// ── The voice the module's own lines are said in (phase 17, D140) ──────────
//
// One fleet setting (§33.4 reading 5): the name of a permission group that has
// a BetterChat style, or nothing for plain chat. News lines and `rust.announce`
// lines are then said in that group's title and colours — composed here, said by
// our plugin with no player as the sender, so they look right whether or not
// BetterChat is loaded.
//
// The style is read at the moment a line is said, never copied into the
// setting: an operator who recolours the group changes the voice with it, and a
// group whose style is taken away stops being a voice rather than leaving a
// stale one behind.

const settingsDb = require('../visibility/visibility.db')
const chatStyle = require('./chatStyle')
const db = require('./permissions.db')
const model = require('./permissions.model')

const VOICE_KEY = 'announce.voice'

/**
 * The chosen group's id as a string, or '' for plain chat.
 *
 * Since groups became per server (D189) a name can belong to several groups, so
 * the setting holds a group's id. A setting written before that holds a NAME,
 * and is read as the first styled group of that name until somebody chooses again.
 */
async function chosen() {
  return (await settingsDb.getSetting(VOICE_KEY)) || ''
}

/** The chosen group's style fields, or null. */
async function chosenFields() {
  const value = await chosen()
  if (!value) return { value, fields: null }

  if (/^\d+$/.test(value)) return { value, fields: await db.getGroupChat(Number(value)) }

  const groups = await db.listGroups()
  for (const group of groups.filter((g) => g.name === model.normaliseName(value))) {
    // eslint-disable-next-line no-await-in-loop
    const fields = await db.getGroupChat(group.id)
    if (fields) return { value: String(group.id), fields }
  }

  return { value, fields: null }
}

/**
 * The format a line is said in right now, or null for plain chat — which is
 * also the answer when the chosen group has since lost its style or gone.
 */
async function currentFormat() {
  const { fields } = await chosenFields()
  return fields ? chatStyle.voiceFormat(fields) : null
}

/** The setting, and every group that could be a voice, for the admin page. */
async function describe() {
  const [{ value }, rows, groups, groupServers] = await Promise.all([
    chosenFields(),
    db.listGroupChat(),
    db.listGroups(),
    db.listGroupServers(),
  ])
  const byId = new Map(groups.map((g) => [g.id, g]))
  const options = []

  // Which servers each group is on, so two groups of one name can be told apart.
  const where = (group) => {
    if (group.allServers) return 'all servers'
    const ids = groupServers.filter((r) => r.groupId === group.id && r.included).map((r) => r.serverId)
    return ids.length ? ids.join(', ') : 'no server'
  }

  for (const [groupId, fields] of model.chatByGroup(rows)) {
    const format = chatStyle.voiceFormat(fields)
    const group = byId.get(groupId)
    if (format && group) {
      options.push({ group: String(groupId), name: group.name, where: where(group), title: fields.Title || group.name, format })
    }
  }

  return { voice: value, options: options.sort((a, b) => a.name.localeCompare(b.name) || a.group.localeCompare(b.group)) }
}

/**
 * Choose the voice by group id. A group is accepted only when it has a style a
 * voice can be made from; '' goes back to plain chat. Resolves `{ ok }` or
 * `{ ok: false, message }`.
 */
async function choose(group, userId = null) {
  const value = String(group || '').trim()

  if (value) {
    const fields = /^\d+$/.test(value) ? await db.getGroupChat(Number(value)) : null
    if (!fields || !chatStyle.voiceFormat(fields)) {
      return { ok: false, message: 'That group has no chat style, so it cannot be a voice. Give it one under Permissions first.' }
    }
  }

  await settingsDb.setSetting(VOICE_KEY, value, userId)
  return { ok: true, voice: value }
}

module.exports = { VOICE_KEY, chosen, currentFormat, describe, choose }