/*
 * UNO Monitor Daemon
 * Kidacro <kidacro@archamedis.net>
 *
 * gather_stats.c - retrieves stats from system
 *
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/sysinfo.h>
#include <sys/vfs.h>

#define MAX_ENTRIES 10

// from monitor_daemon.c
void send_stats();

// local function prototypes
void get_stats();
char *trim(char *str);
static void get_cpu_load();
void get_cpu_temp();
void get_free_mem();
void get_free_space();

// external vars (monitor_daemon.c)
extern const char *cpu_temp_file;
extern const char *cpu_fanspeed_file;
extern char *drive_free_space[MAX_ENTRIES];
extern int drive_free_space_count;
extern FILE *log_stream;
extern int debug;
extern int line_length;
extern int line_count;

// stats vars
// TODO: make the character sizes dynamic based on line_length
//       src/gather_stats.c:43:6: error: variably modified ‘freespace’ at file scope <-- damn C
//       so we have to make a concession and either #define a max or.... no clue... go back to PHP?
char cpuload[4]; // line 1
char cputemp[6]; // line 1
char freemem[6]; // line 1
char freespace[16]; // line 2

// sysinfo vars
int sysinfo(struct sysinfo *info);

// proto:
// struct sysinfo {
//    long uptime;             /* Seconds since boot */
//    unsigned long loads[3];  /* 1, 5, and 15 minute load averages */
//    unsigned long totalram;  /* Total usable main memory size */
//    unsigned long freeram;   /* Available memory size */
//    unsigned long sharedram; /* Amount of shared memory */
//    unsigned long bufferram; /* Memory used by buffers */
//    unsigned long totalswap; /* Total swap space size */
//    unsigned long freeswap;  /* swap space still available */
//    unsigned short procs;    /* Number of current processes */
//    unsigned long totalhigh; /* Total high memory size */
//    unsigned long freehigh;  /* Available high memory size */
//    unsigned int mem_unit;   /* Memory unit size in bytes */
//    char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding to 64 bytes */
//};

// trims end of strings
char *trim(char *str)
{
    size_t len = 0;
    char *frontp = str;
    char *endp = NULL;

    if( str == NULL ) { return NULL; }
    if( str[0] == '\0' ) { return str; }

    len = strlen(str);
    endp = str + len;

    /* Move the front and back pointers to address the first non-whitespace
     * characters from each end.
     */
    while(isspace((unsigned char) *frontp)) { ++frontp; }
    if(endp != frontp) {
        while(isspace((unsigned char) *(--endp)) && endp != frontp) {}
    }

    if(frontp != str && endp == frontp) {
        *str = '\0';
    }
    else if(str + len - 1 != endp) {
        *(endp + 1) = '\0';
    }

    /* Shift the string so that it starts at str so that if it's dynamically
     * allocated, we can still free it on the returned pointer.  Note the reuse
     * of endp to mean the front of the string buffer now.
     */
    endp = str;
    if(frontp != str) {
        while(*frontp) { *endp++ = *frontp++; }
        *endp = '\0';
    }

    return str;
}

// get stats (retreive, combine, and send stats)
// TODO: force trunication for each line to line_length
//       no reason to hardcode '24' below when we know the exact line_length
void get_stats()
{
    char line_1[24], line_2[24], line_3[24];

	get_cpu_load();
	get_cpu_temp();
	get_free_mem();
    get_free_space();

	snprintf(line_1,sizeof(line_1),"#1%s%% %sC %sM@",cpuload,cputemp,freemem);
	snprintf(line_2,sizeof(line_2),"#2%s@",trim(freespace));
	snprintf(line_3,sizeof(line_3),"#3%s@",cpuload);

	send_stats(line_1,line_2,line_3);

	return;
}

static void get_cpu_load()
{
    //static unsigned int lastTotalUser, lastTotalUserLow, lastTotalSys, lastTotalIdle;
    static unsigned long long lastTotalUser, lastTotalUserLow, lastTotalSys, lastTotalIdle;
    float percent;
    static float lastPercent;
    int intPercent, read_result = 0;
    FILE* file;
    unsigned long long totalUser, totalUserLow, totalSys, totalIdle, total;

    file = fopen("/proc/stat", "r");
    read_result = fscanf(file, "cpu %llu %llu %llu %llu", &totalUser, &totalUserLow, &totalSys, &totalIdle);
    fclose(file);

    // if result cannot be read, set to 0
    if(read_result != 4) {
        snprintf(&*cpuload, sizeof(0), "%d", 0);
        return;
    }

    // we dont have a good value, use old value
    if(totalUser < lastTotalUser || totalUserLow < lastTotalUserLow ||
        totalSys < lastTotalSys || totalIdle < lastTotalIdle)
    {
        percent = -1.0;
        //percent = lastPercent;
    }

    // we have a good value, save it and process it
    else
    {
        total = (totalUser - lastTotalUser) + (totalUserLow - lastTotalUserLow) + (totalSys - lastTotalSys);
        percent = total * 100;
        total += (totalIdle - lastTotalIdle);
        percent /= total;
        lastPercent = percent;
    }

    if(debug) {
        fprintf(log_stream,"lasttotalUser: %llu - lasttotalUserLow: %llu - lasttotalSys: %llu - lasttotalIdle: %llu - lastpercent: %f\n",
    lastTotalUser, lastTotalUserLow, lastTotalSys, lastTotalIdle, lastPercent);

        fprintf(log_stream,"totalUser: %llu - totalUserLow: %llu - totalSys: %llu - totalIdle: %llu - percent: %f\n\n",
    totalUser,totalUserLow, totalSys, totalIdle, percent);
    }

    // save curent values for later comparison
    lastTotalUser = totalUser;
    lastTotalUserLow = totalUserLow;
    lastTotalSys = totalSys;
    lastTotalIdle = totalIdle;

    // force percent (float) to int
    intPercent = percent;

	snprintf(&*cpuload, sizeof(intPercent), "%d", intPercent);

    return;
}

void get_cpu_temp()
{
    FILE* ptr;
    char str[10];

    // opening file in readonly mode
    ptr = fopen(&*cpu_temp_file, "r");

    if(NULL == ptr) {
        fprintf(log_stream,"File %s can't be opened!\n",cpu_temp_file);
        return;
    }

    while(fgets(str, 10, ptr) != NULL) {
        if(debug) {
            fprintf(log_stream,"Raw CPU temp: %s\n", str);
        }
    }

    /*
    1 decimal place
    char a = str[0];
    char b = str[1];
    char c = str[2];
    snprintf(&*cputemp,6,"%c%c.%c",a,b,c);
    */

    // no decimals
    char a = str[0];
    char b = str[1];
    snprintf(&*cputemp,6,"%c%c",a,b);

    fclose(ptr);

    return;
}

void get_free_mem()
{
    struct sysinfo info;
    int myfreemem;

    if(sysinfo(&info) < 0) {
        return;
    }

    if(debug) {
        fprintf(log_stream,"RAW free mem: %ld\n",info.freeram);
    }

    myfreemem = info.freeram / 1024 / 1024;
    snprintf(&*freemem,sizeof(freemem),"%d",myfreemem);

    return;
}

void get_free_space()
{
    struct statfs info;
    int n = 0;
    char *mydrive;
    char myfree_string[line_length];
    long unsigned int mytmpfree;

    // clear freespace array b4 loop or strcat will keep adding to it causing a buffer overflow
    memset(freespace, '\0', sizeof(freespace));

    for(n = 0; n < drive_free_space_count; n++) {
        mydrive = drive_free_space[n];
        statfs(mydrive, &info);
        mytmpfree = ((info.f_bavail*4) / 1024 / 1024) + 1;
        snprintf(myfree_string,10,"%ldG ",mytmpfree);
        strcat(freespace,myfree_string);

        if(debug) {
            fprintf(log_stream, "My Drive: %s\n"
" block size : %ld,"
" total data blocks : %ld,"
" free blocks for root: %ld,"
" free blocks for user: %ld,"
" free space in G: %ld\n\n",
mydrive, info.f_bsize, info.f_blocks, info.f_bfree, info.f_bavail, mytmpfree);
        }
    }

    return;
}