<?php

/**
 * webtrees: online genealogy
 * Copyright (C) 2021 webtrees development team
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

declare(strict_types=1);

namespace Fisharebest\Webtrees\Services;

use Fisharebest\Webtrees\Fact;
use Fisharebest\Webtrees\GedcomRecord;
use Fisharebest\Webtrees\Session;
use Illuminate\Support\Collection;

use function explode;

/**
 * Copy and past facts between records.
 */
class ClipboardService
{
    // Maximum number of entries in the clipboard.
    private const CLIPBOARD_SIZE = 10;

    /**
     * Copy a fact to the clipboard.
     *
     * @param Fact $fact
     */
    public function copyFact(Fact $fact): void
    {
        $clipboard   = Session::get('clipboard', []);
        $record_type = $fact->record()->tag();
        $fact_id     = $fact->id();

        // If we are copying the same fact twice, make sure the new one is at the end.
        unset($clipboard[$record_type][$fact_id]);

        $clipboard[$record_type][$fact_id] = $fact->gedcom();

        // The clipboard only holds a limited number of facts.
        $clipboard[$record_type] = array_slice($clipboard[$record_type], -self::CLIPBOARD_SIZE);

        Session::put('clipboard', $clipboard);
    }

    /**
     * Copy a fact from the clipboard to a record.
     *
     * @param string       $fact_id
     * @param GedcomRecord $record
     *
     * @return bool
     */
    public function pasteFact(string $fact_id, GedcomRecord $record): bool
    {
        $clipboard = Session::get('clipboard');

        $record_type = $record->tag();

        if (isset($clipboard[$record_type][$fact_id])) {
            $record->createFact($clipboard[$record_type][$fact_id], true);

            return true;
        }

        return false;
    }

    /**
     * Create a list of facts that can be pasted into a given record
     *
     * @param GedcomRecord $record
     *
     * @return Collection<Fact>
     */
    public function pastableFacts(GedcomRecord $record): Collection
    {
        // The facts are stored in the session.
        return (new Collection(Session::get('clipboard', [])[$record->tag()] ?? []))
            // Put the most recently copied fact at the top of the list.
            ->reverse()
            // Create facts for the record.
            ->map(static function (string $clipping) use ($record): Fact {
                return new Fact($clipping, $record, md5($clipping));
            });
    }

    /**
     * Find facts of a given type, from all records.
     *
     * @param GedcomRecord $record
     * @param Collection   $types
     *
     * @return Collection<Fact>
     */
    public function pastableFactsOfType(GedcomRecord $record, Collection $types): Collection
    {
        // The facts are stored in the session.
        return (new Collection(Session::get('clipboard', [])))
            ->flatten(1)
            ->reverse()
            ->map(static function (string $clipping) use ($record): Fact {
                return new Fact($clipping, $record, md5($clipping));
            })
            ->filter(static function (Fact $fact) use ($types): bool {
                return $types->contains(explode(':', $fact->tag())[1]);
            });
    }
}
