//      Пусть в файле храняться строки, представляющие собой
//      исходный код программы на языке с++. Вывести синтаксически
//      правильные операторы присваивания одной переменной значение
//      другой. Список зарезервированных слов задать в отдельном файле.
//
//  Created by Дмитрий Рябовский on 14/03/2019.
//  Copyright © 2019 Дмитрий Рябовский. All rights reserved.
//

#include <iostream>
#include <fstream>

using namespace std;

enum States {
    State_Start,
    State_Variable,
    State_Assignment,
    State_Complete,
    State_Skip
};


void getWay(char* way_cin_file) {
    cout << "\nВведите путь к файлу:  (../filename.txt)" << endl; // /Users/dmitrijrabovskij/Desktop/C++/labs/4/4/cin.txt
    gets(way_cin_file);
    cout << endl;
}



void getWordsFromOperation (string operation, string& word1, string& word2) {
    int i = 0;
    int k = 0;
    bool check = 0;
    while (operation[i] != '\0') {
        if (operation[i] == '=') {
            check = 1;
            k = 0;
            i++;
        }
        if (operation[i] != ' ' && operation[i] != ';' && int(operation[i]) != 10) {
            if (check) {
                word2.insert(k, 1, operation[i]);
                k++;
            } else {
                word1.insert(k, 1, operation[i]);
                k++;
            }
        }
        i++;
    }
}


bool wordsMatchCheck (string word1, string word2) {
    bool difference = true;
    int i = 0;
    bool check1 = 0;
    while (word1[i] != '\0' && !check1) {
        if (word1[i] != word2[i]) check1 = 1;
        i++;
    }
    difference = check1;
    return difference;
}


bool checkWordsForKeyword (string word1, string word2) {
    bool correct = true;
    string way_keywords_file = "/Users/dmitrijrabovskij/Desktop/C++/labs/4/4/keywords.txt";
    ifstream keywords_file(way_keywords_file);
    if (!keywords_file.is_open()) {
        cout << "Файл не найден! invalid way_keywords_file!!!  " << way_keywords_file << "\n";
        exit(-1);
    }
    int i = 0;
    bool check1 = false;
    bool check2 = false;
    while (!keywords_file.eof()) {
        string buff;
        keywords_file >> buff;
        while (buff[i] != '\0') {
            if (word1[i] != buff[i]) {
                check1 = 1;
            }
            if (word2[i] != buff[i]) {
                check2 = 1;
            }
            i++;
        }
        if (check1 == 0 || check2 == 0) {
            correct = 0;
        }
        check1 = 0;
        check2 = 0;
        i = 0;
    }
    keywords_file.close();
    return correct;
}


bool checkOperationForKeyword (string operation) {
    bool correct = true;
    string word1 = "";
    string word2 = "";
    getWordsFromOperation(operation, word1, word2);
    correct = wordsMatchCheck(word1, word2);
    if (!correct) {
        return correct;
    }
    correct = checkWordsForKeyword(word1, word2);
    return correct;
}


void assignOperatorSearch_found(bool& check, int& i, States& state, string& operation) {
    if (checkOperationForKeyword(operation)) {
        cout << operation << endl << endl;
    }
    check = 0;
    state = State_Start;
    operation = "";
    i = 0;
}


void assignOperatorSearch() {
    char way_cin_file[256] = "";
    getWay(way_cin_file);
    ifstream cin_file(way_cin_file);
    if (!cin_file.is_open()) {
        cout << "Файл не найден!\n";
        assignOperatorSearch();
    } else {
    int symb;
    bool check = 0;
    string operation = "";
    int i = 0;
    States state = State_Start;
    while (!cin_file.eof())
    {
        symb = cin_file.get();
        operation.insert(i, 1, char(symb));
        i++;

        switch (state) {

            case State_Start:
                if ((symb >= 65 && symb <= 90) || (symb >= 97 && symb <= 122) || symb == 95) {
                    state = State_Variable;
                } else if (symb == 32 || symb == 10 || (symb == 59 && !check)) {
                    state = State_Start;
                } else {
                    state = State_Skip;
                }
                break;


            case State_Variable:
                if ((symb >= 65 && symb <= 90) || (symb >= 97 && symb <= 122) || symb == 95 || (symb >= 48 && symb <= 57)) {
                    state = State_Variable;
                } else if (symb == 32 || symb == 10) {
                    if (!check) {
                        state = State_Assignment;
                        check = 1;
                    } else {
                        state = State_Complete;
                    }
                } else {
                    if (check) {
                        if (symb == 59) {
                            assignOperatorSearch_found(check, i, state, operation);                  //end
                        } else {
                            state = State_Skip;
                        }
                    } else {
                        if (symb == 61) {
                            check = 1;                   //State_Assignment
                            state = State_Start;
                        } else {
                            state = State_Skip;
                        }
                    }
                }
                break;


            case State_Assignment:
                if (symb == 61) {
                    state = State_Start;
                } else if (symb == 32 || symb == 10) {
                    state = State_Assignment;
                } else {
                    if ((symb >= 65 && symb <= 90) || (symb >= 97 && symb <= 122) || symb == 95) {
                        check = 0;                           //state_start
                        state = State_Variable;
                        operation = "";
                        operation.insert(0, 1, char(symb));
                        i = 1;
                    } else {
                        state = State_Skip;
                    }
                }
                break;


            case State_Complete:
                if (symb == 59) {
                    assignOperatorSearch_found(check, i, state, operation);                  //end
                    i = 0;
                } else if (symb == 32 || symb == 10) {
                    state = State_Complete;
                } else {
                    if ((symb >= 65 && symb <= 90) || (symb >= 97 && symb <= 122) || symb == 95) {
                        check = 0;                           //state_start
                        state = State_Variable;
                        operation = "";
                        operation.insert(0, 1, char(symb));
                        i = 1;
                    } else {
                        state = State_Skip;
                    }
                }
                break;


            case State_Skip:
                check = 0;
                if (symb == 32 || symb == 10 || symb == 59) {
                    state = State_Start;                         //skip
                    operation = "";
                    i = 0;
                }
                break;
        }
    }
        cin_file.close();
    }
}



 int main() {
    cout << "Пусть в файле храняться строки, представляющие собой\nисходный код программы на языке с++. Вывести синтаксически\nправильные операторы присваивания одной переменной значение\nдругой. Список зарезервированных слов задать в отдельном файле.\n" << endl;
    assignOperatorSearch();
    return 0;
}