#include <math.h>
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "common.h"

int main(int argc, char **argv) {
  if (argc < 5) {
    fprintf(stderr,
            "USAGE: %s data_file label_file outer_iterations thread_count",
            argv[0]);
    exit(1);
  }

  char *data_file_name = argv[1], *label_file_name = argv[2];
  int outer_iterations = atoi(argv[3]);
  int thread_count = atoi(argv[4]);

  omp_set_num_threads(thread_count);

  struct data *data = read_data(data_file_name);
  struct labels *label = read_labels(label_file_name);

  // NAN CHECK
  for (int i = 0; i < data->dimensions * data->rows; i++) {
    if (isnan(data->buf[i]))
      printf("failed at index %d\n", i);
  }

  printf("Running %d iteration(s) with %d thread(s).\n", outer_iterations,
         thread_count);

  FLOAT *w = calloc(data->dimensions, sizeof(FLOAT));
  FLOAT *new_w = calloc(data->dimensions, sizeof(FLOAT));
  FLOAT *ouais = calloc(data->dimensions * data->rows, sizeof(FLOAT));

  for (int iter = 0; iter < outer_iterations; iter++) {
    double start_time = monotonic_seconds();

#pragma omp parallel for default(shared)
    for (int i = 0; i < data->dimensions; i++) {

      // #pragma omp parallel for default(shared)
      for (int j = 0; j < data->rows; j++) {
        FLOAT x_ni_w_ni = 0;

        // #pragma omp parallel for default(shared) reduction(+ : x_ni_w_ni)
        for (int i2 = 0; i2 < data->dimensions; i2++) {
          if (i2 == i)
            continue;

          x_ni_w_ni = data->buf[data->rows * i2 + j] * w[i2];
        }

        ouais[data->rows * i + j] = label->buf[j] - x_ni_w_ni;
      }

      FLOAT numer = 0, denom = 0;

      // #pragma omp parallel for default(shared) reduction(+ : numer, denom)
      for (int j = 0; j < data->rows; j++) {
        FLOAT xij = data->buf[data->rows * i + j];
        numer += xij * ouais[data->rows * i + j];
        denom += xij * xij;
      }

      if (denom == 0) {
        new_w[i] = 0;
        // printf("wtf? %f\n", numer);
      } else
        new_w[i] = numer / denom;
    }

    double end_time = monotonic_seconds();
    print_time(end_time - start_time);

    printf("Done.\nw = [");
    for (int idx = 0; idx < data->dimensions; idx++) {
      w[idx] = new_w[idx];
      printf("%.3f ", w[idx]);
    }
    printf("]\n");

    // memcpy(w, new_w, data->dimensions * sizeof(FLOAT));
  }

  free(ouais);
  free(new_w);
  free(data->buf);
  free(label->buf);
  free(data);
  free(label);

  // NOTE: NOT PART OF THE ASSIGNMENT
  // Perform testing to ensure that the training actually works

  if (argc >= 7) {
    struct data *test_data = read_data(argv[5]);
    struct labels *test_label = read_labels(argv[6]);

    int num_correct = 0;
    for (int j = 0; j < test_data->rows; j++) {
      FLOAT output = 0;
      for (int i = 0; i < test_data->dimensions; i++) {
        output += test_data->buf[test_data->rows * i + j] * w[i];
      }

      // printf("expected: %f, actual: %f\n", test_label->buf[j], output);
      FLOAT correct_answer = test_label->buf[j];
      FLOAT incorrect_answer = -correct_answer;

      if (fabs(output - correct_answer) < fabs(output - incorrect_answer))
        num_correct += 1;
    }

    printf("num correct: %d, out of %d (%.2f%%)\n", num_correct,
           test_data->rows, (100.0 * num_correct) / test_data->rows);
  }

  free(w);

  return 0;
}