icon?.trim()
  if (raw) {
    return raw
  }
  return inferSocialLinkIconName(link.label, link.url)
}

function inferSocialLinkIconName(label: string, url: string): string {
  const lowerLabel = label.toLowerCase()

  try {
    const u = new URL(url.trim())
    if (u.protocol === 'mailto:') {
      return 'i-lucide-mail'
    }
    const host = u.hostname.replace(/^www\./i, '').toLowerCase()

    const byHost: [string, string][] = [
      ['github.com', 'i-simple-icons-github'],
      ['gist.github.com', 'i-simple-icons-github'],
      ['github.io', 'i-simple-icons-github'],
      ['twitter.com', 'i-simple-icons-x'],
      ['x.com', 'i-simple-icons-x'],
      ['linkedin.com', 'i-simple-icons-linkedin'],
      ['youtube.com', 'i-simple-icons-youtube'],
      ['youtu.be', 'i-simple-icons-youtube'],
      ['gitlab.com', 'i-simple-icons-gitlab'],
      ['reddit.com', 'i-simple-icons-reddit'],
      ['discord.com', 'i-simple-icons-discord'],
      ['discord.gg', 'i-simple-icons-discord'],
      ['t.me', 'i-simple-icons-telegram'],
      ['telegram.org', 'i-simple-icons-telegram'],
      ['medium.com', 'i-simple-icons-medium'],
      ['stackoverflow.com', 'i-simple-icons-stackoverflow'],
      ['bsky.app', 'i-simple-icons-bluesky'],
      ['mastodon.social', 'i-simple-icons-mastodon'],
      ['bilibili.com', 'i-simple-icons-bilibili'],
      ['space.bilibili.com', 'i-simple-icons-bilibili'],
      ['weibo.com', 'i-simple-icons-sinaweibo'],
      ['zhihu.com', 'i-simple-icons-zhihu'],
    ]

    for (const [h, icon] of byHost) {
      if (host === h || host.endsWith(`.${h}`)) {
        return icon
      }
    }

    if (host.endsWith('.github.io')) {
      return 'i-simple-icons-github'
    }

    if (host.includes('mastodon')) {
      return 'i-simple-icons-mastodon'
    }
  }
  catch {
    // fall through to label heuristics
  }

  if (/\bgithub\b/i.test(lowerLabel)) {
    return 'i-simple-icons-github'
  }
  if (/\b(x|twitter)\b/i.test(lowerLabel)) {
    return 'i-simple-icons-x'
  }
  if (/\blinkedin\b/i.test(lowerLabel)) {
    return 'i-simple-icons-linkedin'
  }
  if (/\byoutube\b|\byt\b/i.test(lowerLabel)) {
    return 'i-simple-icons-youtube'
  }
  if (/\bmail\b|邮箱|电子邮件/i.test(lowerLabel)) {
    return 'i-lucide-mail'
  }

  return 'i-lucide-link-2'
}