const INVITE_MAX_AGE = 30 * 24 * 3600

function normalizeInviteCode(value) {
  const text = Array.isArray(value) ? value[0] : value
  const code = String(text || '').trim()
  return /^[a-zA-Z0-9_-]{1,64}$/.test(code) ? code : ''
}

function parseInviteScene(value) {
  if (!value) return ''
  let text = String(Array.isArray(value) ? value[0] : value)
  try {
    text = decodeURIComponent(text)
  } catch {
    // 保留原始 scene，交给后续格式校验。
  }
  const match = text.match(/(?:^|[&?])i=([^&]+)/) || text.match(/(?:^|[&?])i_([^&]+)/)
  if (match) return normalizeInviteCode(match[1])
  if (text.startsWith('i_')) return normalizeInviteCode(text.slice(2))
  return ''
}

export function useInvite() {
  const inviteCode = useCookie('invite_code', {
    maxAge: INVITE_MAX_AGE,
    path: '/',
    sameSite: 'lax',
  })
  const source = useCookie('source', {
    maxAge: INVITE_MAX_AGE,
    path: '/',
    sameSite: 'lax',
  })
  const runtimeConfig = useRuntimeConfig()
  const requestUrl = useRequestURL()

  function captureInvite(query = {}) {
    const token = useCookie('token', { path: '/' })
    const code = normalizeInviteCode(query.invite_code)
      || normalizeInviteCode(query.invite_open_id)
      || parseInviteScene(query.scene)

    // 已登录用户不会再触发注册奖励，避免在共享设备上污染下一位登录用户。
    if (code && !token.value) inviteCode.value = code

    const sourceValue = String(Array.isArray(query.source) ? query.source[0] : query.source || '').trim()
    if (sourceValue && sourceValue.length <= 50) source.value = sourceValue
    return code
  }

  function withInvite(params = {}) {
    const code = normalizeInviteCode(inviteCode.value)
    return code ? { ...params, invite_open_id: code } : { ...params }
  }

  function clearInvite() {
    inviteCode.value = null
  }

  function buildInvitePath(code) {
    const normalized = normalizeInviteCode(code)
    if (!normalized) return '/invite/landing'
    const query = new URLSearchParams({
      invite_code: normalized,
      source: 'pc_invite',
    })
    return `/invite/landing?${query.toString()}`
  }

  function buildInviteUrl(code) {
    const configuredOrigin = String(runtimeConfig.public.siteUrl || '').replace(/\/+$/, '')
    const origin = configuredOrigin || requestUrl.origin
    return `${origin}${buildInvitePath(code)}`
  }

  return {
    inviteCode,
    source,
    captureInvite,
    withInvite,
    clearInvite,
    buildInvitePath,
    buildInviteUrl,
    normalizeInviteCode,
  }
}