#include "tokenizer.hpp"

#include <iostream>

static inline std::string &ltrim(std::string &s) {
    s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](int c) {return !std::isspace(c);}));
    return s;
}

Tokenizer::Tokenizer(std::string code) {
    tokentypes = std::vector<std::pair<std::string, std::regex>>();
    tokentypes.push_back( { "PREPROC", std::regex("^(#[a-zA-Z]+\\b)") } );
    tokentypes.push_back( { "FUNCTION", std::regex("^(\\bfunction\\b)", std::regex_constants::icase) } );
    tokentypes.push_back( { "SUB", std::regex("^(\\bsub\\b)", std::regex_constants::icase) } );
    tokentypes.push_back( { "END", std::regex("^(\\bend\\b)", std::regex_constants::icase) } );
    tokentypes.push_back( { "AS", std::regex("^(\\bas\\b)", std::regex_constants::icase) } );
    tokentypes.push_back( { "TYPE", std::regex("^(\\blong\\b)", std::regex_constants::icase) } );
    tokentypes.push_back( { "IDENTIFIER", std::regex("^(\\b[a-zA-Z]+\\b)") } );
    tokentypes.push_back( { "INTEGER", std::regex("^(\\b[0-9]+\\b)") } );
    tokentypes.push_back( { "STRING", std::regex("^(\".*\")") } );
    tokentypes.push_back( { "OPAREN", std::regex("^(\\()") } );
    tokentypes.push_back( { "CPAREN", std::regex("^(\\))") } );
    tokentypes.push_back( { "COMMA", std::regex("^(,)") } );
    tokentypes.push_back( { "QUOTE", std::regex("^(')") } );
    tokentypes.push_back( { "EQUALS", std::regex("^(=)") } );
    this->code = code;
}

std::vector<PBToken> Tokenizer::tokenize() {
    std::vector<PBToken> tokens;
    code = ltrim(code);
    while(code.size() > 0) {
        tokens.push_back(tokenize_one_token());
        code = ltrim(code);
    }
    return tokens;
}

PBToken Tokenizer::tokenize_one_token() {
    PBToken tk;
    for(int tt = 0; tt < TOKEN_TYPE_COUNT; tt++) {
#ifdef DEBUG
        std::cout << "attempting to match " << std::get<0>(tokentypes[tt]) << std::endl;
#endif
        std::regex re = std::get<1>(tokentypes[tt]);
        std::smatch sm;
        if(std::regex_search(code, sm, re)) {
            tk.type = (PBTokenType) tt;
            tk.value = sm[0];
#ifdef DEBUG
            std::cout << "match found" << std::endl;
            std::cout << "tk.type: " << std::get<0>(tokentypes[tk.type]) << std::endl << "tk.value: " << tk.value << std::endl;
#endif
            code = code.substr(tk.value.length());
            return tk;
        }
    }
    throw std::runtime_error("Couldn't match token: " + code.substr(0, code.find_first_of(" \t\r\n")));
}

std::string Tokenizer::dump() {
    return this->code;
}