<?php

declare(strict_types=1);

namespace LIT\MCP\Integrations\Divi\Pages;

use LIT\MCP\Abilities\Ability;
use LIT\MCP\Abilities\Errors;
use LIT\MCP\Abilities\Rev;
use LIT\MCP\Integrations\Divi\BlockTree\NodeIndex;
use LIT\MCP\Integrations\Divi\BlockTree\Outline;
use LIT\MCP\Integrations\Divi\Design\DesignSystemReader;
use WP_Error;

/**
 * lit/divi-outline: the page tree with path IDs, types, admin labels, text excerpts and
 * preset names plus tree_rev (spec §5.3, §5.7). Every Divi write needs this tree_rev.
 */
final class DiviOutlineAbility implements Ability
{
    public function __construct(private DiviPageLoader $loader, private DesignSystemReader $design)
    {
    }

    public function name(): string
    {
        return 'lit/divi-outline';
    }

    public function label(): string
    {
        return 'Divi-Seitenbaum';
    }

    public function description(): string
    {
        return 'Liest den Aufbau einer Divi-Seite: Knoten mit Pfad-ID (s0, s0.r1, s0.r1.c0.m2), Modultyp, '
            . 'Admin-Label, Textauszug und Preset. Liefert tree_rev – Pflicht für jede Divi-Änderung. '
            . 'Optional nur ein Teilbaum (id) oder begrenzte Tiefe (depth).';
    }

    public function inputSchema(): array
    {
        return [
            'type' => 'object',
            'properties' => [
                'post_id' => ['type' => 'integer', 'minimum' => 1],
                'id' => ['type' => 'string', 'description' => 'Nur diesen Teilbaum, z. B. "s1".'],
                'depth' => [
                    'type' => 'integer',
                    'minimum' => 0,
                    'maximum' => 10,
                    'description' => 'Maximale Tiefe unterhalb des Startknotens (0 = nur der Knoten).',
                ],
            ],
            'required' => ['post_id'],
            'additionalProperties' => false,
        ];
    }

    public function outputSchema(): ?array
    {
        return [
            'type' => 'object',
            'properties' => [
                'post_id' => ['type' => 'integer'],
                'title' => ['type' => 'string'],
                'status' => ['type' => 'string'],
                'tree_rev' => ['type' => 'string'],
                'rev' => ['type' => 'string'],
                'outline' => ['type' => 'string'],
                'nodes' => [
                    'type' => 'array',
                    'items' => [
                        'type' => 'object',
                        'properties' => [
                            'id' => ['type' => 'string'],
                            'type' => ['type' => 'string'],
                            'label' => ['type' => 'string'],
                            'excerpt' => ['type' => 'string'],
                            'info' => ['type' => 'string'],
                            'presets' => ['type' => 'array', 'items' => ['type' => 'string']],
                            'children' => ['type' => 'integer'],
                            'editable' => ['type' => 'boolean'],
                            'depth' => ['type' => 'integer'],
                        ],
                        'required' => [
                            'id', 'type', 'label', 'excerpt', 'info', 'presets', 'children', 'editable', 'depth',
                        ],
                    ],
                ],
                'edit_url' => ['type' => 'string'],
                'hints' => ['type' => 'array', 'items' => ['type' => 'string']],
            ],
            'required' => ['post_id', 'tree_rev', 'rev', 'outline', 'nodes', 'hints'],
        ];
    }

    public function annotations(): array
    {
        return ['readonly' => true, 'destructive' => false, 'idempotent' => true];
    }

    public function isDirect(): bool
    {
        return true;
    }

    public function permission(array $input): bool|WP_Error
    {
        $page = $this->loader->load($input['post_id'] ?? null, false);

        return $page instanceof WP_Error ? $page : true;
    }

    public function execute(array $input): mixed
    {
        $page = $this->loader->load($input['post_id'] ?? null, false);
        if ($page instanceof WP_Error) {
            return $page;
        }

        $rootId = isset($input['id']) && is_string($input['id']) && $input['id'] !== '' ? $input['id'] : null;
        if ($rootId !== null && preg_match(NodeIndex::ID_PATTERN, $rootId) !== 1) {
            return Errors::invalidInput('id ist keine Pfad-ID.', ['id' => 'z. B. "s0.r1.c0.m2"']);
        }
        if ($rootId !== null && $page->index->find($rootId) === null) {
            return DiviPageLoader::unknownNode($rootId, $page->post);
        }

        $outline = new Outline($this->design->read()->presetNames());
        $rows = $outline->rows($page->index, $rootId, isset($input['depth']) ? (int) $input['depth'] : null);

        return [
            'post_id' => (int) $page->post->ID,
            'title' => (string) $page->post->post_title,
            'status' => (string) $page->post->post_status,
            'tree_rev' => $page->treeRev(),
            'rev' => Rev::ofPost($page->post),
            'outline' => $outline->text($rows),
            'nodes' => $rows,
            'edit_url' => $page->editUrl(),
            'hints' => $this->hints($page, $rows),
        ];
    }

    /**
     * @param list<array<string, mixed>> $rows
     * @return list<string>
     */
    private function hints(DiviPage $page, array $rows): array
    {
        $hints = [];
        if ($rows === []) {
            $hints[] = $page->isDiviLayout()
                ? 'Die Seite hat noch keinen Divi-Inhalt.'
                : 'Der Inhalt ist kein Divi-Layout (Block-Editor oder klassisch); lit-content-get zeigt ihn.';
        }

        if (in_array(false, array_column($rows, 'editable'), true)) {
            $hints[] = 'Knoten mit "nur lesbar" (globale Module, fremde Blöcke) ändern die Divi-Werkzeuge nicht; '
                . 'ihren Inhalt nur im Divi-Builder bearbeiten.';
        }

        return $hints;
    }
}