/*
PlutoISA
Copyright (C) 2024  Patrick_Pluto

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

#pragma once

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <cstdint>
#include <chrono>
#include <thread>
#include "tpu.hpp"

using namespace std;

uint8_t *registers = ( uint8_t * ) malloc ( 8 * sizeof ( uint8_t ) );
uint8_t *memory = ( uint8_t * ) malloc ( 128 * sizeof ( uint8_t ) );
uint8_t *pointer = ( uint8_t * ) malloc ( sizeof ( uint8_t ) );

void cpuInstructions ( uint8_t *rom ) {
    cout << static_cast<int> ( rom[*pointer] ) << endl;
    cout << static_cast<int> ( *pointer ) << endl;
    switch ( rom[*pointer] ) {
    case 0x00: // GET
        registers[rom[*pointer + 1]] = rom[*pointer + 2];
        *pointer += 3;
        break;
    case 0x01: // LOAD
        registers[rom[*pointer + 1]] = memory[rom[*pointer + 2]];
        *pointer += 3;
        break;
    case 0x02: // STORE
        memory[rom[*pointer + 2]] = registers[rom[*pointer + 1]];
        *pointer += 3;
        break;
    case 0x03: // ADD
        registers[rom[*pointer + 1]] = registers[rom[*pointer + 2]] + registers[rom[*pointer + 3]];
        *pointer += 4;
        break;
    case 0x04: // SUB
        registers[rom[*pointer + 1]] = registers[rom[*pointer + 2]] - registers[rom[*pointer + 3]];
        *pointer += 4;
        break;
    case 0x05: // JMP
        *pointer = rom[*pointer + 1];
        break;
    case 0x06: // JEQ
        if ( rom[*pointer + 2] == registers[rom[*pointer + 3]] ) {
            *pointer = rom[*pointer + 1];
        }
        break;
    case 0x07: // HIN
        cin >> registers[rom[*pointer + 1]];
        *pointer += 2;
        break;
    default:
        cout << "Invalid Instruction, quitting." << endl;
        exit ( 1 );
    }
}

void cpuEmulation ( uint8_t *rom ) {
    const int targetFPS = 20;
    const int frameDuration = 1000 / targetFPS;
    *pointer = 0;

    while ( true ) {
        auto start = chrono::high_resolution_clock::now();

        cpuInstructions ( rom );
        textProcessing ( registers[7] );

        auto end = chrono::high_resolution_clock::now();
        chrono::duration<double, milli> elapsed = end - start;

        if ( elapsed.count() < frameDuration ) {
            this_thread::sleep_for ( chrono::milliseconds ( frameDuration ) - elapsed );
        }
    }
}