#include "rngutil.h"

Interval *new_interval(size_t n_int) {
    Interval *x = malloc(sizeof(Interval));
    x->n_interval = n_int;
    x->indexed = calloc(n_int, sizeof(size_t));
    return x;
}

void free_interval(Interval *x) {
    free(x->indexed);
    free(x);
}

void intervalizing(Interval *interval, size_t n,
                   float *samples /* samples must be sorted */) {

    float lo = samples[0];
    float hi = samples[n - 1];

    float dx = (hi - lo) / interval->n_interval;

    float curr = lo + dx;

    size_t i = 0;
    size_t ind = 0;
    while (i < n) {
        if (samples[i] < curr) {
            i++;
        } else {
            if (ind == interval->n_interval - 1) {
                interval->indexed[ind] = n;
            } else {
                interval->indexed[ind] = i;
            }

            ind++;
            curr = lo + (ind + 1) * dx;
        }
    }
    if (interval->indexed[interval->n_interval - 1] != n) {
        interval->indexed[interval->n_interval - 1] = n;
    }
}

void print_histogram(Interval *interval, size_t n, float *samples) {
    size_t n_interval = interval->n_interval;
    size_t prev_cum_count = 0;

    const int MAX_STARS = 80;

    double avg_count = (double) n / (double) n_interval;
    double scale_max = avg_count * 4;
    printf("------------------------------------------------------\n");
    printf("# Histogram (n_samples: %zu, avg_bin: %.2f) #\n",
           n, avg_count);
    printf("# (scale ref.: %.2f count = %d stars) #\n",
           scale_max, MAX_STARS);
    printf("# min: %6.2f, max: %6.2f\n",
           samples[0], samples[n - 1]);
    size_t i, j;
    for (i = 0; i < n_interval; i++) {
        size_t current_cumulative_count = interval->indexed[i];
        size_t individual_count = current_cumulative_count - prev_cum_count;

        if (current_cumulative_count < prev_cum_count) {
            printf("!\n");
            individual_count = 0;
        }

        int num_stars = (int) (((double) individual_count / scale_max) * MAX_STARS);

        if (num_stars > MAX_STARS) {
            num_stars = MAX_STARS;
        }

        printf("Bin %3zu: [%8zu](%5.2f%%) | ", i, individual_count, (double) individual_count / (double) n * 100.0);
        for (j = 0; j < num_stars; j++) {
            printf("*");
        }

        if (num_stars == MAX_STARS && (double) individual_count > scale_max) {
            printf("+");
        }
        printf("\n");

        prev_cum_count = current_cumulative_count;
    }
    printf("------------------------------------------------------\n");
}