/*
 * libdivecomputer
 *
 * Copyright (C) 2009 Jef Driesen
 *
 * 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 2.1 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA
 */

#include <string.h> // memcpy, memcmp
#include <stdlib.h> // malloc, free
#include <assert.h> // assert

#include "device-private.h"
#include "cressi_edy.h"
#include "serial.h"
#include "utils.h"
#include "checksum.h"
#include "array.h"

#define EXITCODE(rc) \
( \
	rc == -1 ? DEVICE_STATUS_IO : DEVICE_STATUS_TIMEOUT \
)

typedef struct cressi_edy_device_t {
	device_t base;
	struct serial *port;
} cressi_edy_device_t;

static device_status_t cressi_edy_device_read (device_t *abstract, unsigned int address, unsigned char data[], unsigned int size);
static device_status_t cressi_edy_device_dump (device_t *abstract, dc_buffer_t *buffer);
static device_status_t cressi_edy_device_close (device_t *abstract);

static const device_backend_t cressi_edy_device_backend = {
	DEVICE_TYPE_CRESSI_EDY,
	NULL, /* set_fingerprint */
	NULL, /* version */
	cressi_edy_device_read, /* read */
	NULL, /* write */
	cressi_edy_device_dump, /* dump */
	NULL, /* foreach */
	cressi_edy_device_close /* close */
};

static int
device_is_cressi_edy (device_t *abstract)
{
	if (abstract == NULL)
		return 0;

    return abstract->backend == &cressi_edy_device_backend;
}


static device_status_t
cressi_edy_transfer (cressi_edy_device_t *device, const unsigned char command[], unsigned int csize, unsigned char answer[], unsigned int asize, int trailer)
{
	assert (asize >= csize);

	// Flush the serial input buffer.
	int rc = serial_flush (device->port, SERIAL_QUEUE_INPUT);
	if (rc == -1) {
		WARNING ("Failed to flush the serial input buffer.");
		return DEVICE_STATUS_IO;
	}

	// Send the command to the device.
	int n = serial_write (device->port, command, csize);
	if (n != csize) {
		WARNING ("Failed to send the command.");
		return EXITCODE (n);
	}

	// Receive the answer of the device.
	n = serial_read (device->port, answer, asize);
	if (n != asize) {
		WARNING ("Failed to receive the answer.");
		return EXITCODE (n);
	}

	// Verify the echo.
	if (memcmp (answer, command, csize) != 0) {
		WARNING ("Unexpected echo.");
		return DEVICE_STATUS_PROTOCOL;
	}

	// Verify the trailer of the packet.
	if (trailer && answer[asize - 1] != 0x45) {
		WARNING ("Unexpected answer trailer byte.");
		return DEVICE_STATUS_PROTOCOL;
	}

	return DEVICE_STATUS_SUCCESS;
}


static device_status_t
cressi_edy_init1 (cressi_edy_device_t *device)
{
	unsigned char command[3] = {0x41, 0x42, 0x43};
	unsigned char answer[6] = {0};

	return cressi_edy_transfer (device, command, sizeof (command), answer, sizeof (answer), 0);
}


static device_status_t
cressi_edy_init2 (cressi_edy_device_t *device)
{
	unsigned char command[1] = {0x44};
	unsigned char answer[2] = {0};

	return cressi_edy_transfer (device, command, sizeof (command), answer, sizeof (answer), 0);
}


static device_status_t
cressi_edy_init3 (cressi_edy_device_t *device)
{
	unsigned char command[1] = {0x0C};
	unsigned char answer[2] = {0};

	return cressi_edy_transfer (device, command, sizeof (command), answer, sizeof (answer), 1);
}


static device_status_t
cressi_edy_quit (cressi_edy_device_t *device)
{
	unsigned char command[1] = {0x46};
	unsigned char answer[1] = {0};

	return cressi_edy_transfer (device, command, sizeof (command), answer, sizeof (answer), 0);
}


device_status_t
cressi_edy_device_open (device_t **out, const char* name)
{
	if (out == NULL)
		return DEVICE_STATUS_ERROR;

	// Allocate memory.
	cressi_edy_device_t *device = (cressi_edy_device_t *) malloc (sizeof (cressi_edy_device_t));
	if (device == NULL) {
		WARNING ("Failed to allocate memory.");
		return DEVICE_STATUS_MEMORY;
	}

	// Initialize the base class.
	device_init (&device->base, &cressi_edy_device_backend);

	// Set the default values.
	device->port = NULL;

	// Open the device.
	int rc = serial_open (&device->port, name);
	if (rc == -1) {
		WARNING ("Failed to open the serial port.");
		free (device);
		return DEVICE_STATUS_IO;
	}

	// Set the serial communication protocol (1200 8N1).
	rc = serial_configure (device->port, 1200, 8, SERIAL_PARITY_NONE, 1, SERIAL_FLOWCONTROL_NONE);
	if (rc == -1) {
		WARNING ("Failed to set the terminal attributes.");
		serial_close (device->port);
		free (device);
		return DEVICE_STATUS_IO;
	}

	// Set the timeout for receiving data (1000 ms).
	if (serial_set_timeout (device->port, 1000) == -1) {
		WARNING ("Failed to set the timeout.");
		serial_close (device->port);
		free (device);
		return DEVICE_STATUS_IO;
	}

	// Set the DTR and clear the RTS line.
	if (serial_set_dtr (device->port, 1) == -1 ||
		serial_set_rts (device->port, 0) == -1) {
		WARNING ("Failed to set the DTR/RTS line.");
		serial_close (device->port);
		free (device);
		return DEVICE_STATUS_IO;
	}

	// Send the init commands.
	cressi_edy_init1 (device);
	cressi_edy_init2 (device);
	cressi_edy_init3 (device);

	// Set the serial communication protocol (4800 8N1).
	rc = serial_configure (device->port, 4800, 8, SERIAL_PARITY_NONE, 1, SERIAL_FLOWCONTROL_NONE);
	if (rc == -1) {
		WARNING ("Failed to set the terminal attributes.");
		serial_close (device->port);
		free (device);
		return DEVICE_STATUS_IO;
	}

	*out = (device_t*) device;

	return DEVICE_STATUS_SUCCESS;
}


static device_status_t
cressi_edy_device_close (device_t *abstract)
{
	cressi_edy_device_t *device = (cressi_edy_device_t*) abstract;

	if (! device_is_cressi_edy (abstract))
		return DEVICE_STATUS_TYPE_MISMATCH;

	// Send the quit command.
	cressi_edy_quit (device);

	// Close the device.
	if (serial_close (device->port) == -1) {
		free (device);
		return DEVICE_STATUS_IO;
	}

	// Free memory.
	free (device);

	return DEVICE_STATUS_SUCCESS;
}


static device_status_t
cressi_edy_device_read (device_t *abstract, unsigned int address, unsigned char data[], unsigned int size)
{
	cressi_edy_device_t *device = (cressi_edy_device_t*) abstract;

	if (! device_is_cressi_edy (abstract))
		return DEVICE_STATUS_TYPE_MISMATCH;

	assert (address % (CRESSI_EDY_PACKET_SIZE / 4)== 0);
	assert (size    % CRESSI_EDY_PACKET_SIZE == 0);

	// The data transmission is split in packages
	// of maximum $CRESSI_EDY_PACKET_SIZE bytes.

	unsigned int nbytes = 0;
	while (nbytes < size) {
		// Read the package.
		unsigned int number = address / (CRESSI_EDY_PACKET_SIZE / 4);
		unsigned char answer[3 + CRESSI_EDY_PACKET_SIZE + 1] = {0};
		unsigned char command[3] = {0x52,
				(number >> 8) & 0xFF, // high
				(number     ) & 0xFF}; // low
		device_status_t rc = cressi_edy_transfer (device, command, sizeof (command), answer, sizeof (answer), 1);
		if (rc != DEVICE_STATUS_SUCCESS)
			return rc;

		memcpy (data, answer + 3, CRESSI_EDY_PACKET_SIZE);

		nbytes += CRESSI_EDY_PACKET_SIZE;
		address += CRESSI_EDY_PACKET_SIZE;
		data += CRESSI_EDY_PACKET_SIZE;
	}

	return DEVICE_STATUS_SUCCESS;
}


static device_status_t
cressi_edy_device_dump (device_t *abstract, dc_buffer_t *buffer)
{
	if (! device_is_cressi_edy (abstract))
		return DEVICE_STATUS_TYPE_MISMATCH;

	// Erase the current contents of the buffer and
	// allocate the required amount of memory.
	if (!dc_buffer_clear (buffer) || !dc_buffer_resize (buffer, CRESSI_EDY_MEMORY_SIZE)) {
		WARNING ("Insufficient buffer space available.");
		return DEVICE_STATUS_MEMORY;
	}

	return device_dump_read (abstract, dc_buffer_get_data (buffer),
		dc_buffer_get_size (buffer), CRESSI_EDY_PACKET_SIZE);
}