#include <stdio.h>
#include <stdlib.h>
#include <iomanip>
#include <iostream>
#include <time.h>
#include <math.h>
#include <random>

double average(double* arr, int len);
int part_a();
double* run_simulation(int start_cost);
double* get_calls(double mean_time, double total_time);
double exp_dist(double mean);
double get_probability(int X, int N);

int main(){
    part_a();
    //part_b()
    //part_c()
    return 0;
}

int part_a(){
    double* samples = static_cast<double *>(calloc(1000, sizeof(double)));
    double* run_sim_res;
    for(int i = 0; i < 1000; i++){
        //if(i % 1000 == 0)
        //  printf("%d\n", i);
        run_sim_res = run_simulation(100);
        double seats_sold = run_sim_res[0];
        double profit = run_sim_res[1];
        double time_elapsed = run_sim_res[2];
        samples[i] = time_elapsed;
    }
    double avg = average(samples,1000);
    double avg_days = avg/1440.0;
    printf("Average number of days to sell 150 tickets at $100 each is: %f !", avg_days);
    //free(run_sim_res);
    return 0;
}

double average(double* arr, int len) {
    double sum = 0.0;
    for(int i = 0; i < len; i++) {
        sum += arr[i];
    }
    double avg = sum/len;
    return avg;
}

double* run_simulation(int start_cost) {
    double total_time = 60 * 24.0 * 30;
    double mean_time = 120.0;
    int seats = 150;
    int sold = 0;
    double cur_cost = start_cost;
    double profit = 0.0;
    double time_elapsed = 0.0;
    srand(time(0));

    double* calls = get_calls(mean_time,total_time);
    for(int i = 1; i < calls[0]; i++){
        time_elapsed = time_elapsed + calls[i];
        double probability = get_probability(cur_cost,sold);
        double drawn_sample = (double)rand() / (double)RAND_MAX;

        if(drawn_sample <= probability) {
            profit += cur_cost;
            sold += 1;
            if(sold == seats) {
                break;
            }
        }
    }

    double* to_ret = static_cast<double *>(calloc(3, sizeof(double)));
    to_ret[0] = sold;
    to_ret[1] = profit;
    to_ret[2] = time_elapsed;
    return to_ret;
}

double* get_calls(double mean_time, double total_time) {
    double* calls = static_cast<double *>(calloc(500,sizeof(double)));
    int idx = 0;
    double cur_sum = 0.0;
    while(1) {
        double val = exp_dist(mean_time);
        if(cur_sum + val > total_time){
            break;
        }
        calls[idx+1] = val;
        idx++;
        //printf("%d\n", idx);
        cur_sum += val;
    }
    calls[0] = (double) idx;
    return calls;
}

double exp_dist(double mean) {
    double lambda = 1.0/120.0;
    std::random_device rd;
    std::mt19937 generator(rd());
    std::exponential_distribution<double> distribution(lambda);
    double to_ret = distribution(generator);
    return to_ret;
}


double get_probability(int X, int N) {
    double f = (300 - exp(X/100.0))/600.0;
    double g = N/350.0;
    double p = (f > g) ? f : g;
    return p;
}