#include <stdio.h>
#include <stdlib.h>
#include "vm.h"

void virtualMachineInit(VirtualMachine* vm, unsigned int* programMem, unsigned int* ram){
    vm->programMem = programMem;
    vm->ram = ram;

    vm->instructionPointer = 0;
    for (size_t i = 0; i < 5; i++) vm->registers[i] = 0;
    for (size_t i = 0; i < 6; i++) vm->stateRegister[i] = 0;
}

int virtualMachineStep(VirtualMachine* vm) {
    char temp;
    temp = 'A';
    switch (vm->programMem[vm->instructionPointer]) {
        case 0x00:
            return -1;
            break;
        case 0x01:
            vm->ram[vm->registers[vm->programMem[vm->instructionPointer+1]]] = vm->registers[vm->programMem[vm->instructionPointer+2]];
            vm->instructionPointer += 2;
            break;
        case 0x02:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = vm->ram[vm->registers[vm->programMem[vm->instructionPointer+2]]];
            vm->instructionPointer += 2;
            break;
        case 0x03:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = vm->registers[vm->programMem[vm->instructionPointer+2]];
            vm->instructionPointer += 2;
            break;
        case 0x04:
            vm->registers[vm->programMem[vm->instructionPointer+1]]++;
            vm->instructionPointer++;
            break;
        case 0x05:
            vm->registers[vm->programMem[vm->instructionPointer+1]]--;
            vm->instructionPointer++;
            break;
        case 0x06:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = vm->programMem[vm->instructionPointer+2];
            vm->instructionPointer += 2;
            break;
        case 0x07:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = vm->registers[vm->programMem[vm->instructionPointer+2]] + vm->registers[vm->programMem[vm->instructionPointer+3]];
            vm->instructionPointer += 3;
            break;
        case 0x08:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = vm->registers[vm->programMem[vm->instructionPointer+2]] - vm->registers[vm->programMem[vm->instructionPointer+3]];
            vm->instructionPointer += 3;
            break;
        case 0x09:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = vm->registers[vm->programMem[vm->instructionPointer+2]] * vm->registers[vm->programMem[vm->instructionPointer+3]];
            vm->instructionPointer += 3;
            break;
        case 0x0a:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = (unsigned int)(vm->registers[vm->programMem[vm->instructionPointer+2]] == vm->registers[vm->programMem[vm->instructionPointer+3]]);
            vm->instructionPointer += 3;
            break;
        case 0x0b:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = (unsigned int)(vm->registers[vm->programMem[vm->instructionPointer+2]] != vm->registers[vm->programMem[vm->instructionPointer+3]]);
            vm->instructionPointer += 3;
            break;
        case 0x0c:
            vm->registers[vm->programMem[vm->instructionPointer+1]] = (unsigned int)(vm->registers[vm->programMem[vm->instructionPointer+2]] > vm->registers[vm->programMem[vm->instructionPointer+3]]);
            vm->instructionPointer += 3;
            break;
        case 0x0d:
            vm->instructionPointer = vm->registers[vm->programMem[vm->instructionPointer+1]] - 1;
            break;
        case 0x0e:
            if(vm->registers[vm->programMem[vm->instructionPointer+1]] != 0) {
                vm->instructionPointer = vm->registers[vm->programMem[vm->instructionPointer+2]] - 1;
            } else {
                vm->instructionPointer += 2;
            }
            break;
        case 0x0f:
            vm->stateRegister[0] = vm->instructionPointer + 1;
            vm->stateRegister[1] = vm->registers[0];
            vm->stateRegister[2] = vm->registers[1];
            vm->stateRegister[3] = vm->registers[2];
            vm->stateRegister[4] = vm->registers[3];
            vm->stateRegister[5] = vm->registers[4];
            vm->instructionPointer = vm->registers[vm->programMem[vm->instructionPointer+1]] - 1;
            break;
        case 0x10:
            vm->instructionPointer = vm->stateRegister[0];
            vm->registers[0] = vm->stateRegister[1];
            vm->registers[1] = vm->stateRegister[2];
            vm->registers[2] = vm->stateRegister[3];
            vm->registers[3] = vm->stateRegister[4];
            vm->registers[4] = vm->stateRegister[5];
            break;
        case 0x11:
            printf("%d", (int)(vm->registers[vm->programMem[vm->instructionPointer+1]]));
            vm->instructionPointer++;
            break;
        case 0x12:
            printf("%c", (char)(vm->registers[vm->programMem[vm->instructionPointer+1]]));
            vm->instructionPointer++;
            break;
        case 0x13:
            scanf("%u", &(vm->registers[vm->programMem[vm->instructionPointer+1]]));
            vm->instructionPointer++;
            break;
        case 0x14:
            scanf("%c", &temp);
            vm->registers[vm->programMem[vm->instructionPointer+1]] = (unsigned int) temp;
            vm->instructionPointer++;
            break;
        default:
            break;
    };
    vm->instructionPointer++;
    return 0;
}

int virtualMachinePeek(VirtualMachine* vm, size_t address) {
    printf("IP: %u R0: %u R1: %u R2: %u R3: %u R4: %u Address $%zu: %u\n------\n", vm->instructionPointer, vm->registers[0],vm->registers[1],vm->registers[2],vm->registers[3],vm->registers[4], address, vm->ram[address]);
    return vm->ram[address];
}