/*
 * This file is part of the Fun programming language.
 * https://fun-lang.xyz/
 *
 * Copyright 2025 Johannes Findeisen <you@hanez.org>
 * Licensed under the terms of the Apache-2.0 license.
 * https://opensource.org/license/apache-2-0
 */

/**
 * @file index_of.c
 * @brief Implements the OP_INDEX_OF opcode for finding the index of a value in an array in the VM.
 *
 * This file handles the OP_INDEX_OF instruction, which finds the index of a value in an array.
 * The value and array are popped from the stack, and the index (or -1) is pushed back.
 *
 * Behavior:
 * - Pops the value and array from the stack.
 * - Finds the index of the value in the array.
 * - Pushes the index (or -1 if not found) onto the stack.
 *
 * Error Handling:
 * - Exits with an error if the array is of the wrong type.
 *
 * Example:
 * - Bytecode: OP_INDEX_OF
 * - Stack before: [20, [10, 20, 30]]
 * - Stack after: [1]
 */

case OP_INDEX_OF: {
  Value needle = pop_value(vm);
  Value arr = pop_value(vm);
  if (arr.type != VAL_ARRAY) {
    fprintf(stderr, "Runtime type error: INDEX_OF expects (array, value)\n");
    exit(1);
  }
  int idx = array_index_of(&arr, &needle);
  free_value(arr);
  free_value(needle);
  push_value(vm, make_int(idx));
  break;
}
