//
//  main.cpp
//  project 3
//
//  Created by Cunpu Bo on 11-10-6.
//  Copyright 2011年 __MyCompanyName__. All rights reserved.
//

#include <iostream>
#include <string>
#include <cctype>
using namespace std;

string getFirstWord(string text);
string getLastWord(string text);
string extractWord(string& text);
bool isUppercase(string text);
string makeUppercase(string text);
bool hasMultipleExclamations(string text);
bool isGibberishWord(string text);

bool isConsonant(char letter);      //returns true if the argument is a consonant, return it it is a non-letter.
bool keyWord(string word);          //returns true if the argument is a keyword regardless of case

void checkTheTitle(string title,int& point);        //will change the point according to spam rule.
void checkThebody(string body,int& point);          //will change the point according to spam rule.

int main ()
{
    int numOfSpam = 0,numOfLegi = 0;
    string ans;

    do
    {
        string title,body,newLine;
        int point = 0;              //the point is reset every time.


        cout << "Enter the subject line of the email: ";
        getline(cin,title);
        checkTheTitle(title,point);

        cout << "Enter the body of the email.  Press Enter on an empty line to finish." << endl;
        while(true)
        {
            getline(cin,newLine);
            if (newLine == "")          //if the input is empty, the exit the input.
                break;

            body += '\n';
            body += newLine;
        }
        checkThebody(body,point);


        if (point > 100)
        {
            cout << "This email is classified as spam, because its spam score is " << point << "." <<endl;
            numOfSpam++;
        }
        else
        {
            cout << "This email is classified as legitimate, because its spam score is " << point << "." <<endl;
            numOfLegi++;
        }

        cout << "Would you like to classify another email (y or n)?";
        getline(cin,ans);

        while (ans != "y" && ans != "n" )
        {
            cout << "Please enter y or n." << endl;
            cout << "Would you like to classify another email (y or n)?";
            getline(cin,ans);

        }
    }while (ans=="y");

    cout <<endl;
    cout << "Number of spam messages: " << numOfSpam << endl;
    cout << "Number of legitimate messages: " << numOfLegi << endl;
}


//search for the first letter, and then search for the fisrt non-letter; the length between them will be the length of the substring starting from the first returned.
string getFirstWord(string text)
{
    int first = 0,last = 0;

    for (; first < text.size(); first++)
    {
        if (isalpha(text[first]))
        {
            last = first;
            for (; last < text.size(); last++)
                if (!isalpha(text[last]))
                    break;
        }

        if (last != 0)                      //break if the last if changed
            break;
    }
    return text.substr(first,last - first);
}
//the process if similar to getFirstWord, but the search starts from the end.
string getLastWord(string text)
{
    int size = static_cast<int>(text.size());
    int first = size - 1,last = size - 1;


    for (; last < text.size(); last--)
    {
        if (isalpha(text[last]))
        {
            first = last;
            for (; first >= 0; first--)
                if (!isalpha(text[first]))
                    break;
        }

        if (first != size - 1)          //break if the first is changed
            break;
    }


    return text.substr(first + 1,last - first);
}

string extractWord(string& text)
{
    string result = getFirstWord(text);

    int index = static_cast<int>(text.find(result));// find the postion the first word

    if (result == "")                       //if there is no word in the string, then the string itself also is changed to empty string.
        text = "";
    else
        text = text.substr(index + result.size());   //change the text to a string starting from the next character of the first word.

    return result;
}

bool isUppercase(string text)
{
    if (text == makeUppercase(text))
        return true;
    else
        return false;
}

string makeUppercase(string text)
{
    string temp;
    for (int i = 0; i < text.size(); i++)
    {
        temp += toupper(text[i]);
    }
    return temp;
}

//search for the first exclamation, and the search for the first non-exclamation;if the length between them is no less than 3, then return true.
bool hasMultipleExclamations(string text)
{
    int first = 0, last = 0;

    for (; first < text.size(); first++)
    {
        if (text[first] == '!')
        {
            last = first;                              //set the last equal to fisrt.
            for (; last < text.size(); last++)
                if (text[last] != '!')
                {
                    first = last;                   //restart search from the last.
                    break;
                }
        }


        if (last - first >= 3)          //if the length between is over 3,then break.
            break;
    }

    if (last - first >= 3)
        return true;
    else
        return false;
}
//search for the first consonant, and the search for the first non-econsonant;if the length between them is no less than 3, then return true.
bool isGibberishWord(string text)
{
    int first = 0, last = 0;

    for (; first < text.size(); first++)
    {
        if (isConsonant(text[first]))
        {
            last = first;                           //set the last equal to fisrt.
            for (; last < text.size(); last++)
                if (!isConsonant(text[last]))
                {
                    first = last;                      //restart search from the last.
                    break;
                }
        }

        if (last - first >= 3)                          //if the length between is over 3,then break.
            break;
    }

    if (last - first >= 3)
        return true;
    else
        return false;
}


bool isConsonant(char letter)
{
    if (!isalpha(letter))               //if not a letter, return false.
        return false;

    char upperLetter = toupper(letter);

    if (upperLetter == 'A' || upperLetter == 'E' || upperLetter == 'I' || upperLetter == 'O' || upperLetter == 'U')
        return false;
    else
        return true;
}

bool keyWord(string word)
{
    word = makeUppercase(word);
    if (word == "BUY" || word == "CHEAP" || word == "CLICK" || word == "DIPLOMA" || word == "FREE" || word == "LIMITED" || word == "ENLARGE" ||
        word == "MONEY" || word == "NOW" || word == "OFFER" || word == "ONLY" || word == "PILLS" || word == "SEX")
        return true;
    else
        return false;
}

void checkTheTitle(string line,int& point)
{
    int numOfUpper = 0,totalNum = 0;                //count the number of upper words and the total words.

    if (hasMultipleExclamations(line))
    {
        point += 20;
    }


    string lastWord;
    lastWord = getLastWord(line);
    if (isGibberishWord(lastWord))
    {
        point += 40;
    }

    while (true)
    {
        string newWord;
        newWord = extractWord(line);

        if (newWord == "")
            break;
        if (isUppercase(newWord))
            numOfUpper++;
        totalNum++;
    }
    if ((numOfUpper*1.0/totalNum) > 0.9)
    {
        point+=30;
    }

}

void checkThebody(string line,int& point)
{
    int numOfUpper = 0,totalNum = 0;
    while (true)
    {
        string newWord;
        newWord = extractWord(line);

        if (newWord == "")
            break;
        if (keyWord(newWord))
            point += 5;
        if (isUppercase(newWord))
            numOfUpper++;
        totalNum++;

    }
    if ((numOfUpper*1.0/totalNum) > 0.5)
    {
        point+=40;
    }
}