#include <rcc/flash.h>
#include <rcc/rcc.h>
#include <rcc/crs.h>
#include <syscfg/syscfg.h>
#include <gpio/gpio.h>
#include <os/time.h>
#include <spi/spi.h>
#include <usb/usb.h>
#include <usb/descriptor.h>

auto dev_desc = device_desc(0x200, 0, 0, 0, 64, 0x1d50, 0x60f8, 0, 0, 0, 0, 1);
auto conf_desc = configuration_desc(1, 1, 0, 0xc0, 0,
	interface_desc(1, 0, 1, 0xff, 0x00, 0x00, 0,
		endpoint_desc(0x81, 0x02, 64, 0)
	)
);

desc_t dev_desc_p = {sizeof(dev_desc), (void*)&dev_desc};
desc_t conf_desc_p = {sizeof(conf_desc), (void*)&conf_desc};

USB_l0 usb(USB, dev_desc_p, conf_desc_p);

Pin nfc_sck     = GPIOB[3];
Pin nfc_miso    = GPIOB[4];
Pin nfc_mosi    = GPIOB[5];
Pin nfc_ss      = GPIOB[6];
Pin nfc_irq_out = GPIOB[7];
Pin nfc_irq_in  = GPIOC[13];

Pin button      = GPIOA[3];
Pin led         = GPIOA[4];

class CR95HF {
	private:
		SPI_t& spi;
		Pin& ss;
	
	public:
		CR95HF(SPI_t& spi_bus, Pin& p) : spi(spi_bus), ss(p) {}
		
		void send_cmd(uint8_t cmd, uint32_t len, uint8_t* buf) {
			ss.off();
			
			spi.transfer_byte(0);
			spi.transfer_byte(cmd);
			spi.transfer_byte(len);
			
			while(len--) {
				spi.transfer_byte(*buf++);
			}
			
			ss.on();
		}
		
		uint32_t get_response(uint32_t maxlen, uint8_t* buf) {
			uint32_t len = 0;
			
			while(nfc_irq_out.get());
			
			ss.off();
			
			spi.transfer_byte(2);
			*buf++ = spi.transfer_byte();
			len++;
			
			uint32_t datalen = spi.transfer_byte();
			*buf++ = datalen;
			len++;
			
			while(len < datalen + 2) {
				*buf++ = spi.transfer_byte();
				len++;
			}
			
			ss.on();
			
			return len;
		}
};

CR95HF cr95hf(SPI1, nfc_ss);

class USB_NFC : public USB_class_driver {
	private:
		USB_generic& usb;
		
	public:
		USB_NFC(USB_generic& usbd) : usb(usbd) {
			usb.register_driver(this);
		}
		
	protected:
		virtual void handle_set_configuration(uint8_t configuration) {
			if(configuration) {
				usb.hw_conf_ep(0x81, EPType::Bulk, 64);
			}
		}
};

USB_NFC usb_nfc(usb);

int main() {
	rcc_init();
	
	// Initialize system timer.
	STK.LOAD = 32000000 / 8 / 1000; // 1000 Hz.
	STK.VAL = 0;
	STK.CTRL = 0x03;
	
	// Enable CRS.
	RCC.enable(RCC.CRS);
	CRS.enable();
	
	RCC.enable(RCC.GPIOA);
	RCC.enable(RCC.GPIOB);
	RCC.enable(RCC.GPIOC);
	
	led.set_mode(Pin::Output);
	
	RCC.enable(RCC.USB);
	
	usb.init();
	
	Time::sleep(10);
	USB.reg.BCDR |= 1 << 15;
	
	RCC.enable(RCC.SPI1);
	
	nfc_irq_out.set_mode(Pin::Input);
	nfc_irq_in.on();
	nfc_irq_in.set_mode(Pin::Output);
	
	nfc_ss.on();
	nfc_ss.set_mode(Pin::Output);
	nfc_sck.set_speed(Pin::High);
	nfc_sck.set_mode(Pin::AF);
	nfc_miso.set_mode(Pin::AF);
	nfc_mosi.set_mode(Pin::AF);
	
	SPI1.reg.CR1 = (1 << 9) | (1 << 8) | (1 << 6) | (4 << 3) | (1 << 2) | (0 << 1) | (0 << 0); // SSM, SSI, SPE, 36/32MHz, MSTR, CPOL=0, CPHA=0
	SPI1.reg.CR2 = (1 << 12) | (7 << 8); // FRXTH, DS = 8bit
	
	Time::sleep(1);
	nfc_irq_in.off();
	Time::sleep(1);
	nfc_irq_in.on();
	Time::sleep(1);
	
	uint8_t buf[64];
	bool cmd_sent = false;
	uint32_t nfc_delay_until = 0;
	uint8_t bulk_buf[8];
	
	Time::sleep(1000);
	
	cr95hf.send_cmd(0x02, 2, (uint8_t*)"\x01\x05"); // Select ISO 15693
	cr95hf.get_response(64, buf);
	
	while(1) {
		if(Time::time() < nfc_delay_until) {
			// Just do nothing.
		} else if(!cmd_sent) {
			led.off();
			
			cr95hf.send_cmd(0x04, 3, (uint8_t*)"\x26\x01\x00"); // INVENTORY
			cmd_sent = true;
		} else if(!nfc_irq_out.get()) {
			cr95hf.get_response(64, buf);
			cmd_sent = false;
			
			if(buf[0] == 128 && buf[14] == 0) {
				led.on();
				
				uint8_t* id_raw = &buf[11];
				uint8_t* id_buf = bulk_buf;
				for(uint32_t i = 0; i < 8; i++) {
					*id_buf++ = *id_raw--;
				}
				
				if(usb.ep_ready(1)) {
					usb.write(1, (uint32_t*)bulk_buf, sizeof(bulk_buf));
				}
				
				nfc_delay_until = Time::time() + 5000; // Valid for five seconds.
			} else {
				nfc_delay_until = Time::time() + 100; // Retry in 100ms.
			}
		}
		
		usb.process();
	}
}