/*     ____   __     __
        /   /   \  /   \
       /   /      /
      /    \___/  \___/

Date:11/14/17

Name:

Project Description: Project #3; This program is designed to read
in information from a driver's scorecard to include his name, car
number, the date, time, and distance traveled. Using the time and
distance the drivers velocity and acceleration at the given times
will be calculated.

Inputs: The driver's time and distances will be read into the
program as inputs. Those values will then be sent through
a function to calculate the outputs.

Outputs: The outputs include the drivers velocity and acceleration
found based upon the inputs of time and distance.
*/
//*************************************************************

#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <iomanip>

using namespace std; //introduces namespace std

//Prototypes
double to_mph (double);
double v_calc (double, double, double, double);
double a_ftss(double, double, double, double);

int main ( void )
{
//Declare variables
    ifstream infile;
    ofstream output;
    string file_name, date,driver, car_num, data_out;
    double x, y, v1_x, v2_x, accel_x;
    vector <double> data, time, distance, v1_fts={0}, v2_mph={0}, accel={0};
    int size=0;

//Prompt user to choose file needed to read data from input file
    cout<<"What file would you like to use?: ";
    cout<<"(Use the following format: filename.txt)" <<endl;
    cin>>file_name;

    cout<<"What would you like the file for your results to be named?:"
        <<"(Use the following format: filename.txt)" <<endl;
    cin>>data_out;

//Opens input data file
    infile.open(file_name);

//Reads in the first three lines of input file and sets them equal to
//strings
    getline(infile, car_num);
    getline(infile, date);
    getline(infile, driver);

    while(!infile.eof())
        {
/*Reads numeric values into variables x and y where x-values
generate a vector for time and y-values generate a vector for
distance while also calculating the size of the two vectors*/
                    infile>>x>>y;
                    size++;

//Adds x and y values to  the end of respective vectors as long
//as input values are being given
                    time.push_back(x);
                    distance.push_back(y);
        }

            for(int i=1; i<size; i++)
                {
//Calls function v_calc to calulate the velocity in ft/s
//and creates vector v1_fts using velocity values in ft/s
            v1_x=v_calc(distance[i], distance[i-1], time[i], time[i-1]);
            v1_fts.push_back(v1_x);

//Calls function to_mph to calulate the velocity in mph
//and creates vector v2_mph using velocity values in mph
            v2_x=to_mph(v1_x);
            v2_mph.push_back(v2_x);

//Calls function a_ftss to calculate acceleration
//and creates vector accel using acceleration values
            accel_x=a_ftss(v1_fts[i], v1_fts[i-1], time[i], time[i-1] );
            accel.push_back(accel_x);
                }

//Creates and opens outputfile
    output.open(data_out);

//Writes output info to the output file
    output<<car_num<<endl <<date<<endl <<driver<<endl

//Calls vector function accumulate to find sum of all elements in
//vector and divides by the number of elements to yield the average
        <<"Average Velocity: " <<fixed<<setprecision(1)
        <<accumulate(v2_mph.begin(),v2_mph.end(),0)/v2_mph.size()
        <<" " <<"mph" <<endl

//Calls vector function max_element to find the largest velocity
        <<"Max Velocity: "
        <<*max_element(v2_mph.begin(),v2_mph.end())
        <<" "<<"mph" <<endl

        <<"Average Acceleration: "
        <<accumulate(accel.begin(),accel.end(),0)/accel.size()
        <<" " <<"ft/s/2" <<endl

        <<"Max Acceleration: "
        <<*max_element(accel.begin(),accel.end())
        <<" " <<"ft/s/2" <<endl;

//Places the outputs for time, distance, velocity in ft/s and mph,
//and acceleration in the output file 5 values per line
    for(int i=0; i<size; i++)
        {
            output<<time[i] <<"," <<distance[i] <<"," <<v1_fts[i]
                <<"," <<v2_mph[i]<<","<<accel[i] <<endl;
        }

//Closes input file
    infile.close();
    output.close();
    return 0;
}

//Function calculates velocity based on the data from the input file
double v_calc (double distance2, double distance1, double time2 , double time1)
    {
        double v=0;
        v=(distance2-distance1)/(time2-time1);
        return v;
    }

//Function converts velocity from ft/s to mph
double to_mph (double value)
    {
        double mph=0;

        mph=value*3600/5280;

        return mph;
    }

//Function calculates acceleration
double a_ftss(double v1_fts2, double v1_fts1, double time2 , double time1)
    {
        double a=0;
        a=(v1_fts2-v1_fts1)/(time2-time1);
        return a;
    }