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package org.lwjgl.opengl;

/**
 * This is the Windows implementation of the Mouse.
 * @author elias_naur
 */

import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import java.nio.CharBuffer;

import org.lwjgl.LWJGLException;
import org.lwjgl.LWJGLUtil;
import org.lwjgl.BufferUtils;

final class WindowsMouse {
	private final static int BUFFER_SIZE = 50;
	private final static int BUTTON_STATES_SIZE = 7;
	private final static int MOUSE_EVENT_SIZE = 5;

	private final static int DIMOFS_X = 0;
	private final static int DIMOFS_Y = 4;
	private final static int DIMOFS_Z = 8;
	private final static int DIMOFS_BUTTON0 = 12;
	private final static int DIMOFS_BUTTON1 = 13;
	private final static int DIMOFS_BUTTON2 = 14;
	private final static int DIMOFS_BUTTON3 = 15;

	private final long hwnd;
	private final WindowsDirectInput dinput;
	private final WindowsDirectInputDevice mouse;

	private final int mouse_button_count;
	private final boolean has_wheel;

	private final EventQueue event_queue = new EventQueue(MOUSE_EVENT_SIZE);
	/* Buffer to hold a DIMOUSESTATE */
	private final ByteBuffer mouse_state;
	private final IntBuffer temp_data_buffer;

	private final int[] mouse_event = new int[MOUSE_EVENT_SIZE];

	private boolean mouse_grabbed;
	private byte[] win32_message_button_states = new byte[BUTTON_STATES_SIZE];
	private int accum_dwheel;
	private int last_x;
	private int last_y;

	public WindowsMouse(WindowsDirectInput dinput, long hwnd) throws LWJGLException {
		this.hwnd = hwnd;
		this.dinput = dinput;
		try {
			mouse = dinput.createDevice(WindowsDirectInput.MOUSE_TYPE);
			try {
				mouse.setDataFormat(WindowsDirectInput.MOUSE_TYPE);
				mouse.setBufferSize(BUFFER_SIZE);
				if (!acquireNonExclusive())
					throw new LWJGLException("Failed to acquire mouse non-exclusive");
			} catch (LWJGLException e) {
				mouse.release();
				throw e;
			}
		} catch (LWJGLException e) {
			dinput.release();
			throw e;
		}
		MouseEnumerator enumerator = new MouseEnumerator();
		mouse.enumObjects(enumerator);
		this.mouse_button_count = Math.min(enumerator.getButtonCount(), 4);
		this.has_wheel = enumerator.hasWheel();
		mouse_state = BufferUtils.createByteBuffer(3*4 + 4);
		temp_data_buffer = BufferUtils.createIntBuffer(BUFFER_SIZE*2);
	}

	public boolean hasWheel() {
		return has_wheel;
	}

	public int getButtonCount() {
		return mouse_button_count;
	}

	private boolean acquire(int flags) {
		try {
			mouse.setCooperateLevel(hwnd, flags);
			mouse.acquire();
			return true;
		} catch (LWJGLException e) {
			LWJGLUtil.log("Failed to acquire mouse: " + e);
			return false;
		}
	}

	private boolean acquireNonExclusive() {
		return acquire(WindowsDirectInputDevice.DISCL_NONEXCLUSIVE | WindowsDirectInputDevice.DISCL_FOREGROUND) ||
			acquire(WindowsDirectInputDevice.DISCL_NONEXCLUSIVE | WindowsDirectInputDevice.DISCL_BACKGROUND);
	}

	public void destroy() {
		mouse.unacquire();
		mouse.release();
		dinput.release();
	}

	public void poll(IntBuffer coord_buffer, ByteBuffer buttons) {
		int ret = mouse.acquire();
		if (ret != WindowsDirectInput.DI_OK && ret != WindowsDirectInput.DI_NOEFFECT)
			return;
		mouse.poll();
		for (int i = 0; i < coord_buffer.remaining(); i++)
			coord_buffer.put(coord_buffer.position() + i, 0);
		mouse_state.clear();
		ret = mouse.getDeviceState(mouse_state);
		int mouse_state_lx = mouse_state.getInt();
		int mouse_state_ly = mouse_state.getInt();
		int mouse_state_lz = mouse_state.getInt();
		int num_buttons = mouse_button_count;
		if (mouse_grabbed || ret == WindowsDirectInput.DI_OK) {
			if (ret != WindowsDirectInput.DI_OK) { 
				LWJGLUtil.log("Error getting mouse state: (0x" + Integer.toHexString(ret) + ")");
				return;
			}

			coord_buffer.put(coord_buffer.position() + 2, mouse_state_lz);
			if (num_buttons > buttons.remaining())
				num_buttons = buttons.remaining();
			for (int j = 0; j < num_buttons; j++) {
				byte button_state = (mouse_state.get() & 0x80) != 0 ? (byte)1 : (byte)0;
				buttons.put(buttons.position() + j, button_state);
				// track the button state in the windows message buffer state array
				// to get accurate button information when releasing a grab
				win32_message_button_states[j] = button_state;
			}
		} else {
			coord_buffer.put(coord_buffer.position() + 2, accum_dwheel);
			if (num_buttons > win32_message_button_states.length)
				num_buttons = win32_message_button_states.length;
			for (int j = 0; j < num_buttons; j++) {
				buttons.put(buttons.position() + j, win32_message_button_states[j]);
			}
		}
		accum_dwheel = 0;
		if (mouse_grabbed) {
			coord_buffer.put(coord_buffer.position() + 0, mouse_state_lx);
			coord_buffer.put(coord_buffer.position() + 1, -mouse_state_ly);
		} else {
			coord_buffer.put(coord_buffer.position() + 0, last_x);
			coord_buffer.put(coord_buffer.position() + 1, last_y);
		}
	}
	
	private boolean putMouseEventWithCoords(int button, int state, int coord1, int coord2, int dz) {
		mouse_event[0] = button;
		mouse_event[1] = state;
		mouse_event[2] = coord1;
		mouse_event[3] = coord2;
		mouse_event[4] = dz;
		return event_queue.putEvent(mouse_event);
	}

	private boolean putMouseEvent(int button, int state, int dz) {
		if (mouse_grabbed)
			return putMouseEventWithCoords(button, state, 0, 0, dz);
		else
			return putMouseEventWithCoords(button, state, last_x, last_y, dz);
	}

	private void copyDXEvents(IntBuffer buffer) {
		int buffer_index = 0;
		int dx = 0, dy = 0, dwheel = 0;
		int button_state;
		int i;
		while (buffer.hasRemaining()) {
			int dwOfs = buffer.get();
			int dwData = buffer.get();
			button_state = (dwData & 0x80) != 0 ? 1 : 0;
			switch (dwOfs) {
				case DIMOFS_BUTTON0:
					putMouseEventWithCoords(0, button_state, dx, -dy, dwheel);
					dx = dy = dwheel = 0;
					break;
				case DIMOFS_BUTTON1:
					putMouseEventWithCoords(1, button_state, dx, -dy, dwheel);
					dx = dy = dwheel = 0;
					break;
				case DIMOFS_BUTTON2:
					putMouseEventWithCoords(2, button_state, dx, -dy, dwheel);
					dx = dy = dwheel = 0;
					break;
				case DIMOFS_BUTTON3:
					putMouseEventWithCoords(3, button_state, dx, -dy, dwheel);
					dx = dy = dwheel = 0;
					break;
				case DIMOFS_X:
					dx += dwData;
					break;
				case DIMOFS_Y:
					dy += dwData;
					break;
				case DIMOFS_Z:
					dwheel += dwData;
					break;
			}
		}
		if (dx != 0 || dy != 0 || dwheel != 0)
			putMouseEventWithCoords(-1, 0, dx, -dy, dwheel);
	}

	private void readDXBuffer() {
		int ret = mouse.acquire();
		if (ret != WindowsDirectInput.DI_OK && ret != WindowsDirectInput.DI_NOEFFECT)
			return;
		mouse.poll();
		temp_data_buffer.clear();
		ret = mouse.getDeviceData(temp_data_buffer);

		if (ret == WindowsDirectInput.DI_OK) {
			if (mouse_grabbed) {
				temp_data_buffer.flip();
				copyDXEvents(temp_data_buffer);
			}
		} else if (ret == WindowsDirectInput.DI_BUFFEROVERFLOW) { 
			LWJGLUtil.log("Mouse buffer overflowed");
		} else if (ret == WindowsDirectInput.DIERR_INPUTLOST) {
			LWJGLUtil.log("Mouse input lost");
		} else if (ret == WindowsDirectInput.DIERR_NOTACQUIRED) {
			LWJGLUtil.log("Mouse not acquired");
		} else {
			LWJGLUtil.log("unknown mouse error (" + Integer.toHexString(ret) + ")");
		}
	}

	public int read(IntBuffer buffer) {
		readDXBuffer();
		return event_queue.copyEvents(buffer);
	}
		
	public void grab(boolean grab) {
		if(grab) {
			if (!mouse_grabbed) {
				// flush DX event buffer
				readDXBuffer();
				mouse_grabbed = true;
				mouse.unacquire();
				if (!acquire(WindowsDirectInputDevice.DISCL_EXCLUSIVE | WindowsDirectInputDevice.DISCL_FOREGROUND))
					LWJGLUtil.log("Failed to reset cooperative mode");
			}
		} else {
			if (mouse_grabbed) {
				mouse_grabbed = false;
				mouse.unacquire();
				acquireNonExclusive();
			}	
		}
		event_queue.clearEvents();
	}

	public void handleMouseScrolled(int event_dwheel) {
		accum_dwheel += event_dwheel;
		putMouseEvent(-1, 0, event_dwheel);
	}

	public void handleMouseMoved(int x, int y) {
		int dx;
		int dy;
		dx = x - last_x;
		dy = y - last_y;
		last_x = x;
		last_y = y;
		if (mouse_grabbed) {
			putMouseEventWithCoords(-1, 0, dx, dy, 0);
		} else {
			putMouseEventWithCoords(-1, 0, x, y, 0);
		}		
	}

	public void handleMouseButton(int button, int state) {
		putMouseEvent(button, state, 0);
		if (button < BUTTON_STATES_SIZE)
			win32_message_button_states[button] = state != 0 ? (byte)1 : (byte)0;
	}

	private static class MouseEnumerator implements WindowsDirectInputDeviceObjectCallback {
		private int button_count;
		private boolean has_wheel;

		public int getButtonCount() {
			return button_count;
		}

		public boolean hasWheel() {
			return has_wheel;
		}

		public boolean nextObject(int type, String name) {
			LWJGLUtil.log("Found mouse object: " + name);
			switch (type) {
				case WindowsDirectInputDevice.GUID_ZAxis:
					has_wheel = true;
					break;
				case WindowsDirectInputDevice.GUID_Button:
					button_count++;
					break;
				default:
					break;
			}
			return true;
		}
	}
}