import { screen } from "electron";

function ensureWindowOnScreen(
  x: number | undefined,
  y: number | undefined,
  windowWidth: number,
  windowHeight: number,
): { validX: number | undefined; validY: number | undefined } {
  // If no coordinates stored, let Electron position window automatically
  if (x === undefined || y === undefined) {
    return { validX: undefined, validY: undefined };
  }

  const displays = screen.getAllDisplays();

  // Minimum visible pixels required on each edge to be considered "visible enough"
  const MIN_VISIBLE = 50; // Ensure at least 50px from each edge is visible

  // Try to find a display where the window would be almost fully visible
  for (const display of displays) {
    const { bounds } = display;

    // Check if window is mostly within this display
    if (
      x + MIN_VISIBLE >= bounds.x &&
      x + windowWidth - MIN_VISIBLE <= bounds.x + bounds.width &&
      y + MIN_VISIBLE >= bounds.y &&
      y + windowHeight - MIN_VISIBLE <= bounds.y + bounds.height
    ) {
      // Window is adequately visible on this display
      return { validX: x, validY: y };
    }
  }

  // If window isn't adequately visible on any display, try to adjust it to fit the closest display
  const closestDisplay = findClosestDisplay(displays, x, y);
  const { bounds } = closestDisplay;

  // Adjust position to ensure window is fully on screen
  let adjustedX = x;
  let adjustedY = y;

  // Adjust horizontal position if needed
  if (x < bounds.x) {
    adjustedX = bounds.x;
  } else if (x + windowWidth > bounds.x + bounds.width) {
    adjustedX = bounds.x + bounds.width - windowWidth;
  }

  // Adjust vertical position if needed
  if (y < bounds.y) {
    adjustedY = bounds.y;
  } else if (y + windowHeight > bounds.y + bounds.height) {
    adjustedY = bounds.y + bounds.height - windowHeight;
  }

  // If adjustments keep window on screen, use adjusted position
  if (
    adjustedX >= bounds.x &&
    adjustedX + windowWidth <= bounds.x + bounds.width &&
    adjustedY >= bounds.y &&
    adjustedY + windowHeight <= bounds.y + bounds.height
  ) {
    return { validX: adjustedX, validY: adjustedY };
  }

  // If all else fails, center on primary display
  const primaryDisplay = screen.getPrimaryDisplay();
  const primaryBounds = primaryDisplay.bounds;

  return {
    validX: Math.floor(
      primaryBounds.x + (primaryBounds.width - windowWidth) / 2,
    ),
    validY: Math.floor(
      primaryBounds.y + (primaryBounds.height - windowHeight) / 2,
    ),
  };
}

// Helper function to find the closest display to a point
function findClosestDisplay(
  displays: Electron.Display[],
  x: number,
  y: number,
): Electron.Display {
  let closestDisplay = displays[0];
  let shortestDistance = Number.MAX_VALUE;

  for (const display of displays) {
    const { bounds } = display;
    // Calculate distance to center of display
    const displayCenterX = bounds.x + bounds.width / 2;
    const displayCenterY = bounds.y + bounds.height / 2;

    const distance = Math.sqrt(
      Math.pow(x - displayCenterX, 2) + Math.pow(y - displayCenterY, 2),
    );

    if (distance < shortestDistance) {
      shortestDistance = distance;
      closestDisplay = display;
    }
  }

  return closestDisplay;
}

export default ensureWindowOnScreen;