/*
 * This file is part of the libopencm3 project.
 *
 * Copyright (C) 2010 Gareth McMullin <gareth@blacksphere.co.nz>
 * Copyright (C) 2013 Alexandru Gagniuc <mr.nuke.me@gmail.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */
/*
 * This package is _meant_ to be platform independent, just a full
 * cdc-acm impl, with callbacks
 */

#include "usb_cdcacm.h"

#include <stdio.h>
#include <stdlib.h>
#include <libopencm3/usb/usbd.h>
#include <libopencm3/usb/cdc.h>
#include <libopencm3/cm3/scb.h>
// NOTHING ELSE! this file _does_ not know about part specifics!

#include "syscfg.h"
#include "ringb.h"

#define ER_DEBUG
#ifdef ER_DEBUG
#define ER_DPRINTF(fmt, ...) \
    do { printf(fmt, ## __VA_ARGS__); } while (0)
#else
#define ER_DPRINTF(fmt, ...) \
    do { } while (0)
#endif


static uint8_t usbd_control_buffer[128];
static usbd_device *acm_dev;

static const struct usb_device_descriptor dev = {
	.bLength = USB_DT_DEVICE_SIZE,
	.bDescriptorType = USB_DT_DEVICE,
	.bcdUSB = 0x2000,
	.bDeviceClass = USB_CLASS_CDC,
	.bDeviceSubClass = 0,
	.bDeviceProtocol = 0,
	.bMaxPacketSize0 = 64,
	.idVendor = 0xc03e,
	.idProduct = 0xb007,
	.bcdDevice = 0x2000,
	.iManufacturer = 1,
	.iProduct = 2,
	.iSerialNumber = 3,
	.bNumConfigurations = 1,
};

/*
 * This notification endpoint isn't implemented. According to CDC spec it's
 * optional, but its absence causes a NULL pointer dereference in the
 * Linux cdc_acm driver.
 */
static const struct usb_endpoint_descriptor comm_endp[] = {{
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = 0x83,
	.bmAttributes = USB_ENDPOINT_ATTR_INTERRUPT,
	.wMaxPacketSize = 16,
	.bInterval = 1,
}};

static const struct usb_endpoint_descriptor data_endp[] = {{
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = 0x01,
	.bmAttributes = USB_ENDPOINT_ATTR_BULK,
	.wMaxPacketSize = 64,
	.bInterval = 1,
}, {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = 0x82,
	.bmAttributes = USB_ENDPOINT_ATTR_BULK,
	.wMaxPacketSize = 64,
	.bInterval = 1,
}};

static const struct {
	struct usb_cdc_header_descriptor header;
	struct usb_cdc_call_management_descriptor call_mgmt;
	struct usb_cdc_acm_descriptor acm;
	struct usb_cdc_union_descriptor cdc_union;
} __attribute__ ((packed)) cdcacm_functional_descriptors = {
	.header = {
		.bFunctionLength = sizeof(struct usb_cdc_header_descriptor),
		.bDescriptorType = CS_INTERFACE,
		.bDescriptorSubtype = USB_CDC_TYPE_HEADER,
		.bcdCDC = 0x0110,
	},
	.call_mgmt = {
		.bFunctionLength =
			sizeof(struct usb_cdc_call_management_descriptor),
		.bDescriptorType = CS_INTERFACE,
		.bDescriptorSubtype = USB_CDC_TYPE_CALL_MANAGEMENT,
		.bmCapabilities = 0,
		.bDataInterface = 1,
	},
	.acm = {
		.bFunctionLength = sizeof(struct usb_cdc_acm_descriptor),
		.bDescriptorType = CS_INTERFACE,
		.bDescriptorSubtype = USB_CDC_TYPE_ACM,
		.bmCapabilities = (1 << 1),
	},
	.cdc_union = {
		.bFunctionLength = sizeof(struct usb_cdc_union_descriptor),
		.bDescriptorType = CS_INTERFACE,
		.bDescriptorSubtype = USB_CDC_TYPE_UNION,
		.bControlInterface = 0,
		.bSubordinateInterface0 = 1,
	}
};

static const struct usb_interface_descriptor comm_iface[] = {{
	.bLength = USB_DT_INTERFACE_SIZE,
	.bDescriptorType = USB_DT_INTERFACE,
	.bInterfaceNumber = 0,
	.bAlternateSetting = 0,
	.bNumEndpoints = 1,
	.bInterfaceClass = USB_CLASS_CDC,
	.bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
	.bInterfaceProtocol = USB_CDC_PROTOCOL_AT,
	.iInterface = 0,

	.endpoint = comm_endp,

	.extra = &cdcacm_functional_descriptors,
	.extralen = sizeof(cdcacm_functional_descriptors)
}};

static const struct usb_interface_descriptor data_iface[] = {{
	.bLength = USB_DT_INTERFACE_SIZE,
	.bDescriptorType = USB_DT_INTERFACE,
	.bInterfaceNumber = 1,
	.bAlternateSetting = 0,
	.bNumEndpoints = 2,
	.bInterfaceClass = USB_CLASS_DATA,
	.bInterfaceSubClass = 0,
	.bInterfaceProtocol = 0,
	.iInterface = 0,

	.endpoint = data_endp,
}};

static const struct usb_interface ifaces[] = {{
	.num_altsetting = 1,
	.altsetting = comm_iface,
}, {
	.num_altsetting = 1,
	.altsetting = data_iface,
}};

static const struct usb_config_descriptor config = {
	.bLength = USB_DT_CONFIGURATION_SIZE,
	.bDescriptorType = USB_DT_CONFIGURATION,
	.wTotalLength = 0,
	.bNumInterfaces = 2,
	.bConfigurationValue = 1,
	.iConfiguration = 0,
	.bmAttributes = 0x80,
	.bMaxPower = 0x32,

	.interface = ifaces,
};

static char serial[] = "none";
static const char *usb_strings[] = {
	"libopencm3",
	"usb_to_serial_cdcacm",
	serial,
	"DEMO",
};

struct ringb rx_ring;
static uint8_t rx_ring_data[64];
struct ringb tx_ring;
static uint8_t tx_ring_data[128];
bool nakked = false;


static int cdcacm_control_request(usbd_device *usbd_dev,
	struct usb_setup_data *req, uint8_t **buf,
	uint16_t *len,
	void (**complete) (usbd_device *usbd_dev,
	struct usb_setup_data *
	req))
{
	uint8_t dtr, rts;

	(void) complete;
	(void) buf;
	(void) usbd_dev;

	switch (req->bRequest) {
	case USB_CDC_REQ_SET_CONTROL_LINE_STATE:
	{
		/*
		 * This Linux cdc_acm driver requires this to be implemented
		 * even though it's optional in the CDC spec, and we don't
		 * advertise it in the ACM functional descriptor.
		 */

		dtr = (req->wValue & (1 << 0)) ? 1 : 0;
		rts = (req->wValue & (1 << 1)) ? 1 : 0;
		ER_DPRINTF("CTRLRQ:%d Set Line state: dtr:%d rts: %d\n", req->wIndex, dtr, rts);

		// FIXME - need to get port based on wIndex I believe?
		cdcacm_arch_set_line_state(0, dtr, rts);

		return 1;
	}
	case USB_CDC_REQ_SET_LINE_CODING:
	{
		struct usb_cdc_line_coding *coding;

		if (*len < sizeof (struct usb_cdc_line_coding))
			return 0;

		coding = (struct usb_cdc_line_coding *) *buf;
		ER_DPRINTF("CTRLRQ: line coding: %lu(%u:%u:%u)\n", coding->dwDTERate,
			coding->bDataBits, coding->bParityType, coding->bCharFormat);
		return glue_set_line_coding_cb(coding->dwDTERate,
			coding->bDataBits,
			coding->bParityType,
			coding->bCharFormat);
	}
	}
	return 0;
}

static void cdcacm_data_rx_cb(usbd_device *usbd_dev, uint8_t ep)
{
	uint8_t buf[64];
	/* nak right now, we're not sure whether we'll be able to even process this!*/
	usbd_ep_nak_set(usbd_dev, ep, 1);
	int len = usbd_ep_read_packet(usbd_dev, ep, buf, 64);
	ER_DPRINTF("Hrx%db\n", len);
	cdcacm_arch_pin(0, CDCACM_PIN_LED_TX, 1);
	cdcacm_arch_pin(0, CDCACM_PIN_RS485DE, 1);
	for (int x = 0; x < len; x++) {
		if (!ringb_put(&tx_ring, buf[x])) {
			// failed to process usb traffic properly.
			// should _never_ happen, means we failed to nak in time.
			// this is _never_recoverable beyond watchdog reset.
			while(1);
		}
		// look up port to suart mapping which side?
		cdcacm_arch_txirq(0, 1);
	}
	if (ringb_depth(&tx_ring) < 64) {
		ER_DPRINTF("ACK\n");
		usbd_ep_nak_set(usbd_dev, ep, 0);
	} else {
		nakked = true;
	}
}

static void cdcacm_set_config(usbd_device *usbd_dev, uint16_t wValue)
{
	(void) wValue;

	usbd_ep_setup(usbd_dev, 0x01, USB_ENDPOINT_ATTR_BULK, 64,
		cdcacm_data_rx_cb);
	usbd_ep_setup(usbd_dev, 0x82, USB_ENDPOINT_ATTR_BULK, 64, NULL);
	usbd_ep_setup(usbd_dev, 0x83, USB_ENDPOINT_ATTR_INTERRUPT, 16, NULL);

	usbd_register_control_callback(usbd_dev,
		USB_REQ_TYPE_CLASS |
		USB_REQ_TYPE_INTERFACE,
		USB_REQ_TYPE_TYPE |
		USB_REQ_TYPE_RECIPIENT,
		cdcacm_control_request);
}

/* FIXME - need to report this! */
void cdcacm_line_state_changed_cb(uint8_t linemask)
{
	const int size = sizeof (struct usb_cdc_notification) + 2;
	uint8_t buf[size];

	struct usb_cdc_notification *notify = (void *) buf;
	notify->bmRequestType = 0xa1;
	notify->bNotification = USB_CDC_NOTIFY_SERIAL_STATE;
	notify->wValue = 0;
	notify->wIndex = 1;
	notify->wLength = 2;
	uint16_t *data = (void *) &buf[sizeof (struct usb_cdc_notification)];
	*data = linemask;

	while (usbd_ep_write_packet(acm_dev, 0x83, buf, size) == size);
}


/* Y0, moron, nothing's stopping rx irqs from happening, have fun when you overflow temp buffer! */
static void task_drain_rx(struct ringb *r) {
	uint8_t zero_copy_is_for_losers[sizeof(rx_ring_data)];
	int zci = 0;
	int c = ringb_get(r);
	while (c >= 0) {
		zero_copy_is_for_losers[zci++] = c;
		c = ringb_get(r);
	}
	if (zci) {
		trace_send16(STIMULUS_RING_DRAIN, zci);
		ER_DPRINTF("Drx %db\n", zci);
		usbd_ep_write_packet(acm_dev, 0x82, zero_copy_is_for_losers, zci);
	}
}


usbd_device * usb_cdcacm_init(const usbd_driver *driver, const char *userserial)
{
	ringb_init(&rx_ring, rx_ring_data, sizeof(rx_ring_data));
	ringb_init(&tx_ring, tx_ring_data, sizeof(tx_ring_data));
	if (userserial) {
                usb_strings[2] = userserial;
        }

	acm_dev = usbd_init(driver, &dev, &config, usb_strings, 4,
		usbd_control_buffer, sizeof (usbd_control_buffer));
	usbd_register_set_config_callback(acm_dev, cdcacm_set_config);
	return acm_dev;
}


void usb_cdcacm_poll(usbd_device *usbd_dev) // FIXME -drop to acm_dev internal
{
	// Originally, calling this every 50 times caused some rx character droppage,
	// and every 500 times caused _none_.  _probably_ needs to be tied to
	// a timer and something like the current baud rate and the inter character time
	static int i = 0;
	if (i++ > 500) {
		// hacktastic
		if (ringb_depth(&tx_ring) < 64 && nakked) {
			usbd_ep_nak_set(usbd_dev, 1, 0);
			nakked = false;
		}

		task_drain_rx(&rx_ring);
		i = 0;
	}

	
}