/** Build / parse client-side share landing query (no server). */

export type PortraitSharePayload = {
  type: 'portrait'
  title: string
  line: string
  keywords: string[]
}

export type RelationSharePayload = {
  type: 'relation'
  me: string
  other: string
  diff: string
  keywords: string[]
}

export type SharePayload = PortraitSharePayload | RelationSharePayload

export function buildSharePath(payload: SharePayload): string {
  const q = new URLSearchParams()
  q.set('type', payload.type)
  if (payload.type === 'portrait') {
    if (payload.title) q.set('t', payload.title)
    if (payload.line) q.set('l', payload.line)
    if (payload.keywords.length) q.set('k', payload.keywords.slice(0, 6).join(','))
  } else {
    if (payload.me) q.set('me', payload.me)
    if (payload.other) q.set('ot', payload.other)
    if (payload.diff) q.set('d', payload.diff)
    if (payload.keywords.length) q.set('k', payload.keywords.slice(0, 6).join(','))
  }
  return `/share?${q.toString()}`
}

export function parseShareQuery(query: Record<string, unknown>): SharePayload | null {
  const type = String(query.type || '')
  const keywords = String(query.k || '')
    .split(',')
    .map((s) => s.trim())
    .filter(Boolean)
  if (type === 'portrait') {
    const title = String(query.t || '')
    const line = String(query.l || '')
    if (!title && !line && !keywords.length) return null
    return { type: 'portrait', title, line, keywords }
  }
  if (type === 'relation') {
    const me = String(query.me || '')
    const other = String(query.ot || '')
    const diff = String(query.d || '')
    if (!me && !other && !diff) return null
    return { type: 'relation', me, other, diff, keywords }
  }
  return null
}

export async function copyText(text: string): Promise<boolean> {
  try {
    if (navigator.clipboard?.writeText) {
      await navigator.clipboard.writeText(text)
      return true
    }
  } catch {
    /* fall through */
  }
  try {
    const ta = document.createElement('textarea')
    ta.value = text
    ta.style.position = 'fixed'
    ta.style.left = '-9999px'
    document.body.appendChild(ta)
    ta.select()
    const ok = document.execCommand('copy')
    document.body.removeChild(ta)
    return ok
  } catch {
    return false
  }
}