<?php

declare(strict_types=1);

namespace LIT\MCP\Integrations\Divi\Pages;

use Closure;
use LIT\MCP\Abilities\Annotations;
use LIT\MCP\Abilities\Errors;
use WP_Error;

defined('ABSPATH') || exit;

/**
 * lit/divi-node-copy (spec §5.7, E6): a node with everything inside from one Divi entry (page or
 * library entry) to a position in another. The copy keeps its bytes – global instances stay linked –
 * and passes StoredNodeGuard of the target (builder-only values never move to another post for users
 * without unfiltered_html). Source: edit rights via DiviPageLoader (PostGuard / LibraryAccess, P9
 * hiding) and its own source_tree_rev, because path IDs are only valid for the state they were read
 * in; the source is only read, so it needs no lock. Target: like lit-divi-insert (tree_rev lock,
 * StructureRules, all or nothing, DiviWriter::commit with GlobalEdits – a global target entry never
 * gets a nested instance). Follows lit/divi-insert's Tools-tab state (ruling P9/E9). A library entry
 * as source is an insert from the library (E3, audit L5): it needs LibraryAccess::canInsert()
 * (add_library, writable group "Divi-Bibliothek") and follows lit-library-insert's Tools-tab state.
 */
final class DiviNodeCopyAbility extends DiviWriteAbility
{
    /**
     * @param (Closure(): bool)|null $diviWritable Whether lit/divi-insert is enabled; null = always.
     * @param (Closure(): bool)|null $libraryInsertable Whether lit/library-insert is enabled (gates
     *        library entries as source); null = always.
     */
    public function __construct(
        DiviWriter $writer,
        private DiviPageLoader $loader,
        private ?Closure $diviWritable = null,
        private ?Closure $libraryInsertable = null
    ) {
        parent::__construct($writer);
    }

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

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

    public function description(): string
    {
        return 'Kopiert einen Divi-Knoten samt Inhalt von einem Eintrag (source_post_id, source_id und '
            . 'source_tree_rev aus lit-divi-outline der Quelle) an eine Position eines anderen Eintrags (post_id, '
            . 'tree_rev, parent/before/after). Die Kopie ist byte-gleich; globale Module bleiben verknüpft. Quelle '
            . 'und Ziel dürfen auch Bibliothekseinträge sein. Alles oder nichts.';
    }

    public function inputSchema(): array
    {
        return [
            'type' => 'object',
            'properties' => array_merge(DiviSchema::write(), [
                'source_post_id' => ['type' => 'integer', 'minimum' => 1],
                'source_id' => ['type' => 'string', 'description' => 'Pfad-ID des Knotens in der Quelle.'],
                'source_tree_rev' => ['type' => 'string', 'description' => 'tree_rev der Quelle (lit-divi-outline).'],
            ], DiviSchema::position()),
            'required' => ['post_id', 'tree_rev', 'source_post_id', 'source_id', 'source_tree_rev'],
            'additionalProperties' => false,
        ];
    }

    public function annotations(): array
    {
        return Annotations::write(false);
    }

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

    /**
     * lit/divi-insert's Tools-tab state, then the source's own rights and, for a library entry as
     * source, the rights of an insert from the library – in permission() and execute().
     */
    protected function precheck(array $input): ?WP_Error
    {
        if ($this->diviWritable !== null && ! ($this->diviWritable)()) {
            return Errors::unsupported(
                'Divi-Änderungen sind für diese Verbindung abgeschaltet (Gruppe „Divi“ auf „nur lesen“ oder '
                    . 'lit-divi-insert deaktiviert).',
                'Einen Administrator fragen: Einstellungen → LIT MCP → Tools.'
            );
        }

        $source = $this->loader->load($input['source_post_id'] ?? null, false);
        if ($source instanceof WP_Error) {
            return $source;
        }

        return $source->isLibraryItem() ? $this->libraryInsertRefusal() : null;
    }

    /** E3/audit L5: copying out of a library entry is inserting from the library (lit-library-insert). */
    private function libraryInsertRefusal(): ?WP_Error
    {
        if ($this->libraryInsertable !== null && ! ($this->libraryInsertable)()) {
            return Errors::unsupported(
                'Einfügen aus der Divi-Bibliothek ist für diese Verbindung abgeschaltet (lit-library-insert '
                    . 'deaktiviert oder Gruppe „Divi-Bibliothek“ auf „nur lesen“).',
                'Einen Administrator fragen: Einstellungen → LIT MCP → Tools.'
            );
        }

        return $this->loader->library()?->canInsert();
    }

    protected function change(DiviPage $page, array $input, DiviComposition $composition): DiviChange|WP_Error
    {
        $source = $this->loader->load($input['source_post_id'] ?? null, false);
        if ($source instanceof WP_Error) {
            return $source;
        }

        if (! is_string($input['source_tree_rev'] ?? null) || $input['source_tree_rev'] !== $source->treeRev()) {
            return Errors::revMismatch(
                'Die Quelle wurde seit dem letzten Lesen geändert (source_tree_rev passt nicht); nichts wurde '
                    . 'gespeichert.',
                'Die Quelle mit lit-divi-outline neu lesen und source_tree_rev sowie die Pfad-ID übernehmen.'
            );
        }

        $id = is_string($input['source_id'] ?? null) ? $input['source_id'] : '';
        $node = $source->index->find($id);
        if ($node === null) {
            return DiviErrors::unknownNode($id, $source->post);
        }

        $copy = $node->copy();
        if ($source->isLibraryItem()) {
            // Finding 9: library entries from Divi's dialog use CRLF; unified before every takeover
            // (LibraryContent::load), as lit-library-insert and lit/library-save do.
            $copy->unifyLineBreaks();
        }
        $problems = $composition->storedGuard()->problems($copy);
        if ($problems !== []) {
            return Errors::invalidInput(
                'Der Knoten enthält Einstellungen, die nur im Divi-Builder übertragen werden dürfen; nichts wurde '
                    . 'gespeichert.',
                ['source_id' => implode('; ', $problems)]
            );
        }

        $editor = $composition->editor();
        $position = $editor->position($page->index, $input);
        if (is_string($position)) {
            return DiviErrors::position($position);
        }

        $violation = $editor->insert($position, [$copy]);
        if ($violation !== null) {
            return Errors::invalidInput(
                'Der Knoten passt nicht an diese Stelle; nichts wurde gespeichert.',
                ['source_id' => $violation]
            );
        }

        return (new DiviChange(sprintf('Knoten %s aus Eintrag %d kopiert', $id, (int) $source->post->ID)))
            ->record($copy, 'inserted');
    }
}