// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
 */
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <stdbool.h>
#include <string.h>

#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "bpf_util.h"

#define SLOTS 100

static void clear_stats(int fd)
{
        unsigned int nr_cpus = bpf_num_possible_cpus();
        __u64 values[nr_cpus];
        __u32 key;

        memset(values, 0, sizeof(values));
        for (key = 0; key < SLOTS; key++)
                bpf_map_update_elem(fd, &key, values, BPF_ANY);
}

const char *color[] = {
        "\033[48;5;255m",
        "\033[48;5;252m",
        "\033[48;5;250m",
        "\033[48;5;248m",
        "\033[48;5;246m",
        "\033[48;5;244m",
        "\033[48;5;242m",
        "\033[48;5;240m",
        "\033[48;5;238m",
        "\033[48;5;236m",
        "\033[48;5;234m",
        "\033[48;5;232m",
};
const int num_colors = ARRAY_SIZE(color);

const char nocolor[] = "\033[00m";

const char *sym[] = {
        " ",
        " ",
        ".",
        ".",
        "*",
        "*",
        "o",
        "o",
        "O",
        "O",
        "#",
        "#",
};

bool full_range = false;
bool text_only = false;

static void print_banner(void)
{
        if (full_range)
                printf("|1ns     |10ns     |100ns    |1us      |10us     |100us"
                       "    |1ms      |10ms     |100ms    |1s       |10s\n");
        else
                printf("|1us      |10us     |100us    |1ms      |10ms     "
                       "|100ms    |1s       |10s\n");
}

static void print_hist(int fd)
{
        unsigned int nr_cpus = bpf_num_possible_cpus();
        __u64 total_events = 0;
        long values[nr_cpus];
        __u64 max_cnt = 0;
        __u64 cnt[SLOTS];
        __u64 value;
        __u32 key;
        int i;

        for (key = 0; key < SLOTS; key++) {
                bpf_map_lookup_elem(fd, &key, values);
                value = 0;
                for (i = 0; i < nr_cpus; i++)
                        value += values[i];
                cnt[key] = value;
                total_events += value;
                if (value > max_cnt)
                        max_cnt = value;
        }
        clear_stats(fd);
        for (key = full_range ? 0 : 29; key < SLOTS; key++) {
                int c = num_colors * cnt[key] / (max_cnt + 1);

                if (text_only)
                        printf("%s", sym[c]);
                else
                        printf("%s %s", color[c], nocolor);
        }
        printf(" # %lld\n", total_events);
}

int main(int ac, char **argv)
{
        struct bpf_link *links[2];
        struct bpf_program *prog;
        struct bpf_object *obj;
        char filename[256];
        int map_fd, i, j = 0;

        for (i = 1; i < ac; i++) {
                if (strcmp(argv[i], "-a") == 0) {
                        full_range = true;
                } else if (strcmp(argv[i], "-t") == 0) {
                        text_only = true;
                } else if (strcmp(argv[i], "-h") == 0) {
                        printf("Usage:\n"
                               "  -a display wider latency range\n"
                               "  -t text only\n");
                        return 1;
                }
        }

        snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]);
        obj = bpf_object__open_file(filename, NULL);
        if (libbpf_get_error(obj)) {
                fprintf(stderr, "ERROR: opening BPF object file failed\n");
                return 0;
        }

        /* load BPF program */
        if (bpf_object__load(obj)) {
                fprintf(stderr, "ERROR: loading BPF object file failed\n");
                goto cleanup;
        }

        map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
        if (map_fd < 0) {
                fprintf(stderr, "ERROR: finding a map in obj file failed\n");
                goto cleanup;
        }

        bpf_object__for_each_program(prog, obj) {
                links[j] = bpf_program__attach(prog);
                if (libbpf_get_error(links[j])) {
                        fprintf(stderr, "ERROR: bpf_program__attach failed\n");
                        links[j] = NULL;
                        goto cleanup;
                }
                j++;
        }

        printf("  heatmap of IO latency\n");
        if (text_only)
                printf("  %s", sym[num_colors - 1]);
        else
                printf("  %s %s", color[num_colors - 1], nocolor);
        printf(" - many events with this latency\n");

        if (text_only)
                printf("  %s", sym[0]);
        else
                printf("  %s %s", color[0], nocolor);
        printf(" - few events\n");

        for (i = 0; ; i++) {
                if (i % 20 == 0)
                        print_banner();
                print_hist(map_fd);
                sleep(2);
        }

cleanup:
        for (j--; j >= 0; j--)
                bpf_link__destroy(links[j]);

        bpf_object__close(obj);
        return 0;
}