import { CPU } from '../cpu/cpu';
import { AVRIOPort, portBConfig, PinState } from './gpio';

const PINB = 0x23;
const DDRB = 0x24;
const PORTB = 0x25;

describe('GPIO', () => {
  it('should invoke the listeners when the port is written to', () => {
    const cpu = new CPU(new Uint16Array(1024));
    const port = new AVRIOPort(cpu, portBConfig);
    const listener = jest.fn();
    cpu.writeData(DDRB, 0x0f);
    port.addListener(listener);
    cpu.writeData(PORTB, 0x55);
    expect(listener).toHaveBeenCalledWith(0x55, 0);
    expect(cpu.data[0x23]).toEqual(0x5); // PINB should return port value
  });

  it('should invoke the listeners when DDR changes (issue #28)', () => {
    const cpu = new CPU(new Uint16Array(1024));
    const port = new AVRIOPort(cpu, portBConfig);
    const listener = jest.fn();
    cpu.writeData(PORTB, 0x55);
    port.addListener(listener);
    cpu.writeData(DDRB, 0xf0);
    expect(listener).toHaveBeenCalledWith(0x55, 0x55);
  });

  it('should invoke the listeners when pullup register enabled (issue #62)', () => {
    const cpu = new CPU(new Uint16Array(1024));
    const port = new AVRIOPort(cpu, portBConfig);
    const listener = jest.fn();
    port.addListener(listener);
    cpu.writeData(PORTB, 0x55);
    expect(listener).toHaveBeenCalledWith(0x55, 0);
  });

  it('should toggle the pin when writing to the PIN register', () => {
    const cpu = new CPU(new Uint16Array(1024));
    const port = new AVRIOPort(cpu, portBConfig);
    const listener = jest.fn();
    port.addListener(listener);
    cpu.writeData(DDRB, 0x0f);
    cpu.writeData(PORTB, 0x55);
    cpu.writeData(PINB, 0x01);
    expect(listener).toHaveBeenCalledWith(0x54, 0x55);
    expect(cpu.data[PINB]).toEqual(0x4); // PINB should return port value
  });

  describe('removeListener', () => {
    it('should remove the given listener', () => {
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      const listener = jest.fn();
      port.addListener(listener);
      cpu.writeData(DDRB, 0x0f);
      port.removeListener(listener);
      cpu.writeData(PORTB, 0x99);
      expect(listener).toBeCalledTimes(1);
    });
  });

  describe('pinState', () => {
    it('should return PinState.High when the pin set to output and HIGH', () => {
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      cpu.writeData(DDRB, 0x1);
      cpu.writeData(PORTB, 0x1);
      expect(port.pinState(0)).toEqual(PinState.High);
    });

    it('should return PinState.Low when the pin set to output and LOW', () => {
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      cpu.writeData(DDRB, 0x8);
      cpu.writeData(PORTB, 0xf7);
      expect(port.pinState(3)).toEqual(PinState.Low);
    });

    it('should return PinState.Input by default (reset state)', () => {
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      expect(port.pinState(1)).toEqual(PinState.Input);
    });

    it('should return PinState.InputPullUp when the pin is set to input with pullup', () => {
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      cpu.writeData(DDRB, 0);
      cpu.writeData(PORTB, 0x2);
      expect(port.pinState(1)).toEqual(PinState.InputPullUp);
    });

    it('should reflect the current port state when called inside a listener', () => {
      // Related issue: https://github.com/wokwi/avr8js/issues/9
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      const listener = jest.fn(() => {
        expect(port.pinState(0)).toBe(PinState.High);
      });
      expect(port.pinState(0)).toBe(PinState.Input);
      cpu.writeData(DDRB, 0x01);
      port.addListener(listener);
      cpu.writeData(PORTB, 0x01);
      expect(listener).toHaveBeenCalled();
    });

    it('should reflect the current port state when called inside a listener after DDR change', () => {
      // Related issue: https://github.com/wokwi/avr8js/issues/47
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      const listener = jest.fn(() => {
        expect(port.pinState(0)).toBe(PinState.Low);
      });
      expect(port.pinState(0)).toBe(PinState.Input);
      port.addListener(listener);
      cpu.writeData(DDRB, 0x01);
      expect(listener).toHaveBeenCalled();
    });
  });

  describe('setPin', () => {
    it('should set the value of the given pin', () => {
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      cpu.writeData(DDRB, 0);
      port.setPin(4, true);
      expect(cpu.data[0x23]).toEqual(0x10);
      port.setPin(4, false);
      expect(cpu.data[0x23]).toEqual(0x0);
    });

    it('should only update PIN register when pin in Input mode', () => {
      const cpu = new CPU(new Uint16Array(1024));
      const port = new AVRIOPort(cpu, portBConfig);
      cpu.writeData(DDRB, 0x10);
      cpu.writeData(PORTB, 0x0);
      port.setPin(4, true);
      expect(cpu.data[PINB]).toEqual(0x0);
      cpu.writeData(DDRB, 0x0);
      expect(cpu.data[PINB]).toEqual(0x10);
    });
  });
});