#ifndef BDL_VM_H
#define BDL_VM_H

#include "types.h"
#include "errors.h"
#include "chunk.h"
#include "ops.h"
#include "debug.h"

typedef struct VM {
    Chunk *chunk;
    u8 *pc;
} VM;

VM vm_init(void);
void vm_free(VM vm);
void vm_interpret(VM vm);

VM
vm_init(void) {
    VM vm = {
        .chunk = chunk_init(),
    };
    return vm;
}

void
vm_free(VM vm) {
    chunk_free(vm.chunk);
}

void
vm_interpret(VM vm) {
    if (vm.chunk->code == NULL || array_size(vm.chunk->code) == 0) {
        error_push((Error){
            .type = ERR_TYPE_RUNTIME,
            .value = ERR_EMPTY_CHUNK,
        });
        return;
    }

    vm.pc = vm.chunk->code;
    u8 *last = vm.chunk->code + array_size(vm.chunk->code);
    while (vm.pc < last) {
#ifdef DEBUG_TRACE_EXECUTION
    disassemble_instruction(vm.chunk, (vm.pc - vm.chunk->code));
#endif
        u8 instruction = *vm.pc++;
        switch (instruction) {
            case OP_CONSTANT: {
                u8 constant = *vm.pc++;
                Object obj = vm.chunk->constants[constant];
                display(obj);
                printf("\n");
            } break;
            case OP_RETURN: {
                return;
            } break;
            default: {
                error_push((Error){
                    .type = ERR_TYPE_RUNTIME,
                    .value = ERR_NOT_IMPLEMENTED,
                    .line = vm.chunk->lines[0].line,
                    .col = vm.chunk->lines[0].col,
                });
                return;
            } break;
        }
    }

    error_push((Error){
        .type = ERR_TYPE_RUNTIME,
        .value = ERR_PC_OOB,
        .line = vm.chunk->lines[0].line,
        .col = vm.chunk->lines[0].col,
    });
}

#endif // BDL_VM_H