// Assignment 1 (C++).cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include <stdio.h>
#include <vector>
#include <string>

int main()
{
    std::cout << "┌────────────────────────────────────────────────┐\n";
    std::cout << "│  159.341 2021 Semester 1, Assignment 1 (C++)   │\n";
    std::cout << "│     Submitted by Brychan Dempsey, 14299890     │\n";
    std::cout << "└────────────────────────────────────────────────┘\n";

    bool exit = false;
    while (!exit) {
        MemoryStream ms(1024);
        

    }
}
bool IsWhiteSpace(char c) {
    if (c == ' ' || c == '\r' || c == '\n') {
        return true;
    }
    return false;
}

void skipWhitespace(MemoryStream ms) {
    char c = ms.PeekChar();
    while (ms.position < ms.length && IsWhiteSpace(c)) {
        ms.ReadChar();
        c = ms.PeekChar();
    }
}

std::string FindNextWord(MemoryStream ms, long &position) {
    std::string nextWord;
    long start = ms.position;
    char curr = ms.ReadChar();
    while (ms.position < ms.length && IsWhiteSpace(curr))
    {
        curr = ms.ReadChar();
    }
    nextWord.push_back(curr);
    while (ms.position < ms.length)
    {
        curr = ms.ReadChar();
        if (IsWhiteSpace(curr) || curr == ';')
        {
            ms.position--;
            break;
        }
        else
        {
            nextWord.push_back(curr);
        }
    }
    position = ms.position;
    ms.position = start;
    return nextWord;
}

struct MemoryStream {
public:
    long position = 0;
    long length = 0;
private:
    
    std::vector<char> chars;

    bool ensureCapacity(long step) {
        // Size exceeds the bounds of the vector, resize
        if (position + step >= chars.size()) {
            chars.resize(position + step);
        }
    }

public:
    MemoryStream(long Reserved) {
        chars.assign(Reserved, 0);
    }

    char ReadChar() {
        if (++position >= length) return -1;
        return chars[position];
    }

    char PeekChar() {
        char result = ReadChar();
        position--;
        return result;
    }

    bool writeChar(char c) {
        ensureCapacity(1);
        if (position == length) length++;
        chars[++position] = c;
    }

    bool writeChars(const char* c, int count) {
        ensureCapacity(count);
        if (position >= length - count) length = position + count;
        for (int i = 0; i < count; i++)
        {
            chars[i + position] = *(c + i);
        }
    }
};

struct Parser {
    std::vector<std::string> symbolNames;
    std::vector<std::string> symbolValues;

    void Exit() {
        std::exit(0);
    }

    void StartParsing(MemoryStream ms, bool dynamicInput = false) {
        long startLength = ms.length;
        long lastLinePos = 0;
        long initPos = 0;
        bool cont = false;
        while (true) {
            if (dynamicInput) {
                lastLinePos = ms.position;
                if (!cont)
                {
                    std::cout << "Enter a command: " << std::endl;
                }
                std::string s;
                std::getline(std::cin, s);
                long pos = ms.position;
                ms.writeChars(s.c_str(), s.size());
                ms.position = pos;
            }
            if (!cont) {
                initPos = ms.position;
            }
            else {
                ms.position = initPos;
            }
            skipWhitespace(ms);
            long position = 0;
            std::string word = FindNextWord(ms, position);
            try {
                if (word._Equal("set")) {

                }
                else if (word._Equal("exit")) {

                }
                else if (word._Equal("append")) {

                }
                else if (word._Equal("list")) {

                }
                else if (word._Equal("print")) {

                }
            }
            catch (std::exception e)
            {

            }
        }
    }

};