import { ViewportOffset, CONSTANTS } from '../types';
import { clamp, calculateDistance } from './math';

// Zoom-related functions
export const calculateZoomDelta = (
  wheelDelta: number,
  accelerationFactor: number,
  baseMultiplier = 0.001
): number => clamp(wheelDelta * baseMultiplier * accelerationFactor, -0.5, 0.5);

export const calculateInitialViewport = (initialZoom: number): ViewportOffset => {
  // When fully zoomed out, we want to see the entire content area
  // The target distribution is sized to match the viewport at minimum zoom
  // So at any higher zoom level, we need to position appropriately
  const windowWidth = window.innerWidth;
  const windowHeight = window.innerHeight;
  
  // Center the viewport on the target area
  const areaWidth = windowWidth / CONSTANTS.ZOOM_LEVELS.min;
  const areaHeight = windowHeight / CONSTANTS.ZOOM_LEVELS.min;
  
  return {
    x: (areaWidth - windowWidth / initialZoom) / 2,
    y: (areaHeight - windowHeight / initialZoom) / 2
  };
};

export const clampZoom = (zoom: number): number => 
  clamp(zoom, CONSTANTS.ZOOM_LEVELS.min, CONSTANTS.ZOOM_LEVELS.max);

// Touch-related functions
export const calculateTouchDistance = (touch1: React.Touch | Touch, touch2: React.Touch | Touch): number =>
  calculateDistance(touch1.clientX, touch1.clientY, touch2.clientX, touch2.clientY);

export const calculateZoomFactor = (currentDistance: number, startDistance: number): number =>
  startDistance > 0 ? currentDistance / startDistance : 1;