<?php

declare(strict_types=1);

use MeshVault\Catalog\ManagedPath;
use Phinx\Migration\AbstractMigration;

/** Writers must be stopped for both directions, including the read-only preflight. */
final class CatalogIdentity extends AbstractMigration
{
    public function up(): void
    {
        $problems = [];
        foreach ($this->fetchAll('SELECT id, managed_path FROM files ORDER BY id') as $file) {
            try {
                ManagedPath::validate($file['managed_path']);
            } catch (InvalidArgumentException) {
                $problems[] = 'noncanonical managed path on file ID ' . $file['id'];
            }
        }
        $duplicates = $this->fetchAll('SELECT f.id FROM files f INNER JOIN
            (SELECT managed_path FROM files GROUP BY managed_path HAVING COUNT(*) > 1) d
            ON f.managed_path = d.managed_path ORDER BY f.id');
        if ($duplicates !== []) {
            $problems[] = 'duplicate managed paths on file IDs ' . implode(', ', array_column($duplicates, 'id'));
        }
        $this->reject(
            $problems,
            'Resolve paths and ownership explicitly; do not merge or delete records automatically.'
        );

        $this->table('files')
            ->dropForeignKey('model_id')
            ->changeColumn('model_id', 'integer', ['null' => true, 'signed' => false])
            ->addForeignKey('model_id', 'models', 'id', ['delete' => 'RESTRICT', 'update' => 'NO_ACTION'])
            ->removeIndexByName('idx_files_model_path')
            ->addIndex(['managed_path'], ['unique' => true, 'name' => 'idx_files_managed_path'])
            ->addIndex(['model_id'], ['name' => 'idx_files_model_id'])
            ->update();
        $this->table('models')
            ->removeIndexByName('idx_models_folder_name')
            ->addIndex(['folder_id', 'name'], ['name' => 'idx_models_folder_name'])
            ->update();
    }

    public function down(): void
    {
        $problems = [];
        $unassigned = $this->fetchAll('SELECT id FROM files WHERE model_id IS NULL ORDER BY id');
        if ($unassigned !== []) {
            $problems[] = 'unassigned file IDs ' . implode(', ', array_column($unassigned, 'id'));
        }
        $duplicates = $this->fetchAll('SELECT m.id FROM models m INNER JOIN
            (SELECT folder_id, name FROM models GROUP BY folder_id, name HAVING COUNT(*) > 1) d
            ON m.folder_id = d.folder_id AND m.name = d.name ORDER BY m.id');
        if ($duplicates !== []) {
            $problems[] = 'duplicate same-folder titles on model IDs ' . implode(', ', array_column($duplicates, 'id'));
        }
        $this->reject(
            $problems,
            'Resolve by explicitly assigning files and disambiguating model titles before retrying.'
        );

        $this->table('files')
            ->dropForeignKey('model_id')
            ->changeColumn('model_id', 'integer', ['null' => false, 'signed' => false])
            ->addForeignKey('model_id', 'models', 'id', ['delete' => 'CASCADE', 'update' => 'NO_ACTION'])
            ->removeIndexByName('idx_files_managed_path')
            ->removeIndexByName('idx_files_model_id')
            ->addIndex(['model_id', 'managed_path'], ['unique' => true, 'name' => 'idx_files_model_path'])
            ->update();
        $this->table('models')
            ->removeIndexByName('idx_models_folder_name')
            ->addIndex(['folder_id', 'name'], ['unique' => true, 'name' => 'idx_models_folder_name'])
            ->update();
    }

    private function reject(array $problems, string $guidance): void
    {
        if ($problems !== []) {
            throw new RuntimeException('Catalog identity preflight: ' . implode('; ', $problems) . '. ' . $guidance);
        }
    }
}