/**
 * Generate list of integers from 10 to 2000 in increments of 10
 */
function generateIntegers(start: number, end: number, step: number): number[] {
  const integers: number[] = [];
  for (let i = start; i <= end; i += step) {
    integers.push(i);
  }
  return integers;
}

/**
 * Precomputed list of integers (10, 20, 30, ..., 2000)
 */
export const INTEGERS = generateIntegers(10, 2000, 10);

/**
 * Get the index of an integer in the precomputed list, or -1 if not found
 */
export function getIntegerIndex(integer: number): number {
  return INTEGERS.indexOf(integer);
}

/**
 * Get the integer at a specific index in the precomputed list
 */
export function getIntegerAtIndex(index: number): number | undefined {
  return INTEGERS[index];
}

/**
 * Get the next integer in the precomputed list
 */
export function getNextInteger(currentInteger: number): number {
  const index = getIntegerIndex(currentInteger);
  if (index === -1 || index === INTEGERS.length - 1) {
    return currentInteger; // Stay at current if not found or at end
  }
  return INTEGERS[index + 1];
}

/**
 * Get the previous integer in the precomputed list
 */
export function getPreviousInteger(currentInteger: number): number {
  const index = getIntegerIndex(currentInteger);
  if (index === -1 || index === 0) {
    return currentInteger; // Stay at current if not found or at start
  }
  return INTEGERS[index - 1];
}

/**
 * Calculate the best initial integer based on viewport dimensions
 * The grid size will be n × n pixels
 * 
 * @param maxInteger - Maximum allowed integer (default 2000)
 * @returns The largest integer that will fit in the viewport without scrolling
 */
export function getInitialIntegerForViewport(maxInteger: number = 2000): number {
  // MUI's 'md' breakpoint is 900px
  const isMobile = window.innerWidth < 900;
  
  let availableWidth: number;
  let availableHeight: number;
  
  if (isMobile) {
    // Mobile layout: controls at top, full width available
    // Account for left/right padding (~20px total on mobile)
    availableWidth = window.innerWidth - 20;
    
    // Account for controls section at top (approximately 400-450px) and padding
    // Being conservative with 500px to ensure it fits
    availableHeight = window.innerHeight - 500;
  } else {
    // Desktop layout: sidebar on left
    // Account for sidebar (300px) and padding/margins (~50px total)
    availableWidth = window.innerWidth - 350;
    
    // Account for top/bottom padding (~50px total)
    availableHeight = window.innerHeight - 50;
  }
  
  // Use the smaller dimension to ensure it fits both ways
  const availableSize = Math.min(availableWidth, availableHeight);
  
  // Find the largest integer where n fits in the available space
  // Round down to nearest multiple of 10
  const targetInteger = Math.floor(availableSize / 10) * 10;
  
  // Find the largest integer in our list that doesn't exceed the target or max
  const maxAllowedInteger = Math.min(targetInteger, maxInteger);
  
  // Find the largest integer in our list that doesn't exceed the max
  for (let i = INTEGERS.length - 1; i >= 0; i--) {
    if (INTEGERS[i] <= maxAllowedInteger) {
      return INTEGERS[i];
    }
  }
  
  // Fallback to smallest integer if viewport is too small
  return INTEGERS[0];
}