#include <stdio.h>
#include <stdint.h>
#include "BinCmdMap.h"
#include "OperandStack.h"

void runV1Program(FILE* program);
void add(OperandStack* stack);
void sub(OperandStack* stack);
void mult(OperandStack* stack);
void div(OperandStack* stack);

int main() {
    FILE* program = fopen("./test.bin", "r");
    if (program == NULL) {
        // TODO: check for errors (e.g. file not found)
        return -1;
    }

    uint8_t version;
    size_t nread = fread(&version, 1, 1, program);

    switch (version) {
        case 1:
            runV1Program(program);
            break;
        default:
            printf("Unkown binary version: %i.\n \
                    Probably the program was compiled with a more recent \
                    version.", version);
    }

    fclose(program);
    return 0;
}

void runV1Program(FILE* program) {
    OperandStack stack = {};
    uint8_t opcode;

    while (fread(&opcode, sizeof(opcode), 1, program) == 1) {

        switch (opcode) {
            case CMD_CONST:
                int32_t val;
                fread(&val, sizeof(int32_t), 1, program);
                // TODO: check for errors
                OStackPush(&stack, val);
                break;
            case CMD_ADD:
                add(&stack);
                break;
            case CMD_SUB:
                sub(&stack);
                break;
            case CMD_MULT:
                mult(&stack);
                break;
            case CMD_DIV:
                div(&stack);
                break;
            default:
                printf("Unkown command");
        }
    }
    // TODO check for errors
    // (feof(program) == 0);

    int result;
    OStackPop(&stack, &result);
    printf("%i\n", result);
}

void add(OperandStack* stack) {
    int operandA;
    int operandB;

    OStackPop(stack, &operandA);
    OStackPop(stack, &operandB);

    int result = operandA + operandB;
    OStackPush(stack, result);
}

void sub(OperandStack* stack) {
    int operandA;
    int operandB;

    OStackPop(stack, &operandA);
    OStackPop(stack, &operandB);

    int result = operandA - operandB;
    OStackPush(stack, result);
}

void mult(OperandStack* stack) {
    int operandA;
    int operandB;

    OStackPop(stack, &operandA);
    OStackPop(stack, &operandB);

    int result = operandA * operandB;
    OStackPush(stack, result);
}

void div(OperandStack* stack) {
    int operandA;
    int operandB;

    OStackPop(stack, &operandA);
    OStackPop(stack, &operandB);

    int result = operandA / operandB;
    OStackPush(stack, result);
}