// ── 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 { attacker, duration, weapon } 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',
  // RunicNPC bosses (runicnpc stage 6): the game says both to the whole server.
  // The death names its killer, so the server shows it only where presence is on.
  'npc.boss.spawned',
  'npc.boss.died',
  // Rust's own world events (protocol 14, PLAN_REDESIGNS §14.3.1): the server
  // reads each one for the viewer, so a name is here only where it may be.
  'world.event',
  // Dynamic PVP's zones opening (§14.3.3). A closing (`pvp.zone.deleted`) is
  // staff's and is not asked for here; the map shows a zone go.
  'pvp.zone.created',
  // Dangerous Treasures (§14.3.4): a chest opening, and one won. The server reads
  // each for the viewer, so the winner's name is here only where it may be; the
  // ending (`dt.ended`) is staff's, and the map shows the chest go.
  'dt.started',
  'dt.won',
  // Guarded Crate (§14.3.5): a crate landing, and one cleared, read per viewer
  // like a treasure. A timeout (`gc.failed`) is staff's; the map shows it go.
  'gc.started',
  'gc.ended',
  // RaidableBases (§11.4): a base appearing, raided, bought or locked to a
  // player, read per viewer; its despawn (`raid.ended`) is staff's, and the map shows it go.
  'raid.started',
  'raid.completed',
  'raid.purchased',
  'raid.locked',
])

/** 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'] },
  { id: 'bosses', label: 'Bosses', kinds: ['npc.boss.spawned', 'npc.boss.died'] },
  { id: 'world', label: 'World events', kinds: ['world.event', 'pvp.zone.created', 'dt.started', 'dt.won', 'gc.started', 'gc.ended', 'raid.started', 'raid.completed', 'raid.purchased', 'raid.locked'] },
])

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: '' }

    // A boss's name is the profile's, as typed (`name`), never a prefab's.
    case 'npc.boss.spawned':
      return { tone: 'server', actor: name, verb: 'has appeared', subject: null, detail: 'a boss' }

    case 'npc.boss.died': {
      const fought = Number(frame.damagers) > 1 ? `${frame.damagers} players fought it` : ''
      return frame.killerName
        ? { tone: 'kill', actor: frame.killerName, verb: 'killed', subject: name, detail: fought }
        : { tone: 'death', actor: name, verb: 'was killed', subject: null, detail: fought }
    }

    case 'world.event':
      return worldLine(frame)

    case 'pvp.zone.created':
    case 'pvp.zone.deleted':
      return pvpLine(row.kind, frame)

    case 'dt.started':
    case 'dt.won':
    case 'dt.ended':
      return treasureLine(row.kind, frame)

    case 'gc.started':
    case 'gc.ended':
    case 'gc.failed':
      return guardedLine(row.kind, frame)

    case 'raid.started':
    case 'raid.completed':
    case 'raid.ended':
    case 'raid.purchased':
    case 'raid.locked':
      return raidLine(row.kind, frame)

    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 ${weapon(frame)}` : null,
    frame.distance ? `${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',
        // One of RunicNPC's (runicnpc stage 4): its own name, as typed on its profile,
        // rather than the prefab it is built from. Older frames carry only the prefab.
        actor: frame.attackerNpc || attacker(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 }
  }
}

/** Where a locked crate is, as the end of a sentence. */
const CRATE_PLACES = Object.freeze({
  oilrig_large: 'on Large Oil Rig',
  oilrig_small: 'on Small Oil Rig',
  cargo: 'on the cargo ship',
  ghostship: 'on a ghost ship',
  chinook: 'dropped by a Chinook',
})

/**
 * Who a downed helicopter, Chinook or Bradley credits, as a phrase: "Alice",
 * "Alice and Bob", "Alice, Bob and 2 others". Null when the line names nobody
 * — below the presence audience the server sends `creditedCount` and no names.
 */
export function creditedPhrase(frame) {
  const names = (Array.isArray(frame.credited) ? frame.credited : []).map((c) => c && c.name).filter(Boolean)
  if (names.length === 0) return null
  const total = Math.max(names.length, Number(frame.creditedCount) || 0)
  const shown = names.slice(0, 2)
  const more = total - shown.length
  if (more > 0) return `${shown.join(', ')} and ${more} other${more === 1 ? '' : 's'}`
  return shown.length === 2 ? `${shown[0]} and ${shown[1]}` : shown[0]
}

/**
 * Rust's own world events (protocol 14), one sentence per type. The server has
 * already read the frame for this viewer: it carries `grid`, a `name` only for
 * the presence audience, and `credited` by the server's rule (D372, D376). A
 * line therefore never decides who may read a name; it only says what it has.
 */
function worldLine(frame) {
  const grid = frame.grid || ''
  const who = frame.name || null
  const place = CRATE_PLACES[frame.where] || 'somewhere on the map'
  const by = creditedPhrase(frame)
  const downed = (what) => (by
    ? { tone: 'kill', actor: null, verb: `${what} by`, subject: by, detail: grid }
    : { tone: 'kill', actor: null, verb: what, subject: null, detail: grid })
  const say = (verb, detail = grid) => ({ tone: 'server', actor: null, verb, subject: null, detail })
  const harbour = frame.harbourName || 'the harbour'

  switch (frame.event) {
    case 'heli.arrived':
      return say('A patrol helicopter has arrived')
    case 'heli.left':
      return say('The patrol helicopter has left', '')
    case 'heli.downed':
      return downed('Patrol helicopter downed')
    case 'chinook.downed':
      return downed('Chinook shot down')
    case 'bradley.destroyed':
      return downed(frame.where === 'launch_site' ? "Launch Site's Bradley destroyed" : frame.where === 'road' ? 'Road Bradley destroyed' : 'Bradley destroyed')
    case 'bradley.spawned': {
      const n = Number(frame.count) || 1
      if (frame.where === 'road') return say(n > 1 ? `${n} road Bradleys are out` : 'A road Bradley is out', '')
      return say('Bradley is patrolling Launch Site', '')
    }
    case 'cargo.arrived':
      return say('The cargo ship has arrived')
    case 'cargo.docking':
      return say(`The cargo ship is docking at ${harbour}`)
    case 'cargo.docked':
      return say(`The cargo ship has docked at ${harbour}`)
    case 'cargo.undocked':
      return say(`The cargo ship has cast off from ${harbour}`)
    case 'cargo.left':
      return say('The cargo ship is leaving', '')
    case 'chinook.arrived':
      return say('A Chinook is inbound with a locked crate')
    case 'chinook.dropped':
      return say(frame.monumentName ? `A Chinook dropped a locked crate at ${frame.monumentName}` : 'A Chinook dropped a locked crate')
    case 'airdrop.called':
      return who ? { tone: 'server', actor: who, verb: 'called an airdrop', subject: null, detail: grid } : say('An airdrop is on its way')
    case 'airdrop.landed':
      return say('An airdrop has landed', [who ? `called by ${who}` : null, grid].filter(Boolean).join(' · '))
    case 'airdrop.looted':
      return who ? { tone: 'server', actor: who, verb: 'looted an airdrop', subject: null, detail: grid } : say('An airdrop was looted')
    case 'crate.hack.started':
      return who
        ? { tone: 'server', actor: who, verb: `started hacking the locked crate ${place}`, subject: null, detail: grid }
        : say(`A locked crate ${place} is being hacked`)
    case 'crate.unlocked':
      return say(`The locked crate ${place} is open`)
    case 'crate.looted':
      return who
        ? { tone: 'server', actor: who, verb: `looted the locked crate ${place}`, subject: null, detail: grid }
        : say(`The locked crate ${place} was looted`)
    case 'vendor.arrived':
      return say('The Travelling Vendor has arrived')
    case 'vendor.left':
      return say('The Travelling Vendor has left', '')
    case 'satellite.crashed':
      return say('A satellite has crashed')
    case 'deepsea.opened':
      return say('The Deep Sea is open', '')
    case 'deepsea.closed':
      return say('The Deep Sea has closed', '')
    default:
      // A type this build has no words for, which only staff are sent: its own name.
      return { tone: 'other', actor: who, verb: String(frame.event || 'world event'), subject: null, detail: grid }
  }
}

/**
 * What a Dynamic PVP zone is around, by its event (Dynamic PVP 5.2.0's own
 * names). The server sends `event` to the public only for these; a monument's or
 * an operator's own event reaches staff as written.
 */
export const PVP_AROUND = Object.freeze({
  Helicopter: 'the downed patrol helicopter',
  Bradley: 'the destroyed Bradley',
  Satellite: 'the crashed satellite',
  TimedSupply: 'an airdrop',
  SupplySignal: 'a signalled airdrop',
  CargoShip: 'the cargo ship',
  HackableCrate: 'a locked crate',
  ExcavatorIgnition: 'the Giant Excavator',
  GhostShip: 'a ghost ship',
  DeepSeaIsland: 'a Deep Sea island',
  IslandCannon: 'an island cannon',
})

/** How long a zone was given, as a detail: "for 10 min", or cargo's whole visit. */
function pvpLasts(frame) {
  const sec = Number(frame.durationSec)
  if (!(sec > 0)) return frame.event === 'CargoShip' ? 'while the ship is here' : ''
  return sec < 120 ? `for ${Math.round(sec)} s` : `for ${Math.round(sec / 60)} min`
}

/** Dynamic PVP's zones (protocol 14, PLAN_REDESIGNS §14.3.3). The line names nobody. */
function pvpLine(kind, frame) {
  const around = PVP_AROUND[frame.event] ? ` around ${PVP_AROUND[frame.event]}` : frame.event ? ` (${frame.event})` : ''
  if (kind === 'pvp.zone.deleted') {
    return { tone: 'server', actor: null, verb: `The PvP zone${around} has closed`, subject: null, detail: '' }
  }
  const detail = [frame.grid || null, pvpLasts(frame) || null].filter(Boolean).join(' · ')
  return { tone: 'kill', actor: null, verb: `A PvP zone opened${around}`, subject: null, detail }
}

/**
 * Dangerous Treasures (protocol 14, PLAN_REDESIGNS §14.3.4). The server has read
 * the frame for this viewer: `grid`, `invaderCount`, and the winner's `name` only
 * for the presence audience (D376).
 */
function treasureLine(kind, frame) {
  const grid = frame.grid || ''
  if (kind === 'dt.started') {
    return { tone: 'server', actor: null, verb: 'A Dangerous Treasures event has started', subject: null, detail: grid }
  }
  if (kind === 'dt.ended') {
    return { tone: 'server', actor: null, verb: 'A Dangerous Treasures event has ended', subject: null, detail: grid }
  }
  const n = Number(frame.invaderCount)
  const fought = n > 1 ? `${n} players fought for it` : ''
  const detail = [grid || null, fought || null].filter(Boolean).join(' · ')
  return frame.name
    ? { tone: 'kill', actor: frame.name, verb: 'won the treasure', subject: null, detail }
    : { tone: 'kill', actor: null, verb: 'The treasure was won', subject: null, detail }
}

/**
 * Guarded Crate (protocol 14, PLAN_REDESIGNS §14.3.5). The server has read the
 * frame for this viewer: `grid`, `won` (whether a player killed the last
 * guard), and the clearer's `name` only for the presence audience (D376).
 */
function guardedLine(kind, frame) {
  const detail = frame.grid || ''
  if (kind === 'gc.started') {
    return { tone: 'server', actor: null, verb: 'A guarded crate landed', subject: null, detail }
  }
  if (kind === 'gc.failed') {
    return { tone: 'server', actor: null, verb: 'A guarded crate timed out with its guards standing', subject: null, detail }
  }
  if (frame.won === false) {
    return { tone: 'server', actor: null, verb: 'A guarded crate ended with nobody clearing it', subject: null, detail }
  }
  return frame.name
    ? { tone: 'kill', actor: frame.name, verb: 'cleared the guarded crate', subject: null, detail }
    : { tone: 'kill', actor: null, verb: 'The guarded crate was cleared', subject: null, detail }
}

/** "Alice", "Alice and Bob", "Alice, Bob and 3 others". */
export function raiderNames(names, count) {
  const shown = (names || []).slice(0, 2)
  const rest = Math.max(0, (Number(count) || shown.length) - shown.length)
  if (shown.length === 0) return null
  if (rest === 0) return shown.length === 2 ? `${shown[0]} and ${shown[1]}` : shown[0]
  return `${shown.join(', ')} and ${rest} other${rest === 1 ? '' : 's'}`
}

/**
 * RaidableBases (protocol 14, PLAN_REDESIGNS §11.4). The server has read the
 * frame for this viewer: `grid`, the plugin's own `difficulty` name (D386), `pvp`,
 * and the raiders' `names` or a buyer's `name` only for the presence audience
 * (D376, D390); `raiderCount` for everyone.
 */
function raidLine(kind, frame) {
  const base = frame.difficulty ? `${frame.difficulty} raid base` : 'raid base'
  const a = /^[aeiou]/i.test(base) ? 'An' : 'A'
  const detail = [frame.grid || null, frame.pvp === true ? 'PvP' : null].filter(Boolean).join(' · ')

  if (kind === 'raid.started') return { tone: 'server', actor: null, verb: `${a} ${base} appeared`, subject: null, detail }
  if (kind === 'raid.ended') return { tone: 'server', actor: null, verb: `${a} ${base} despawned`, subject: null, detail }

  if (kind === 'raid.completed') {
    const who = raiderNames(frame.names, frame.raiderCount)
    if (who) return { tone: 'kill', actor: who, verb: `raided ${a.toLowerCase()} ${base}`, subject: null, detail }
    const count = Number(frame.raiderCount) || 0
    const by = count > 0 ? `by ${count} player${count === 1 ? '' : 's'}` : null
    return { tone: 'kill', actor: null, verb: `${a} ${base} was raided`, subject: null, detail: [detail, by].filter(Boolean).join(' · ') }
  }

  if (kind === 'raid.purchased') {
    return frame.name
      ? { tone: 'server', actor: frame.name, verb: `bought ${a.toLowerCase()} ${base}`, subject: null, detail }
      : { tone: 'server', actor: null, verb: `${a} ${base} was bought`, subject: null, detail }
  }

  return frame.name
    ? { tone: 'server', actor: null, verb: `${a} ${base} was locked to ${frame.name}`, subject: null, detail }
    : { tone: 'server', actor: null, verb: `${a} ${base} was locked to a player`, subject: null, detail }
}

export default { describe, FEED_KINDS, FILTERS, kindsFor }