feast/src/game/combat/tests.ts

import { CombatTest, Stat, Vigor } from '../combat'
import { Creature } from '../entity'
import { LogEntry, LogLines, PropElem, LogLine } from '../interface'

function logistic (x0: number, L: number, k: number): (x: number) => number {
  return (x: number) => {
    return L / (1 + Math.exp(-k * (x - x0)))
  }
}

abstract class RandomTest implements CombatTest {
  test (user: Creature, target: Creature): boolean {
    return Math.random() < this.odds(user, target)
  }

  abstract odds(user: Creature, target: Creature): number
  abstract explain(user: Creature, target: Creature): LogEntry
}

export class StatVigorTest extends RandomTest {
  private f: (x: number) => number

  constructor (public readonly stat: Stat, k = 0.1) {
    super()
    this.f = logistic(0, 1, k)
  }

  odds (user: Creature, target: Creature): number {
    let userPercent = 1
    let targetPercent = 1

    Object.keys(Vigor).forEach(key => {
      userPercent *= user.vigors[key as Vigor] / user.maxVigors[key as Vigor]
      targetPercent *= target.vigors[key as Vigor] / target.maxVigors[key as Vigor]

      userPercent = Math.max(0, userPercent)
      targetPercent = Math.max(0, targetPercent)
    })

    if (userPercent === 0) {
      targetPercent *= 4
    }

    if (targetPercent === 0) {
      userPercent *= 4
    }

    console.log(userPercent, targetPercent, this.f(user.stats[this.stat] * userPercent - target.stats[this.stat] * targetPercent))
    return this.f(user.stats[this.stat] * userPercent - target.stats[this.stat] * targetPercent)
  }

  explain (user: Creature, target: Creature): LogEntry {
    let result: LogEntry

    let userPercent = 1
    let targetPercent = 1

    Object.keys(Vigor).forEach(key => {
      userPercent *= user.vigors[key as Vigor] / user.maxVigors[key as Vigor]
      targetPercent *= target.vigors[key as Vigor] / target.maxVigors[key as Vigor]

      userPercent = Math.max(0, userPercent)
      targetPercent = Math.max(0, targetPercent)
    })

    if (userPercent === 0) {
      targetPercent *= 4
    }

    if (targetPercent === 0) {
      userPercent *= 4
    }
    const userMod = user.stats[this.stat] * userPercent
    const targetMod = target.stats[this.stat] * targetPercent
    const delta = (userMod - targetMod)

    if (delta === 0) {
      result = new LogLine('You and the target have the same effective', new PropElem(this.stat), '.')
    } else if (delta < 0) {
      result = new LogLine('You effectively have ', new PropElem(this.stat, -delta), ' less than your foe.')
    } else {
      result = new LogLine('You effectively have ', new PropElem(this.stat, delta), ' more than you foe.')
    }

    result = new LogLine(result, 'Your odds of success are ' + (100 * this.odds(user, target)).toFixed(1) + '%')

    return result
  }
}

export class StatTest extends RandomTest {
  private f: (x: number) => number

  constructor (public readonly stat: Stat, k = 0.1) {
    super()
    this.f = logistic(0, 1, k)
  }

  odds (user: Creature, target: Creature): number {
    return this.f(user.stats[this.stat] - target.stats[this.stat])
  }

  explain (user: Creature, target: Creature): LogEntry {
    const delta: number = user.stats[this.stat] - target.stats[this.stat]
    let result: LogEntry

    if (delta === 0) {
      result = new LogLine('You and the target have the same ', new PropElem(this.stat), '.')
    } else if (delta < 0) {
      result = new LogLine('You have ', new PropElem(this.stat, -delta), ' less than your foe.')
    } else {
      result = new LogLine('You have ', new PropElem(this.stat, delta), ' more than you foe.')
    }

    result = new LogLine(result, 'Your odds of success are ' + (100 * this.odds(user, target)).toFixed(1) + '%')

    return result
  }
}

export class ChanceTest extends RandomTest {
  constructor (public readonly chance: number) {
    super()
  }

  odds (user: Creature, target: Creature): number {
    return this.chance
  }

  explain (user: Creature, target: Creature): LogEntry {
    return new LogLine('You have a flat ' + (100 * this.chance) + '% chance.')
  }
}