#include "molasses/lexer.h"
#include "molasses/parser_primitives.h"
#include <cstring>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <sstream>
#include <stack>
#include <string>
#include <variant>

using compile_element = std::variant<molasses::lexed_output, molasses::generate_context, std::string>;

int main(int argc, char** argv) {
	std::vector<std::string> arguments;
    while(argc > 1) {
        argv++;
        arguments.emplace_back(*argv, strlen(*argv));
        argc--;
    }

    std::stack<compile_element> compile_stack;

    for(auto elem : arguments) {
        if(elem == "generate") {
            if(std::holds_alternative<std::string>(compile_stack.top())) {
                auto filename = std::get<std::string>(compile_stack.top());
                compile_stack.pop();
                if(std::holds_alternative<molasses::generate_context>(compile_stack.top())) {
                    auto generator = std::get<molasses::generate_context>(compile_stack.top());
                    compile_stack.pop();
                    auto assembler = molasses::generate(generator);
                    std::ofstream output(filename+".s");
                    for(const auto& line : assembler) {
                        output << line;
                    }
                    compile_stack.emplace(filename);
                } else throw std::runtime_error("generate expects a parsed output");
            } else throw std::runtime_error("generate expects a filename");
        } else if(elem == "parse") {
            molasses::parser_context ctx;
            ctx = molasses::register_integers(ctx);
            ctx = molasses::register_i32_operations(ctx);

            if(std::holds_alternative<molasses::lexed_output>(compile_stack.top())) {
                auto lexer = std::get<molasses::lexed_output>(compile_stack.top());
                compile_stack.pop();
                auto generator = molasses::parse(ctx, lexer);
                compile_stack.emplace(generator);
            } else throw std::runtime_error("parse expects a lexed output");
        } else if(elem == "lex") {
            if(std::holds_alternative<std::string>(compile_stack.top())) {
                auto filename = std::get<std::string>(compile_stack.top());
                compile_stack.pop();
                if(not std::filesystem::exists(filename)) throw std::runtime_error("file "+filename+" does not exist");
                std::ifstream t(filename);
                std::stringstream buffer;
                buffer << t.rdbuf();
                auto lexed = molasses::lex(buffer.str());
                compile_stack.emplace(lexed);
            } else throw std::runtime_error("lex expects a filename");
        } else if(elem == "merge") {
            if(std::holds_alternative<molasses::lexed_output>(compile_stack.top())) {
                auto lexer_1 = std::get<molasses::lexed_output>(compile_stack.top());
                compile_stack.pop();
                if(std::holds_alternative<molasses::lexed_output>(compile_stack.top())) {
                    auto lexer_2 = std::get<molasses::lexed_output>(compile_stack.top());
                    compile_stack.pop();
                    compile_stack.emplace(molasses::concatenate(lexer_1, lexer_2));
                } else throw std::runtime_error("merge expects 2 lexed outputs");
            } else throw std::runtime_error("merge expects 2 lexed outputs");
        } else if(elem == "assemble") {
            if(std::holds_alternative<std::string>(compile_stack.top())) {
                auto filename = std::get<std::string>(compile_stack.top());
                compile_stack.pop();
                std::stringstream compile; compile << "clang -c " << filename << ".s -o " << filename << ".o";
                std::stringstream link; link << "ld -e _start " << filename << ".o -o " << filename;
                std::cout << compile.str() << std::endl;
                system(compile.str().c_str());
                std::cout << link.str() << std::endl;
                system(link.str().c_str());
            } else throw std::runtime_error("assemble expects an assembly file");
        } else compile_stack.emplace(elem);
    }
}