src/lib/services/captureService.ts

/**
 * Pokemon-style Capture Mechanics for Pictuary
 * Based on Pokemon Emerald's capture formula from POKEMON_CAPTURE_MECHANICS.md
 */

export interface CaptureResult {
  success: boolean;
  shakes: number; // 0-3 shakes before success/failure
  odds: number; // Internal capture odds for debugging
}

export interface CaptureAttemptParams {
  // Target Piclet stats
  maxHp: number;
  currentHp: number;
  baseCatchRate: number; // Species-specific catch rate (3-255)
  
  // Status effects (optional)
  statusEffect?: 'sleep' | 'freeze' | 'poison' | 'burn' | 'paralysis' | 'toxic' | null;
  
  // Battle context (optional - for future specialty ball mechanics)
  battleTurn?: number;
  picletLevel?: number;
}

/**
 * Get the catch rate multiplier for a given tier
 * Maps Pictuary tiers to Pokemon-style catch rates
 */
export function getCatchRateForTier(tier: string): number {
  switch (tier.toLowerCase()) {
    case 'legendary': return 3;   // Hardest to catch (like legendary Pokemon)
    case 'high': return 25;       // Hard to catch (like pseudolegendaries)
    case 'medium': return 75;     // Standard catch rate
    case 'low': return 150;       // Easy to catch (like common Pokemon)
    default: return 75;           // Default to medium
  }
}

/**
 * Get status condition multiplier for capture rate
 */
function getStatusMultiplier(status: string | null | undefined): number {
  switch (status) {
    case 'sleep':
    case 'freeze':
      return 2.0; // Best status conditions for catching
    case 'poison':
    case 'burn':
    case 'paralysis':
    case 'toxic':
      return 1.5; // Good status conditions
    default:
      return 1.0; // No status effect
  }
}

/**
 * Calculate initial capture odds using Pokemon formula
 * Formula: odds = (catchRate × ballMultiplier ÷ 10) × (maxHP × 3 - currentHP × 2) ÷ (maxHP × 3) × statusMultiplier
 */
function calculateCaptureOdds(params: CaptureAttemptParams): number {
  const { maxHp, currentHp, baseCatchRate, statusEffect } = params;
  
  // Ball multiplier - since we don't have different camera types, use baseline 1.0x (10 in Pokemon terms)
  const ballMultiplier = 10;
  
  // HP factor: (maxHP × 3 - currentHP × 2) ÷ (maxHP × 3)
  // This creates the 3x capture boost when HP is at 1
  const hpFactor = (maxHp * 3 - currentHp * 2) / (maxHp * 3);
  
  // Status multiplier
  const statusMultiplier = getStatusMultiplier(statusEffect);
  
  // Core formula
  const odds = (baseCatchRate * ballMultiplier / 10) * hpFactor * statusMultiplier;
  
  return Math.max(0, Math.floor(odds));
}

/**
 * Calculate shake probability when capture odds <= 254
 * Formula: shakeOdds = 1048560 ÷ sqrt(sqrt(16711680 ÷ odds))
 */
function calculateShakeOdds(captureOdds: number): number {
  if (captureOdds === 0) return 0;
  
  const shakeOdds = 1048560 / Math.sqrt(Math.sqrt(16711680 / captureOdds));
  return Math.floor(shakeOdds);
}

/**
 * Simulate individual shake success
 * Each shake has a (shakeOdds / 65536) chance of success
 */
function simulateShake(shakeOdds: number): boolean {
  const randomValue = Math.floor(Math.random() * 65536);
  return randomValue < shakeOdds;
}

/**
 * Attempt to capture a Piclet using Pokemon mechanics
 * Returns detailed results including number of shakes
 */
export function attemptCapture(params: CaptureAttemptParams): CaptureResult {
  const odds = calculateCaptureOdds(params);
  
  // Immediate capture if odds > 254
  if (odds > 254) {
    return {
      success: true,
      shakes: 3,
      odds
    };
  }
  
  // If odds are 0, capture fails immediately
  if (odds === 0) {
    return {
      success: false,
      shakes: 0,
      odds
    };
  }
  
  // Calculate shake probability
  const shakeOdds = calculateShakeOdds(odds);
  
  // Simulate up to 3 shakes
  let shakes = 0;
  for (let i = 0; i < 3; i++) {
    if (simulateShake(shakeOdds)) {
      shakes++;
    } else {
      // Shake failed, capture fails
      return {
        success: false,
        shakes,
        odds
      };
    }
  }
  
  // All 3 shakes succeeded - capture success!
  return {
    success: true,
    shakes: 3,
    odds
  };
}

/**
 * Calculate capture rate percentage for display purposes
 * This gives players an approximate idea of their chances
 */
export function calculateCapturePercentage(params: CaptureAttemptParams): number {
  const odds = calculateCaptureOdds(params);
  
  // Immediate capture
  if (odds > 254) return 100;
  
  // No chance
  if (odds === 0) return 0;
  
  // For odds <= 254, we need to calculate the probability of getting 3 successful shakes
  const shakeOdds = calculateShakeOdds(odds);
  const shakeSuccessRate = shakeOdds / 65536;
  
  // Probability of 3 consecutive successful shakes
  const captureRate = Math.pow(shakeSuccessRate, 3) * 100;
  
  return Math.min(100, Math.max(0.1, captureRate)); // At least 0.1% to show something
}

/**
 * Get a user-friendly description of capture difficulty based on percentage
 */
export function getCaptureDescription(percentage: number): string {
  if (percentage >= 95) return "Almost certain";
  if (percentage >= 75) return "Very likely";
  if (percentage >= 50) return "Good chance";
  if (percentage >= 25) return "Moderate chance";
  if (percentage >= 10) return "Low chance";
  if (percentage >= 5) return "Very low chance";
  return "Extremely difficult";
}

/**
 * Simulate multiple capture attempts to get average results (for testing/balancing)
 */
export function simulateMultipleCaptures(params: CaptureAttemptParams, attempts: number = 1000): {
  successRate: number;
  averageShakes: number;
  distribution: { [key: number]: number };
} {
  let successes = 0;
  let totalShakes = 0;
  const shakeDistribution: { [key: number]: number } = { 0: 0, 1: 0, 2: 0, 3: 0 };
  
  for (let i = 0; i < attempts; i++) {
    const result = attemptCapture(params);
    if (result.success) successes++;
    totalShakes += result.shakes;
    shakeDistribution[result.shakes]++;
  }
  
  return {
    successRate: (successes / attempts) * 100,
    averageShakes: totalShakes / attempts,
    distribution: shakeDistribution
  };
}