<?php
namespace nur\sery\db\sqlite;

use nur\sery\cl;
use nur\sery\db\CapacitorChannel;
use nur\sery\db\CapacitorStorage;
use nur\sery\php\func;
use nur\sery\ValueException;

/**
 * Class SqliteStorage
 */
class SqliteStorage extends CapacitorStorage {
  function __construct($sqlite) {
    $this->db = Sqlite::with($sqlite);
  }

  /** @var Sqlite */
  protected $db;

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

  const PRIMARY_KEY_DEFINITION = [
    "id_" => "integer primary key autoincrement",
  ];

  protected function _create(CapacitorChannel $channel): void {
    if (!$channel->isCreated()) {
      $cols = $this->ColumnDefinitions($channel);
      $this->db->exec([
        "create table if not exists",
        "table" => $channel->getTableName(),
        "cols" => $cols,
      ]);
      $channel->setCreated();
    }
  }

  function _exists(CapacitorChannel $channel): bool {
    $tableName = $this->db->get([
      "select name from sqlite_schema",
      "where" => [
        "name" => $channel->getTableName(),
      ],
    ]);
    return $tableName !== null;
  }

  function _ensureExists(CapacitorChannel $channel): void {
    $this->_create($channel);
  }

  function _reset(CapacitorChannel $channel): void {
    $this->db->exec([
      "drop table if exists",
      $channel->getTableName(),
    ]);
    $channel->setCreated(false);
  }

  function _charge(CapacitorChannel $channel, $item, $func, ?array $args): int {
    $this->_create($channel);
    $tableName = $channel->getTableName();
    $now = date("Y-m-d H:i:s");
    $row = cl::merge(
      $channel->getSum("item", $item),
      $this->unserialize($channel, $channel->getItemValues($item)));
    $prow = null;
    $rowIds = $this->getRowIds($channel, $row, $primaryKeys);
    if ($rowIds !== null) {
      # modification
      $prow = $this->db->one([
        "select",
        "from" => $tableName,
        "where" => $rowIds,
      ]);
    }

    $insert = null;
    if ($prow === null) {
      # création
      $row = cl::merge($row, [
        "created_" => $now,
        "modified_" => $now,
      ]);
      $insert = true;
      if ($func === null) $func = "->onCreate";
      func::ensure_func($func, $channel, $args);
      $values = $this->unserialize($channel, $row);
      $args = [$item, $values, ...$args];
    } else {
      # modification
      if ($channel->_wasSumModified("item", $row, $prow)) {
        $insert = false;
        $row = cl::merge($row, [
          "modified_" => $now,
        ]);
      }
      if ($func === null) $func = "->onUpdate";
      func::ensure_func($func, $channel, $args);
      $values = $this->unserialize($channel, $row);
      $pvalues = $this->unserialize($channel, $prow);
      $args = [$item, $values, $pvalues, ...$args];
    }

    $updates = func::call($func, ...$args);
    if (is_array($updates) && $updates) {
      if ($insert === null) $insert = false;
      if (!array_key_exists("modified_", $updates)) {
        $updates["modified_"] = $now;
      }
      $row = cl::merge($row, $this->serialize($channel, $updates));
    }

    if ($insert === null) {
      # aucune modification
      return 0;
    } elseif ($insert) {
      $this->db->exec([
        "insert",
        "into" => $tableName,
        "values" => $row,
      ]);
    } else {
      $this->db->exec([
        "update",
        "table" => $tableName,
        "values" => $row,
        "where" => $rowIds,
      ]);
    }
    return 1;
  }

  function _discharge(CapacitorChannel $channel, bool $reset=true): iterable {
    $rows = $this->db->all([
      "select item__",
      "from" => $channel->getTableName(),
    ]);
    foreach ($rows as $row) {
      yield unserialize($row['item__']);
    }
    if ($reset) $this->_reset($channel);
  }

  protected function verifixFilter(CapacitorChannel $channel, &$filter): void {
    if ($filter !== null && !is_array($filter)) {
      $id = $filter;
      $channel->verifixId($id);
      $filter = ["id_" => $id];
    }
    $filter = $this->serialize($channel, $filter);
  }

  function _count(CapacitorChannel $channel, $filter): int {
    $this->verifixFilter($channel, $filter);
    return $this->db->get([
      "select count(*)",
      "from" => $channel->getTableName(),
      "where" => $filter,
    ]);
  }

  function _one(CapacitorChannel $channel, $filter): ?array {
    if ($filter === null) throw ValueException::null("filter");
    $this->verifixFilter($channel, $filter);
    $row = $this->db->one([
      "select",
      "from" => $channel->getTableName(),
      "where" => $filter,
    ]);
    return $this->unserialize($channel, $row);
  }

  function _all(CapacitorChannel $channel, $filter): iterable {
    $this->verifixFilter($channel, $filter);
    $rows = $this->db->all([
      "select",
      "from" => $channel->getTableName(),
      "where" => $filter,
    ], null, $this->getPrimaryKeys($channel));
    foreach ($rows as $key => $row) {
      yield $key => $this->unserialize($channel, $row);
    }
  }

  function _each(CapacitorChannel $channel, $filter, $func, ?array $args): int {
    if ($func === null) $func = "->onEach";
    func::ensure_func($func, $channel, $args);
    $onEach = func::_prepare($func);
    $sqlite = $this->db;
    $tableName = $channel->getTableName();
    $commited = false;
    $count = 0;
    $sqlite->beginTransaction();
    $commitThreshold = $channel->getEachCommitThreshold();
    try {
      $args ??= [];
      foreach ($this->_all($channel, $filter) as $rowValues) {
        $rowIds = $this->getRowIds($channel, $rowValues);
        $updates = func::_call($onEach, [$rowValues["item"], $rowValues, ...$args]);
        if (is_array($updates) && $updates) {
          if (!array_key_exists("modified_", $updates)) {
            $updates["modified_"] = date("Y-m-d H:i:s");
          }
          $sqlite->exec([
            "update",
            "table" => $tableName,
            "values" => $this->serialize($channel, $updates),
            "where" => $rowIds,
          ]);
          if ($commitThreshold !== null) {
            $commitThreshold--;
            if ($commitThreshold == 0) {
              $sqlite->commit();
              $sqlite->beginTransaction();
              $commitThreshold = $channel->getEachCommitThreshold();
            }
          }
        }
        $count++;
      }
      $sqlite->commit();
      $commited = true;
      return $count;
    } finally {
      if (!$commited) $sqlite->rollback();
    }
  }

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