/*********************************************************************************
 *      Copyright:  (C) 2021 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  relay.c
 *    Description:  This file is used to control Relay
 *
 *
 * Pin connection:
 *                 Relay Module           Raspberry Pi Board
 *                  VCC       <----->      5V
 *                   I        <----->      #Pin16(BCM GPIO23)
 *                  GND       <----->      GND
 *
 * System install:
 *                  sudo apt install -y libgpiod-dev gpiod
 *
 *
 ********************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <signal.h>
#include <getopt.h>
#include <libgen.h>

#include <gpiod.h>
#include "logger.h"
#include "relay.h"

#define DELAY     500

static relay_info_t    relay_info[RELAY_CNT] =
{
    {"relay1",  23, 1, NULL },
};

int init_relay(relay_ctx_t *ctx)
{
    int            i, rv;
    relay_info_t  *relay;

    if( !ctx )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

	ctx->relay = relay_info;
	ctx->count = RELAY_CNT;

    ctx->chip = gpiod_chip_open_by_name("gpiochip0");
    if( !ctx->chip )
    {
        log_error("open gpiochip failure, maybe you need running as root\n");
        return -2;
    }


    for(i=0; i<ctx->count; i++)
    {
        relay = &ctx->relay[i];

        relay->line = gpiod_chip_get_line(ctx->chip, relay->gpio);
        if( !relay->line )
        {
            log_error("open gpioline for %s[%d] failed\n", relay->name, relay->gpio);
            rv = -3;
            goto failed;
        }

        rv  = gpiod_line_request_output(relay->line, relay->name, !relay->active);
        if( rv )
        {
            log_error("request gpio output for %5s[%d] failed\n", relay->name, relay->gpio);
            rv = -4;
            goto failed;
        }

        log_debug("request %s[%d] for gpio output okay\n", relay->name, relay->gpio);
    }

    return 0;

failed:
    term_relay(ctx);
    return rv;
}

int term_relay(relay_ctx_t *ctx)
{
    int            i;
    relay_info_t  *relay;

    if( !ctx )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

    if( !ctx->chip )
        return 0;

    for(i=0; i<ctx->count; i++)
    {
        relay = &ctx->relay[i];

        if( relay->line )
            gpiod_line_release(relay->line);
    }

    gpiod_chip_close(ctx->chip);
    return 0;
}


int turn_relay(int which, int cmd)
{
    int             rv = 0;
    relay_info_t   *relay;
    relay_ctx_t     ctx;

    if( which<0 || which>=RELAY_CNT )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

	if( (rv=init_relay(&ctx)) < 0 )
	{
		log_error("Initial relay failure, rv=%d\n", rv);
		return -2;
	}

    relay = &ctx.relay[which];

    if( OFF == cmd )
    {
        gpiod_line_set_value(relay->line, !relay->active);
    }
    else
    {
        gpiod_line_set_value(relay->line, relay->active);
    }

	term_relay(&ctx);

    return 0;
}