<?php

namespace SleekDB;

use Closure;
use SleekDB\Exceptions\InvalidArgumentException;

class QueryBuilder
{

  /**
   * @var Store
   */
  protected $store;
  /**
   * @var Cache
   */
  protected $cache;

  protected $whereConditions = [];

  protected $skip = 0;
  protected $limit = 0;
  protected $orderBy = [];
  protected $nestedWhere = []; // TODO remove with version 3.0
  protected $search = [];
  protected $searchOptions = [
    "minLength" => 2,
    "scoreKey" => "searchScore",
    "mode" => "or",
    "algorithm" => Query::SEARCH_ALGORITHM["hits"]
  ];

  protected $fieldsToSelect = [];
  protected $fieldsToExclude = [];
  protected $groupBy = [];
  protected $havingConditions = [];

  protected $listOfJoins = [];
  protected $distinctFields = [];

  protected $useCache;
  protected $regenerateCache = false;
  protected $cacheLifetime;


  // will also not be used for cache token
  protected $propertiesNotUsedInConditionsArray = [
    "propertiesNotUsedInConditionsArray",
    "propertiesNotUsedForCacheToken",
    "store",
    "cache",
  ];

  protected $propertiesNotUsedForCacheToken = [
    "useCache",
    "regenerateCache",
    "cacheLifetime"
  ];

  /**
   * QueryBuilder constructor.
   * @param Store $store
   */
  public function __construct(Store $store)
  {
    $this->store = $store;
    $this->useCache = $store->_getUseCache();
    $this->cacheLifetime = $store->_getDefaultCacheLifetime();
    $this->searchOptions = $store->_getSearchOptions();
  }

  /**
   * Select specific fields
   * @param array $fieldNames
   * @return QueryBuilder
   */
  public function select(array $fieldNames): QueryBuilder
  {
    foreach ($fieldNames as $key => $fieldName) {
      if(is_string($key)){
        $this->fieldsToSelect[$key] = $fieldName;
      } else {
        $this->fieldsToSelect[] = $fieldName;
      }
    }
    return $this;
  }

  /**
   * Exclude specific fields
   * @param string[] $fieldNames
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function except(array $fieldNames): QueryBuilder
  {
    $errorMsg = "If except is used an array containing strings with fieldNames has to be given";
    foreach ($fieldNames as $fieldName) {
      if (empty($fieldName)) {
        continue;
      }
      if (!is_string($fieldName)) {
        throw new InvalidArgumentException($errorMsg);
      }
      $this->fieldsToExclude[] = $fieldName;
    }
    return $this;
  }

  /**
   * Add conditions to filter data.
   * @param array $conditions
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function where(array $conditions): QueryBuilder
  {
    if (empty($conditions)) {
      throw new InvalidArgumentException("You need to specify a where clause");
    }

    $this->whereConditions[] = $conditions;

    return $this;
  }

  /**
   * Add or-where conditions to filter data.
   * @param array $conditions array(array(string fieldName, string condition, mixed value) [, array(...)])
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function orWhere(array $conditions): QueryBuilder
  {

    if (empty($conditions)) {
      throw new InvalidArgumentException("You need to specify a where clause");
    }

    $this->whereConditions[] = "or";
    $this->whereConditions[] = $conditions;

    return $this;
  }

  /**
   * Set the amount of data record to skip.
   * @param int|string $skip
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function skip($skip = 0): QueryBuilder
  {
    if((!is_string($skip) || !is_numeric($skip)) && !is_int($skip)){
      throw new InvalidArgumentException("Skip has to be an integer or a numeric string");
    }

    if(!is_int($skip)){
      $skip = (int) $skip;
    }

    if($skip < 0){
      throw new InvalidArgumentException("Skip has to be an integer >= 0");
    }

    $this->skip = $skip;

    return $this;
  }

  /**
   * Set the amount of data record to limit.
   * @param int|string $limit
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function limit($limit = 0): QueryBuilder
  {

    if((!is_string($limit) || !is_numeric($limit)) && !is_int($limit)){
      throw new InvalidArgumentException("Limit has to be an integer or a numeric string");
    }

    if(!is_int($limit)){
      $limit = (int) $limit;
    }

    if($limit <= 0){
      throw new InvalidArgumentException("Limit has to be an integer > 0");
    }

    $this->limit = $limit;

    return $this;
  }

  /**
   * Set the sort order.
   * @param array $criteria to order by. array($fieldName => $order). $order can be "asc" or "desc"
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function orderBy( array $criteria): QueryBuilder
  {
    foreach ($criteria as $fieldName => $order){

      if(!is_string($order)) {
        throw new InvalidArgumentException('Order has to be a string! Please use "asc" or "desc" only.');
      }

      $order = strtolower($order);

      if(!is_string($fieldName)) {
        throw new InvalidArgumentException("Field name has to be a string");
      }

      if (!in_array($order, ['asc', 'desc'])) {
        throw new InvalidArgumentException('Please use "asc" or "desc" only.');
      }

      $this->orderBy[] = [
        'fieldName' => $fieldName,
        'order' => $order
      ];
    }

    return $this;
  }

  /**
   * Do a fulltext like search against one or multiple fields.
   * @param string|array $fields one or multiple fieldNames as an array
   * @param string $query
   * @param array $options
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function search($fields, string $query, array $options = []): QueryBuilder
  {
    if(!is_array($fields) && !is_string($fields)){
      throw new InvalidArgumentException("Fields to search through have to be either a string or an array.");
    }

    if(!is_array($fields)){
      $fields = (array)$fields;
    }

    if (empty($fields)) {
      throw new InvalidArgumentException('Cant perform search due to no field name was provided');
    }

    if(count($fields) > 100){
      trigger_error('Searching through more than 100 fields is not recommended and can be resource heavy.', E_USER_WARNING);
    }

    if (!empty($query)) {
      $this->search = [
        'fields' => $fields,
        'query' => $query
      ];
      if(!empty($options)){
        if(array_key_exists("minLength", $options) && is_int($options["minLength"]) && $options["minLength"] > 0){
          $this->searchOptions["minLength"] = $options["minLength"];
        }
        if(array_key_exists("mode", $options) && is_string($options["mode"])){
          $searchMode = strtolower(trim($options["mode"]));
          if(in_array($searchMode, ["and", "or"])){
            $this->searchOptions["mode"] = $searchMode;
          }
        }
        if(array_key_exists("scoreKey", $options) && (is_string($options["scoreKey"]) || is_null($options["scoreKey"]))){
          $this->searchOptions["scoreKey"] = $options["scoreKey"];
        }
        if(array_key_exists("algorithm", $options) && in_array($options["algorithm"], Query::SEARCH_ALGORITHM, true)){
          $this->searchOptions["algorithm"] = $options["algorithm"];
        }
      }
    }
    return $this;
  }

  /**
   * @param Closure $joinFunction
   * @param string $propertyName
   * @return QueryBuilder
   */
  public function join(Closure $joinFunction, string $propertyName): QueryBuilder
  {
    $this->listOfJoins[] = [
      'propertyName' => $propertyName,
      'joinFunction' => $joinFunction
    ];
    return $this;
  }


  /**
   * Return distinct values.
   * @param array|string $fields
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function distinct($fields = []): QueryBuilder
  {
    $fieldType = gettype($fields);
    if ($fieldType === 'array') {
      if ($fields === array_values($fields)) {
        // Append fields.
        $this->distinctFields = array_merge($this->distinctFields, $fields);
      } else {
        throw new InvalidArgumentException(
          'Field value in distinct() method can not be an associative array, 
          please provide a string or a list of string as a non-associative array.'
        );
      }
    } else if ($fieldType === 'string' && !empty($fields)) {
      $this->distinctFields[] = trim($fields);
    } else {
      throw new InvalidArgumentException(
        'Field value in distinct() is invalid.'
      );
    }
    return $this;
  }

  /**
   * Use caching for current query
   * @param null|int $lifetime time to live as int in seconds or null to regenerate cache on every insert, update and delete
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function useCache(int $lifetime = null): QueryBuilder
  {
    $this->useCache = true;
    if((!is_int($lifetime) || $lifetime < 0) && !is_null($lifetime)){
      throw new InvalidArgumentException("lifetime has to be int >= 0 or null");
    }
    $this->cacheLifetime = $lifetime;
    return $this;
  }

  /**
   * Disable cache for the query.
   * @return QueryBuilder
   */
  public function disableCache(): QueryBuilder
  {
    $this->useCache = false;
    return $this;
  }

  /**
   * Re-generate the cache for the query.
   * @return QueryBuilder
   */
  public function regenerateCache(): QueryBuilder
  {
    $this->regenerateCache = true;
    return $this;
  }

  /**
   * @return Query
   */
  public function getQuery(): Query
  {
    return new Query($this);
  }

  /**
   * @param array $groupByFields
   * @param string|null $countKeyName
   * @param bool $allowEmpty
   * @return QueryBuilder
   */
  public function groupBy(array $groupByFields, string $countKeyName = null, bool $allowEmpty = false): QueryBuilder
  {
    $this->groupBy = [
      "groupByFields" => $groupByFields,
      "countKeyName" => $countKeyName,
      "allowEmpty" => $allowEmpty
    ];
    return $this;
  }

  /**
   * Filter result data of groupBy
   * @param array $criteria
   * @return QueryBuilder
   * @throws InvalidArgumentException
   */
  public function having(array $criteria): QueryBuilder
  {
    if (empty($criteria)) {
      throw new InvalidArgumentException("You need to specify a having clause");
    }
    $this->havingConditions = $criteria;
    return $this;
  }

  /**
   * Returns a an array used to generate a unique token for the current query.
   * @return array
   */
  public function _getCacheTokenArray(): array
  {
    $properties = [];
    $conditionsArray = $this->_getConditionProperties();

    foreach ($conditionsArray as $propertyName => $propertyValue){
      if(!in_array($propertyName, $this->propertiesNotUsedForCacheToken, true)){
        $properties[$propertyName] = $propertyValue;
      }
    }

    return $properties;
  }

  /**
   * Returns an array containing all information needed to execute an query.
   * @return array
   */
  public function _getConditionProperties(): array
  {
    $allProperties = get_object_vars($this);
    $properties = [];

    foreach ($allProperties as $propertyName => $propertyValue){
      if(!in_array($propertyName, $this->propertiesNotUsedInConditionsArray, true)){
        $properties[$propertyName] = $propertyValue;
      }
    }

    return $properties;
  }

  /**
   * Returns the Store object used to create the QueryBuilder object.
   * @return Store
   */
  public function _getStore(): Store{
      return $this->store;
  }

  /**
   * Add "in" condition to filter data.
   * @param string $fieldName
   * @param array $values
   * @return QueryBuilder
   * @throws InvalidArgumentException
   * @deprecated since version 2.4, use where and orWhere instead.
   */
  public function in(string $fieldName, array $values = []): QueryBuilder
  {
    if (empty($fieldName)) {
      throw new InvalidArgumentException('Field name for in clause can not be empty.');
    }

    // Add to conditions with "AND" operation
    $this->whereConditions[] = [$fieldName, "in", $values];
    return $this;
  }

  /**
   * Add "not in" condition to filter data.
   * @param string $fieldName
   * @param array $values
   * @return QueryBuilder
   * @throws InvalidArgumentException
   * @deprecated since version 2.4, use where and orWhere instead.
   */
  public function notIn(string $fieldName, array $values = []): QueryBuilder
  {
    if (empty($fieldName)) {
      throw new InvalidArgumentException('Field name for notIn clause can not be empty.');
    }

    // Add to conditions with "AND" operation
    $this->whereConditions[] = [$fieldName, "not in", $values];
    return $this;
  }

  /**
   * Add a where statement that is nested. ( $x or ($y and $z) )
   * @param array $conditions
   * @return QueryBuilder
   * @throws InvalidArgumentException
   * @deprecated since version 2.3, use where or orWhere instead.
   */
  public function nestedWhere(array $conditions): QueryBuilder
  {
    // TODO remove with version 3.0
    if(empty($conditions)){
      throw new InvalidArgumentException("You need to specify nested where clauses");
    }

    if(count($conditions) > 1){
      throw new InvalidArgumentException("You are not allowed to specify multiple elements at the first depth!");
    }

    $outerMostOperation = (array_keys($conditions))[0];
    $outerMostOperation = (is_string($outerMostOperation)) ? strtolower($outerMostOperation) : $outerMostOperation;

    $allowedOuterMostOperations = [0, "and", "or"];

    if(!in_array($outerMostOperation, $allowedOuterMostOperations, true)){
      throw new InvalidArgumentException("Outer most operation has to one of the following: ( 0 / and / or ) ");
    }

    $this->nestedWhere = $conditions;

    return $this;
  }

}