<?php

/*
 * Copyright (c) Alexandre Gomes Gaigalas <alganet@gmail.com>
 * SPDX-License-Identifier: MIT
 */

declare(strict_types=1);

namespace Respect\Validation\Message\Formatter;

use Respect\Validation\Message\Renderer;
use Respect\Validation\Message\StringFormatter;
use Respect\Validation\Result;

use function array_filter;
use function array_reduce;
use function count;
use function rtrim;
use function sprintf;
use function str_repeat;

use const PHP_EOL;

final readonly class NestedListStringFormatter implements StringFormatter
{
    /** @param array<string|int, mixed> $templates */
    public function format(Result $result, Renderer $renderer, array $templates): string
    {
        return $this->formatRecursively($result, $renderer, $templates, 0);
    }

    /** @param array<string|int, mixed> $templates */
    private function formatRecursively(
        Result $result,
        Renderer $renderer,
        array $templates,
        int $depth,
        Result ...$siblings,
    ): string {
        $formatted = '';
        $displayedName = null;
        if ($this->isVisible($result, ...$siblings)) {
            $indentation = str_repeat(' ', $depth * 2);
            $displayedName = $result->name;
            $formatted .= sprintf('%s- %s' . PHP_EOL, $indentation, $renderer->render($result, $templates));
            $depth++;
        }

        foreach ($result->children as $child) {
            $formatted .= $this->formatRecursively(
                $displayedName === $child->name ? $child->withoutName() : $child,
                $renderer,
                $templates,
                $depth,
                ...array_filter($result->children, static fn(Result $sibling) => $sibling !== $child),
            );
            $formatted .= PHP_EOL;
        }

        return rtrim($formatted, PHP_EOL);
    }

    private function isVisible(Result $result, Result ...$siblings): bool
    {
        if ($result->hasCustomTemplate()) {
            return true;
        }

        // Parents of an only child are not visible by default
        if (count($result->children) !== 1) {
            return true;
        }

        // Only children are always visible
        if (count($siblings) === 0) {
            return false;
        }

        // The visibility of a result then will depend on whether any of its siblings is visible
        return array_reduce(
            $siblings,
            fn(bool $carry, Result $currentSibling) => $carry || $this->isVisible(
                $currentSibling,
                ...array_filter($siblings, static fn(Result $sibling) => $sibling !== $currentSibling),
            ),
            true,
        );
    }
}