stn := @use("../../../libraries/stn/src/lib.hb");
.{string, memory, buffer, log} := stn

pci := @use("../../../libraries/pci/src/lib.hb");
.{PCIAddress, get_ids, config_read32} := pci;

.{dt_get} := @use("../../../libraries/dt_api/src/lib.hb")

reg := @use("./reg.hb")

PCI_VENDOR_ID_VMWARE := 0x15AD
PCI_DEVICE_ID_VMWARE_SVGA2 := 1029

read_reg := fn(svga_dev: ^SVGADevice, index: u32): u32 {
	memory.outl(svga_dev.ioBase, index)
	return memory.inl(svga_dev.ioBase + 4)
}

write_reg := fn(svga_dev: ^SVGADevice, index: u32, value: u32): void {
	memory.outl(svga_dev.ioBase, index)
	memory.outl(svga_dev.ioBase + 4, value)
	return
}

FIFO := struct {
	reserved_size: u32,
	using_bounce_buffer: u8,
	//bounce_buffer: [u8; 1024 * 1024],
	next_fence: u32,
}
new_fifo := fn(): FIFO {
	//bounce_buffer := @as([u8; 1024 * 1024], idk)
	/*bounce_buffer,*/
	return FIFO.(0, 0, 0)
}

IRQ := struct {
	pending: u32,
	switchContext: u32,
	//IntrContext   oldContext;
	//IntrContext   newContext;
	count: u32,
}

new_irq := fn(): IRQ {
	return IRQ.(0, 0, 0)
}

SVGADevice := struct {
	pciAddr: PCIAddress,
	ioBase: u32,
	fifoMem: ^u32,
	fbMem: ^u8,
	fifoSize: int,
	fbSize: int,
	vramSize: int,
	deviceVersionId: int,
	capabilities: int,
	width: int,
	height: int,
	bpp: int,
	pitch: int,
	fifo: FIFO,
	irq: IRQ,
}

svga_device := fn(): SVGADevice {
	pci_addr := PCIAddress.(0, 0, 0)
	fifo := new_fifo()
	irq := new_irq()
	return SVGADevice.(pci_addr, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, fifo, irq)
}

// TODO : this function is broken
GetBARAddr := fn(addr: PCIAddress, index: int): u32 {
	//bar := config_read32(addr, offsetof(PCIConfigSpace, BAR[index]));
	bar := config_read32(0, 3, 0, 0)
	PCI_CONF_BAR_IO := 0

	mask := 0xF

	/*
	if bar & PCI_CONF_BAR_IO {
		0x3
	} else {
	}*/

	return bar & (mask ^ 0xFFFFFFFF)
}

setup_device := fn(svga_dev: ^SVGADevice): void {
	// TODO: Fix this 
	// refer to https://git.ablecorp.us/able/vmware-svga/src/commit/eea7ddcd0d34702f8f0a33c1933718706c6318c5/lib/refdriver/svga.c#L55


	svga_dev.pciAddr = PCIAddress.(0, 3, 0)
	/*
	pci_id := get_ids(svga_dev.pciAddr.bus, svga_dev.pciAddr.device, svga_dev.pciAddr.function)

	if pci_id.vendor != PCI_VENDOR_ID_VMWARE | pci_id.device != PCI_DEVICE_ID_VMWARE_SVGA2 {
		log.error("SVGA device not found\0")
		return
	}
	*/

	svga_dev.ioBase = config_read32(svga_dev.pciAddr.bus, svga_dev.pciAddr.device, svga_dev.pciAddr.function, 0x10) & 0xFFFFFFF0
	write_reg(svga_dev, reg.SVGA_REG_ENABLE, reg.SVGA_REG_ENABLE_ENABLE)
	svga_dev.capabilities = read_reg(svga_dev, 0x1)
	svga_dev.deviceVersionId = read_reg(svga_dev, 0x2)

	svga_dev.fbMem = GetBARAddr(svga_dev.pciAddr, 1)

	// hardcode values for now
	svga_dev.width = 1024
	svga_dev.height = 768
	svga_dev.bpp = 32
	svga_dev.pitch = svga_dev.width * 4

	svga_dev.fbSize = svga_dev.width * svga_dev.height * svga_dev.bpp / 8

	svga_dev.vramSize = read_reg(svga_dev, 0x10)
	log.info("SVGA device initialized successfully\0")

	return
}

setup_framebuffer := fn(svga_dev: ^SVGADevice): void {
	write_reg(svga_dev, reg.SVGA_REG_WIDTH, svga_dev.width)
	write_reg(svga_dev, reg.SVGA_REG_HEIGHT, svga_dev.height)
	write_reg(svga_dev, reg.SVGA_REG_BITS_PER_PIXEL, svga_dev.bpp)

	log.info("Framebuffer setup complete\0")
	return
}

draw_pixel := fn(svga_dev: ^SVGADevice, x: int, y: int, color: u32): void {
	/*
	if x >= svga_dev.width || y >= svga_dev.height {
		return // what happens if we write outside here : )
	}
	*/

	offset := y * svga_dev.pitch + x * svga_dev.bpp / 8
	mem_addr := svga_dev.fbMem + offset
	memory.outl(mem_addr, color)

	return
}

clear_screen := fn(svga_dev: ^SVGADevice, color: u32): void {
	y := 0
	loop if y == svga_dev.height break else {
		x := 0
		loop if x == svga_dev.width break else {
			draw_pixel(svga_dev, x, y, color)
			x += 1
		}
		y += 1
	}
	return
}