/**
 * Chip pin drive registry — the bridge between a custom-chip's WASM-driven
 * output pins and the SPICE electrical engine.
 *
 * When a custom-chip drives an OUTPUT pin (ChipRuntime), it records the pin's
 * voltage here keyed by `${chipId}:${pinName}`. The SPICE netlist builder's
 * `custom-chip` mapper (spice/componentToSpice) reads these to emit a DC
 * voltage source on the chip pin's net, exactly like a board GPIO. That makes
 * the chip drive LEDs, resistors and any analog part wired to it through
 * ngspice, in addition to the digital PinManager path.
 *
 * Presence of a key == that pin is a driven output. Absence == input / Hi-Z.
 */

const drives = new Map<string, number>();

function key(chipId: string, pinName: string): string {
  return `${chipId} ${pinName}`;
}

/**
 * Record (or clear) a chip output pin's drive voltage. Pass `null` to mark the
 * pin as a non-driving input. Returns true if the registry actually changed
 * (so callers can skip a redundant SPICE re-solve).
 */
export function setChipPinDrive(chipId: string, pinName: string, voltage: number | null): boolean {
  const k = key(chipId, pinName);
  if (voltage == null) {
    return drives.delete(k);
  }
  if (drives.get(k) === voltage) return false;
  drives.set(k, voltage);
  return true;
}

/** All driven output pins for a chip, with their voltages. */
export function getChipDrivenPins(chipId: string): { pin: string; voltage: number }[] {
  const prefix = `${chipId} `;
  const out: { pin: string; voltage: number }[] = [];
  for (const [k, v] of drives) {
    if (k.startsWith(prefix)) out.push({ pin: k.slice(prefix.length), voltage: v });
  }
  return out;
}

/** Forget every drive for a chip (on dispose / simulation stop). */
export function clearChipDrives(chipId: string): void {
  const prefix = `${chipId} `;
  for (const k of Array.from(drives.keys())) {
    if (k.startsWith(prefix)) drives.delete(k);
  }
}