import browser from 'webextension-polyfill'

export const PERMISSIONS_REQUIRED = {
  getPublicKey: 1,
  getRelays: 5,
  signEvent: 10,
  'nip04.encrypt': 20,
  'nip04.decrypt': 20
}

const ORDERED_PERMISSIONS = [
  [1, ['getPublicKey']],
  [5, ['getRelays']],
  [10, ['signEvent']],
  [20, ['nip04.encrypt']],
  [20, ['nip04.decrypt']]
]

const PERMISSION_NAMES = {
  getPublicKey: 'read your public key',
  getRelays: 'read your list of preferred relays',
  signEvent: 'sign events using your private key',
  'nip04.encrypt': 'encrypt messages to peers',
  'nip04.decrypt': 'decrypt messages from peers'
}

export function getAllowedCapabilities(permission) {
  let requestedMethods = []
  for (let i = 0; i < ORDERED_PERMISSIONS.length; i++) {
    let [perm, methods] = ORDERED_PERMISSIONS[i]
    if (perm > permission) break
    requestedMethods = requestedMethods.concat(methods)
  }

  if (requestedMethods.length === 0) return 'nothing'

  return requestedMethods.map(method => PERMISSION_NAMES[method])
}

export function getPermissionsString(permission) {
  let capabilities = getAllowedCapabilities(permission)

  if (capabilities.length === 0) return 'none'
  if (capabilities.length === 1) return capabilities[0]

  return (
    capabilities.slice(0, -1).join(', ') +
    ' and ' +
    capabilities[capabilities.length - 1]
  )
}

export async function readPermissions() {
  let {permissions = {}} = await browser.storage.local.get('permissions')

  // delete expired
  var needsUpdate = false
  for (let host in permissions) {
    if (
      permissions[host].condition === 'expirable' &&
      permissions[host].created_at < Date.now() / 1000 - 5 * 60
    ) {
      delete permissions[host]
      needsUpdate = true
    }
  }
  if (needsUpdate) browser.storage.local.set({permissions})

  return permissions
}

export async function readPermissionLevel(host) {
  return (await readPermissions())[host]?.level || 0
}

export async function updatePermission(host, permission) {
  var permissions = await browser.storage.local.get('permissions').permissions
  permissions[host] = {
    ...permission,
    created_at: Math.round(Date.now() / 1000)
  }
  browser.storage.local.set({permissions})
}