// retoor <retoor@molodetz.nl>

#include "stats_collector.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sysinfo.h>

static long long g_prev_user = 0;
static long long g_prev_nice = 0;
static long long g_prev_system = 0;
static long long g_prev_idle = 0;

double stats_get_cpu_usage(void) {
    long long user, nice, system, idle, iowait, irq, softirq;

    FILE *f = fopen("/proc/stat", "r");
    if (!f) return 0.0;

    if (fscanf(f, "cpu %lld %lld %lld %lld %lld %lld %lld",
             &user, &nice, &system, &idle, &iowait, &irq, &softirq) != 7) {
        fclose(f);
        return 0.0;
    }
    fclose(f);

    long long prev_total = g_prev_user + g_prev_nice + g_prev_system + g_prev_idle;
    long long total = user + nice + system + idle;
    long long totald = total - prev_total;
    long long idled = idle - g_prev_idle;

    g_prev_user = user;
    g_prev_nice = nice;
    g_prev_system = system;
    g_prev_idle = idle;

    return totald == 0 ? 0.0 : (double)(totald - idled) * 100.0 / totald;
}

void stats_get_memory_usage(double *used_gb) {
    struct sysinfo info;
    if (sysinfo(&info) != 0) {
        *used_gb = 0;
        return;
    }
    *used_gb = (double)(info.totalram - info.freeram - info.bufferram) * info.mem_unit / (1024.0 * 1024.0 * 1024.0);
}

void stats_get_network(long long *bytes_sent, long long *bytes_recv) {
    FILE *f = fopen("/proc/net/dev", "r");
    if (!f) {
        *bytes_sent = 0;
        *bytes_recv = 0;
        return;
    }

    char line[256];
    if (!fgets(line, sizeof(line), f) || !fgets(line, sizeof(line), f)) {
        fclose(f);
        *bytes_sent = 0;
        *bytes_recv = 0;
        return;
    }

    long long total_recv = 0, total_sent = 0;
    while (fgets(line, sizeof(line), f)) {
        char iface[32];
        long long r, t;
        if (sscanf(line, "%31[^:]: %lld %*d %*d %*d %*d %*d %*d %*d %lld", iface, &r, &t) == 3) {
            char *trimmed = iface;
            while (*trimmed == ' ') trimmed++;
            if (strcmp(trimmed, "lo") != 0) {
                total_recv += r;
                total_sent += t;
            }
        }
    }
    fclose(f);
    *bytes_sent = total_sent;
    *bytes_recv = total_recv;
}

void stats_get_disk(long long *sectors_read, long long *sectors_written) {
    FILE *f = fopen("/proc/diskstats", "r");
    if (!f) {
        *sectors_read = 0;
        *sectors_written = 0;
        return;
    }

    char line[2048];
    long long total_read = 0, total_written = 0;
    while (fgets(line, sizeof(line), f)) {
        char device[64];
        long long sr = 0, sw = 0;

        char major[16], minor[16], dev[64];
        char rc[32], rm[32], srd[32], rtm[32], rtm2[32], wc[32], wm[32], swd[32];
        int nfields = sscanf(line, "%15s %15s %63s %31s %31s %31s %31s %31s %31s %31s %31s %31s",
                         major, minor, dev, rc, rm, srd, rtm, rtm2, wc, wm, swd, swd);
        if (nfields >= 11) {
            strncpy(device, dev, sizeof(device) - 1);
            device[sizeof(device) - 1] = '\0';
            char *endptr;
            sr = strtoll(srd, &endptr, 10);
            if (endptr == srd) sr = 0;
            sw = strtoll(swd, &endptr, 10);
            if (endptr == swd) sw = 0;

            if (strncmp(device, "loop", 4) != 0 && strncmp(device, "ram", 3) != 0) {
                size_t len = strlen(device);
                if ((strncmp(device, "sd", 2) == 0 && len == 3) ||
                    (strncmp(device, "nvme", 4) == 0 && strstr(device, "n1p") == NULL) ||
                    (strncmp(device, "vd", 2) == 0 && len == 3) ||
                    (strncmp(device, "hd", 2) == 0 && len == 3)) {
                    total_read += sr;
                    total_written += sw;
                }
            }
        }
    }
    fclose(f);
    *sectors_read = total_read;
    *sectors_written = total_written;
}

void stats_get_load_averages(double *load1, double *load5, double *load15) {
    FILE *f = fopen("/proc/loadavg", "r");
    if (!f) {
        *load1 = *load5 = *load15 = 0.0;
        return;
    }

    if (fscanf(f, "%lf %lf %lf", load1, load5, load15) != 3) {
        *load1 = *load5 = *load15 = 0.0;
    }
    fclose(f);
}