<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Form\Extension\Validator\ViolationMapper;

use Symfony\Component\Form\Exception\OutOfBoundsException;
use Symfony\Component\PropertyAccess\PropertyPath;
use Symfony\Component\PropertyAccess\PropertyPathInterface;

/**
 * @author Bernhard Schussek <bschussek@gmail.com>
 *
 * @implements \IteratorAggregate<int, string>
 */
class ViolationPath implements \IteratorAggregate, PropertyPathInterface
{
    /** @var list<string> */
    private array $elements = [];
    private array $isIndex = [];
    private array $mapsForm = [];
    private string $pathAsString = '';
    private int $length = 0;

    /**
     * Creates a new violation path from a string.
     *
     * @param string $violationPath The property path of a {@link \Symfony\Component\Validator\ConstraintViolation} object
     */
    public function __construct(string $violationPath)
    {
        $path = new PropertyPath($violationPath);
        $elements = $path->getElements();
        $data = false;

        for ($i = 0, $l = \count($elements); $i < $l; ++$i) {
            if (!$data) {
                // The element "data" has not yet been passed
                if ('children' === $elements[$i] && $path->isProperty($i)) {
                    // Skip element "children"
                    ++$i;

                    // Next element must exist and must be an index
                    // Otherwise consider this the end of the path
                    if ($i >= $l || !$path->isIndex($i)) {
                        break;
                    }

                    // All the following index items (regardless if .children is
                    // explicitly used) are children and grand-children
                    for (; $i < $l && $path->isIndex($i); ++$i) {
                        $this->elements[] = $elements[$i];
                        $this->isIndex[] = true;
                        $this->mapsForm[] = true;
                    }

                    // Rewind the pointer as the last element above didn't match
                    // (even if the pointer was moved forward)
                    --$i;
                } elseif ('data' === $elements[$i] && $path->isProperty($i)) {
                    // Skip element "data"
                    ++$i;

                    // End of path
                    if ($i >= $l) {
                        break;
                    }

                    $this->elements[] = $elements[$i];
                    $this->isIndex[] = $path->isIndex($i);
                    $this->mapsForm[] = false;
                    $data = true;
                } else {
                    // Neither "children" nor "data" property found
                    // Consider this the end of the path
                    break;
                }
            } else {
                // Already after the "data" element
                // Pick everything as is
                $this->elements[] = $elements[$i];
                $this->isIndex[] = $path->isIndex($i);
                $this->mapsForm[] = false;
            }
        }

        $this->length = \count($this->elements);

        $this->buildString();
    }

    public function __toString(): string
    {
        return $this->pathAsString;
    }

    public function getLength(): int
    {
        return $this->length;
    }

    public function getParent(): ?PropertyPathInterface
    {
        if ($this->length <= 1) {
            return null;
        }

        $parent = clone $this;

        --$parent->length;
        array_pop($parent->elements);
        array_pop($parent->isIndex);
        array_pop($parent->mapsForm);

        $parent->buildString();

        return $parent;
    }

    public function getElements(): array
    {
        return $this->elements;
    }

    public function getElement(int $index): string
    {
        if (!isset($this->elements[$index])) {
            throw new OutOfBoundsException(\sprintf('The index "%s" is not within the violation path.', $index));
        }

        return $this->elements[$index];
    }

    public function isProperty(int $index): bool
    {
        if (!isset($this->isIndex[$index])) {
            throw new OutOfBoundsException(\sprintf('The index "%s" is not within the violation path.', $index));
        }

        return !$this->isIndex[$index];
    }

    public function isIndex(int $index): bool
    {
        if (!isset($this->isIndex[$index])) {
            throw new OutOfBoundsException(\sprintf('The index "%s" is not within the violation path.', $index));
        }

        return $this->isIndex[$index];
    }

    public function isNullSafe(int $index): bool
    {
        return false;
    }

    /**
     * Returns whether an element maps directly to a form.
     *
     * Consider the following violation path:
     *
     *     children[address].children[office].data.street
     *
     * In this example, "address" and "office" map to forms, while
     * "street does not.
     *
     * @throws OutOfBoundsException if the offset is invalid
     */
    public function mapsForm(int $index): bool
    {
        if (!isset($this->mapsForm[$index])) {
            throw new OutOfBoundsException(\sprintf('The index "%s" is not within the violation path.', $index));
        }

        return $this->mapsForm[$index];
    }

    /**
     * Returns a new iterator for this path.
     */
    public function getIterator(): ViolationPathIterator
    {
        return new ViolationPathIterator($this);
    }

    /**
     * Builds the string representation from the elements.
     */
    private function buildString(): void
    {
        $this->pathAsString = '';
        $data = false;

        foreach ($this->elements as $index => $element) {
            if ($this->mapsForm[$index]) {
                $this->pathAsString .= ".children[$element]";
            } elseif (!$data) {
                $this->pathAsString .= '.data'.($this->isIndex[$index] ? "[$element]" : ".$element");
                $data = true;
            } else {
                $this->pathAsString .= $this->isIndex[$index] ? "[$element]" : ".$element";
            }
        }

        if ('' !== $this->pathAsString) {
            // remove leading dot
            $this->pathAsString = substr($this->pathAsString, 1);
        }
    }
}