/* Program to reverse a .dat sound file.
 */

#include "DoubleStack.hh"

#include <iostream>  // For error messages
#include <fstream>   // File I/O
#include <iomanip>   // For setprecision
#include <string>    // For STL strings

using namespace std; // This line is necessary for easy use of C++ standard libraries.

int main( int argc, char *argv[] )
{
    ifstream fin;
    ofstream fout;
    DoubleStack s;


    //
    // Check to see if this program was called correctly
    //
    if(argc != 3) 
    {
        cerr << " Incorrect number of arguments" << endl
             << " Usage: " << endl
             << "\t" << argv[0]   // argv[0] is the name of the program
             << " <input file> <output file>" << endl << endl;

        return 1;
    }


    //
    // Open and read the input file
    //
    fin.open(argv[1]);

    if(!fin.is_open())
    {
        cerr << " Error opening input file " << argv[ 1 ] 
             << ", quitting" << endl;

        return 1;
    }

    // Read in the first line of the .dat file. We want to store
    // the "sample rate" in a variable, but we can ignore the rest of the line.
    int sampleRate;
    string strJunk;
    char charJunk;

    fin >> charJunk >> strJunk >> strJunk;
    fin >> sampleRate;

    // Read in the file and place values from the second column in the stack.
    // The first column values are thrown away.  We stop reading if there is
    // an error in the file stream or if we reach the end of the file

    double timestep, data;
    
    while(fin.good())
    {
        fin >> timestep >> data;
        s.push(data);
    }


    //
    // Close the input file and open the output file
    // 
    fin.close();
    fout.open(argv[2]);

    if(!fout.is_open())
    {
        cerr << " Error opening output file " << argv[2] 
             << ", quitting" << endl;
        return 0;
    }

    // This prints out the line "; Sample Rate <sample rate>", printing
    // the frequency rate stored in the "sampleRate" variable.
    fout << "; Sample Rate " << sampleRate << endl;
    
    // Since the first column consists of numbers which start at 0 and 
    // increase by 1/sampleRate every time slice, we'll just use numSteps 
    // to recalculate these numbers.
    int numSteps = 0;

    // We use the setprecision I/O manipulator in order to print our 
    // doubles with a greater number of decimal places
    fout << setprecision(8);
    
    // Print the values in reverse order (by popping them off the stack).
    // The first column just consists of numbers which start at 0 and 
    // increase by 1/sampleRate per row, so we'll use numSteps/sampleRate 
    // to recalculate the appropriate values.  Uniform spacing will 
    // be accomplished by printing a tab.

    while(!s.isEmpty())
    {
        fout << (double)numSteps / sampleRate << "\t" << s.top() << endl;

	s.pop();
        numSteps++;
    }

    // Close the output file
    fout.close();

    return 0;
}