#include "labeltable.h"
#include <stdlib.h>
#include <string.h>

LabelTable_t* rava_labeltable_create(RavaInstructionList_t* instructions) {
    if (!instructions) return NULL;

    LabelTable_t* table = malloc(sizeof(LabelTable_t));
    if (!table) return NULL;

    int max_label = 0;
    for (size_t i = 0; i < instructions->count; i++) {
        if (instructions->instructions[i].opcode == RAVA_OP_LABEL) {
            int lid = instructions->instructions[i].operand.label_id;
            if (lid > max_label) max_label = lid;
        }
    }

    table->max_label_id = (size_t)max_label;
    table->label_to_pc = calloc((size_t)(max_label + 1), sizeof(int));
    if (!table->label_to_pc) {
        free(table);
        return NULL;
    }

    for (int i = 0; i <= max_label; i++) {
        table->label_to_pc[i] = -1;
    }

    for (size_t i = 0; i < instructions->count; i++) {
        if (instructions->instructions[i].opcode == RAVA_OP_LABEL) {
            int lid = instructions->instructions[i].operand.label_id;
            table->label_to_pc[lid] = (int)(i + 1);
        }
    }

    return table;
}

void rava_labeltable_destroy(LabelTable_t* table) {
    if (!table) return;
    free(table->label_to_pc);
    free(table);
}

size_t rava_labeltable_lookup(LabelTable_t* table, int label_id) {
    if (!table || label_id < 0 || (size_t)label_id > table->max_label_id) {
        return 0;
    }
    int pc = table->label_to_pc[label_id];
    return (pc >= 0) ? (size_t)pc : 0;
}