// ── One stored frame as one line of a feed ────────────────────────────────
//
// `GET /public/rust/servers/:id/events` answers rows shaped
// `{ id, kind, t, wipeId, steamId, frame }`, where `frame` is the whole frame
// the plugin emitted — this module stores what it is given and indexes only the
// columns it serves (PROTOCOL.md §8.4, and the `raw` column in schema.sql). So
// everything a killfeed line needs is in `frame`, under the names the plugin
// wrote, and this file is the one place that knows them.
//
// **It returns PARTS, not a sentence.** A component wants the names emphasised
// and the detail muted, and a function returning `"Alice killed Bob"` forces
// either a `dangerouslySetInnerHTML` or a re-parse. Parts also make this
// testable without a DOM, which is the whole reason it is not a component.
//
// ── The rule for an unknown kind ──────────────────────────────────────────
//
// It renders as itself. A later protocol adds kinds, an operator's module may be
// older than their game host, and a feed that DROPPED what it did not recognise
// would be a page that quietly says less than the truth. The server's allowlist
// has already decided this row may be seen (`server/catalogue.js`); what is left
// here is presentation, and the honest presentation of a kind we have no words
// for is its own name.

import { duration, prefab } from './format.js'

/**
 * Kinds this feed asks for.
 *
 * `player.tally` is public and deliberately NOT here: it is an aggregate the
 * plugin flushes every sixty seconds per active player (§8.6), so a feed
 * including it would be mostly wood counts. It is the leaderboard's input, and
 * the leaderboard is where it shows up.
 */
export const FEED_KINDS = Object.freeze([
  'player.death',
  'player.connected',
  'player.disconnected',
  'player.respawned',
  'player.chat',
  'server.wipe',
  'server.initialized',
  'server.shutdown',
])

/** The filters the feed offers, and the kinds each one asks the API for. */
export const FILTERS = Object.freeze([
  { id: 'all', label: 'Everything', kinds: FEED_KINDS },
  { id: 'kills', label: 'Kills', kinds: ['player.death'] },
  { id: 'chat', label: 'Chat', kinds: ['player.chat'] },
  {
    id: 'sessions',
    label: 'Comings and goings',
    kinds: ['player.connected', 'player.disconnected', 'player.respawned'],
  },
  { id: 'server', label: 'Server', kinds: ['server.wipe', 'server.initialized', 'server.shutdown'] },
])

export function kindsFor(filterId) {
  const filter = FILTERS.find((f) => f.id === filterId)
  return (filter || FILTERS[0]).kinds
}

/**
 * One row as `{ tone, actor, join, verb, subject, detail }`.
 *
 * `actor` and `subject` are names and are emphasised; `verb` and `detail` are
 * prose. Any of them may be empty. `tone` is the row's category, for the small
 * colour the component gives it — never for deciding what a row means.
 *
 * `join` is what goes between the actor and the verb, and it exists for exactly
 * one case: chat. "Brannock see you in september" is not a sentence anybody
 * writes, and putting the colon in the message would put presentation inside the
 * text a player typed.
 */
export function describe(row) {
  const frame = (row && row.frame) || {}
  const name = frame.name || null

  switch (row && row.kind) {
    case 'player.death':
      return death(frame, name)

    case 'player.connected':
      return { tone: 'join', actor: name, verb: 'connected', subject: null, detail: '' }

    case 'player.disconnected':
      return {
        tone: 'leave',
        actor: name,
        verb: 'disconnected',
        subject: null,
        // Two optional halves, and the session is the interesting one: the plugin
        // omits `sessionSec` for a player who was already on when it loaded, so an
        // absent value means "unknown", never zero (§8.4's note, and OnPlayerDisconnected).
        detail: [frame.reason || null, frame.sessionSec ? `after ${duration(frame.sessionSec)}` : null]
          .filter(Boolean)
          .join(' · '),
      }

    case 'player.respawned':
      return { tone: 'join', actor: name, verb: 'respawned', subject: null, detail: '' }

    case 'player.chat':
      return {
        tone: 'chat',
        actor: name,
        join: ': ',
        // The message is the row, so it goes in `verb` where a component renders
        // it unemphasised — and it is the one field on this wire a player chooses
        // the bytes of. React escapes it; nothing here may ever stop doing that.
        verb: frame.message || '',
        subject: null,
        detail: frame.channel && frame.channel !== 'Global' ? frame.channel : '',
      }

    case 'server.wipe':
      return {
        tone: 'server',
        actor: null,
        verb: 'The map was wiped',
        subject: null,
        detail: frame.wipeId ? `new wipe ${frame.wipeId}` : '',
      }

    case 'server.initialized':
      return { tone: 'server', actor: null, verb: 'The server came up', subject: null, detail: '' }

    case 'server.shutdown':
      return { tone: 'server', actor: null, verb: 'The server went down', subject: null, detail: '' }

    default:
      return { tone: 'other', actor: name, verb: String((row && row.kind) || 'unknown'), subject: null, detail: '' }
  }
}

/**
 * A death, which is four different sentences.
 *
 * The plugin distinguishes `player`, `self`, `npc` and `environment` precisely so
 * that a reader does not have to guess from an absent field, and collapsing any
 * two of them loses something (see `DescribeAttacker` in the bridge plugin). A
 * killfeed that reported a fall as a kill by nobody is the failure this avoids.
 */
function death(frame, name) {
  const where = [
    frame.weapon ? `with ${prefab(frame.weapon)}` : null,
    frame.distance ? `${Math.round(frame.distance)}m` : null,
    frame.grid || null,
    frame.sleeping ? 'while sleeping' : null,
  ]
    .filter(Boolean)
    .join(' · ')

  switch (frame.attackerType) {
    case 'player':
      return { tone: 'kill', actor: frame.attackerName || null, verb: 'killed', subject: name, detail: where }

    case 'self':
      return { tone: 'death', actor: name, verb: 'died by their own hand', subject: null, detail: where }

    case 'npc':
      return {
        tone: 'death',
        actor: prefab(frame.attackerName) || 'Something',
        verb: 'killed',
        subject: name,
        detail: where,
      }

    // `environment` and anything else: falling, drowning, the world. `HitInfo`
    // is legitimately null on this path, so an absent attacker type is this case
    // rather than a missing field to complain about.
    default:
      return { tone: 'death', actor: name, verb: 'died', subject: null, detail: where }
  }
}

export default { describe, FEED_KINDS, FILTERS, kindsFor }