/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
 * Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <errno.h>
#include <glib.h>
#include "libsigrok.h"
#include "libsigrok-internal.h"
#include "protocol.h"

static void log_dmm_packet(const uint8_t *buf)
{
	sr_dbg("DMM packet: %02x %02x %02x %02x %02x %02x %02x"
	       " %02x %02x %02x %02x %02x %02x %02x",
	       buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6],
	       buf[7], buf[8], buf[9], buf[10], buf[11], buf[12], buf[13]);
}

static void handle_packet(const uint8_t *buf, struct sr_dev_inst *sdi,
			  int dmm, void *info)
{
	float floatval;
	struct sr_datafeed_packet packet;
	struct sr_datafeed_analog analog;
	struct dev_context *devc;

	log_dmm_packet(buf);
	devc = sdi->priv;

	memset(&analog, 0, sizeof(struct sr_datafeed_analog));

	analog.channels = sdi->channels;
	analog.num_samples = 1;
	analog.mq = -1;

	dmms[dmm].packet_parse(buf, &floatval, &analog, info);
	analog.data = &floatval;

	/* If this DMM needs additional handling, call the resp. function. */
	if (dmms[dmm].dmm_details)
		dmms[dmm].dmm_details(&analog, info);

	if (analog.mq != -1) {
		/* Got a measurement. */
		packet.type = SR_DF_ANALOG;
		packet.payload = &analog;
		sr_session_send(devc->cb_data, &packet);
		devc->num_samples++;
	}
}

/** Request packet, if required. */
SR_PRIV int req_packet(struct sr_dev_inst *sdi, int dmm)
{
	struct dev_context *devc;
	struct sr_serial_dev_inst *serial;
	int ret;

	if (!dmms[dmm].packet_request)
		return SR_OK;

	devc = sdi->priv;
	serial = sdi->conn;

	if (devc->req_next_at && (devc->req_next_at > g_get_monotonic_time())) {
		sr_spew("Not requesting new packet yet, %" PRIi64 " ms left.",
			((devc->req_next_at - g_get_monotonic_time()) / 1000));
		return SR_OK;
	}

	ret = dmms[dmm].packet_request(serial);
	if (ret < 0) {
		sr_err("Failed to request packet: %d.", ret);
		return ret;
	}

	if (dmms[dmm].req_timeout_ms)
		devc->req_next_at = g_get_monotonic_time() + (dmms[dmm].req_timeout_ms * 1000);

	return SR_OK;
}

static void handle_new_data(struct sr_dev_inst *sdi, int dmm, void *info)
{
	struct dev_context *devc;
	int len, i, offset = 0;
	struct sr_serial_dev_inst *serial;

	devc = sdi->priv;
	serial = sdi->conn;

	/* Try to get as much data as the buffer can hold. */
	len = DMM_BUFSIZE - devc->buflen;
	len = serial_read(serial, devc->buf + devc->buflen, len);
	if (len == 0)
		return; /* No new bytes, nothing to do. */
	if (len < 0) {
		sr_err("Serial port read error: %d.", len);
		return;
	}
	devc->buflen += len;

	/* Now look for packets in that data. */
	while ((devc->buflen - offset) >= dmms[dmm].packet_size) {
		if (dmms[dmm].packet_valid(devc->buf + offset)) {
			handle_packet(devc->buf + offset, sdi, dmm, info);
			offset += dmms[dmm].packet_size;

			/* Request next packet, if required. */
			if (!dmms[dmm].packet_request)
				break;
			if (dmms[dmm].req_timeout_ms || dmms[dmm].req_delay_ms)
				devc->req_next_at = g_get_monotonic_time() +
					dmms[dmm].req_delay_ms * 1000;
			req_packet(sdi, dmm);
		} else {
			offset++;
		}
	}

	/* If we have any data left, move it to the beginning of our buffer. */
	for (i = 0; i < devc->buflen - offset; i++)
		devc->buf[i] = devc->buf[offset + i];
	devc->buflen -= offset;
}

static int receive_data(int fd, int revents, int dmm, void *info, void *cb_data)
{
	struct sr_dev_inst *sdi;
	struct dev_context *devc;
	int64_t time;

	(void)fd;

	if (!(sdi = cb_data))
		return TRUE;

	if (!(devc = sdi->priv))
		return TRUE;

	if (revents == G_IO_IN) {
		/* Serial data arrived. */
		handle_new_data(sdi, dmm, info);
	} else {
		/* Timeout; send another packet request if DMM needs it. */
		if (dmms[dmm].packet_request && (req_packet(sdi, dmm) < 0))
			return FALSE;
	}

	if (devc->limit_samples && devc->num_samples >= devc->limit_samples) {
		sr_info("Requested number of samples reached.");
		sdi->driver->dev_acquisition_stop(sdi, cb_data);
		return TRUE;
	}

	if (devc->limit_msec) {
		time = (g_get_monotonic_time() - devc->starttime) / 1000;
		if (time > (int64_t)devc->limit_msec) {
			sr_info("Requested time limit reached.");
			sdi->driver->dev_acquisition_stop(sdi, cb_data);
			return TRUE;
		}
	}

	return TRUE;
}

#define RECEIVE_DATA(ID_UPPER, DMM_DRIVER) \
SR_PRIV int receive_data_##ID_UPPER(int fd, int revents, void *cb_data) { \
	struct DMM_DRIVER##_info info; \
	return receive_data(fd, revents, ID_UPPER, &info, cb_data); }

/* Driver-specific receive_data() wrappers */
RECEIVE_DATA(BBCGM_M2110, metex14) /* metex14_info used as a dummy. */
RECEIVE_DATA(DIGITEK_DT4000ZC, fs9721)
RECEIVE_DATA(TEKPOWER_TP4000ZC, fs9721)
RECEIVE_DATA(METEX_ME31, metex14)
RECEIVE_DATA(PEAKTECH_3410, metex14)
RECEIVE_DATA(MASTECH_MAS345, metex14)
RECEIVE_DATA(VA_VA18B, fs9721)
RECEIVE_DATA(VA_VA40B, fs9721)
RECEIVE_DATA(METEX_M3640D, metex14)
RECEIVE_DATA(METEX_M4650CR, metex14)
RECEIVE_DATA(PEAKTECH_4370, metex14)
RECEIVE_DATA(PCE_PCE_DM32, fs9721)
RECEIVE_DATA(RADIOSHACK_22_168, metex14)
RECEIVE_DATA(RADIOSHACK_22_805, metex14)
RECEIVE_DATA(RADIOSHACK_22_812, rs9lcd)
RECEIVE_DATA(TECPEL_DMM_8061_SER, fs9721)
RECEIVE_DATA(VOLTCRAFT_M3650CR, metex14)
RECEIVE_DATA(VOLTCRAFT_M3650D, metex14)
RECEIVE_DATA(VOLTCRAFT_M4650CR, metex14)
RECEIVE_DATA(VOLTCRAFT_ME42, metex14)
RECEIVE_DATA(VOLTCRAFT_VC820_SER, fs9721)
RECEIVE_DATA(VOLTCRAFT_VC830_SER, fs9922)
RECEIVE_DATA(VOLTCRAFT_VC840_SER, fs9721)
RECEIVE_DATA(UNI_T_UT60A_SER, fs9721)
RECEIVE_DATA(UNI_T_UT60E_SER, fs9721)
RECEIVE_DATA(UNI_T_UT60G_SER, es519xx)
RECEIVE_DATA(UNI_T_UT61B_SER, fs9922)
RECEIVE_DATA(UNI_T_UT61C_SER, fs9922)
RECEIVE_DATA(UNI_T_UT61D_SER, fs9922)
RECEIVE_DATA(UNI_T_UT61E_SER, es519xx)
RECEIVE_DATA(ISO_TECH_IDM103N, es519xx)
RECEIVE_DATA(TENMA_72_7745_SER, fs9721)
RECEIVE_DATA(TENMA_72_7750_SER, es519xx)