<?php

namespace app\core;

class Database{
    public \PDO $pdo;

    public function __construct(array $config){
        $dsn = $config['dsn'] ?? '';
        $user = $config['user'] ?? '';
        $password = $config['password'] ?? '';
        $this->pdo = new \PDO($dsn, $user, $password);
        $this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
    }

    public function applyMigrations(){
        $this->createMigrationsTable();
        $appliedMigrations = $this->getAppliedMigrations();
        
        $newMigrations = [];
        $files = scandir(Application::$ROOT_DIR.'/migrations');
        $toApplyMigrations = array_diff($files, $appliedMigrations);

        foreach($toApplyMigrations as $migration){
            if($migration === '.' || $migration === '..'){
                continue;
            }

            require_once Application::$ROOT_DIR.'/migrations/'.$migration;
            $className = pathinfo($migration, PATHINFO_FILENAME);

            $instance = new $className();
            $this->log("Applying migration $migration" . PHP_EOL);
            $instance->up();
            $this->log("Applied migration $migration" . PHP_EOL);

            $newMigrations[] = $migration;
        }

        if(!empty($newMigrations)){
            $this->saveMigrations($newMigrations);
        }else{
            $this->log('All migrations are applied');
        }
    }

    public function createMigrationsTable(){
        $this->pdo->exec("
        CREATE TABLE IF NOT EXISTS migrations (
            id INT AUTO_INCREMENT,
            migration varchar(255),
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
            PRIMARY KEY (id)
            ) 
         ENGINE=INNODB;");
    }

    public function getAppliedMigrations(){
        $statement = $this->pdo->prepare("SELECT migration FROM migrations");
        $statement->execute();

        return $statement->fetchAll(\PDO::FETCH_COLUMN);
    }

    public function saveMigrations(array $migrations){
        $str = implode(",", array_map(fn($m) => "('$m')", $migrations));
        $statement = $this->pdo->prepare("INSERT INTO migrations (migration) VALUES $str");
        $statement->execute();
    }

    public function prepare($sql){
        return $this->pdo->prepare($sql);
    }

    protected function log($message){
        echo '['.date('Y-m-d H:i:s').'] - '.$message.PHP_EOL;
    }
}