<?php
namespace nulib\db;

use nulib\cl;
use nulib\php\func;
use nulib\ValueException;
use Traversable;

/**
 * Class Capacitor: un objet permettant d'attaquer un canal spécifique d'une
 * instance de {@link CapacitorStorage}
 */
class Capacitor implements ITransactor {
  function __construct(CapacitorStorage $storage, CapacitorChannel $channel, bool $ensureExists=true) {
    $this->storage = $storage;
    $this->channel = $channel;
    $this->channel->setCapacitor($this);
    if ($ensureExists) $this->ensureExists();
  }

  /** @var CapacitorStorage */
  protected $storage;

  function getStorage(): CapacitorStorage {
    return $this->storage;
  }

  function db(): IDatabase {
    return $this->getStorage()->db();
  }

  /** @var CapacitorChannel */
  protected $channel;

  function getChannel(): CapacitorChannel {
    return $this->channel;
  }

  function getTableName(): string {
    return $this->getChannel()->getTableName();
  }

  function getCreateSql(): string {
    $channel = $this->channel;
    return $this->storage->_getMigration($channel)->getSql(get_class($channel), $this->db());
  }

  /** @var CapacitorChannel[]  */
  protected ?array $subChannels = null;

  protected ?array $subManageTransactions = null;

  function willUpdate(...$channels): self {
    if ($this->subChannels === null) {
      # désactiver la gestion des transaction sur le channel local aussi
      $this->subChannels[] = $this->channel;
    }
    if ($channels) {
      foreach ($channels as $channel) {
        if ($channel instanceof Capacitor) $channel = $channel->getChannel();
        if ($channel instanceof CapacitorChannel) {
          $this->subChannels[] = $channel;
        } else {
          throw ValueException::invalid_type($channel, CapacitorChannel::class);
        }
      }
    }
    return $this;
  }

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

  function beginTransaction(?callable $func=null, bool $commit=true): void {
    $db = $this->db();
    if ($this->subChannels !== null) {
      # on gère des subchannels: ne débuter la transaction que si ce n'est déjà fait
      if ($this->subManageTransactions === null) {
        foreach ($this->subChannels as $channel) {
          $name = $channel->getName();
          $this->subManageTransactions ??= [];
          if (!array_key_exists($name, $this->subManageTransactions)) {
            $this->subManageTransactions[$name] = $channel->isManageTransactions();
          }
          $channel->setManageTransactions(false);
        }
        if (!$db->inTransaction()) $db->beginTransaction();
      }
    } elseif (!$db->inTransaction()) {
      $db->beginTransaction();
    }
    if ($func !== null) {
      $commited = false;
      try {
        func::call($func, $this);
        if ($commit) {
          $this->commit();
          $commited = true;
        }
      } finally {
        if ($commit && !$commited) $this->rollback();
      }
    }
  }

  protected function beforeEndTransaction(): void {
    if ($this->subManageTransactions !== null) {
      foreach ($this->subChannels as $channel) {
        $name = $channel->getName();
        $channel->setManageTransactions($this->subManageTransactions[$name]);
      }
      $this->subManageTransactions = null;
    }
  }

  function commit(): void {
    $this->beforeEndTransaction();
    $db = $this->db();
    if ($db->inTransaction()) $db->commit();
  }

  function rollback(): void {
    $this->beforeEndTransaction();
    $db = $this->db();
    if ($db->inTransaction()) $db->rollback();
  }

  function exists(): bool {
    return $this->storage->_exists($this->channel);
  }

  function ensureExists(): void {
    $this->storage->_ensureExists($this->channel);
  }

  function reset(bool $recreate=false): void {
    $this->storage->_reset($this->channel, $recreate);
  }

  function charge($item, $func=null, ?array $args=null, ?array &$row=null): int {
    if ($this->subChannels !== null) $this->beginTransaction();
    return $this->storage->_charge($this->channel, $item, $func, $args, $row);
  }

  function chargeAll(?iterable $items, $func=null, ?array $args=null): int {
    $count = 0;
    if ($items !== null) {
      if ($func !== null) {
        $func = func::with($func, $args)->bind($this->channel);
      }
      foreach ($items as $item) {
        $count += $this->charge($item, $func);
      }
    }
    return $count;
  }

  function discharge(bool $reset=true): Traversable {
    return $this->storage->_discharge($this->channel, $reset);
  }

  function count($filter=null): int {
    return $this->storage->_count($this->channel, $filter);
  }

  function one($filter, ?array $mergeQuery=null): ?array {
    return $this->storage->_one($this->channel, $filter, $mergeQuery);
  }

  function all($filter, ?array $mergeQuery=null): Traversable {
    return $this->storage->_all($this->channel, $filter, $mergeQuery);
  }

  function each($filter, $func=null, ?array $args=null, ?array $mergeQuery=null, ?int &$nbUpdated=null): int {
    if ($this->subChannels !== null) $this->beginTransaction();
    return $this->storage->_each($this->channel, $filter, $func, $args, $mergeQuery, $nbUpdated);
  }

  function delete($filter, $func=null, ?array $args=null): int {
    if ($this->subChannels !== null) $this->beginTransaction();
    return $this->storage->_delete($this->channel, $filter, $func, $args);
  }

  function dbAll(array $query, ?array $params=null): iterable {
    $primaryKeys = $this->channel->getPrimaryKeys();
    return $this->storage->db()->all(cl::merge([
      "select",
      "from" => $this->getTableName(),
    ], $query), $params, $primaryKeys);
  }

  function dbOne(array $query, ?array $params=null): ?array {
    return $this->storage->db()->one(cl::merge([
      "select",
      "from" => $this->getTableName(),
    ], $query), $params);
  }

  /** @return int|false */
  function dbUpdate(array $query, ?array $params=null) {
    return $this->storage->db()->exec(cl::merge([
      "update",
      "table" => $this->getTableName(),
    ], $query), $params);
  }

  function close(): void {
    $this->storage->close();
  }
}