velxio/frontend/src/utils/pinPositionCalculator.ts

/**
 * Pin Position Calculator
 *
 * Converts pin coordinates from element space to canvas space (pixels).
 * This is the CRITICAL piece for wire system - without accurate pin positions,
 * wires cannot connect properly to components.
 *
 * Coordinate Systems:
 * 1. Element Space: Pin positions in pinInfo are in CSS pixels relative to element origin
 * 2. Canvas Space: Absolute positioning in pixels on the canvas
 *
 * Note: wokwi-elements pinInfo x/y are already in CSS pixels.
 */

/**
 * Calculates the absolute canvas position of a specific pin.
 *
 * @param componentId - The DOM ID of the component element
 * @param pinName - The name of the pin (e.g., 'A', 'C', 'GND.1', '13')
 * @param componentX - Component's X position on canvas (pixels). For a
 *   rotated component this is still the UNROTATED inner-element top-left
 *   (callers already add the wrapper offset of 4 horizontal / 6 vertical).
 * @param componentY - Component's Y position on canvas (pixels)
 * @param rotation - Optional CSS rotation in degrees applied to the
 *   component's wrapper (0 / 90 / 180 / 270). When non-zero the pin
 *   position is rotated around the wrapper's center so wire endpoints
 *   land on the visually-rotated pin instead of the old layout-space pin.
 * @returns Absolute canvas coordinates { x, y } or null if pin not found
 */
export function calculatePinPosition(
  componentId: string,
  pinName: string,
  componentX: number,
  componentY: number,
  rotation: number = 0,
): { x: number; y: number } | null {
  // Get the DOM element
  const element = document.getElementById(componentId);
  if (!element) {
    console.warn(`[pinPositionCalculator] Component ${componentId} not found in DOM`);
    return null;
  }

  // Access the pinInfo property (all wokwi-elements expose this)
  const pinInfo = (element as any).pinInfo;
  if (!pinInfo || !Array.isArray(pinInfo)) {
    console.warn(`[pinPositionCalculator] Component ${componentId} does not have pinInfo`);
    return null;
  }

  // Find the specific pin
  let pin = pinInfo.find((p: any) => p.name === pinName);
  // Fallback: try numbered variant (e.g. GND → GND.1) for pins that have suffix variants
  if (!pin && !pinName.includes('.')) {
    pin = pinInfo.find((p: any) => p.name === `${pinName}.1`);
  }
  // Fallback: GP-prefix → match description field (e.g. 'GP15' → description 'GPIO15')
  // Needed for Nano RP2040 Connect which uses D-prefix pin names but GPIO descriptions
  if (!pin && pinName.startsWith('GP')) {
    const gpioNum = parseInt(pinName.substring(2), 10);
    if (!isNaN(gpioNum)) {
      pin = pinInfo.find((p: any) => p.description === `GPIO${gpioNum}`);
    }
  }
  if (!pin) {
    console.warn(`[pinPositionCalculator] Pin ${pinName} not found on component ${componentId}`);
    console.warn(
      `Available pins:`,
      pinInfo.map((p: any) => p.name),
    );
    return null;
  }

  // Unrotated pin position in canvas space.
  let pinX = componentX + pin.x;
  let pinY = componentY + pin.y;

  // Rotation: the DynamicComponent wrapper applies
  //   transform: rotate(<deg>deg);  transform-origin: center center;
  // around its OWN center (the wrapper, not the inner web component). So
  // when the user rotates 90° the pin moves on an arc centered on the
  // wrapper center, not on the component origin or the pin's own axis.
  //
  // We compute the wrapper center in canvas space from `offsetWidth /
  // offsetHeight` of the wrapper — those reflect the layout box and are
  // UNAFFECTED by CSS transforms, so reading them right after a state
  // change but before React commits the new transform is safe.
  //
  // Wrapper top-left ≈ inner-element top-left minus the wrapper padding
  // + border. updateWirePositions / recalculateAllWirePositions add
  // (+4, +6) to component.x / component.y to land on the inner-element
  // top-left, so the wrapper top-left is (componentX - 4, componentY - 6).
  // This convention is hardcoded in the store; we honour it here so the
  // math stays consistent across the rotation boundary.
  const angle = ((rotation % 360) + 360) % 360;
  if (angle !== 0) {
    const wrapper = element.closest('.dynamic-component-wrapper') as HTMLElement | null;
    if (wrapper) {
      const wrapperW = wrapper.offsetWidth;
      const wrapperH = wrapper.offsetHeight;
      const wrapperLeft = componentX - 4;
      const wrapperTop = componentY - 6;
      const pivotX = wrapperLeft + wrapperW / 2;
      const pivotY = wrapperTop + wrapperH / 2;
      const theta = (angle * Math.PI) / 180;
      const cos = Math.cos(theta);
      const sin = Math.sin(theta);
      const dx = pinX - pivotX;
      const dy = pinY - pivotY;
      pinX = pivotX + (dx * cos - dy * sin);
      pinY = pivotY + (dx * sin + dy * cos);
    }
  }

  return { x: pinX, y: pinY };
}

/**
 * Gets all pins for a component with their absolute canvas positions.
 * Useful for rendering pin overlays and finding nearby pins.
 *
 * @param componentId - The DOM ID of the component element
 * @param componentX - Component's X position on canvas
 * @param componentY - Component's Y position on canvas
 * @returns Array of pins with absolute positions and signal info
 */
export function getAllPinPositions(
  componentId: string,
  componentX: number,
  componentY: number,
): Array<{ name: string; x: number; y: number; signals: any[] }> {
  const element = document.getElementById(componentId);
  if (!element) return [];

  const pinInfo = (element as any).pinInfo;
  if (!pinInfo || !Array.isArray(pinInfo)) return [];

  return pinInfo.map((pin: any) => ({
    name: pin.name,
    x: componentX + pin.x,
    y: componentY + pin.y,
    signals: pin.signals || [],
  }));
}

/**
 * Finds the closest pin to a given canvas position.
 * Useful for snapping wire endpoints to nearby pins.
 *
 * @param componentId - The component to search
 * @param componentX - Component's X position
 * @param componentY - Component's Y position
 * @param targetX - Target X coordinate to find nearest pin
 * @param targetY - Target Y coordinate to find nearest pin
 * @param maxDistance - Maximum distance in pixels to consider (default 20)
 * @returns Closest pin info or null if none within maxDistance
 */
export function findClosestPin(
  componentId: string,
  componentX: number,
  componentY: number,
  targetX: number,
  targetY: number,
  maxDistance: number = 20,
): { name: string; x: number; y: number; signals: any[] } | null {
  const pins = getAllPinPositions(componentId, componentX, componentY);

  let closestPin: { name: string; x: number; y: number; signals: any[] } | null = null;
  let minDistance = maxDistance;

  for (const pin of pins) {
    const distance = Math.sqrt(Math.pow(pin.x - targetX, 2) + Math.pow(pin.y - targetY, 2));

    if (distance < minDistance) {
      minDistance = distance;
      closestPin = pin;
    }
  }

  return closestPin;
}