#include <iostream>
#include <fstream>
#include <vector>

#include "expression.hpp"

void program_loop(std::istream& in, std::ostream& out, std::ostream& err) {
    std::string line;

    while (std::getline(in, line)) {
        if (line == "exit") {
            break;
        }

        auto e = parse_expression(line); // or change this to parser.parse_expression(line);

        if (e) {
            auto result = e->evaluate();
            if (result) {
                out << *result << std::endl;
            } else {
                err << "Evaluation failed" << std::endl;
            }
        } else {
            err << "Parsing failed" << std::endl;
        }
    }
}


int main(int argc, char* argv[]) try {

    std::vector<std::string> args(argv + 1, argv + argc);

    if (args.empty()) {
        program_loop(std::cin, std::cout, std::cerr);
    } else {
        for (const auto& arg : args) {
            std::ifstream file(arg);
            if (file) {
                program_loop(file, std::cout, std::cerr);
            } else {
                std::cerr << "Failed to open file: " << arg << std::endl;
            }
        }
    }

    return 0;
} catch (const std::exception& e) {
    std::cerr << "Error: " << e.what() << std::endl;

    return 1;
} catch (...) {
    std::cerr << "Unknown error" << std::endl;

    return 2;
}