<?php

declare(strict_types=1);

namespace andrewkydev\Database\Migration;

use andrewkydev\Database\Config\DatabaseConfig;
use andrewkydev\Database\Query\QueryRunner;
use andrewkydev\Database\Schema\SchemaManager;

final class MigrationManager {
    /** @var array<int, Migration> */
    private array $migrations = [];

    public function __construct(
        private SchemaManager $schema,
        private QueryRunner $query,
        private DatabaseConfig $config
    ) {
    }

    public function register(Migration $migration): void {
        $this->migrations[$migration->version()] = $migration;
    }

    public function runPending(): void {
        if (!$this->config->migrationsEnabled) {
            return;
        }
        $this->ensureTable();
        $applied = $this->appliedVersions();
        ksort($this->migrations);
        foreach ($this->migrations as $version => $migration) {
            if (in_array($version, $applied, true)) {
                continue;
            }
            $migration->up($this->schema, $this->query);
            $this->query->execute(
                'INSERT INTO ' . $this->config->migrationsTable . ' (version, applied_at) VALUES (?, ?)',
                [$version, date('Y-m-d H:i:s')]
            );
        }
    }

    private function ensureTable(): void {
        $sql = 'CREATE TABLE IF NOT EXISTS ' . $this->config->migrationsTable . ' ('
            . 'version INT PRIMARY KEY, '
            . 'applied_at VARCHAR(32) NOT NULL'
            . ')';
        $this->query->execute($sql);
    }

    /**
     * @return int[]
     */
    private function appliedVersions(): array {
        $rows = $this->query->query('SELECT version FROM ' . $this->config->migrationsTable);
        $versions = [];
        foreach ($rows as $row) {
            $versions[] = (int) $row['version'];
        }
        return $versions;
    }
}