<?php
namespace nur\b\coll;

use nur\A;
use nur\b\ValueException;
use nur\data\types\Metadata;

/**
 * Class ArrayViewStack: une vue vers un ensemble de tableaux organisés en pile.
 * seul le tableau sur la pile du haut est modifiable.
 */
class ArrayViewStack implements IArray {
  use TBaseArray, TGenericArray, TArrayMdBasic, TAutomethods;

  const _AUTO_GETTERS = null;
  const _AUTO_SETTERS = null;
  const _AUTO_DELETERS = null;
  const _AUTO_CI_GETTERS = null;
  const _AUTO_CI_SETTERS = null;
  const _AUTOGEN_LITERALS = null;
  const _AUTOGEN_METHODS = null;

  /** @var array schéma des données de cette vue */
  const SCHEMA = null;

  function __construct(&$source=null, $pkeys=null) {
    if ($source !== null) $this->push($source, $pkeys);
  }

  protected $stack = [];

  function stackDepth(): int {
    return count($this->stack);
  }

  function &root(): array {
    return $this->stack;
  }

  function push(&$source, $pkeys=null): self {
    if ($source === null) $source = [];
    if (is_array($source)) $root =& $source;
    elseif ($source instanceof IArray) $root =& $source->array();
    else throw ValueException::unexpected_type(["array", IArray::class], $source);
    if ($pkeys === "" || $pkeys === null) $pkeys = [];
    if (is_string($pkeys)) $pkeys = explode(".", $pkeys);
    if (!is_array($pkeys)) throw ValueException::unexpected_type(["array", "string"], $pkeys);

    $data =& $root;
    foreach ($pkeys as $pkey) {
      if (!is_array($data)) $data = [$data];
      elseif (!array_key_exists($pkey, $data)) $data[$pkey] = null;
      $data =& $data[$pkey];
    }
    $key = A::last($pkeys);
    $md = $this->md();
    if ($md !== null) $md->ensureSchema($data, $key);

    array_unshift($this->stack, null);
    $this->stack[0] =& $data;
    return $this;
  }

  function &pop(): array {
    $data =& $this->stack[0];
    array_shift($this->stack);
    return $data;
  }

  function &peek(int $index=1): array {
    $count = count($this->stack);
    if ($count > 0) {
      while ($index < 0) $index += $count;
    }
    return $this->stack[$index];
  }

  function __toString(): string { return var_export($this->stack, true); }
  function &array(): ?array { return $this->stack[0]; }
  function keys(): array {
    $keys = [];
    foreach ($this->stack as $data) {
      $dataKeys = array_fill_keys(array_keys($data), true);
      A::merge2($keys, $dataKeys);
    }
    return array_keys($keys);
  }
  function count(): int { return count($this->keys()); }

  function _has($key): bool {
    foreach ($this->stack as $data) {
      if (array_key_exists($key, $data)) return true;
    }
    return false;
  }
  function &_get($key, $default=null) {
    foreach ($this->stack as $data) {
      if (array_key_exists($key, $data)) return $data[$key];
    }
    return $default;
  }
  function _set($key, $value) {
    if ($key === null) $this->stack[0][] = $value;
    else $this->stack[0][$key] = $value;
    return $this;
  }
  function _del($key) {
    unset($this->stack[0][$key]);
    return $this;
  }

  /**
   * retourner le gestionnaire de schéma. le mieux dans les classes dérivées est
   * d'utiliser le trait {@link TArrayMd} qui maintient un cache partagé entre
   * toutes les instances de la classe.
   */
  protected function md(): ?Metadata {
    $schema = static::SCHEMA;
    if ($schema === null) return null;
    else return new Metadata($schema);
  }

  # Rajouter ceci dans les classes dérivées:
  #use TArrayMd, TAutoconstsStatic; // ou TArrayMdDynamic, TAutoconstsDynamic
  #const _AUTOGEN_CONSTS = ["" => [self::class, "_AUTOGEN_CONSTS"]];
  ##--autogen-dynamic--
}