nerdware/apps/server/src/game/modes/quiz/quiz-round.ts

// Épreuve Quiz : une question = une manche. Pas de DJ, pas d'audio.
// Formats : mcq, truefalse (choix), free (saisie libre, matching tolérant).

import type {
  Answer,
  QuizPerPlayerResult,
  QuizQuestionPayload,
  QuizRevealTruth,
  ScoreDelta,
} from "@nerdware/shared"
import { hasDb } from "../../../db"
import { botCorrectChance } from "../../bot"
import { markQuestionPlayed } from "../../../db/quiz-repo"
import { fuzzyMatch } from "../../match"
import type {
  GameRound,
  RoundContext,
  RoundRecapInfo,
  RoundStart,
} from "../../round"
import type { ServerRoom } from "../../../rooms"
import type { QuizQuestion } from "./questions"
import { takeQuestion } from "./pool"

const BASE_POINTS = 100
const SPEED_BONUS_MAX = 100

/** Données privées de la manche (jamais diffusées). */
interface QuizRoundData {
  question: QuizQuestion
  /** Premier instant de vote par joueur, pour le bonus rapidité. */
  votedAt: Map<string, number>
}

function asChoice(answer: Answer): number | null {
  const v = (answer as { choiceIndex?: unknown }).choiceIndex
  return typeof v === "number" ? v : null
}

function asText(answer: Answer): string | null {
  const v = (answer as { text?: unknown }).text
  return typeof v === "string" ? v : null
}

/** Formats à réponse libre (saisie texte + matching tolérant). */
function isTextFormat(question: QuizQuestion): boolean {
  return question.format === "free" || question.format === "image_reveal"
}

/** Réponse correcte ? Selon le format de la question. */
function isCorrect(question: QuizQuestion, answer: Answer | undefined): boolean {
  if (!answer) {
    return false
  }
  if (isTextFormat(question)) {
    const text = asText(answer)
    if (!text) {
      return false
    }
    return (question.acceptedAnswers ?? []).some((a) => fuzzyMatch(text, a))
  }
  return asChoice(answer) === question.correctIndex
}

export class QuizRound implements GameRound {
  readonly type = "quiz" as const

  constructor(private readonly now: () => number = Date.now) {}

  start(room: ServerRoom): RoundStart {
    const { question, fromDb } = takeQuestion(room)
    // Anti-répétition cross-session : on enregistre la question jouée (DB only).
    if (fromDb && hasDb) {
      void markQuestionPlayed(room.code, question.id)
    }
    const payload: QuizQuestionPayload = {
      format: question.format,
      prompt: question.prompt,
      category: question.category,
      difficulty: question.difficulty,
    }
    if (question.format === "mcq" || question.format === "truefalse") {
      payload.choices = question.choices
    }
    if (question.format === "image_reveal") {
      payload.imageUrl = question.imageUrl
    }
    const data: QuizRoundData = { question, votedAt: new Map() }
    return { djId: null, payload, data }
  }

  submitAnswer(ctx: RoundContext, playerId: string, answer: Answer): void {
    // Premier vote verrouillé (idempotent) : on ignore les votes suivants.
    if (ctx.votes.has(playerId)) {
      return
    }
    const { question, votedAt } = ctx.data as QuizRoundData
    if (isTextFormat(question)) {
      const text = asText(answer)
      if (text === null || text.trim().length === 0) {
        return
      }
      ctx.votes.set(playerId, { text })
    } else {
      const choiceIndex = asChoice(answer)
      const count = question.choices?.length ?? 0
      if (choiceIndex === null || choiceIndex < 0 || choiceIndex >= count) {
        return
      }
      ctx.votes.set(playerId, { choiceIndex })
    }
    votedAt.set(playerId, this.now())
  }

  reveal(ctx: RoundContext): {
    truth: QuizRevealTruth
    perPlayerResult: QuizPerPlayerResult
  } {
    const { question } = ctx.data as QuizRoundData
    const perPlayerResult: QuizPerPlayerResult = {}
    for (const player of ctx.room.players.values()) {
      const vote = ctx.votes.get(player.id)
      perPlayerResult[player.id] = {
        choiceIndex: vote ? asChoice(vote) : null,
        correct: isCorrect(question, vote),
      }
    }
    const truth: QuizRevealTruth = isTextFormat(question)
      ? { answer: question.acceptedAnswers?.[0] ?? "" }
      : { correctIndex: question.correctIndex }
    return { truth, perPlayerResult }
  }

  score(ctx: RoundContext): ScoreDelta[] {
    const { question, votedAt } = ctx.data as QuizRoundData
    const total = ctx.endsAt - ctx.startedAt
    const deltas: ScoreDelta[] = []
    for (const [playerId, vote] of ctx.votes) {
      if (!isCorrect(question, vote)) {
        continue
      }
      // Bonus rapidité : proportionnel au temps restant au moment du vote.
      const at = votedAt.get(playerId) ?? ctx.endsAt
      const remaining = Math.max(0, Math.min(1, (ctx.endsAt - at) / total))
      const bonus = Math.round(SPEED_BONUS_MAX * remaining)
      deltas.push({ playerId, delta: BASE_POINTS + bonus })
    }
    return deltas
  }

  botAnswer(ctx: RoundContext): Answer {
    const { question } = ctx.data as QuizRoundData
    // Le bot répond juste selon le niveau choisi, sinon une réponse plausible.
    const rightish = Math.random() < botCorrectChance(ctx.room.settings.botDifficulty)
    if (isTextFormat(question)) {
      return {
        text: rightish ? (question.acceptedAnswers?.[0] ?? "?") : "euh…",
      }
    }
    const count = question.choices?.length ?? 1
    if (rightish && typeof question.correctIndex === "number") {
      return { choiceIndex: question.correctIndex }
    }
    return { choiceIndex: Math.floor(Math.random() * count) }
  }

  recap(ctx: RoundContext): RoundRecapInfo {
    const { question } = ctx.data as QuizRoundData
    const answer = isTextFormat(question)
      ? (question.acceptedAnswers?.[0] ?? "")
      : (question.choices?.[question.correctIndex ?? 0] ?? "")
    const answers = []
    for (const player of ctx.room.players.values()) {
      const vote = ctx.votes.get(player.id)
      if (!vote) {
        continue
      }
      const text = isTextFormat(question)
        ? (asText(vote) ?? "")
        : (question.choices?.[asChoice(vote) ?? -1] ?? "?")
      answers.push({
        playerId: player.id,
        answer: text,
        correct: isCorrect(question, vote),
      })
    }
    return {
      label: question.prompt,
      answer,
      category: question.category,
      imageUrl:
        question.format === "image_reveal" ? question.imageUrl : undefined,
      answers,
    }
  }
}