import type { CanvasNode, Viewport } from "@/types/canvas";

export function getCanvasFitViewport(
  nodes: Pick<CanvasNode, "position" | "size">[],
  container: { width: number; height: number },
  occlusionRight = 0
): Viewport | null {
  const visibleWidth = container.width - Math.max(0, occlusionRight);
  if (visibleWidth <= 0 || container.height <= 0) return null;
  const validNodes = nodes.filter(
    (node) =>
      [
        node.position.x,
        node.position.y,
        node.size.width,
        node.size.height,
      ].every(Number.isFinite) &&
      node.size.width > 0 &&
      node.size.height > 0
  );
  if (!validNodes.length) return null;
  const minX = Math.min(...validNodes.map((node) => node.position.x));
  const minY = Math.min(...validNodes.map((node) => node.position.y));
  const maxX = Math.max(
    ...validNodes.map((node) => node.position.x + node.size.width)
  );
  const maxY = Math.max(
    ...validNodes.map((node) => node.position.y + node.size.height)
  );
  const padding = Math.min(80, visibleWidth / 4, container.height / 4);
  const zoom = Math.min(
    4,
    visibleWidth / (maxX - minX + 2 * padding),
    container.height / (maxY - minY + 2 * padding)
  );
  return {
    x: visibleWidth / 2 - ((minX + maxX) / 2) * zoom,
    y: container.height / 2 - ((minY + maxY) / 2) * zoom,
    zoom,
  };
}