/**
 * This file is part of the Fun programming language.
 * https://hanez.org/project/fun/
 *
 * 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 arr_push.c
 * @brief Implements the OP_ARR_PUSH opcode for appending elements to arrays in the VM.
 *
 * This file handles the OP_ARR_PUSH instruction, which appends a value to the end of an array.
 * The array and value are popped from the stack, and the new length of the array is pushed back onto the stack.
 *
 * Behavior:
 * - Pops the value and array from the stack.
 * - Appends the value to the end of the array.
 * - Pushes the new length of the array onto the stack.
 *
 * Error Handling:
 * - Exits with an error if the array is of the wrong type.
 * - Exits with an error if memory allocation fails during the append operation.
 *
 * Example:
 * // Bytecode: OP_ARR_PUSH
 * // Stack before: [42, [10, 20, 30]]
 * // Stack after: [4]
 *
 * @author Johannes Findeisen
 * @date 2025-10-16
 */

case OP_PUSH: {
    Value v = pop_value(vm);
    Value arr = pop_value(vm);
    if (arr.type != VAL_ARRAY) {
        fprintf(stderr, "Runtime type error: ARR_PUSH expects array\n");
        exit(1);
    }
    int n = array_push(&arr, v);
    if (n < 0) {
        fprintf(stderr, "Runtime error: push failed (OOM?)\n");
        exit(1);
    }
    free_value(arr);
    push_value(vm, make_int(n));
    break;
}