import { CombatTest, Stat, Vigor, Stats, StatToVigor, VoreStats, VoreStat } from '../combat'
import { Creature } from "../creature"
import { LogEntry, LogLines, PropElem, LogLine, nilLog } from '../interface'
import { Verb } from '../language'

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

/**
 * A [[Scorer]] produces a score for a creature in a certain situation.
 *
 * It takes the current score and returns a new one.
 */
export interface Scorer {
  userScore (attacker: Creature, score: number): number;
  targetScore (defender: Creature, score: number): number;
  explain(user: Creature, target: Creature): LogEntry;
}

export class OpposedStatScorer implements Scorer {
  private maxStatVigorPenalty = 0.5
  private maxTotalVigorPenalty = 0.1

  constructor (private userStats: Partial<Stats & VoreStats>, private targetStats: Partial<Stats & VoreStats>) {

  }

  explain (user: Creature, target: Creature): LogEntry {
    return new LogLines(
      new LogLine(
        `Pits `,
        ...Object.entries(this.userStats).map(([stat, frac]) => {
          if (frac !== undefined) {
            return new LogLine(`${(frac * 100).toFixed(0)}% `, new PropElem(stat as Stat))
          } else {
            return nilLog
          }
        }),
        ` against `,
        ...Object.entries(this.targetStats).map(([stat, frac]) => {
          if (frac !== undefined) {
            return new LogLine(`${(frac * 100).toFixed(0)}% `, new PropElem(stat as Stat))
          } else {
            return nilLog
          }
        })
      ),
      new LogLine(
        `Score delta: ${(this.computeScore(user, this.userStats) - this.computeScore(target, this.targetStats)).toFixed(1)}`
      )
    )
  }

  userScore (attacker: Creature, score: number): number {
    return score + this.computeScore(attacker, this.userStats)
  }

  targetScore (defender: Creature, score: number): number {
    return score + this.computeScore(defender, this.targetStats)
  }

  private computeScore (subject: Creature, parts: Partial<Stats & VoreStats>): number {
    const total = Object.entries(parts).reduce((total: number, [stat, frac]) => {
      if (stat in Stat) {
        let value = subject.stats[stat as Stat] * (frac === undefined ? 0 : frac)

        const vigor = StatToVigor[stat as Stat]
        value = value * (1 - this.maxStatVigorPenalty) + value * this.maxStatVigorPenalty * subject.vigors[vigor] / subject.maxVigors[vigor]

        return total + value
      } else if (stat in VoreStat) {
        const value = subject.voreStats[stat as VoreStat] * (frac === undefined ? 0 : frac)

        return total + value
      } else {
        return total
      }
    }, 0)

    const modifiedTotal = Object.keys(Vigor).reduce(
      (total, vigor) => {
        const base = total * (1 - this.maxTotalVigorPenalty)
        const modified = total * this.maxTotalVigorPenalty * subject.vigors[vigor as Vigor] / subject.maxVigors[vigor as Vigor]
        return base + modified
      },
      total
    )

    return modifiedTotal
  }
}

// TODO this will need to be able to return a LogEntry at some point

abstract class RandomTest implements CombatTest {
  constructor (public fail: (user: Creature, target: Creature) => LogEntry) {

  }

  test (user: Creature, target: Creature): boolean {
    const userFail = user.effects.map(effect => effect.failTest(user, target))
    if (userFail.some(result => result.failed)) {
      return false
    }
    const targetFail = target.effects.map(effect => effect.failTest(target, user))
    if (targetFail.some(result => result.failed)) {
      return true
    }

    return Math.random() < this.odds(user, target)
  }

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

export enum TestCategory {
  Attack = "Attack",
  Vore = "Vore"
}

export class CompositionTest extends RandomTest {
  private f: (x: number) => number
  private k = 0.1

  constructor (
    private scorers: Scorer[],
    fail: (user: Creature, target: Creature) => LogEntry,
    public category: TestCategory,
    private bias = 0
  ) {
    super(fail)
    this.f = logistic(0, 1, this.k)
  }

  explain (user: Creature, target: Creature): LogEntry {
    return new LogLines(
      ...this.scorers.map(scorer => scorer.explain(user, target))
    )
  }

  odds (user: Creature, target: Creature): number {
    const userScore = this.scorers.reduce((score, scorer) => scorer.userScore(user, score), 0)
    const targetScore = this.scorers.reduce((score, scorer) => scorer.targetScore(target, score), 0)

    const userMod = user.effects.reduce((score, effect) => score + effect.modTestOffense(user, target, this.category), 0)
    const targetMod = target.effects.reduce((score, effect) => score + effect.modTestDefense(target, user, this.category), 0)

    return this.f(userScore - targetScore + this.bias)
  }
}

export class OpposedStatTest extends RandomTest {
  private f: (x: number) => number
  private k = 0.1

  // how much a stat can be reduced by its corresponding vigor being low
  private maxStatVigorPenalty = 0.5

  // how much the total score can be reduced by each vigor being low
  private maxTotalVigorPenalty = 0.1

  constructor (
    public readonly userStats: Partial<Stats & VoreStats>,
    public readonly targetStats: Partial<Stats & VoreStats>,
    fail: (user: Creature, target: Creature) => LogEntry,
    public category: TestCategory,
    private bias = 0
  ) {
    super(fail)
    this.f = logistic(0, 1, this.k)
  }

  odds (user: Creature, target: Creature): number {
    const userScore = this.getScoreOffense(user, target, this.userStats)
    const targetScore = this.getScoreDefense(target, user, this.targetStats)

    return this.f(userScore - targetScore + this.bias)
  }

  explain (user: Creature, target: Creature): LogEntry {
    return new LogLines(
      new LogLine(
        `Pits `,
        ...Object.entries(this.userStats).map(([stat, frac]) => {
          if (frac !== undefined) {
            return new LogLine(`${(frac * 100).toFixed(0)}% of `, new PropElem(stat as Stat), `, `)
          } else {
            return nilLog
          }
        }),
        ` against `,
        ...Object.entries(this.targetStats).map(([stat, frac]) => {
          if (frac !== undefined) {
            return new LogLine(`${(frac * 100).toFixed(0)}% of `, new PropElem(stat as Stat), `, `)
          } else {
            return nilLog
          }
        })
      ),
      new LogLine(
        `${user.name.capital}: ${this.getScoreOffense(user, target, this.userStats)} // ${this.getScoreDefense(target, user, this.targetStats)} :${target.name.capital}`
      ),
      new LogLine(
        `${user.name.capital} ${user.name.conjugate(new Verb("have", "has"))} a ${(this.odds(user, target) * 100).toFixed(0)}% chance of winning this test.`
      )
    )
  }

  private getScoreDefense (defender: Creature, attacker: Creature, parts: Partial<Stats>): number {
    return this.getScore(defender, parts) + defender.effects.reduce((total, effect) => total + effect.modTestDefense(defender, attacker, this.category), 0)
  }

  private getScoreOffense (attacker: Creature, defender: Creature, parts: Partial<Stats>): number {
    return this.getScore(attacker, parts) + attacker.effects.reduce((total, effect) => total + effect.modTestOffense(attacker, defender, this.category), 0)
  }

  private getScore (actor: Creature, parts: Partial<Stats>): number {
    const total = Object.entries(parts).reduce((total: number, [stat, frac]) => {
      if (stat in Stat) {
        let value = actor.stats[stat as Stat] * (frac === undefined ? 0 : frac)

        const vigor = StatToVigor[stat as Stat]
        value = value * (1 - this.maxStatVigorPenalty) + value * this.maxStatVigorPenalty * actor.vigors[vigor] / actor.maxVigors[vigor]

        return total + value
      } else if (stat in VoreStat) {
        const value = actor.voreStats[stat as VoreStat] * (frac === undefined ? 0 : frac)

        return total + value
      } else {
        return total
      }
    }, 0)

    const modifiedTotal = Object.keys(Vigor).reduce(
      (total, vigor) => {
        return total * (1 - this.maxStatVigorPenalty) + total * this.maxStatVigorPenalty * actor.vigors[vigor as Vigor] / actor.maxVigors[vigor as Vigor]
      },
      total
    )

    return modifiedTotal
  }
}

export class StatVigorSizeTest extends RandomTest {
  private f: (x: number) => number
  private k = 0.1

  constructor (public readonly stat: Stat, private bias = 0, fail: (user: Creature, target: Creature) => LogEntry) {
    super(fail)
    this.f = logistic(0, 1, this.k)
  }

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

    Object.keys(Vigor).forEach(key => {
      userPercent *= user.vigors[key as Vigor] / Math.max(1, user.maxVigors[key as Vigor])
      targetPercent *= target.vigors[key as Vigor] / Math.max(1, 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 sizeOffset = Math.log2(user.voreStats.Mass / target.voreStats.Mass)

    return this.f(this.bias + sizeOffset * 5 + 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 sizeOffset = Math.log2(user.voreStats.Mass / target.voreStats.Mass)

    const userMod = user.stats[this.stat] * userPercent
    const targetMod = target.stats[this.stat] * targetPercent
    const delta = userMod - targetMod + sizeOffset * 5

    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 StatVigorTest extends RandomTest {
  private f: (x: number) => number
  private k = 0.1

  constructor (public readonly stat: Stat, private bias = 0, fail: (user: Creature, target: Creature) => LogEntry) {
    super(fail)
    this.f = logistic(0, 1, this.k)
  }

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

    Object.keys(Vigor).forEach(key => {
      userPercent *= user.vigors[key as Vigor] / Math.max(1, user.maxVigors[key as Vigor])
      targetPercent *= target.vigors[key as Vigor] / Math.max(1, 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
    }

    return this.f(this.bias + 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
  private k = 0.1

  constructor (public readonly stat: Stat, private bias = 0, fail: (user: Creature, target: Creature) => LogEntry) {
    super(fail)
    this.f = logistic(0, 1, this.k)
  }

  odds (user: Creature, target: Creature): number {
    return this.f(this.bias + 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, fail: (user: Creature, target: Creature) => LogEntry) {
    super(fail)
  }

  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.')
  }
}