/////////////////////////////////////////////////////
//
// args.cpp
//
// Jeff Ondich and the CS257 class
//
// Written communally during class to illustrate
// one approach to parsing command-line arguments
// in C/C++.  The basic approach is: (1) set your
// default behaviors, (2) scan through the arguments
// to set non-default behaviors, and (3) execute
// the specified behaviors.
//
// The program's job, such as it is, is to change
// its input to upper case, sending the output
// to standard out.  The input can come from either
// a file or standard in, and there are usage and
// version flags that override the input->output
// and just print suitable messages.
//
/////////////////////////////////////////////////////

#include <iostream>
#include <fstream>
using namespace std;

void printUsageStatement( const char *progName );
void printVersionStatement( const char *progName );
void capitalize( istream& in );

int main( int argc, char *argv[] )
{
    // args [-u] [-v] [file]
    // -u flag prints usage statement
    // -v flag prints version info
    // file, or stdin if file is absent, gets printed
    // in all caps to stdout.


    // Set default behaviors.
    char *fileName = NULL;
    bool printUsage = false;
    bool printVersion = false;

    for( int k=1; k < argc; k++ )
    {
        if( strcmp( argv[k], "-u" ) == 0 )
            printUsage = true;

        else if( strcmp( argv[k], "-v" ) == 0 )
            printVersion = true;

        else if( k < argc - 1 ) // Too many arguments
        {
            printUsage = true;
            break;
        }

        else // There's a single file specified.
        {
            fileName = argv[k];
        }
    }

    if( printUsage  ||  printVersion )
    {
        if( printVersion )
            printVersionStatement( argv[0] );

        if( printUsage )
            printUsageStatement( argv[0] );

        exit( 1 );
    }


    if( fileName != NULL )
    {
        ifstream fin;
        fin.open( fileName );
        if( !fin.is_open() )
        {
            cerr << "Can't open file " << fileName << endl;
            exit( 1 );
        }

        capitalize( fin );
    }
    else
        capitalize( cin );


    return 0;
}

void printUsageStatement( const char *progName )
{
    cerr << "Usage: " << progName << " [-u] [-v] [file]" << endl;
}

void printVersionStatement( const char *progName )
{
    cerr << "Version: " << progName << " -0.1" << endl;
}

void capitalize( istream& in )
{
    char ch;
    while( in.get( ch ) )
    {
        ch = toupper( ch );
        cout << ch;
    }
}