<?php
namespace nulib\db\pdo;

use Generator;
use nulib\cl;
use nulib\db\_private\_config;
use nulib\db\_private\Tvalues;
use nulib\db\IDatabase;
use nulib\db\ITransactor;
use nulib\php\func;
use nulib\ValueException;

class Pdo implements IDatabase {
  use Tvalues;

  static function with($pdo, ?array $params=null): self {
    if ($pdo instanceof static) {
      return $pdo;
    } elseif ($pdo instanceof self) {
      # recréer avec les mêmes paramètres
      return new static(null, cl::merge([
        "dbconn" => $pdo->dbconn,
        "options" => $pdo->options,
        "config" => $pdo->config,
        "migration" => $pdo->migration,
      ], $params));
    } else {
      return new static($pdo, $params);
    }
  }

  static function config_errmodeException_lowerCase(self $pdo): void {
    $pdo->db->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
    $pdo->db->setAttribute(\PDO::ATTR_CASE, \PDO::CASE_LOWER);
  }
  const CONFIG_errmodeException_lowerCase = [self::class, "config_errmodeException_lowerCase"];

  static function config_unbufferedQueries(self $pdo): void {
    $pdo->db->setAttribute(\PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);
  }
  const CONFIG_unbufferedQueries = [self::class, "config_unbufferedQueries"];

  protected const OPTIONS = [
    \PDO::ATTR_PERSISTENT => true,
  ];

  protected const DEFAULT_CONFIG = [
    self::CONFIG_errmodeException_lowerCase,
  ];

  protected const CONFIG = null;

  protected const MIGRATION = null;

  const dbconn_SCHEMA = [
    "name" => "string",
    "user" => "?string",
    "pass" => "?string",
  ];

  const params_SCHEMA = [
    "dbconn" => ["array"],
    "options" => ["?array|callable"],
    "replace_config" => ["?array|callable"],
    "config" => ["?array|callable"],
    "migration" => ["?array|string|callable"],
    "auto_open" => ["bool", true],
  ];

  function __construct($dbconn=null, ?array $params=null) {
    if ($dbconn !== null) {
      if (!is_array($dbconn)) {
        $dbconn = ["name" => $dbconn];
        #XXX à terme, il faudra interroger config
        #$tmp = config::db($dbconn);
        #if ($tmp !== null) $dbconn = $tmp;
        #else $dbconn = ["name" => $dbconn];
      }
      $params["dbconn"] = $dbconn;
    }
    # dbconn
    $this->dbconn = $params["dbconn"] ?? null;
    $this->dbconn["name"] ??= null;
    $this->dbconn["user"] ??= null;
    $this->dbconn["pass"] ??= null;
    # options
    $this->options = $params["options"] ?? static::OPTIONS;
    # configuration
    $config = $params["replace_config"] ?? null;
    if ($config === null) {
      $config = $params["config"] ?? static::CONFIG;
      if (is_callable($config)) $config = [$config];
      $config = cl::merge(static::DEFAULT_CONFIG, $config);
    }
    $this->config = $config;
    # migrations
    $this->migration = $params["migration"] ?? static::MIGRATION;
    #
    $defaultAutoOpen = self::params_SCHEMA["auto_open"][1];
    if ($params["auto_open"] ?? $defaultAutoOpen) {
      $this->open();
    }
  }

  protected ?array $dbconn;

  /** @var array|callable */
  protected $options;

  /** @var array|string|callable */
  protected $config;

  /** @var array|string|callable */
  protected $migration;

  protected ?\PDO $db = null;

  function open(): self {
    if ($this->db === null) {
      $dbconn = $this->dbconn;
      $options = $this->options;
      if (is_callable($options)) {
        $options = func::with($options)->bind($this, true)->invoke();
      }
      $this->db = new \PDO($dbconn["name"], $dbconn["user"], $dbconn["pass"], $options);
      _config::with($this->config)->configure($this);
      //_migration::with($this->migration)->migrate($this);
    }
    return $this;
  }

  function close(): void {
    $this->db = null;
  }

  protected function db(): \PDO {
    $this->open();
    return $this->db;
  }

  /** @return int|false */
  function _exec(string $query) {
    return $this->db()->exec($query);
  }

  function exec($query, ?array $params=null) {
    $db = $this->db();
    $query = new _pdoQuery($query, $params);
    if ($query->_use_stmt($db, $stmt, $sql)) {
      if ($stmt->execute() === false) return false;
      if ($query->isInsert()) return $db->lastInsertId();
      else return $stmt->rowCount();
    } else {
      $rowCount = $db->exec($sql);
      if ($query->isInsert()) return $db->lastInsertId();
      else return $rowCount;
    }
  }

  /** @var ITransactor[] */
  protected ?array $transactors = null;

  function willUpdate(...$transactors): self {
    foreach ($transactors as $transactor) {
      if ($transactor instanceof ITransactor) {
        $this->transactors[] = $transactor;
        $transactor->willUpdate();
      } else {
        throw ValueException::invalid_type($transactor, ITransactor::class);
      }
    }
    return $this;
  }

  function inTransaction(): bool {
    return $this->db()->inTransaction();
  }

  function beginTransaction(?callable $func=null, bool $commit=true): void {
    $this->db()->beginTransaction();
    if ($this->transactors !== null) {
      foreach ($this->transactors as $transactor) {
        $transactor->beginTransaction();
      }
    }
    if ($func !== null) {
      $commited = false;
      try {
        func::call($func, $this);
        if ($commit) {
          $this->commit();
          $commited = true;
        }
      } finally {
        if ($commit && !$commited) $this->rollback();
      }
    }
  }

  function commit(): void {
    $this->db()->commit();
    if ($this->transactors !== null) {
      foreach ($this->transactors as $transactor) {
        $transactor->commit();
      }
    }
  }

  function rollback(): void {
    $this->db()->rollBack();
    if ($this->transactors !== null) {
      foreach ($this->transactors as $transactor) {
        $transactor->rollback();
      }
    }
  }

  function get($query, ?array $params=null, bool $entireRow=false) {
    $db = $this->db();
    $query = new _pdoQuery($query, $params);
    $stmt = null;
    try {
      /** @var \PDOStatement $stmt */
      if ($query->_use_stmt($db, $stmt, $sql)) {
        if ($stmt->execute() === false) return null;
      } else {
        $stmt = $db->query($sql);
      }
      $row = $stmt->fetch(\PDO::FETCH_ASSOC);
      if ($row === false) return null;
      $this->verifixRow($row);
      if ($entireRow) return $row;
      else return cl::first($row);
    } finally {
      if ($stmt instanceof \PDOStatement) $stmt->closeCursor();
    }
  }

  function one($query, ?array $params=null): ?array {
    return $this->get($query, $params, true);
  }

  function all($query, ?array $params=null, $primaryKeys=null): iterable {
    $db = $this->db();
    $query = new _pdoQuery($query, $params);
    $stmt = null;
    try {
      /** @var \PDOStatement $stmt */
      if ($query->_use_stmt($db, $stmt, $sql)) {
        if ($stmt->execute() === false) return;
      } else {
        $stmt = $db->query($sql);
      }
      $primaryKeys = cl::withn($primaryKeys);
      while (($row = $stmt->fetch(\PDO::FETCH_ASSOC)) !== false) {
        $this->verifixRow($row);
        if ($primaryKeys !== null) {
          $key = implode("-", cl::select($row, $primaryKeys));
          yield $key => $row;
        } else {
          yield $row;
        }
      }
    } finally {
      if ($stmt instanceof \PDOStatement) $stmt->closeCursor();
    }
  }
}