#include <iostream>
#include <string>
#include <vector>
#include <fstream>
#include "lex.h"

using namespace std;

Lex getNextToken(istream &in, int &linenum);

Token getKeywords(string str, Token orig);

ostream &operator<<(ostream &out, const Lex &tok);

string printnamedex(const Lex &tok);

ostream &operator<<(ostream &out, const Lex &tok) {
    if (tok.GetToken() == ID || tok.GetToken() == INT || tok.GetToken() == STR || tok.GetToken() == ERR) {
        out << printnamedex(tok) << tok.GetLexeme() << ")";
    } else {
        out << printnamedex(tok);
    }
    return out;
}

string printnamedex(const Lex &tok) {
    string retval;

    switch (tok.GetToken()) {
        case ID:
            retval = "ID(";
            break;
        case INT:
            retval = "INT(";
            break;
        case STR:
            retval = "STR(";
            break;

        case PRINT:
            retval = "PRINT";
            break;
        case ERR:
            retval = "Error on line ";
            retval += to_string(tok.GetLinenum()+1);
            retval += " (";
            break;
        case LET:
            retval = "LET";
            break;
        case IF:
            retval = "IF";
            break;
        case LOOP:
            retval = "LOOP";
            break;
        case BEGIN:
            retval = "BEGIN";
            break;
        case END:
            retval = "END";
            break;
        case PLUS:
            retval = "PLUS";
            break;
        case MINUS:
            retval = "MINUS";
            break;
        case STAR:
            retval = "STAR";
            break;
        case SLASH:
            retval = "SLASH";
            break;
        case BANG:
            retval = "BANG";
            break;
        case LPAREN:
            retval = "LPAREN";
            break;
        case RPAREN:
            retval = "RPAREN";
            break;
        case SC:
            retval = "SC";
            break;
        case DONE:
            retval = "DONE";
            break;
    }
    return retval;
}

Lex getNextToken(istream &in, int &linenum) {
    char newchar = '\0';

    string oper = ";+-!\\*()";

    Token checktoken = ERR;
    string checklex = "";
    int checkline = -1;

    bool flush = false;

    Lex nextLex;

    while (true) {
        in.get(newchar);

        if (in.eof()) {
            nextLex = Lex(DONE, "", linenum);
            return nextLex;
        }


        if (checktoken == STR) {
            if (newchar == '\\') {
                char escaped;
                in.get(escaped);
                if (escaped == 'n') {
                    checklex += '\n';
                } else
                    checklex += escaped;
            } else if (newchar == '\"') {
                checkline = linenum;
                flush = true;
            } else if (newchar == EOF || newchar == '\n') {
                checktoken = ERR;
                checkline = linenum;
                if(newchar == '\n')
                    checklex += "\n";
                flush = true;
            } else
                checklex += newchar;
        } else if (checktoken == INT) {

            if (isdigit(newchar))
                checklex += newchar;
            else {
                in.unget();
                checkline = linenum;
                flush = true;
            }
        } else if (checktoken == ID) {

            if (isalnum(newchar))
                checklex += newchar;
            else {
                checkline = linenum;
                flush = true;
            }
        } else if (checktoken == ERR) {
            if (isdigit(newchar)) {
                checklex += newchar;
                checktoken = INT;
                continue;
            }
            if (isalpha(newchar)) {
                checklex += newchar;
                checktoken = ID;
                continue;
            }

            if(isspace(newchar) && newchar != '\n')
                continue;

            switch (newchar) {
                case '\"':
                    checktoken = STR;
                    break;
                case '/':
                    char nextchar;
                    nextchar = in.peek();
                    if (nextchar == '/') {
                        string s;
                        while (true) {
                            char nextchar;
                            in.get(nextchar);
                            if (nextchar == '\n') {
                                linenum++;
                                break;
                            }
                        }
                    } else {
                        checktoken = SLASH;
                        checkline = linenum;
                        flush = true;
                    }
                    break;
                case ' ':
                    break;
                case '\n':
                    linenum++;
                    break;
                case EOF:
                    checktoken = DONE;
                    checkline = linenum;
                    flush = true;
                    break;
                case '+':
                    checktoken = PLUS;
                    checkline = linenum;
                    flush = true;
                    break;
                case '-':
                    checktoken = MINUS;
                    checkline = linenum;
                    flush = true;
                    break;
                case '*':
                    checktoken = STAR;
                    checkline = linenum;
                    flush = true;
                    break;
                case '!':
                    checktoken = BANG;
                    checkline = linenum;
                    flush = true;
                    break;
                case '(':
                    checktoken = LPAREN;
                    checkline = linenum;
                    flush = true;
                    break;
                case ')':
                    checktoken = RPAREN;
                    checkline = linenum;
                    flush = true;
                    break;
                case ';':
                    checktoken = SC;
                    checkline = linenum;
                    flush = true;
                    break;
                default:
                    checktoken = ERR;
                    checklex += newchar;
                    checkline = linenum;
                    flush = true;
                    break;
            }
        }


        if (flush) {
            checktoken = getKeywords(checklex, checktoken);
            nextLex = Lex(checktoken, checklex, checkline);
            return nextLex;
        }
    }

}

Token getKeywords(string str, Token orig) {
    if (orig == ID) {
        if (str.compare("print") == 0) {
            return PRINT;
        } else if (str.compare("if") == 0) {
            return IF;
        } else if (str.compare("loop") == 0) {
            return LOOP;
        } else if (str.compare("let") == 0) {
            return LET;
        } else if (str.compare("begin") == 0) {
            return BEGIN;
        } else if (str.compare("end") == 0) {
            return END;
        }
    }

    return orig;
}