export type PromptLevel = 0 | 1 | 2 | 3 | 4

// Galperin stages mapped to prompt levels
export const GALPERIN_STAGES = {
  HAND: 0,           // Concrete: full model, show the answer
  EXTERNAL_SPEECH: 1, // Prompts the child to say out loud
  INNER_SPEECH: 2,   // Partial prompt, whisper
  MENTAL: 3,         // Verbal cue only
  MASTERED: 4,       // No prompt
} as const

export interface PromptState {
  level: PromptLevel
  consecutiveCorrect: number
  consecutiveIncorrect: number
}

export function getInitialState(): PromptState {
  return {
    level: 0,
    consecutiveCorrect: 0,
    consecutiveIncorrect: 0,
  }
}

export function evaluateResponse(
  state: PromptState,
  correct: boolean,
  masterThreshold: number = 3,
  regressThreshold: number = 2,
): PromptState {
  if (correct) {
    const newCorrect = state.consecutiveCorrect + 1
    const newLevel =
      newCorrect >= masterThreshold
        ? (Math.min(state.level + 1, 4) as PromptLevel)
        : state.level
    return {
      level: newLevel,
      consecutiveCorrect: newCorrect,
      consecutiveIncorrect: 0,
    }
  }

  const newIncorrect = state.consecutiveIncorrect + 1
  const newLevel =
    newIncorrect >= regressThreshold
      ? (Math.max(state.level - 1, 0) as PromptLevel)
      : state.level
  return {
    level: newLevel,
    consecutiveCorrect: 0,
    consecutiveIncorrect: newIncorrect,
  }
}

export function shouldShowPrompt(level: PromptLevel): boolean {
  return level < 3
}

export function isMastered(level: PromptLevel): boolean {
  return level >= 4
}