/* vim: tabstop=4 shiftwidth=4 noexpandtab
 * This file is part of ToaruOS and is released under the terms
 * of the NCSA / University of Illinois License - see LICENSE.md
 * Copyright (C) 2014-2018 K. Lange
 *
 * Mouse driver
 *
 */
#include <kernel/system.h>
#include <kernel/logging.h>
#include <kernel/pipe.h>
#include <kernel/module.h>
#include <kernel/mouse.h>
#include <kernel/args.h>

static uint8_t mouse_cycle = 0;
static uint8_t mouse_byte[4];

#define PACKETS_IN_PIPE 1024
#define DISCARD_POINT 32

#define MOUSE_IRQ 12

#define MOUSE_PORT   0x60
#define MOUSE_STATUS 0x64
#define MOUSE_ABIT   0x02
#define MOUSE_BBIT   0x01
#define MOUSE_WRITE  0xD4
#define MOUSE_F_BIT  0x20
#define MOUSE_V_BIT  0x08

#define MOUSE_DEFAULT 0
#define MOUSE_SCROLLWHEEL 1
#define MOUSE_BUTTONS 2

static int8_t mouse_mode = MOUSE_DEFAULT;

static fs_node_t * mouse_pipe;

void (*ps2_mouse_alternate)(void) = NULL;

static void mouse_wait(uint8_t a_type) {
	uint32_t timeout = 100000;
	if (!a_type) {
		while (--timeout) {
			if ((inportb(MOUSE_STATUS) & MOUSE_BBIT) == 1) {
				return;
			}
		}
		debug_print(INFO, "mouse timeout");
		return;
	} else {
		while (--timeout) {
			if (!((inportb(MOUSE_STATUS) & MOUSE_ABIT))) {
				return;
			}
		}
		debug_print(INFO, "mouse timeout");
		return;
	}
}

static void mouse_write(uint8_t write) {
	mouse_wait(1);
	outportb(MOUSE_STATUS, MOUSE_WRITE);
	mouse_wait(1);
	outportb(MOUSE_PORT, write);
}

static uint8_t mouse_read(void) {
	mouse_wait(0);
	char t = inportb(MOUSE_PORT);
	return t;
}

static int mouse_handler(struct regs *r) {
	uint8_t status = inportb(MOUSE_STATUS);
	while ((status & MOUSE_BBIT) && (status & MOUSE_F_BIT)) {
		if (ps2_mouse_alternate) {
			ps2_mouse_alternate();
			break;
		}
		int8_t mouse_in = inportb(MOUSE_PORT);
		switch (mouse_cycle) {
			case 0:
				mouse_byte[0] = mouse_in;
				if (!(mouse_in & MOUSE_V_BIT)) break;
				++mouse_cycle;
				break;
			case 1:
				mouse_byte[1] = mouse_in;
				++mouse_cycle;
				break;
			case 2:
				mouse_byte[2] = mouse_in;
				if (mouse_mode == MOUSE_SCROLLWHEEL || mouse_mode == MOUSE_BUTTONS) {
					++mouse_cycle;
					break;
				}
				goto finish_packet;
			case 3:
				mouse_byte[3] = mouse_in;
				goto finish_packet;
		}
		goto read_next;
finish_packet:
		mouse_cycle = 0;
		/* We now have a full mouse packet ready to use */
		mouse_device_packet_t packet;
		packet.magic = MOUSE_MAGIC;
		int x = mouse_byte[1];
		int y = mouse_byte[2];
		if (x && mouse_byte[0] & (1 << 4)) {
			/* Sign bit */
			x = x - 0x100;
		}
		if (y && mouse_byte[0] & (1 << 5)) {
			/* Sign bit */
			y = y - 0x100;
		}
		if (mouse_byte[0] & (1 << 6) || mouse_byte[0] & (1 << 7)) {
			/* Overflow */
			x = 0;
			y = 0;
		}
		packet.x_difference = x;
		packet.y_difference = y;
		packet.buttons = 0;
		if (mouse_byte[0] & 0x01) {
			packet.buttons |= LEFT_CLICK;
		}
		if (mouse_byte[0] & 0x02) {
			packet.buttons |= RIGHT_CLICK;
		}
		if (mouse_byte[0] & 0x04) {
			packet.buttons |= MIDDLE_CLICK;
		}

		if (mouse_mode == MOUSE_SCROLLWHEEL && mouse_byte[3]) {
			if ((int8_t)mouse_byte[3] > 0) {
				packet.buttons |= MOUSE_SCROLL_DOWN;
			} else if ((int8_t)mouse_byte[3] < 0) {
				packet.buttons |= MOUSE_SCROLL_UP;
			}
		}

		mouse_device_packet_t bitbucket;
		while (pipe_size(mouse_pipe) > (int)(DISCARD_POINT * sizeof(packet))) {
			read_fs(mouse_pipe, 0, sizeof(packet), (uint8_t *)&bitbucket);
		}
		write_fs(mouse_pipe, 0, sizeof(packet), (uint8_t *)&packet);
read_next:
		break;
	}
	irq_ack(MOUSE_IRQ);
	return 1;
}

static int ioctl_mouse(fs_node_t * node, int request, void * argp) {
	if (request == 1) {
		mouse_cycle = 0;
		return 0;
	}
	return -1;
}

static int mouse_install(void) {
	debug_print(NOTICE, "Initializing PS/2 mouse interface");
	uint8_t status, result;
	IRQ_OFF;

	while ((inportb(0x64) & 1)) {
		inportb(0x60);
	}

	mouse_pipe = make_pipe(sizeof(mouse_device_packet_t) * PACKETS_IN_PIPE);
	mouse_wait(1);
	outportb(MOUSE_STATUS, 0xA8);
	mouse_read();
	mouse_wait(1);
	outportb(MOUSE_STATUS, 0x20);
	mouse_wait(0);
	status = inportb(0x60) | 3;
	mouse_wait(1);
	outportb(MOUSE_STATUS, 0x60);
	mouse_wait(1);
	outportb(MOUSE_PORT, status);
	mouse_write(0xF6);
	mouse_read();
	mouse_write(0xF4);
	mouse_read();

	/* Try to enable scroll wheel (but not buttons) */
	if (!args_present("nomousescroll")) {
		mouse_write(0xF2);
		mouse_read();
		result = mouse_read();
		mouse_write(0xF3);
		mouse_read();
		mouse_write(200);
		mouse_read();
		mouse_write(0xF3);
		mouse_read();
		mouse_write(100);
		mouse_read();
		mouse_write(0xF3);
		mouse_read();
		mouse_write(80);
		mouse_read();
		mouse_write(0xF2);
		mouse_read();
		result = mouse_read();
		if (result == 3) {
			mouse_mode = MOUSE_SCROLLWHEEL;
		}
	}

	/* keyboard scancode set */
	mouse_wait(1);
	outportb(MOUSE_PORT, 0xF0);
	mouse_wait(1);
	outportb(MOUSE_PORT, 0x02);
	mouse_wait(1);
	mouse_read();

	irq_install_handler(MOUSE_IRQ, mouse_handler, "ps2 mouse");
	IRQ_RES;

	uint8_t tmp = inportb(0x61);
	outportb(0x61, tmp | 0x80);
	outportb(0x61, tmp & 0x7F);
	inportb(MOUSE_PORT);

	while ((inportb(0x64) & 1)) {
		inportb(0x60);
	}

	mouse_pipe->flags = FS_CHARDEVICE;
	mouse_pipe->ioctl = ioctl_mouse;

	vfs_mount("/dev/mouse", mouse_pipe);
	return 0;
}

static int mouse_uninstall(void) {
	/* TODO */
	return 0;
}

MODULE_DEF(ps2mouse, mouse_install, mouse_uninstall);