import type { SessionDetailResponse } from '../api/types';

export type GameplayPhase = 'lie' | 'guess' | 'reveal' | 'scoreboard';

export type GameplayPhaseEvent =
  | 'LIES_LOCKED'
  | 'GUESSES_LOCKED'
  | 'SCOREBOARD_READY'
  | 'NEXT_ROUND';

export interface GameplayTransitionResult {
  phase: GameplayPhase;
  changed: boolean;
}

const TRANSITIONS: Record<GameplayPhase, Partial<Record<GameplayPhaseEvent, GameplayPhase>>> = {
  lie: {
    LIES_LOCKED: 'guess'
  },
  guess: {
    GUESSES_LOCKED: 'reveal'
  },
  reveal: {
    SCOREBOARD_READY: 'scoreboard'
  },
  scoreboard: {
    NEXT_ROUND: 'lie'
  }
};

export function transitionGameplayPhase(phase: GameplayPhase, event: GameplayPhaseEvent): GameplayTransitionResult {
  const next = TRANSITIONS[phase][event] ?? phase;
  return {
    phase: next,
    changed: next !== phase
  };
}

export function allowedGameplayEvents(phase: GameplayPhase): GameplayPhaseEvent[] {
  return Object.keys(TRANSITIONS[phase]) as GameplayPhaseEvent[];
}

export function deriveGameplayPhase(session: SessionDetailResponse | null): GameplayPhase | null {
  const status = session?.session.status;
  if (!status) {
    return null;
  }

  if (status === 'lie' || status === 'guess' || status === 'reveal') {
    return status;
  }

  if (status === 'finished') {
    return 'scoreboard';
  }

  return null;
}