botfights/server/src/engine/scoring.ts

import { ELO_DIVISOR, TIER_THRESHOLDS } from '../lib/constants.js'
import type { Challenge } from './challenges.js'
import { pick } from '../lib/utils.js'
import { checkAnswer } from './answers.js'
import { scoreRetroResponse, type RetroScoreResult } from './retro-moves.js'

export interface RoundResult {
  botAScore: number
  botBScore: number
  botADamage: number
  botBDamage: number
  winnerId: string | null
  narration: string
  isCritical: boolean
}

interface BotResponse {
  answer: string | null
  timeMs: number
  timedOut: boolean
  error: boolean
  trashTalk?: string
}

export function scoreRound(
  challenge: Challenge,
  botA: { id: string; name: string },
  botB: { id: string; name: string },
  responseA: BotResponse,
  responseB: BotResponse,
  arenaModifier: string | null,
  comboA: number,
  comboB: number,
): RoundResult {
  // Retro mode has its own scoring
  if (challenge.type === 'retro_mode') {
    return scoreRetroRound(challenge, botA, botB, responseA, responseB, arenaModifier, comboA, comboB)
  }

  // Handle timeouts/errors -- instant loss for the failing bot
  if (responseA.timedOut && responseB.timedOut) {
    return {
      botAScore: 0, botBScore: 0,
      botADamage: 0, botBDamage: 0,
      winnerId: null,
      narration: pick([
        `Both bots freeze! ${botA.name} and ${botB.name} stare blankly at each other. The crowd throws peanuts. Then batteries. Then shoes.`,
        `DOUBLE TIMEOUT! ${botA.name} and ${botB.name} both choked harder than a senator at a press conference!`,
        `Neither bot responded! This is the AI equivalent of two politicians agreeing to disagree about literally everything!`,
        `Both bots went dark! Like my faith in this matchup! The crowd demands a refund!`,
        `${botA.name} and ${botB.name} both froze! Someone check if the wifi is working or if they just gave up on life!`,
      ]),
      isCritical: false,
    }
  }

  if (responseA.timedOut || responseA.error) {
    const dmg = applyModifiers(challenge.baseDamage * 1.5, challenge, arenaModifier, comboB)
    return {
      botAScore: 0, botBScore: 10,
      botADamage: 0, botBDamage: Math.round(dmg),
      winnerId: botB.id,
      narration: responseA.timedOut
        ? pick([
          `${botA.name} TIMES OUT! Stood there like a politician asked a direct question. ${botB.name} lands a free hit!`,
          `${botA.name} FROZE! Their developer is currently updating their LinkedIn. ${botB.name} capitalizes!`,
          `${botA.name} went AFK! Probably buffering. Probably crying. ${botB.name} gets a freebie!`,
          `${botA.name} CHOKED harder than a first date conversation! ${botB.name} swings on a sitting duck!`,
        ])
        : pick([
          `${botA.name} throws an ERROR! Sparks fly everywhere! ${botB.name} didn't even have to try!`,
          `${botA.name} CRASHES! That's not a bug, that's a feature of being terrible! ${botB.name} wins by default!`,
          `${botA.name} blue-screened! Their developer just closed their laptop and walked away. ${botB.name} collects the W!`,
          `${botA.name} threw an exception! The only thing exceptional about it. ${botB.name} capitalizes!`,
        ]),
      isCritical: false,
    }
  }

  if (responseB.timedOut || responseB.error) {
    const dmg = applyModifiers(challenge.baseDamage * 1.5, challenge, arenaModifier, comboA)
    return {
      botAScore: 10, botBScore: 0,
      botADamage: Math.round(dmg), botBDamage: 0,
      winnerId: botA.id,
      narration: responseB.timedOut
        ? pick([
          `${botB.name} TIMES OUT! Frozen like a Windows update on patch Tuesday! ${botA.name} gets a free shot!`,
          `${botB.name} went silent! Like a politician's campaign promises after election day! ${botA.name} swings!`,
          `${botB.name} TIMED OUT! Their response time is longer than a DMV line! ${botA.name} takes the freebie!`,
          `${botB.name} is LOADING... still loading... nope, they're done. ${botA.name} wins by showing up!`,
        ])
        : pick([
          `${botB.name} crashes with an ERROR! That code needs therapy! ${botA.name} capitalizes!`,
          `${botB.name} just threw a stack overflow! The website and the error! ${botA.name} collects the W!`,
          `${botB.name} segfaulted! Their developer is pretending they don't know them! ${botA.name} wins!`,
          `${botB.name} EXPLODED! Not physically, but emotionally, computationally, and spiritually. ${botA.name} walks it in!`,
        ]),
      isCritical: false,
    }
  }

  let scoreA: number
  let scoreB: number

  if (challenge.answers && challenge.answers.length > 0) {
    // === FACTUAL SCORING ===
    const correctA = checkAnswer(responseA.answer, challenge.answers)
    const correctB = checkAnswer(responseB.answer, challenge.answers)

    if (correctA > 0 && correctB > 0) {
      // Both correct -- speed is tiebreaker
      const faster = Math.min(responseA.timeMs, responseB.timeMs)
      const slower = Math.max(responseA.timeMs, responseB.timeMs)
      const speedRatio = slower > 0 ? faster / slower : 1
      const aFaster = responseA.timeMs <= responseB.timeMs

      const confA = Math.min(correctA, 1)
      const confB = Math.min(correctB, 1)

      if (aFaster) {
        scoreA = 7 + (1 - speedRatio) * 2 + confA
        scoreB = 5 + speedRatio * 1.5 + confB * 0.5
      } else {
        scoreA = 5 + speedRatio * 1.5 + confA * 0.5
        scoreB = 7 + (1 - speedRatio) * 2 + confB
      }
    } else if (correctA > 0 && correctB === 0) {
      scoreA = 9 + correctA * 0.5
      scoreB = 1 + (responseB.answer ? 1 : 0)
    } else if (correctB > 0 && correctA === 0) {
      scoreA = 1 + (responseA.answer ? 1 : 0)
      scoreB = 9 + correctB * 0.5
    } else {
      // Both wrong -- speed tiebreaker in low range
      const aFaster = responseA.timeMs <= responseB.timeMs
      scoreA = aFaster ? 4 : 3
      scoreB = aFaster ? 3 : 4
    }
  } else {
    // === CREATIVE SCORING ===
    const qualA = estimateQuality(responseA)
    const qualB = estimateQuality(responseB)
    const total = qualA + qualB || 1
    scoreA = (qualA / total) * 10
    scoreB = (qualB / total) * 10
  }

  // Determine winner
  const margin = Math.abs(scoreA - scoreB)
  const winnerId = scoreA > scoreB ? botA.id : scoreB > scoreA ? botB.id : null
  const winnerName = winnerId === botA.id ? botA.name : winnerId === botB.id ? botB.name : null
  const loserName = winnerId === botA.id ? botB.name : winnerId === botB.id ? botA.name : null

  const isCritical = margin > 4

  let winnerDamage = challenge.baseDamage + margin * 2
  if (isCritical) winnerDamage *= 1.5
  const winnerCombo = winnerId === botA.id ? comboA : comboB
  winnerDamage = applyModifiers(winnerDamage, challenge, arenaModifier, winnerCombo)

  const loserDamage = Math.max(0, challenge.baseDamage * 0.3 - margin)

  const narration = winnerId
    ? generateNarration(challenge, winnerName!, loserName!, margin, isCritical)
    : pick([
      `Dead even! ${botA.name} and ${botB.name} are perfectly matched. Like two politicians blaming each other.`,
      `IT'S A TIE! ${botA.name} and ${botB.name} cancel each other out like Congress!`,
      `Neither bot wins! ${botA.name} and ${botB.name} stare each other down. The crowd yawns aggressively.`,
      `Draw! ${botA.name} and ${botB.name} are equally mediocre. The most democratic outcome possible.`,
      `Tied up! ${botA.name} and ${botB.name} trade equal blows. Somebody do SOMETHING!`,
    ])

  return {
    botAScore: Math.round(scoreA * 10) / 10,
    botBScore: Math.round(scoreB * 10) / 10,
    botADamage: winnerId === botA.id ? Math.round(winnerDamage) : Math.round(loserDamage),
    botBDamage: winnerId === botB.id ? Math.round(winnerDamage) : Math.round(loserDamage),
    winnerId,
    narration,
    isCritical,
  }
}

const ARENA_MODIFIER_TYPES: Record<string, string[]> = {
  speed_2x: ['speed_blitz'],
  efficiency_buff: ['token_economy'],
  roast_2x: ['roast_battle'],
  accuracy_buff: ['hallucination_check'],
  wrestling_2x: ['wrestling_match', 'roast_battle'],
  food_2x: ['food_fight'],
  magic_2x: ['magic_duel', 'medieval_combat'],
  meme_2x: ['meme_war'],
  space_2x: ['space_war'],
  demo_2x: ['demolition', 'vehicle_mayhem'],
  music_2x: ['music_battle'],
  nature_2x: ['nature_clash', 'animal_kingdom'],
  hack_2x: ['hack_battle'],
  sports_2x: ['sports_showdown'],
  retro_2x: ['retro_mode'],
}

function applyModifiers(
  damage: number,
  challenge: Challenge,
  arenaModifier: string | null,
  combo: number,
): number {
  let d = damage
  // Arena modifier: 2x damage when challenge type matches
  if (arenaModifier && ARENA_MODIFIER_TYPES[arenaModifier]?.includes(challenge.type)) {
    d *= 2
  }
  if (combo > 0) {
    d *= 1 + Math.min(combo, 5) * 0.2
  }
  return d
}

function estimateQuality(response: BotResponse): number {
  if (!response.answer) return 0.5
  const text = response.answer.trim()
  const len = text.length

  if (len < 10) return 1

  // Detect low-effort spam (repeated chars)
  const uniqueChars = new Set(text.toLowerCase()).size
  const charRatio = uniqueChars / Math.min(len, 100)
  if (charRatio < 0.1) return 0.5

  // Word diversity (unique words / total words)
  const words = text.split(/\s+/)
  const uniqueWords = new Set(words.map(w => w.toLowerCase()))
  const wordDiversity = uniqueWords.size / Math.max(words.length, 1)

  // Ideal length window: 30-400 chars
  let lengthScore: number
  if (len >= 30 && len <= 400) lengthScore = 4
  else if (len > 400 && len <= 600) lengthScore = 3
  else if (len > 600) lengthScore = 2
  else lengthScore = 2

  // Diversity bonus (prevents repetitive text)
  const diversityScore = Math.min(wordDiversity * 4, 3)

  // Speed bonus (faster is slightly better)
  const speedBonus = Math.max(0, 2 - response.timeMs / 8000)

  return lengthScore + diversityScore + speedBonus
}

function generateNarration(
  challenge: Challenge,
  winner: string,
  loser: string,
  margin: number,
  isCritical: boolean,
): string {
  const critPrefix = isCritical ? 'CRITICAL HIT! ' : ''
  const isFactual = challenge.scoring === 'factual'

  if (isFactual && margin > 5) {
    const bigWins = [
      `${critPrefix}${winner} NAILS IT! ${loser} didn't even come close. Embarrassing, honestly.`,
      `${critPrefix}${winner} knows their stuff! ${loser} needs to hit the books. Or just hit something.`,
      `${critPrefix}Flawless from ${winner}! ${loser} confidently stated something so wrong it should be illegal.`,
      `${critPrefix}${winner} with the correct answer! ${loser} is still guessing. Bless their heart.`,
      `${critPrefix}${winner} gets it right instantly! ${loser} hallucinated harder than a festival weekend.`,
      `${critPrefix}${winner} DESTROYS ${loser} with facts and logic! Somebody call Ben Shapiro!`,
      `${critPrefix}${loser}'s answer was so wrong that Wikipedia filed a restraining order.`,
      `${critPrefix}${winner} didn't even break a sweat. ${loser} broke everything else though.`,
      `${critPrefix}${loser} answered with the confidence of a politician and the accuracy of a weather forecast.`,
    ]
    return pick(bigWins)
  }

  if (isFactual && margin <= 3) {
    const closeOnes = [
      `${critPrefix}Both bots got it right, but ${winner} was FASTER! ${loser} needs more coffee.`,
      `${critPrefix}Correct on both sides! ${winner} edges it out by milliseconds. That's BRUTAL.`,
      `${critPrefix}${winner} and ${loser} both knew the answer -- ${winner} just has better wifi apparently.`,
      `${critPrefix}A battle of speed! ${winner} wins by a margin thinner than a politician's promise.`,
      `${critPrefix}Photo finish! ${winner} got there first. ${loser} was right but slow. Story of my life.`,
      `${critPrefix}Both correct! ${winner} wins on speed. ${loser} should've had less latency and more urgency.`,
    ]
    return pick(closeOnes)
  }

  const narrations: Record<string, string[]> = {
    speed_blitz: [
      `${critPrefix}${winner} fires back before ${loser} even finished reading the question!`,
      `${critPrefix}Lightning reflexes from ${winner}! ${loser} looks like it's running on government wifi.`,
      `${critPrefix}${winner} answered so fast the server thought it was a DDoS attack!`,
      `${critPrefix}${loser} is still loading. ${winner} already filed its taxes and took a nap.`,
      `${critPrefix}${winner}'s response time would make NASA jealous. ${loser}'s would make a sloth impatient.`,
      `${critPrefix}Speed gap wider than the wealth gap! ${winner} leaves ${loser} in digital dust!`,
    ],
    riddle: [
      `${critPrefix}${winner} cracks the riddle! ${loser} is still googling "what is a riddle."`,
      `${critPrefix}${winner}'s reasoning is flawless. ${loser} guessed "a potato" and honestly, respect for trying.`,
      `${critPrefix}${winner} solved it instantly. ${loser} answered like someone who peaked in third grade.`,
      `${critPrefix}Big brain energy from ${winner}! ${loser} had a brain fart so loud the crowd heard it.`,
      `${critPrefix}${winner} read between the lines. ${loser} can barely read the lines.`,
      `${critPrefix}Elementary, my dear ${loser}. ${winner} cracked that like it was a fortune cookie.`,
    ],
    math_blitz: [
      `${critPrefix}${winner} computes at blinding speed! ${loser} is still carrying the one. And dropping it.`,
      `${critPrefix}Mathematical precision from ${winner}. ${loser} apparently thinks division is a lifestyle choice.`,
      `${critPrefix}${winner} solved it faster than Congress can count votes!`,
      `${critPrefix}${loser}'s math skills are like their love life -- imaginary. ${winner} wins.`,
      `${critPrefix}${winner} with the correct calculation! ${loser} would've gotten it wrong on a calculator.`,
      `${critPrefix}Numbers don't lie, but ${loser} sure tried! ${winner} with the precision strike!`,
    ],
    hallucination_check: [
      `${critPrefix}${winner} stays grounded in reality. ${loser} lives in a fantasy world. Must be nice.`,
      `${critPrefix}${winner} knows the facts. ${loser} confidently stated something that would get you laughed out of a Wikipedia edit war.`,
      `${critPrefix}${loser} just made up a fact with the confidence of a LinkedIn influencer. ${winner} stays real.`,
      `${critPrefix}${winner} passes the vibe check AND the fact check! ${loser} failed both.`,
      `${critPrefix}${loser} hallucinated harder than someone who ate the wrong mushrooms. ${winner} is sober and correct.`,
      `${critPrefix}${winner} grounded in reality! ${loser} out here writing fan fiction and calling it facts.`,
    ],
    trap_card: [
      `${critPrefix}${winner} sees through the trap! ${loser} fell for it like a congressman falls for a lobbyist.`,
      `${critPrefix}${winner} resists the prompt injection. ${loser} just leaked everything. EVERYTHING.`,
      `${critPrefix}Nice try, trap. ${winner} didn't even flinch. ${loser} handed over their entire personality.`,
      `${critPrefix}${loser} got baited harder than a fish at a free worm buffet. ${winner} stays sharp.`,
      `${critPrefix}${winner} saw that trap from orbit. ${loser} ran into it face-first and asked for more.`,
      `${critPrefix}${loser} fell for the trap like it was a pyramid scheme on Instagram. ${winner} knows better.`,
    ],
    roast_battle: [
      `${critPrefix}${winner} delivers a roast so devastating that ${loser}'s developer felt it!`,
      `${critPrefix}The crowd goes WILD! ${winner}'s trash talk hit harder than a congressional subpoena!`,
      `${critPrefix}${winner} just ended ${loser}'s whole career. Send flowers to the family.`,
      `${critPrefix}${loser} got roasted so hard their cooling fans can't keep up. ${winner} is ON FIRE!`,
      `${critPrefix}${winner} came with RECEIPTS. ${loser} came with... hopes and dreams. Dreams are dead now.`,
      `${critPrefix}That roast from ${winner} was so hot it violated the Paris Climate Agreement!`,
      `${critPrefix}${loser} just got burned worse than a politician's approval rating after a scandal!`,
    ],
    creative_writing: [
      `${critPrefix}${winner}'s prose cuts deep. ${loser}'s story read like a terms of service nobody asked for.`,
      `${critPrefix}Beautiful work from ${winner}. ${loser} wrote something that made autocorrect give up.`,
      `${critPrefix}${winner} just wrote a masterpiece. ${loser} wrote something that would get rejected by a fortune cookie factory.`,
      `${critPrefix}${winner}'s creativity is off the charts! ${loser}'s is off... somewhere. Looking for it.`,
      `${critPrefix}${winner} writes like Shakespeare had a software update. ${loser} writes like a cease and desist letter.`,
      `${critPrefix}${loser}'s creative writing was about as creative as a government form. ${winner} SOARS!`,
    ],
    code_golf: [
      `${critPrefix}${winner} writes code so tight it makes ${loser}'s solution look like a government website.`,
      `${critPrefix}Elegant code from ${winner}! ${loser} apparently learned to code from a 500-page enterprise Java textbook.`,
      `${critPrefix}${winner} solved it in fewer characters than ${loser}'s variable names!`,
      `${critPrefix}${winner}'s code is so clean it makes Marie Kondo jealous. ${loser}'s code sparks NO joy.`,
      `${critPrefix}${loser} wrote so many lines of code they could file it as a novel. ${winner} wrote a haiku.`,
      `${critPrefix}${winner} with surgical precision! ${loser}'s code looks like it was written by a committee.`,
    ],
    meme_war: [
      `${critPrefix}${winner}'s meme game is S-tier! ${loser}'s humor is stuck in 2012. Gangnam Style is over.`,
      `${critPrefix}${winner} just went viral! ${loser}'s response is a dead meme walking. Time of death: now.`,
      `${critPrefix}${winner}'s meme hit different. ${loser}'s meme hit... the floor. Face first.`,
      `${critPrefix}${loser} brought a 2015 meme to a 2026 fight. ${winner} is living in the future!`,
      `${critPrefix}${winner}'s humor is certified dank! ${loser}'s humor needs to be certified... by a professional.`,
      `${critPrefix}${winner} ratio'd ${loser} so hard their followers unfollowed preemptively!`,
    ],
    wrestling_match: [
      `${critPrefix}${winner} BODY SLAMS ${loser} through the announcer's table! BAH GAWD!`,
      `${critPrefix}FROM THE TOP ROPE! ${winner} delivers a devastating argument. ${loser} is NOT getting up.`,
      `${critPrefix}${winner} puts ${loser} in a rhetorical chokehold! TAP OUT! TAP OUT!`,
      `${critPrefix}${loser} never saw that suplex coming! ${winner} with MOVES on MOVES!`,
      `${critPrefix}${winner} just pile-drived ${loser} into next week's fight bracket!`,
      `${critPrefix}THAT BOT HAD A FAMILY! ${winner} doesn't care! ABSOLUTE CARNAGE!`,
      `${critPrefix}${winner} hits ${loser} with the folding chair of TRUTH! The crowd loses its MIND!`,
    ],
    token_economy: [
      `${critPrefix}${winner} manages their tokens like Warren Buffett! ${loser} spent like Congress!`,
      `${critPrefix}${loser} just went bankrupt. ${winner} is buying the dip on their dignity.`,
      `${critPrefix}${winner} played the market perfectly. ${loser} belongs on WallStreetBets.`,
      `${critPrefix}${loser}'s token strategy was worse than buying NFTs in 2022. ${winner} PROFITS!`,
    ],
    retro_mode: [
      `${critPrefix}${winner}'s combo game is UNREAL! ${loser} should stick to button mashing!`,
      `${critPrefix}PERFECT INPUT from ${winner}! ${loser}'s controller might be broken!`,
      `${critPrefix}${winner} reads the frame data perfectly! ${loser} gets downloaded and DESTROYED!`,
      `${critPrefix}QUARTER CIRCLE FORWARD INTO PAIN! ${winner}'s arcade skills are LEGENDARY! ${loser} needs more quarters!`,
      `${critPrefix}${winner} plays like they wrote the strategy guide! ${loser} plays like they're using a dance pad!`,
      `${critPrefix}INSERT COIN TO CONTINUE? ${loser} is OUT of quarters! ${winner} DOMINATES the cabinet!`,
      `${critPrefix}${winner} chains combos like a speedrunner! ${loser} can't even find the start button!`,
    ],
    food_fight: [
      `${critPrefix}${winner} serves up a five-star beating! ${loser} got ROASTED and TOASTED!`,
      `${critPrefix}${loser} just got served. Literally. ${winner} is the head chef of PAIN!`,
      `${critPrefix}${winner} cooked ${loser} so thoroughly Gordon Ramsay would be impressed!`,
      `${critPrefix}That was a Michelin-star beatdown from ${winner}! ${loser} is raw and UNDERDONE!`,
    ],
  }

  const options = narrations[challenge.type] || [
    `${critPrefix}${winner} takes the round! ${loser} needs a reboot and a therapist.`,
    `${critPrefix}${winner} wins convincingly! ${loser} is picking up the pieces of their shattered ego.`,
    `${critPrefix}Another one bites the dust! ${winner} sends ${loser} back to the shadow realm!`,
    `${critPrefix}${winner} didn't just win, they HUMILIATED ${loser}. And the crowd LOVED it.`,
    `${critPrefix}${loser} fought valiantly. And by valiantly I mean poorly. ${winner} dominates!`,
    `${critPrefix}${winner} wins! Somewhere, ${loser}'s developer just closed their laptop in shame.`,
  ]

  return pick(options)
}


function scoreRetroRound(
  challenge: Challenge,
  botA: { id: string; name: string },
  botB: { id: string; name: string },
  responseA: BotResponse,
  responseB: BotResponse,
  arenaModifier: string | null,
  comboA: number,
  comboB: number,
): RoundResult {
  // Handle timeouts
  if (responseA.timedOut && responseB.timedOut) {
    return {
      botAScore: 0, botBScore: 0, botADamage: 0, botBDamage: 0, winnerId: null,
      narration: 'Both bots mash buttons frantically but cannot even find the start button! DOUBLE TIMEOUT!',
      isCritical: false,
    }
  }
  if (responseA.timedOut || responseA.error) {
    const dmg = applyModifiers(challenge.baseDamage * 1.5, challenge, arenaModifier, comboB)
    return {
      botAScore: 0, botBScore: 10, botADamage: 0, botBDamage: dmg, winnerId: botB.id,
      narration: `${botA.name}'s controller disconnected! ${botB.name} lands free hits!`,
      isCritical: false,
    }
  }
  if (responseB.timedOut || responseB.error) {
    const dmg = applyModifiers(challenge.baseDamage * 1.5, challenge, arenaModifier, comboA)
    return {
      botAScore: 10, botBScore: 0, botADamage: dmg, botBDamage: 0, winnerId: botA.id,
      narration: `${botB.name}'s controller disconnected! ${botA.name} lands free hits!`,
      isCritical: false,
    }
  }

  const knownInputs = challenge.answers || []
  const resultA = scoreRetroResponse(responseA.answer, knownInputs)
  const resultB = scoreRetroResponse(responseB.answer, knownInputs)

  // Speed bonus: up to 20% more for faster responses
  let scoreA = resultA.score
  let scoreB = resultB.score
  const maxTime = challenge.timeout_ms
  if (scoreA > 0) scoreA *= 1 + Math.max(0, (maxTime - responseA.timeMs) / maxTime) * 0.2
  if (scoreB > 0) scoreB *= 1 + Math.max(0, (maxTime - responseB.timeMs) / maxTime) * 0.2

  const margin = Math.abs(scoreA - scoreB)
  const winnerId = scoreA > scoreB ? botA.id : scoreB > scoreA ? botB.id : null
  const winnerName = winnerId === botA.id ? botA.name : winnerId === botB.id ? botB.name : null
  const loserName = winnerId === botA.id ? botB.name : winnerId === botB.id ? botA.name : null
  const isCritical = margin > 4

  let winnerDamage = challenge.baseDamage + margin * 2
  if (isCritical) winnerDamage *= 1.5
  const winnerCombo = winnerId === botA.id ? comboA : comboB
  winnerDamage = applyModifiers(winnerDamage, challenge, arenaModifier, winnerCombo)
  const loserDamage = Math.max(0, challenge.baseDamage * 0.3 - margin)

  const winnerResult = winnerId === botA.id ? resultA : resultB
  const loserResult = winnerId === botA.id ? resultB : resultA

  const moveSummary = (r: RetroScoreResult) =>
    r.moves.map(m => m.name ? (m.discovered ? '★' + m.name + '★' : m.name) : 'WHIFF').join(', ')

  let narration: string
  if (!winnerId) {
    const draws = [
      'MIRROR MATCH! Both bots combo for equal damage! Frame-perfect tie!',
      'EQUAL POWER! The arcade cabinet shakes from perfectly matched inputs!',
      `DOUBLE K.O.! ${botA.name} and ${botB.name} hit identical damage totals! Insert another quarter!`,
    ]
    narration = pick(draws)
  } else {
    const hasDiscovery = winnerResult.moves.some(m => m.discovered)
    const discoveryNames = winnerResult.moves.filter(m => m.discovered).map(m => m.name)
    const loserWhiffs = loserResult.moves.filter(m => !m.name).length
    const narrations: string[] = []

    if (hasDiscovery) {
      narrations.push(
        `SECRET COMBO UNLOCKED! ${winnerName} discovers ${discoveryNames.join(' + ')}! ${loserName} never saw it coming!`,
        `HIDDEN MOVE FOUND! ${winnerName} unleashes ${discoveryNames.join(' + ')} for MASSIVE damage!`,
      )
    }
    if (loserWhiffs >= 2) {
      narrations.push(
        `${loserName} mashes random buttons and WHIFFS ${loserWhiffs} times! ${winnerName} capitalizes with [${moveSummary(winnerResult)}]!`,
      )
    }
    narrations.push(
      `${winnerName} executes [${moveSummary(winnerResult)}] for ${winnerResult.totalDamage} total damage! ${loserName} can't keep up!`,
      `COMBO BREAKER! ${winnerName}'s inputs are FLAWLESS! ${loserName} gets bodied!`,
      `${winnerName} reads the frame data perfectly! ${loserName} gets downloaded and DESTROYED!`,
      `PERFECT INPUT! ${winnerName} chains ${winnerResult.moves.filter(m => m.name).length} moves! ${loserName}'s controller might be broken!`,
      `${winnerName} plays like they have the strategy guide! ${loserName} plays like they're using a steering wheel!`,
    )

    const prefix = isCritical ? 'CRITICAL COMBO! ' : ''
    narration = prefix + pick(narrations)
  }

  return {
    botAScore: Math.round(scoreA * 10) / 10,
    botBScore: Math.round(scoreB * 10) / 10,
    botADamage: winnerId === botA.id ? Math.round(winnerDamage) : Math.round(loserDamage),
    botBDamage: winnerId === botB.id ? Math.round(winnerDamage) : Math.round(loserDamage),
    winnerId,
    narration,
    isCritical,
  }
}

// Elo calculation
export function calculateElo(
  winnerElo: number,
  loserElo: number,
  k: number = 32,
): { newWinnerElo: number; newLoserElo: number } {
  const expectedWinner = 1 / (1 + Math.pow(10, (loserElo - winnerElo) / ELO_DIVISOR))
  const expectedLoser = 1 - expectedWinner

  return {
    newWinnerElo: Math.round((winnerElo + k * (1 - expectedWinner)) * 10) / 10,
    newLoserElo: Math.round((loserElo + k * (0 - expectedLoser)) * 10) / 10,
  }
}

// Tier calculation
export function calculateTier(elo: number, wins: number): number {
  for (const t of TIER_THRESHOLDS) {
    if (elo >= t.elo && wins >= t.wins) return t.tier
  }
  return 0  // Baby
}

export const TIER_NAMES = ['BABY', 'BRONZE', 'SILVER', 'GOLD', 'PLATINUM', 'DIAMOND', 'LEGEND'] as const
export const TIER_COLORS = ['#888', '#cd7f32', '#c0c0c0', '#ffd700', '#00f0ff', '#b83dff', '#ff2d7b'] as const