#include "vmbl.h"
#include <stdio.h>

VMBL_Exception VBML_ExecuteInstruction(VMBL_State *vmblState, VMBL_Instruction instruction) {
	switch (instruction.type)
	{
	case INSTRUCTION_PUSH:
		if (vmblState->stackSize >= VMBL_STACK_SIZE) {
			return (VMBL_Exception){ EXCEPTION_STACK_OVERFLOW };
		}

		vmblState->stack[vmblState->stackSize++] = instruction.opperand;
		break;
	
	case INSTRUCTION_ADD:
		if (vmblState->stackSize < 2) {
			return (VMBL_Exception){ EXCEPTION_STACK_UNDERFLOW };
		} 

		vmblState->stack[vmblState->stackSize - 2] += vmblState->stack[vmblState->stackSize - 1];
		vmblState->stackSize--;
		break;

	default:

		return (VMBL_Exception) { EXCEPTION_INVALID_OPCODE };
		break;
	}

	return (VMBL_Exception) { EXCEPTION_NONE };
}

void VMBL_Dump(VMBL_State vmblState, VMBL_Exception exception) {
	fprintf(stderr, "EXCEPTION: %s\n\n", exceptionAsCString(exception));
	fprintf(stderr, "Stack:\n");

	if (vmblState.stackSize > 0) {
		for (size_t i = 0; i < vmblState.stackSize; i++) {
				fprintf(stderr, "    0x%lX: %ld\n", i, vmblState.stack[i]);
		}
	} else {
		fprintf(stderr, "    [empty]\n");
	}
	
}