//	ENGR 131, Monday 3:30 Recitation
//	HW #11 - Files and Strings
//	(Solution)

#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
//#include <useful.h>
//#include <useful.cpp>

using std::cout;
using std::cin;
using std::endl;
using std::ifstream;
using std::ofstream;
using std::string;
using std::getline;
//using aer::GetInteger;

string GetString(string prompt);
void openfile(ifstream& in, string infilename);
string FindReplace(ifstream& in, string search, bool replace);
void DispStats(ifstream& in);
int GetInteger(const string& prompt, int min, int max);
bool Ask(const string& prompt);

int main()
{
	ifstream in;
	ofstream out;
	string infilename;
	int choice;

	string tofind;
	bool replace;

	string newfile;

	for(;;)	// main program loop
	{
		cout << "\nWhat would you like to do?\n"
			 << "1. Open a new file\n"
			 << "2. Find every instance of a given word\n"
			 << "3. Calculate the file's statistics (# words, etc.)\n"
			 << "4. Quit\n";

		choice = GetInteger("Enter choice", 1, 4);

		switch(choice)
		{
		case 1:	infilename = GetString("What file would you like to open?");
				openfile(in, infilename);
				break;

		case 2:	if(!in.is_open())
				{
					infilename = GetString("What file would you like to open?");
					openfile(in, infilename);
				}
				tofind = GetString("What string would you like to search for?");
				replace = Ask("Would you like to replace it with another string");
				newfile = FindReplace(in, tofind, replace);
				in.ignore(1024);
				in.clear();
				in.close();
				out.open(infilename.c_str());
				out << newfile;
				out.close();
				openfile(in, infilename);
				break;

		case 3: if(!in.is_open())
				{
					infilename = GetString("What file would you like to open?");
					openfile(in, infilename);
				}
				DispStats(in);
				in.ignore(1024);
				in.clear();
				in.close();
				openfile(in, infilename);
				break;

		case 4:	break;

		}

		if(choice == 4) break;
	}

	return 0;
}



void openfile(ifstream& in, string infilename)
{
	for(;;)
	{
		in.open(infilename.c_str());

		if(!in.is_open())
		{
			cout << "\nThe file could not be opened.  This could be because it:\n"
				 << "- does not exist\n"
				 << "- is in use by another application\n"
				 << "- is in the incorrect directory (it must either be in this\n"
				 << "   directory, or include a full path)\n"
				 << "Enter a new filename.\n\n";
			infilename = GetString("What file would you like to open?");
		}

		else break;
	}
}


string GetString(string prompt)
{
	string input;

	for(;;)
	{
		cout << prompt << ": ";
		getline(cin, input);

		if(cin.fail())
			cout << "\nThat was an invalid entry. Try again.\n";

		else break;
	}

	cin.clear();
	cin.ignore(1024,'\n');
	return input;
}


int GetInteger(const string& prompt, int min, int max)
{
	int num;

	for(;;)
	{
		cout << prompt << ": ";
		cin >> num;

		if(cin.fail() || num < min || num > max)
		{
			cout << "That was an invalid entry. Try again.\n";
			cin.clear();
			cin.ignore(1024,'\n');
		}
		else break;
	}

	cin.clear();
	cin.ignore(1024, '\n');
	return num;
}



void DispStats(ifstream& in)
//Displays the number of words, number of sentences, number of lines, and average sentence length
{
	int words = 0, sentences = 0, lines = 0;
	
	//int period, space;
	char current = '\0', prev = '\0';

	string line, complete = "";

	// read in file, counting lines and adding each line to the entire string
	for(;;)
	{
		getline(in, line);

		if(in.fail())
			break;

		lines++;

		//count words and sentences
		for(int i = 0; i < line.length(); i++)
		{
			current = line[i];
			if(i != 0)	prev = line[i-1];
			if(isspace(current) && !isspace(prev) && prev != '.')
				words++;
			else if(current == '.')
			{
				sentences++;
				if(!isspace(prev))
					words++;
			}
		}
		prev = '\n';

	}

	cout << "\nStatistics calculated:"
		 << "\nWords: " << words
		 << "\nSentences: " << sentences
		 << "\nLines: " << lines << endl;
	if(sentences > 0)
		cout << "Average sentence length: " << double(words)/double(sentences) << " words\n";
}
				

string FindReplace(ifstream& in, string search, bool replace)
{
	string line = "";
	int i, begin;
	bool replacethis, changed = false, found = false;
	string file = "";
	string replacewith = "";

	if(replace)
	{
		string prompt = "What word would you like to replace " + search + " with?";
		replacewith = GetString(prompt);
	}

	for(;;)
	{
		getline(in, line);

		if(in.fail())
			break;

		begin = 0;

		for(;;)
		{
			if(line.find(search, begin) == string::npos)		// find doesn't occur on this line
				break;

			found = true;
			begin = line.find(search, begin);
			
			cout << endl << line << endl;
			for(i = 0; i < begin; i++)
				cout << ' ';
			for(i = 0; i < search.size(); i++)
				cout << '^';
			cout << endl;

			if(replace)
			{
				cout << "Would you like to replace this occurrence of ";
				replacethis = Ask(search);

				if(replacethis)
				{
					changed = true;
					line.replace(begin, search.size(), replacewith);
					cout << "The line is now:\n" << line << endl;
					begin += replacewith.size();
				}
				else 
				{
					begin += search.size();
				}
			}
			else 
			{
				begin += search.size();
			}
		}

		file += line + '\n';
	}

	cout << "\nDone searching file.\n";
	if(!found)
		cout << "No instances of " << search << " found in this file\n";
	return file;
}

bool Ask(const string& prompt)
{
	char ans;

	for(;;)
	{
		cout << prompt << "? ";
		cin >> ans;

		if(cin.fail() || (toupper(ans) != 'Y' && toupper(ans) != 'N'))
		{
			cout << "That was an invalid response. Only enter 'Y' or 'N', please\n";
			cin.clear();
			cin.ignore(1024,'\n');
		}

		else break;
	}

	cin.clear();
	cin.ignore(1024,'\n');

	return (toupper(ans) == 'Y');
}