import { nip19 } from 'nostr-tools'

export function extractKeyFromInput(rawInput: string): string | null {
  const trimmed = rawInput.trim()
  if (trimmed.length === 0) {
    return null
  }
  const fromUrl = extractKeyFromUrl(trimmed)
  return fromUrl ?? extractKeyFromText(trimmed)
}

function extractKeyFromUrl(url: string): string | null {
  try {
    const urlObj = new URL(url)
    const {protocol} = urlObj
    if (protocol === 'nostr:' || protocol === 'nostr://') {
      const path = urlObj.pathname ?? urlObj.href.replace(/^nostr:?\/\//, '')
      if (path.startsWith('nsec')) {
        return path
      }
    }
    const nsecMatch = url.match(/nsec1[a-z0-9]+/i)
    return nsecMatch?.[0] ?? null
  } catch {
    return null
  }
}

function extractKeyFromText(text: string): string | null {
  const nsec = extractNsec(text)
  if (nsec) {
    return nsec
  }
  const trimmed = text.trim()
  return trimmed.length > 0 ? trimmed : null
}

function extractNsec(text: string): string | null {
  const nsecMatch = text.match(/nsec1[a-z0-9]+/i)
  return nsecMatch?.[0] ?? null
}

export function isValidPrivateKeyFormat(key: string): boolean {
  try {
    const decoded = nip19.decode(key)
    if (decoded.type !== 'nsec') {
      return false
    }
    return typeof decoded.data === 'string' || decoded.data instanceof Uint8Array
  } catch {
    return /^[0-9a-f]{64}$/i.test(key)
  }
}