// What Admin → Teams → Voice channels decides (TEAMS.md §7.3, phase 9).
//
// Extracted for the reason `teamIntegrations.js` is: the interesting parts are
// decisions — when the panel refuses to let voice be switched on, how close the
// guild is to running out of roles, what a row's state actually means to the
// person reading it — and a decision written inline in JSX is one nothing can
// assert on.
//
// **These rules MIRROR the server's and do not replace them.** The server refuses
// to enable voice while the bot cannot manage channels and roles (422) whether or
// not this file ever ran, and the reconciler applies the threshold and the grace
// window regardless of what the screen says. What is here is so the screen agrees
// with those answers before making the round trip.

/** Wording for each state the server can report on a row. */
export const STATE_LABELS = {
  none: 'Not provisioned',
  active: 'Active',
  pending_removal: 'Scheduled for removal',
  error: 'Error',
}

export const stateLabel = (state) => STATE_LABELS[state] || state || 'Unknown'

/**
 * Is the panel allowed to offer the enable switch?
 *
 * The preflight answers three separate questions and they fail differently: the
 * bot is not connected at all, it is connected but missing a permission, or it
 * could not be reached. An operator can act on each of those and they need
 * different actions, so the reason is passed through rather than flattened to a
 * boolean.
 */
export function enableBlockedReason(preflight) {
  if (!preflight) return 'The bot’s status is unknown.'
  if (!preflight.connected) return preflight.reason || 'The Discord bot is not connected.'
  if (preflight.missingPermissions && preflight.missingPermissions.length > 0) {
    return `The bot is missing ${preflight.missingPermissions.join(' and ')} in this guild.`
  }
  if (!preflight.ready) return preflight.reason || 'The bot cannot manage channels and roles yet.'
  return null
}

// Below this many free roles the panel starts saying so. Not a server rule and
// deliberately not one: it is a warning, and the server's only hard behaviour is
// to refuse the create that would exceed the cap.
const HEADROOM_WARNING = 25

/**
 * How much room is left, and whether to say something about it.
 *
 * The 250-role cap is the ceiling this phase's shape brings with it. Access is a
 * per-Team role, so it is not "how big can a Team be" — the old overwrite design's
 * limit — but "how many Teams can have voice at all", and the difference matters
 * to an operator with sixty guilds on their shard. It is guild-wide and shared
 * with every role they created themselves, which is why the count comes from the
 * bot rather than from core's own rows.
 */
export function roleHeadroom(preflight) {
  if (!preflight || !preflight.roleCap) return null
  const used = Number(preflight.roleCount) || 0
  const cap = Number(preflight.roleCap)
  const free = Math.max(0, cap - used)
  return { used, cap, free, tight: free <= HEADROOM_WARNING, exhausted: free === 0 }
}

/** How a row's grace window reads while it is running. */
export function removalCountdown(row, now = new Date()) {
  if (!row || row.state !== 'pending_removal' || !row.removeAfter) return null
  const ms = new Date(row.removeAfter).getTime() - now.getTime()
  if (ms <= 0) return 'due for removal on the next pass'
  const days = Math.floor(ms / 86400000)
  if (days >= 1) return `in ${days} day${days === 1 ? '' : 's'}`
  const hours = Math.max(1, Math.round(ms / 3600000))
  return `in ${hours} hour${hours === 1 ? '' : 's'}`
}

/**
 * Parse the staff-role field an operator types.
 *
 * Comma-separated ids, because that is what a person copying role ids out of
 * Discord ends up with. Validated rather than filtered, mirroring the server: a
 * quietly dropped id is a settings screen showing a save that did not happen.
 */
export function parseStaffRoles(text) {
  const parts = String(text || '')
    .split(',')
    .map((part) => part.trim())
    .filter(Boolean)
  const bad = parts.filter((part) => !/^[0-9]{5,32}$/.test(part))
  return { roles: parts, invalid: bad }
}

export const formatStaffRoles = (roles) => (roles || []).join(', ')

/**
 * The sentence under the enable switch, which changes meaning with the state.
 *
 * "Off" is not "nothing is provisioned": switching voice off suspends the
 * reconciler in BOTH directions and leaves existing channels in place, which is
 * deliberate — a checkbox must not delete structure in somebody's guild — but it
 * is also surprising unless the screen says so.
 */
export function statusSummary(settings, rows) {
  const provisioned = (rows || []).filter((row) => row.channelRef).length
  if (!settings || !settings.enabled) {
    return provisioned > 0
      ? `Off. ${provisioned} channel${provisioned === 1 ? '' : 's'} remain in Discord and are no longer being kept in step — remove them below if they are not wanted.`
      : 'Off. No channels are provisioned.'
  }
  return `On. Teams with at least ${settings.minMembers} member${settings.minMembers === 1 ? '' : 's'} get a voice channel and a role; ${provisioned} provisioned.`
}