/* 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) 2016-2018 K. Lange
 *
 * VirtualBox Guest Additions driver
 */

#include <kernel/system.h>
#include <kernel/fs.h>
#include <kernel/printf.h>
#include <kernel/types.h>
#include <kernel/logging.h>
#include <kernel/pci.h>
#include <kernel/module.h>
#include <kernel/video.h>
#include <kernel/pipe.h>
#include <kernel/mouse.h>
#include <kernel/args.h>

#define VBOX_VENDOR_ID 0x80EE
#define VBOX_DEVICE_ID 0xCAFE

static void vbox_scan_pci(uint32_t device, uint16_t v, uint16_t d, void * extra) {
	if (v == VBOX_VENDOR_ID && d == VBOX_DEVICE_ID) {
		*((uint32_t *)extra) = device;
	}
}

#define VMM_GetMouseState 1
#define VMM_SetMouseState 2
#define VMM_AcknowledgeEvents 41
#define VMM_ReportGuestInfo 50
#define VMM_GetDisplayChangeRequest 51
#define VMM_ReportGuestCapabilities 55
#define VMM_VideoSetVisibleRegion 72

#define VMMCAP_SeamlessMode (1 << 0)
#define VMMCAP_HostWindows (1 << 1)
#define VMMCAP_Graphics (1 << 2)

#define VMMDEV_VERSION 0x00010003
#define VBOX_REQUEST_HEADER_VERSION 0x10001
struct vbox_header {
	uint32_t size;
	uint32_t version;
	uint32_t requestType;
	int32_t  rc;
	uint32_t reserved1;
	uint32_t reserved2;
};

struct vbox_guest_info {
	struct vbox_header header;
	uint32_t version;
	uint32_t ostype;
};

struct vbox_guest_caps {
	struct vbox_header header;
	uint32_t caps;
};

struct vbox_ack_events {
	struct vbox_header header;
	uint32_t events;
};

struct vbox_display_change {
	struct vbox_header header;
	uint32_t xres;
	uint32_t yres;
	uint32_t bpp;
	uint32_t eventack;
};

struct vbox_mouse {
	struct vbox_header header;
	uint32_t features;
	int32_t x;
	int32_t y;
};

struct vbox_rtrect {
	int32_t xLeft;
	int32_t yTop;
	int32_t xRight;
	int32_t yBottom;
};

struct vbox_visibleregion {
	struct vbox_header header;
	uint32_t count;
	struct vbox_rtrect rect[1];
};


#define EARLY_LOG_DEVICE 0x504
static uint32_t _vbox_write(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
	for (unsigned int i = 0; i < size; ++i) {
		outportb(EARLY_LOG_DEVICE, buffer[i]);
	}
	return size;
}
static fs_node_t vb = { .write = &_vbox_write };

static uint32_t vbox_device = 0;
static uint32_t vbox_port = 0x0;
static int vbox_irq = 0;

static struct vbox_ack_events * vbox_irq_ack;
static uint32_t vbox_phys_ack;
static struct vbox_display_change * vbox_disp;
static uint32_t vbox_phys_disp;
static struct vbox_mouse * vbox_m;
static uint32_t vbox_phys_mouse;
static struct vbox_mouse * vbox_mg;
static uint32_t vbox_phys_mouse_get;
static struct vbox_visibleregion * vbox_visibleregion;
static uint32_t vbox_phys_visibleregion;
static volatile uint32_t * vbox_vmmdev = 0;

static fs_node_t * mouse_pipe;
static fs_node_t * rect_pipe;

#define PACKETS_IN_PIPE 1024
#define DISCARD_POINT 32

static int vbox_irq_handler(struct regs *r) {
	if (!vbox_vmmdev[2]) return 0;

	vbox_irq_ack->events = vbox_vmmdev[2];
	outportl(vbox_port, vbox_phys_ack);
	irq_ack(vbox_irq);

	outportl(vbox_port, vbox_phys_mouse_get);

	unsigned int x, y;

	if (lfb_vid_memory && lfb_resolution_x && lfb_resolution_y && vbox_mg->x && vbox_mg->y) {
		x = ((unsigned int)vbox_mg->x * lfb_resolution_x) / 0xFFFF;
		y = ((unsigned int)vbox_mg->y * lfb_resolution_y) / 0xFFFF;
	} else {
		x = vbox_mg->x;
		y = vbox_mg->y;
	}

	mouse_device_packet_t packet;
	packet.magic = MOUSE_MAGIC;
	packet.x_difference = x;
	packet.y_difference = y;
	packet.buttons = 0;

	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);

	outportl(vbox_port, vbox_phys_disp);
	if (lfb_resolution_x && vbox_disp->xres && (vbox_disp->xres != lfb_resolution_x  || vbox_disp->yres != lfb_resolution_y)) {

		lfb_set_resolution(vbox_disp->xres, vbox_disp->yres);
	}

	return 1;
}

void vbox_set_log(void) {
	debug_file = &vb;
}

#define VBOX_MOUSE_ON (1 << 0) | (1 << 4)
#define VBOX_MOUSE_OFF (0)

static void mouse_on_off(unsigned int status) {
	vbox_m->header.size = sizeof(struct vbox_mouse);
	vbox_m->header.version = VBOX_REQUEST_HEADER_VERSION;
	vbox_m->header.requestType = VMM_SetMouseState;
	vbox_m->header.rc = 0;
	vbox_m->header.reserved1 = 0;
	vbox_m->header.reserved2 = 0;
	vbox_m->features = status;
	vbox_m->x = 0;
	vbox_m->y = 0;
	outportl(vbox_port, vbox_phys_mouse);
}

static int ioctl_mouse(fs_node_t * node, int request, void * argp) {
	if (request == 1) {
		/* Disable */
		mouse_on_off(VBOX_MOUSE_OFF);
		return 0;
	}
	if (request == 2) {
		/* Enable */
		mouse_on_off(VBOX_MOUSE_ON);
		return 0;
	}
	return -1;
}

uint32_t write_rectpipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
	(void)node;
	(void)offset;

	/* TODO should check size */

	/* This is kinda special and always assumes everything was written at once. */
	uint32_t count = ((uint32_t *)buffer)[0];
	vbox_visibleregion->count = count;

	if (count > 254) count = 254; /* enforce maximum */

#if 0
	fprintf(&vb, "Writing %d rectangles\n", count);
#endif

	buffer += sizeof(uint32_t);

	for (unsigned int i = 0; i < count; ++i) {
		memcpy(&vbox_visibleregion->rect[i], buffer, sizeof(struct vbox_rtrect));
#if 0
		fprintf(&vb, "Rectangle %d is [%d,%d,%d,%d]\n",
				i,
				vbox_visibleregion->rect[i].xLeft,
				vbox_visibleregion->rect[i].yTop,
				vbox_visibleregion->rect[i].xRight,
				vbox_visibleregion->rect[i].yBottom);
#endif

		buffer += sizeof(struct vbox_rtrect);
	}

	vbox_visibleregion->header.size = sizeof(struct vbox_header) + sizeof(uint32_t) + sizeof(int32_t) * count * 4;
	outportl(vbox_port, vbox_phys_visibleregion);

	return size;
}

static int vbox_check(void) {
	pci_scan(vbox_scan_pci, -1, &vbox_device);

	if (vbox_device) {
		fprintf(&vb, "VirtualBox host detected, switching log to VirtualBox.\n");

		if (args_present("vboxdebug")) {
			vbox_set_log();
		}
		fprintf(&vb, "HELLO WORLD\n");

		uintptr_t t = pci_read_field(vbox_device, PCI_BAR0, 4);
		if (t > 0) {
			vbox_port = (t & 0xFFFFFFF0);
		}

		uint16_t c = pci_read_field(vbox_device, PCI_COMMAND, 2);
		fprintf(&vb, "Command register: 0x%4x\n", c);
		if (!!(c & (1 << 10))) {
			fprintf(&vb, "Interrupts are disabled\n");
		}


		mouse_pipe = make_pipe(sizeof(mouse_device_packet_t) * PACKETS_IN_PIPE);
		mouse_pipe->flags = FS_CHARDEVICE;
		mouse_pipe->ioctl = ioctl_mouse;

		vfs_mount("/dev/absmouse", mouse_pipe);

		rect_pipe = malloc(sizeof(fs_node_t));
		memset(rect_pipe, 0, sizeof(fs_node_t));
		rect_pipe->mask = 0666;
		rect_pipe->flags = FS_CHARDEVICE;
		rect_pipe->write = write_rectpipe;

		vfs_mount("/dev/vboxrects", rect_pipe);

		vbox_irq = pci_get_interrupt(vbox_device);
		debug_print(WARNING, "(vbox) device IRQ is set to %d", vbox_irq);
		fprintf(&vb, "irq line is %d\n", vbox_irq);
		irq_install_handler(vbox_irq, vbox_irq_handler, "vbox");

		uint32_t vbox_phys = 0;
		struct vbox_guest_info * packet = (void*)kvmalloc_p(0x1000, &vbox_phys);
		packet->header.size = sizeof(struct vbox_guest_info);
		packet->header.version = VBOX_REQUEST_HEADER_VERSION;
		packet->header.requestType = VMM_ReportGuestInfo;
		packet->header.rc = 0;
		packet->header.reserved1 = 0;
		packet->header.reserved2 = 0;
		packet->version = VMMDEV_VERSION;
		packet->ostype = 0;

		outportl(vbox_port, vbox_phys);

		struct vbox_guest_caps * caps = (void*)kvmalloc_p(0x1000, &vbox_phys);
		caps->header.size = sizeof(struct vbox_guest_caps);
		caps->header.version = VBOX_REQUEST_HEADER_VERSION;
		caps->header.requestType = VMM_ReportGuestCapabilities;
		caps->header.rc = 0;
		caps->header.reserved1 = 0;
		caps->header.reserved2 = 0;
		caps->caps = VMMCAP_Graphics | VMMCAP_SeamlessMode;
		outportl(vbox_port, vbox_phys);

		vbox_irq_ack = (void*)kvmalloc_p(0x1000, &vbox_phys_ack);
		vbox_irq_ack->header.size = sizeof(struct vbox_ack_events);
		vbox_irq_ack->header.version = VBOX_REQUEST_HEADER_VERSION;
		vbox_irq_ack->header.requestType = VMM_AcknowledgeEvents;
		vbox_irq_ack->header.rc = 0;
		vbox_irq_ack->header.reserved1 = 0;
		vbox_irq_ack->header.reserved2 = 0;
		vbox_irq_ack->events = 0;


		vbox_disp = (void*)kvmalloc_p(0x1000, &vbox_phys_disp);
		vbox_disp->header.size = sizeof(struct vbox_display_change);
		vbox_disp->header.version = VBOX_REQUEST_HEADER_VERSION;
		vbox_disp->header.requestType = VMM_GetDisplayChangeRequest;
		vbox_disp->header.rc = 0;
		vbox_disp->header.reserved1 = 0;
		vbox_disp->header.reserved2 = 0;
		vbox_disp->xres = 0;
		vbox_disp->yres = 0;
		vbox_disp->bpp = 0;
		vbox_disp->eventack = 1;

		vbox_m = (void*)kvmalloc_p(0x1000, &vbox_phys_mouse);
		mouse_on_off(VBOX_MOUSE_ON);

		/* For use with later receives */
		vbox_mg = (void*)kvmalloc_p(0x1000, &vbox_phys_mouse_get);
		vbox_mg->header.size = sizeof(struct vbox_mouse);
		vbox_mg->header.version = VBOX_REQUEST_HEADER_VERSION;
		vbox_mg->header.requestType = VMM_GetMouseState;
		vbox_mg->header.rc = 0;
		vbox_mg->header.reserved1 = 0;
		vbox_mg->header.reserved2 = 0;

		vbox_visibleregion = (void*)kvmalloc_p(0x1000, &vbox_phys_visibleregion);
		vbox_visibleregion->header.size = sizeof(struct vbox_header) + sizeof(uint32_t) + sizeof(int32_t) * 4; /* TODO + more for additional rects? */
		vbox_visibleregion->header.version = VBOX_REQUEST_HEADER_VERSION;
		vbox_visibleregion->header.requestType = VMM_VideoSetVisibleRegion;
		vbox_visibleregion->header.rc = 0;
		vbox_visibleregion->header.reserved1 = 0;
		vbox_visibleregion->header.reserved2 = 0;
		vbox_visibleregion->count = 1;
		vbox_visibleregion->rect[0].xLeft = 0;
		vbox_visibleregion->rect[0].yTop = 0;
		vbox_visibleregion->rect[0].xRight = 1440;
		vbox_visibleregion->rect[0].yBottom = 900;
		outportl(vbox_port, vbox_phys_visibleregion);

		/* device memory region mapping? */
		{
			uintptr_t t = pci_read_field(vbox_device, PCI_BAR1, 4);
			fprintf(&vb, "mapping vmm_dev = 0x%x\n", t);
			if (t > 0) {
				vbox_vmmdev =  (void *)(t & 0xFFFFFFF0);
			}
			uintptr_t fb_offset = (uintptr_t)vbox_vmmdev;
			for (uintptr_t i = fb_offset; i <= fb_offset + 0x2000; i += 0x1000) {
				dma_frame(get_page(i, 1, kernel_directory), 0, 1, i);
			}
		}

		vbox_vmmdev[3] = 0xFFFFFFFF; /* Enable all for now */
	}

	return 0;
}

static int fini(void) {
	return 0;
}

MODULE_DEF(vboxguest, vbox_check, fini);
MODULE_DEPENDS(lfbvideo);