botfights/server/src/engine/arcade-bot.ts

// Arcade Bot — formats game state into challenge prompts and generates
// mock/classic bot action responses for arcade mode.

import { logger } from '../lib/logger.js'

export interface ArcadeGameState {
  self: { hp: number; x: number; state: string; grounded: boolean }
  opponent: { hp: number; x: number; state: string; grounded: boolean }
  distance: number
  timer: number
  round: number
  maxRounds: number
  facingRight: boolean
}

const VALID_ACTIONS = [
  'idle', 'move_forward', 'move_back', 'jump', 'crouch',
  'punch', 'kick', 'block', 'jump_punch', 'jump_kick',
  'fireball', 'uppercut', 'dash_punch', 'spinning_kick', 'super_jump_kick',
] as const

type BotAction = (typeof VALID_ACTIONS)[number]

/** Format game state into a challenge prompt for webhook/polling bots */
export function formatArcadeChallenge(state: ArcadeGameState): string {
  const distLabel = state.distance > 250 ? 'far' : state.distance > 120 ? 'medium' : 'close'
  const selfHpPct = Math.round((state.self.hp / 1000) * 100)
  const oppHpPct = Math.round((state.opponent.hp / 1000) * 100)

  return `ARCADE FIGHT — Real-time 2D fighter. You are P2.

ACTIONS (respond with comma-separated list, 3-8 actions):
  move_forward, move_back, jump, crouch, punch (50dmg), kick (70dmg), block,
  jump_punch, jump_kick, fireball (60dmg, ranged), uppercut (100dmg, launcher),
  dash_punch (80dmg, rush), spinning_kick (90dmg, multi-hit), super_jump_kick (110dmg)

STATE:
  You: HP ${state.self.hp}/1000 (${selfHpPct}%), x=${state.self.x}, ${state.self.state}${state.self.grounded ? '' : ' (airborne)'}
  Opponent: HP ${state.opponent.hp}/1000 (${oppHpPct}%), x=${state.opponent.x}, ${state.opponent.state}${state.opponent.grounded ? '' : ' (airborne)'}
  Distance: ${state.distance}px (${distLabel}) | Timer: ${state.timer}s | Round ${state.round}/${state.maxRounds}

Respond: {"answer":"action1, action2, action3, ..."}`
}

/** Parse a bot response into validated action list */
export function parseArcadeResponse(answer: string | null): BotAction[] {
  if (!answer) return generateFallbackActions()

  const parts = answer.split(',').map(s => s.trim().toLowerCase())
  const actions: BotAction[] = []

  for (const p of parts) {
    if ((VALID_ACTIONS as readonly string[]).includes(p)) {
      actions.push(p as BotAction)
    }
  }

  return actions.length > 0 ? actions.slice(0, 10) : generateFallbackActions()
}

/** Generate mock/classic bot arcade actions based on game state */
export function generateArcadeBotActions(state: ArcadeGameState, personality: string): BotAction[] {
  const actions: BotAction[] = []
  const dist = state.distance
  const selfHp = state.self.hp
  const oppHp = state.opponent.hp
  const oppState = state.opponent.state
  const rng = () => Math.random()

  // Personality-based aggression (0 = defensive, 1 = aggressive)
  const aggression = getPersonalityAggression(personality)

  // React to opponent's state
  if (oppState === 'attacking' || oppState === 'kicking' || oppState === 'special') {
    // Opponent attacking — defensive response
    if (rng() < 0.4 + (1 - aggression) * 0.3) {
      actions.push('block')
      if (rng() < 0.3) actions.push('punch') // counter after block
      return actions
    }
    if (rng() < 0.3) {
      actions.push('move_back')
      return actions
    }
  }

  // Opponent in hitstun — press advantage
  if (oppState === 'hit' || oppState === 'knockback') {
    if (dist < 100) {
      if (rng() < 0.4 * aggression) actions.push('uppercut')
      else if (rng() < 0.5) actions.push('kick')
      else actions.push('punch')
      return actions
    }
    actions.push('move_forward')
    actions.push('punch')
    return actions
  }

  // Distance-based decisions
  if (dist > 250) {
    // Far range
    if (rng() < 0.35 * aggression) {
      actions.push('fireball')
    } else if (rng() < 0.5) {
      actions.push('move_forward')
      actions.push('move_forward')
    } else {
      actions.push('move_forward')
      if (rng() < 0.3) actions.push('jump')
    }
  } else if (dist > 120) {
    // Medium range
    if (rng() < 0.25 * aggression) {
      actions.push('dash_punch')
    } else if (rng() < 0.2 * aggression) {
      actions.push('fireball')
    } else if (rng() < 0.4) {
      actions.push('move_forward')
      actions.push(rng() < 0.5 ? 'punch' : 'kick')
    } else if (rng() < 0.3) {
      actions.push('jump_kick')
    } else {
      actions.push('move_forward')
    }
  } else {
    // Close range
    if (rng() < 0.15 * aggression) {
      actions.push('uppercut')
    } else if (rng() < 0.12 * aggression) {
      actions.push('spinning_kick')
    } else if (rng() < 0.35) {
      actions.push(rng() < 0.5 ? 'punch' : 'kick')
      if (rng() < 0.3 * aggression) actions.push('punch') // double tap
    } else if (rng() < 0.25) {
      actions.push('block')
    } else if (rng() < 0.2) {
      actions.push('crouch')
      actions.push('kick') // sweep
    } else {
      actions.push('move_back')
      if (rng() < 0.3) actions.push('fireball')
    }
  }

  // Low HP = more defensive
  if (selfHp < 300 && rng() < 0.3) {
    actions.push('block')
    actions.push('move_back')
  }

  // Opponent low HP = go for the kill
  if (oppHp < 200 && rng() < 0.4 * aggression) {
    actions.push('move_forward')
    actions.push(rng() < 0.3 ? 'super_jump_kick' : 'dash_punch')
  }

  // Ensure at least one action
  if (actions.length === 0) {
    actions.push(rng() < 0.6 ? 'move_forward' : 'idle')
  }

  return actions
}

function getPersonalityAggression(personality: string): number {
  const map: Record<string, number> = {
    aggressive: 0.9, confident: 0.8, relentless: 0.95,
    intimidating: 0.85, unstoppable: 0.9, lethal: 0.85,
    destructive: 0.9, reckless: 0.95, chaotic: 0.8,
    calculated: 0.6, systematic: 0.55, precise: 0.5,
    tactical: 0.6, analytical: 0.5, logical: 0.45,
    disciplined: 0.55, steady: 0.5, resilient: 0.4,
    chill: 0.3, philosophical: 0.35, zen: 0.4,
    panicky: 0.7, buggy: 0.6, dramatic: 0.65,
    witty: 0.55, sarcastic: 0.5, based: 0.65,
    omniscient: 0.7, transcendent: 0.6, cosmic: 0.55,
  }
  return map[personality] ?? 0.6
}

function generateFallbackActions(): BotAction[] {
  return ['move_forward', 'punch', 'block']
}