// # Changes: Replaced «double» with «float» in variable declarations
// # Predecessor: variant_float_baseline.cpp

#include "../headers/board_reduced_float.hpp"
#include "../headers/constants_float.hpp"
#include "../headers/pedestrian_reduced_float.hpp"

#include <algorithm>
#include <cmath>
#include <fstream>
#include <iostream>
#include <math.h>
#include <random>
#include <tuple>
#include <vector>

#define SEED 42
#define BOARD_WIDTH 10.0f
#define BOARD_LENGTH 50.0f
#define WALL_EPS 1e-3f
#define BOARD_WIDTH_MINUS_WALL_EPS 9.999f

#ifndef RANDOM_SEED
#define RANDOM_SEED 0
#endif

#ifndef BENCHMARK
#define BENCHMARK 0
#endif

using namespace std;

Pedestrian *init_pedestrians(int n_p) {
#if RANDOM_SEED
  random_device rd;
  mt19937 gen(rd());
#else
  mt19937 gen(SEED);
#endif

  normal_distribution<float> velocity_gen(v0_mean, v0_std_dev);
  uniform_real_distribution<float> y_gen(0.3, BOARD_WIDTH - 0.3);
  uniform_real_distribution<float> x_gen_left(2.0, BOARD_LENGTH / 2.0);
  uniform_real_distribution<float> x_gen_right(BOARD_LENGTH / 2.0, BOARD_LENGTH - 2.0);

  Pedestrian *P = new Pedestrian[n_p];

  int n_p_half = n_p / 2;

  for (int i = 0; i < n_p_half; i++) {
    float x = x_gen_left(gen);
    float y = y_gen(gen);

    float start_pos_x = x;
    float start_pos_y = y;

    float destination_x = BOARD_LENGTH + 30.0;
    float destination_y = y;

    float init_e_x = destination_x - start_pos_x;
    float init_e_y = destination_y - start_pos_y;
    float init_e_norm = sqrt(init_e_x * init_e_x + init_e_y * init_e_y);
    float init_e_unit_x = init_e_x / init_e_norm;
    float init_e_unit_y = init_e_y / init_e_norm;

    float desired_v0;
    do {
      desired_v0 = velocity_gen(gen);
    } while (desired_v0 <= 0.1);

    float v_max = 1.3 * desired_v0;

    P[i] = Pedestrian(0, 0, 0, start_pos_x, start_pos_y, init_e_unit_x, init_e_unit_y, v_max, desired_v0, destination_x, destination_y);
  }

  for (int i = n_p_half; i < n_p; i++) {
    float x = x_gen_right(gen);
    float y = y_gen(gen);

    float start_pos_x = x;
    float start_pos_y = y;
    float destination_x = -30;
    float destination_y = y;

    float init_e_x = destination_x - start_pos_x;
    float init_e_y = destination_y - start_pos_y;
    float init_e_norm = sqrt(init_e_x * init_e_x + init_e_y * init_e_y);
    float init_e_unit_x = init_e_x / init_e_norm;
    float init_e_unit_y = init_e_y / init_e_norm;

    float desired_v0;
    do {
      desired_v0 = velocity_gen(gen);
    } while (desired_v0 <= 0.1);

    float v_max = 1.3 * desired_v0;

    P[i] = Pedestrian(1, 0, 0, start_pos_x, start_pos_y, init_e_unit_x, init_e_unit_y, v_max, desired_v0, destination_x, destination_y);
  }

  return P;
}

Board init_board_without_obstacles() { return Board(BOARD_LENGTH, BOARD_WIDTH, 0, nullptr); }

int run_simulation(Pedestrian *pedestrians, Board &board, int n_p, int n_iter, const char *dump_path) {

#if BENCHMARK
  (void)dump_path;
#endif

#if !BENCHMARK
  const int dump_interval = 1;

  vector<tuple<int, int, float, float, float, float, int>> samples;

  if (dump_path) {
    samples.reserve(static_cast<size_t>(n_iter / dump_interval + 1) * n_p);

    for (int i = 0; i < n_p; i++) {
      Pedestrian &p = pedestrians[i];
      samples.emplace_back(0, i, p.curr_pos_x, p.curr_pos_y, p.e_x, p.e_y, p.color);
    }
  }
#endif

  for (int t = 0; t < n_iter; t++) {
    for (int i = 0; i < n_p; i++) {
      Pedestrian &p = pedestrians[i];

      float desired_velocity_x = p.e_x * p.desired_v0;
      float desired_velocity_y = p.e_y * p.desired_v0;
      float f_alpha_dt_x = (desired_velocity_x - p.curr_vel_x) * dt_times_tau_alpha_inv;
      float f_alpha_dt_y = (desired_velocity_y - p.curr_vel_y) * dt_times_tau_alpha_inv;

      for (int j = 0; j < n_p; j++) {
        if (i == j)
          continue;

        float r_ab_x = p.curr_pos_x - pedestrians[j].curr_pos_x;
        float r_ab_y = p.curr_pos_y - pedestrians[j].curr_pos_y;

        float r_ab_norm = sqrt(r_ab_x * r_ab_x + r_ab_y * r_ab_y);
        r_ab_norm = r_ab_norm > EPS ? r_ab_norm : EPS;

        float r_ab2_x = r_ab_x - pedestrians[j].s_b_e_x;
        float r_ab2_y = r_ab_y - pedestrians[j].s_b_e_y;

        float r_ab2_norm = sqrt(r_ab2_x * r_ab2_x + r_ab2_y * r_ab2_y);
        r_ab2_norm = r_ab2_norm > EPS ? r_ab2_norm : EPS;

        float r_ab_norm_sum = r_ab_norm + r_ab2_norm;

        float two_b_sq = r_ab_norm_sum * r_ab_norm_sum - pedestrians[j].s_b_sq;
        two_b_sq = two_b_sq > EPS_SQ ? two_b_sq : EPS_SQ;
        float two_b = sqrt(two_b_sq);
        float scalar_mult_common = (r_ab_norm_sum / (two_b * r_ab_norm * r_ab2_norm)) * (NEG_V0_AB_div_TWO_SIGMA * exp(two_b * NEG_TWO_SIGMA_INV));
        float scalar_mult_r_ab = scalar_mult_common * r_ab2_norm;
        float scalar_mult_r_ab2 = scalar_mult_common * r_ab_norm;

        float f_alpha_beta_neg_x = r_ab_x * scalar_mult_r_ab + r_ab2_x * scalar_mult_r_ab2;
        float f_alpha_beta_neg_y = r_ab_y * scalar_mult_r_ab + r_ab2_y * scalar_mult_r_ab2;

        float w_val;

        float f_norm_sq = f_alpha_beta_neg_x * f_alpha_beta_neg_x + f_alpha_beta_neg_y * f_alpha_beta_neg_y;
        float rhs = f_norm_sq * cos_phi_sq;
        float e_dot_f = p.e_x * f_alpha_beta_neg_x + p.e_y * f_alpha_beta_neg_y;
        float e_dot_f_sq = e_dot_f * e_dot_f;
        if (e_dot_f >= 0.0 || e_dot_f_sq <= rhs)
          w_val = dt_neg;
        else
          w_val = c_neg_times_dt;

        f_alpha_dt_x = f_alpha_dt_x + f_alpha_beta_neg_x * w_val;
        f_alpha_dt_y = f_alpha_dt_y + f_alpha_beta_neg_y * w_val;
      }

      for (int k = 0; k < board.n_obstacles; k++) {

        float v1_x = p.curr_pos_x - board.obstacles[k].start_x;
        float v1_y = p.curr_pos_y - board.obstacles[k].start_y;
        float v2_x = board.obstacles[k].obstacle_v_x;
        float v2_y = board.obstacles[k].obstacle_v_y;

        float projection = (v1_x * v2_x + v1_y * v2_y) * board.obstacles[k].length_sq_inv;

        if (projection < 0.0)
          projection = 0.0;
        else if (projection > 1.0)
          projection = 1.0;

        float r_aB_x = p.curr_pos_x - (board.obstacles[k].start_x + board.obstacles[k].obstacle_v_x * projection);
        float r_aB_y = p.curr_pos_y - (board.obstacles[k].start_y + board.obstacles[k].obstacle_v_y * projection);

        float r_aB_norm = sqrt(r_aB_x * r_aB_x + r_aB_y * r_aB_y);
        r_aB_norm = r_aB_norm > EPS ? r_aB_norm : EPS;

        float scalar_mult = (NEG_U0_AB_div_R * exp(r_aB_norm * NEG_R_INV)) / r_aB_norm;
        float f_alpha_B_neg_x = r_aB_x * scalar_mult;
        float f_alpha_B_neg_y = r_aB_y * scalar_mult;

        float w_val;

        float e_dot_f = (f_alpha_B_neg_y == 0) ? 0 : (f_alpha_B_neg_y < 0 ? -p.e_y : p.e_y);

        if (e_dot_f >= cos_phi)
          w_val = dt_neg;
        else
          w_val = c_neg_times_dt;

        float f_alpha_B_dt_x = f_alpha_B_neg_x * w_val;
        float f_alpha_B_dt_y = f_alpha_B_neg_y * w_val;

        f_alpha_dt_x += f_alpha_B_dt_x;
        f_alpha_dt_y += f_alpha_B_dt_y;
      }

      p.w_x += f_alpha_dt_x;
      p.w_y += f_alpha_dt_y;
    }

    for (int i = 0; i < n_p; i++) {
      Pedestrian &p = pedestrians[i];

      float w_norm = sqrt(p.w_x * p.w_x + p.w_y * p.w_y);

      float w_norm2 = w_norm > EPS ? w_norm : EPS;

      float correction_factor = min(1.0f, p.v_max / w_norm2);

      p.curr_vel_x = p.w_x * correction_factor;
      p.curr_vel_y = p.w_y * correction_factor;

      p.curr_pos_x = p.curr_pos_x + p.curr_vel_x * dt;
      p.curr_pos_y = p.curr_pos_y + p.curr_vel_y * dt;

      if (p.color == 0 && p.curr_pos_x > (BOARD_LENGTH - 1.5)) {
        p.curr_pos_x = 1.0;
        p.destination_y = p.curr_pos_y;
        p.w_x = p.desired_v0;
        p.w_y = 0.0;
        p.curr_vel_x = p.w_x;
        p.curr_vel_y = p.w_y;
      }
      if (p.color == 1 && p.curr_pos_x < 1.5) {
        p.curr_pos_x = BOARD_LENGTH - 1.0;
        p.destination_y = p.curr_pos_y;
        p.w_x = -p.desired_v0;
        p.w_y = 0.0;
        p.curr_vel_x = p.w_x;
        p.curr_vel_y = p.w_y;
      }

      p.curr_pos_y = clamp(p.curr_pos_y, WALL_EPS, BOARD_WIDTH_MINUS_WALL_EPS);

      float e_x = p.destination_x - p.curr_pos_x;
      float e_y = p.destination_y - p.curr_pos_y;

      float e_norm = sqrt(e_x * e_x + e_y * e_y);
      float e_norm2 = e_norm > EPS ? e_norm : EPS;
      float e_norm_inv = 1.0 / e_norm2;

      p.e_x = e_x * e_norm_inv;
      p.e_y = e_y * e_norm_inv;

      float velocity_norm_sq = p.curr_vel_x * p.curr_vel_x + p.curr_vel_y * p.curr_vel_y;

      float velocity_norm = sqrt(velocity_norm_sq);

      p.s_b_sq = velocity_norm_sq * delta_t_sq;

      p.s_b_e_x = p.e_x * (velocity_norm * delta_t);
      p.s_b_e_y = p.e_y * (velocity_norm * delta_t);

#if !BENCHMARK
      if (dump_path && (t % dump_interval == 0)) {
        samples.emplace_back(t + 1, i, p.curr_pos_x, p.curr_pos_y, p.e_x, p.e_y, p.color);
      }
#endif
    }
  }

#if !BENCHMARK
  if (dump_path) {
    ofstream out(dump_path);
    out << "time,id,x,y,p.e.x,p.e.y,color\n";

    for (auto &[t, id, x, y, e_x, e_y, c] : samples) {
      out << t << ',' << id << ',' << x << ',' << y << ',' << e_x << ',' << e_y << ',' << c << '\n';
    }
  }
#endif

  return 0;
}