<?php

namespace LearnPress\Databases;

use Exception;
use LearnPress\Filters\FilterBase;
use wpdb;

defined( 'ABSPATH' ) || exit();

/**
 * Class DataBase
 *
 * @since 4.2.9.3
 * @version 1.0.0
 */
class DataBase {
	private static $_instance;
	public $wpdb, $tb_users;
	public $tb_lp_courses;
	public $tb_lp_user_items, $tb_lp_user_itemmeta;
	public $tb_posts, $tb_postmeta, $tb_options;
	public $tb_terms, $tb_term_relationships, $tb_term_taxonomy;
	public $tb_lp_order_items, $tb_lp_order_itemmeta;
	public $tb_lp_sections, $tb_lp_section_items;
	public $tb_lp_quiz_questions;
	public $tb_lp_user_item_results;
	public $tb_lp_question_answers;
	public $tb_lp_question_answermeta;
	public $tb_lp_upgrade_db;
	public $tb_lp_sessions;
	public $tb_lp_files;
	public $tb_thim_cache;
	private $collate         = '';
	public $max_index_length = '191';

	protected function __construct() {
		/**
		 * @var wpdb $wpdb
		 */
		global $wpdb;
		$prefix = $wpdb->prefix;

		$this->wpdb                      = $wpdb;
		$this->tb_users                  = $wpdb->users;
		$this->tb_posts                  = $wpdb->posts;
		$this->tb_postmeta               = $wpdb->postmeta;
		$this->tb_options                = $wpdb->options;
		$this->tb_terms                  = $wpdb->terms;
		$this->tb_term_relationships     = $wpdb->term_relationships;
		$this->tb_term_taxonomy          = $wpdb->term_taxonomy;
		$this->tb_lp_courses             = $prefix . 'learnpress_courses';
		$this->tb_lp_user_items          = $prefix . 'learnpress_user_items';
		$this->tb_lp_user_itemmeta       = $prefix . 'learnpress_user_itemmeta';
		$this->tb_lp_order_items         = $prefix . 'learnpress_order_items';
		$this->tb_lp_order_itemmeta      = $prefix . 'learnpress_order_itemmeta';
		$this->tb_lp_section_items       = $prefix . 'learnpress_section_items';
		$this->tb_lp_sections            = $prefix . 'learnpress_sections';
		$this->tb_lp_quiz_questions      = $prefix . 'learnpress_quiz_questions';
		$this->tb_lp_user_item_results   = $prefix . 'learnpress_user_item_results';
		$this->tb_lp_question_answers    = $prefix . 'learnpress_question_answers';
		$this->tb_lp_question_answermeta = $prefix . 'learnpress_question_answermeta';
		$this->tb_lp_upgrade_db          = $prefix . 'learnpress_upgrade_db';
		$this->tb_lp_sessions            = $prefix . 'learnpress_sessions';
		$this->tb_lp_files               = $prefix . 'learnpress_files';
		$this->tb_thim_cache             = $prefix . 'thim_cache';
		$this->wpdb->hide_errors();
		$this->set_collate();
	}

	/**
	 * Get Instance
	 *
	 * @return DataBase
	 */
	public static function getInstance() {
		if ( is_null( self::$_instance ) ) {
			self::$_instance = new self();
		}

		return self::$_instance;
	}

	public function set_collate() {
		$collate = '';

		if ( $this->wpdb->has_cap( 'collation' ) ) {
			if ( ! empty( $this->wpdb->charset ) ) {
				$collate .= 'DEFAULT CHARACTER SET ' . $this->wpdb->charset;
			}

			if ( ! empty( $this->wpdb->collate ) ) {
				$collate .= ' COLLATE ' . $this->wpdb->collate;
			}
		}

		$this->collate = $collate;
	}

	public function get_collate(): string {
		return $this->collate;
	}

	/**
	 * Check table exists.
	 *
	 * @param string $name_table
	 *
	 * @return bool|int
	 */
	public function check_table_exists( string $name_table ) {
		return $this->wpdb->query( $this->wpdb->prepare( "SHOW TABLES LIKE '%s'", $name_table ) );
	}

	/**
	 * Clone table
	 *
	 * @param string $name_table .
	 *
	 * @throws Exception
	 */
	public function clone_table( string $name_table ): bool {
		if ( ! current_user_can( ADMIN_ROLE ) ) {
			throw new Exception( 'You don\'t have permission' );
		}

		$table_bk = $name_table . '_bk';

		// Drop table bk if exists.
		$this->drop_table( $table_bk );

		// Clone table
		$this->wpdb->query( "CREATE TABLE $table_bk LIKE $name_table" );
		$this->wpdb->query( "INSERT INTO $table_bk SELECT * FROM $name_table" );

		/*dbDelta(
			"CREATE TABLE $table_bk LIKE $name_table;
			INSERT INTO $table_bk SELECT * FROM $name_table;"
		);*/

		$this->check_execute_has_error();

		return true;
	}

	/**
	 * Check column table
	 *
	 * @param string $name_table .
	 * @param string $name_col .
	 *
	 * @return bool|int
	 */
	public function check_col_table( string $name_table = '', string $name_col = '' ) {
		$query = $this->wpdb->prepare( "SHOW COLUMNS FROM $name_table LIKE '%s'", $name_col );

		return $this->wpdb->query( $query );
	}

	/**
	 * Drop Column of Table
	 *
	 * @param string $name_table .
	 * @param string $name_col .
	 *
	 * @return bool|int
	 * @throws Exception
	 */
	public function drop_col_table( string $name_table = '', string $name_col = '' ) {
		if ( ! current_user_can( 'administrator' ) ) {
			return false;
		}

		$check_table = $this->check_col_table( $name_table, $name_col );

		if ( $check_table ) {
			$execute = $this->wpdb->query( "ALTER TABLE $name_table DROP COLUMN $name_col" );

			$this->check_execute_has_error();

			return $execute;
		}

		return true;
	}

	/**
	 * Add Column of Table
	 *
	 * @param string $name_table .
	 * @param string $name_col .
	 * @param string $type .
	 * @param string $after_col .
	 *
	 * @return bool|int
	 * @throws Exception
	 */
	public function add_col_table( string $name_table, string $name_col, string $type, string $after_col = '' ) {
		if ( ! current_user_can( ADMIN_ROLE ) ) {
			throw new Exception( 'You don\'t have permission' );
		}

		$query_add = '';

		$col_exists = $this->check_col_table( $name_table, $name_col );

		if ( ! empty( $after_col ) ) {
			$query_add .= "AFTER $after_col";
		}

		if ( ! $col_exists ) {
			$execute = $this->wpdb->query( "ALTER TABLE $name_table ADD COLUMN $name_col $type $query_add" );

			$this->check_execute_has_error();

			return $execute;
		}

		return true;
	}

	/**
	 * Drop Index of Table
	 *
	 * @param string $name_table .
	 *
	 * @return void
	 * @throws Exception
	 */
	public function drop_indexs_table( string $name_table ) {
		$show_index = "SHOW INDEX FROM $name_table";
		$indexs     = $this->wpdb->get_results( $show_index );

		foreach ( $indexs as $index ) {
			if ( 'PRIMARY' === $index->Key_name || '1' !== $index->Seq_in_index ) {
				continue;
			}

			$query = "ALTER TABLE $name_table DROP INDEX $index->Key_name";

			$this->wpdb->query( $query );
			$this->check_execute_has_error();
		}
	}

	/**
	 * Add Index of Table
	 *
	 * @param string $name_table .
	 * @param array $indexs .
	 *
	 * @return bool|int
	 * @throws Exception
	 */
	public function add_indexs_table( string $name_table, array $indexs ) {
		$add_index    = '';
		$count_indexs = count( $indexs ) - 1;

		// Drop indexs .
		$this->drop_indexs_table( $name_table );

		foreach ( $indexs as $index ) {
			if ( $count_indexs === array_search( $index, $indexs ) ) {
				$add_index .= ' ADD INDEX ' . $index . ' (' . $index . ')';
			} else {
				$add_index .= ' ADD INDEX ' . $index . ' (' . $index . '),';
			}
		}

		$execute = $this->wpdb->query(
			"ALTER TABLE $name_table
			$add_index"
		);

		$this->check_execute_has_error();

		return $execute;
	}

	/**
	 * Drop table
	 *
	 * @param string $name_table .
	 *
	 * @return bool|int
	 * @throws Exception
	 */
	public function drop_table( string $name_table = '' ) {
		if ( ! current_user_can( ADMIN_ROLE ) ) {
			throw new Exception( 'You don\'t have permission' );
		}

		// Check table exists.
		$tb_exists = $this->check_table_exists( $name_table );
		if ( $tb_exists ) {
			$execute = $this->wpdb->query( "DROP TABLE $name_table" );

			$this->check_execute_has_error();

			return $execute;
		}

		return true;
	}

	/**
	 * Get list columns name of table
	 *
	 * @param string $name_table
	 *
	 * @return array
	 * @throws Exception
	 * @version 1.0.0
	 * @since 4.1.6
	 * @author tungnx
	 */
	public function get_cols_of_table( string $name_table ): array {
		$query = "SHOW COLUMNS FROM $name_table";

		$result = $this->wpdb->get_col( $query );

		$this->check_execute_has_error();

		return $result;
	}

	/**
	 * Create table learnpress_user_item_results
	 *
	 * @return bool|int
	 * @throws Exception
	 */
	public function create_tb_lp_user_item_results() {
		$collate = $this->get_collate();

		$execute = $this->wpdb->query(
			"
			CREATE TABLE IF NOT EXISTS $this->tb_lp_user_item_results(
				id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
				user_item_id bigint(20) unsigned NOT NULL,
				result longtext,
				PRIMARY KEY (id),
				KEY user_item_id (user_item_id)
			) $collate
			"
		);

		$this->check_execute_has_error();

		return $execute;
	}

	/**
	 * Create table learnpress_upgrade_db
	 *
	 * @return bool|int
	 * @throws Exception
	 */
	public function create_tb_lp_upgrade_db() {
		$collate = $this->get_collate();

		$execute = $this->wpdb->query(
			"
			CREATE TABLE IF NOT EXISTS {$this->tb_lp_upgrade_db}(
				step varchar(50) PRIMARY KEY UNIQUE,
				status varchar(10),
				KEY status (status)
			) $collate
			"
		);

		$this->check_execute_has_error();

		return $execute;
	}

	/**
	 * Set step completed.
	 *
	 * @param string $step .
	 * @param string $status .
	 *
	 * @return int|bool
	 */
	public function set_step_complete( string $step, string $status ) {
		if ( ! current_user_can( 'administrator' ) ) {
			return false;
		}

		return $this->wpdb->insert(
			$this->tb_lp_upgrade_db,
			array(
				'step'   => $step,
				'status' => $status,
			),
			array( '%s', '%s' )
		);
	}

	/**
	 * Get steps completed.
	 *
	 * @return array|object|null
	 */
	public function get_steps_completed() {
		return $this->wpdb->get_results( "SELECT step, status FROM {$this->tb_lp_upgrade_db}", OBJECT_K );
	}

	/**
	 * Check execute current has any errors.
	 *
	 * @throws Exception
	 */
	public function check_execute_has_error() {
		if ( $this->wpdb->last_error ) {
			throw new Exception( $this->wpdb->last_error );
		}
	}

	/**
	 * Important: Reason need set again indexes for table options of WP
	 * because if want change value of "option_name" will error "database error Duplicate entry"
	 * So before set must drop and add when done all
	 *
	 * @throws Exception
	 * @version 1.0.0
	 * @since 4.0.3
	 * @author tungnx
	 */
	public function create_indexes_tb_options() {
		$this->drop_indexs_table( $this->tb_options );
		$result = $this->wpdb->query(
			"
			ALTER TABLE $this->tb_options
			ADD UNIQUE option_name (option_name),
			ADD INDEX autoload (autoload)
			"
		);

		$this->check_execute_has_error();

		return $result;
	}

	/**
	 * Rename table
	 *
	 * @throws Exception
	 * @version 1.0.0
	 * @since 4.0.3
	 * @author tungnx
	 */
	public function rename_table( string $name_table = '', string $new_name = '' ) {
		if ( ! current_user_can( ADMIN_ROLE ) ) {
			throw new Exception( 'You don\'t have permission' );
		}

		$tb_exists = $this->check_table_exists( $name_table );

		if ( ! $tb_exists ) {
			throw new Exception( 'Table not exists' );
		}

		$result = $this->wpdb->query(
			"
			ALTER TABLE $name_table
			RENAME $new_name
			"
		);
		$this->check_execute_has_error();

		return $result;
	}

	/**
	 * Check key postmeta exist on Database
	 *
	 * @param int $post_id
	 * @param string $key
	 *
	 * @return bool|int
	 */
	public function check_key_postmeta_exists( int $post_id = 0, string $key = '' ) {
		return $this->wpdb->query(
			$this->wpdb->prepare(
				"
				SELECT meta_id FROM $this->tb_postmeta
				WHERE meta_key = %s
				AND post_id = %d
				",
				$key,
				$post_id
			)
		);
	}

	/**
	 * Get total pages
	 *
	 * @param int $limit
	 * @param int $total_rows
	 *
	 * @return int
	 */
	public static function get_total_pages( int $limit = 0, int $total_rows = 0 ): int {
		if ( $limit == 0 ) {
			return 0;
		}

		$total_pages = (int) ceil( $total_rows / $limit );

		return (int) $total_pages;
	}

	/**
	 * Get query string single row
	 *
	 * @param FilterBase $filter
	 *
	 * @since 4.2.5
	 * @version 1.0.1
	 */
	public function get_query_single_row( &$filter ) {
		$filter->limit               = 1;
		$filter->return_string_query = true;
		$filter->run_query_count     = false;
	}

	/**
	 * Get result query
	 *
	 * @param FilterBase $filter
	 * @param int $total_rows
	 *
	 * @return array|object|null|int|string
	 * @throws Exception
	 * @author tungnx
	 * @version 1.0.2
	 * @since 4.1.6
	 */
	public function execute( $filter, int &$total_rows = 0 ) {
		$result = null;

		// Where
		$WHERE = array( 'WHERE 1=1' );

		// Fields select
		$FIELDS = '*';
		if ( ! empty( $filter->only_fields ) ) {
			$FIELDS = implode( ',', array_unique( $filter->only_fields ) );
		} elseif ( ! empty( $filter->fields ) ) {
			// exclude more fields
			if ( ! empty( $filter->exclude_fields ) ) {
				foreach ( $filter->exclude_fields as $field ) {
					$index_field = array_search( $field, $filter->fields );
					if ( $index_field ) {
						unset( $filter->fields[ $index_field ] );
					}
				}
			}

			foreach ( $filter->fields as $key => $field ) {
				if ( $field === 'order' ) {
					// Replace order with `order` to avoid conflict with SQL reserved word.
					$filter->fields[ $key ] = '`order`';
					break;
				}
			}

			$FIELDS = implode( ',', array_unique( $filter->fields ) );
		}
		$FIELDS = apply_filters( 'lp/query/fields', $FIELDS, $filter );

		$INNER_JOIN = array();
		$INNER_JOIN = array_merge( $INNER_JOIN, $filter->join );
		$INNER_JOIN = apply_filters( 'lp/query/inner_join', $INNER_JOIN, $filter );
		$INNER_JOIN = implode( ' ', array_unique( $INNER_JOIN ) );

		$WHERE = array_merge( $WHERE, $filter->where );
		$WHERE = apply_filters( 'lp/query/where', $WHERE, $filter );
		$WHERE = implode( ' ', array_unique( $WHERE ) );

		// Group by
		$GROUP_BY = '';
		if ( $filter->group_by ) {
			$GROUP_BY .= 'GROUP BY ' . $filter->group_by;
			$GROUP_BY  = apply_filters( 'lp/query/group_by', $GROUP_BY, $filter );
		}

		// Order by
		$ORDER_BY = '';
		if ( $filter->order_by ) {
			$filter->order = strtoupper( $filter->order );
			if ( ! in_array( $filter->order, [ 'DESC', 'ASC' ] ) ) {
				$filter->order = 'DESC';
			}

			$ORDER_BY .= 'ORDER BY ' . $filter->order_by . ' ' . $filter->order . ' ';
			$ORDER_BY  = apply_filters( 'lp/query/order_by', $ORDER_BY, $filter );
		}

		// Limit
		$LIMIT = '';
		if ( $filter->limit != - 1 ) {
			$filter->limit = absint( $filter->limit );
			/*if ( $filter->limit > $filter->max_limit ) {
				$filter->limit = $filter->max_limit;
			}*/
			$offset = $filter->limit * ( $filter->page - 1 );
			$LIMIT  = $this->wpdb->prepare( 'LIMIT %d, %d', $offset, $filter->limit );
		}

		// For nest query
		if ( $filter->return_string_query ) {
			$LIMIT = '';
		}

		// From table or group select
		$COLLECTION = '';
		if ( ! empty( $filter->collection ) ) {
			$COLLECTION = $filter->collection;
		}

		// Alias table
		$ALIAS_COLLECTION = 'X';
		if ( ! empty( $filter->collection_alias ) ) {
			$ALIAS_COLLECTION = $filter->collection_alias;
		}

		// Query
		$query = "SELECT $FIELDS FROM $COLLECTION AS $ALIAS_COLLECTION
		$INNER_JOIN
		$WHERE
		$GROUP_BY
		$ORDER_BY
		$LIMIT
		";

		if ( $filter->return_string_query ) {
			return $query;
		} elseif ( ! empty( $filter->union ) ) {
			$query  = implode( ' UNION ', array_unique( $filter->union ) );
			$query .= $GROUP_BY;
			$query .= $ORDER_BY;
			$query .= $LIMIT;
		}

		if ( ! $filter->query_count ) {
			// Debug string query
			if ( $filter->debug_string_query ) {
				return $query;
			}

			$result = $this->wpdb->get_results( $query );
		}

		// Query total rows
		if ( $filter->run_query_count ) {
			$query       = str_replace( array( $LIMIT, $ORDER_BY ), '', $query );
			$query_total = "SELECT COUNT($filter->field_count) FROM ($query) AS $ALIAS_COLLECTION";
			$total_rows  = (int) $this->wpdb->get_var( $query_total );

			$this->check_execute_has_error();

			if ( $filter->query_count ) {
				// Debug string query
				if ( $filter->debug_string_query ) {
					return $query_total;
				}

				return $total_rows;
			}
		}

		$this->check_execute_has_error();

		return $result;
	}

	/**
	 * Query update
	 *
	 * @param FilterBase $filter
	 *
	 * @throws Exception
	 * @since 4.1.7
	 * @version 1.0.1
	 */
	public function update_execute( $filter ) {

		$COLLECTION = $filter->collection;

		// SET value
		$SET = apply_filters( 'lp/query/update/set', $filter->set, $filter );
		$SET = implode( ',', array_unique( $SET ) );

		// Where
		$WHERE = array( 'WHERE 1=1' );
		$WHERE = array_merge( $WHERE, $filter->where );
		$WHERE = apply_filters( 'lp/query/update/where', $WHERE, $filter );
		$WHERE = implode( ' ', array_unique( $WHERE ) );

		$query = "
			UPDATE $COLLECTION
			SET $SET
			$WHERE
		";

		$result = $this->wpdb->query( $query );

		$this->check_execute_has_error();

		return $result;
	}

	/**
	 * Query delete
	 *
	 * @param FilterBase $filter
	 * @param string $table
	 *
	 * @return bool|int|\mysqli_result|string|null
	 * @throws Exception
	 * @since 4.1.7
	 * @version 1.0.1
	 */
	public function delete_execute( $filter, string $table = '' ) {
		$COLLECTION = $filter->collection;

		// Where
		$WHERE = array( 'WHERE 1=1' );
		$WHERE = array_merge( $WHERE, $filter->where );
		$WHERE = apply_filters( 'lp/query/delete/where', $WHERE, $filter );
		$WHERE = implode( ' ', array_unique( $WHERE ) );

		// Join
		$INNER_JOIN = array();
		$INNER_JOIN = array_merge( $INNER_JOIN, $filter->join );
		$INNER_JOIN = apply_filters( 'lp/query/delete/inner_join', $INNER_JOIN, $filter );
		$INNER_JOIN = implode( ' ', array_unique( $INNER_JOIN ) );

		$query = "
			DELETE $table FROM $COLLECTION
			$INNER_JOIN
			$WHERE
		";

		if ( $filter->return_string_query ) {
			return $query;
		}

		$result = $this->wpdb->query( $query );

		$this->check_execute_has_error();

		return $result;
	}

	/**
	 * Get values of list object by key
	 *
	 * @param array $arr_object
	 * @param string $key
	 *
	 * @return array
	 */
	public static function get_values_by_key( array $arr_object, string $key = 'ID' ): array {
		$arr_object_ids = array();
		foreach ( $arr_object as $object ) {
			$arr_object_ids[] = $object->{$key};
		}

		return $arr_object_ids;
	}

	/**
	 * Insert data
	 *
	 * @param array $args
	 *
	 * @return int
	 * @throws Exception
	 * @version 1.0.1
	 * @since 4.2.9
	 */
	public function insert_data( array $args ): int {
		$data               = $args['data'] ?? [];
		$filter             = $args['filter'] ?? null;
		$table_name         = $args['table_name'] ?? '';
		$key_auto_increment = $args['key_auto_increment'] ?? '';
		$key_auto_increment = sanitize_key( $key_auto_increment );

		if ( empty( $data ) || ! is_array( $data ) ) {
			throw new Exception( __( 'Data must be an array!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		/*if ( ! $filter instanceof FilterBase ) {
			throw new Exception( __( 'Invalid filter!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}*/

		if ( empty( $filter->all_fields ) ) {
			throw new Exception( __( 'Filter must have property all_fields!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		if ( empty( $table_name ) ) {
			throw new Exception( __( 'Table name is required!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		if ( empty( $key_auto_increment ) || ! is_string( $key_auto_increment ) ) {
			throw new Exception( __( 'Key auto increment must be a string!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		foreach ( $data as $col_name => $value ) {
			if ( ! in_array( $col_name, $filter->all_fields ) ) {
				unset( $data[ $col_name ] );
			}
		}

		// unset key is auto increment.
		unset( $data[ $key_auto_increment ] );

		$this->wpdb->insert( $table_name, $data );

		$this->check_execute_has_error();

		return $this->wpdb->insert_id;
	}

	/**
	 * Update data
	 *
	 * @param array $args
	 *
	 * @return bool
	 *
	 * @throws Exception
	 * @since 4.2.9
	 * @version 1.0.1
	 */
	public function update_data( array $args ): bool {
		$data       = $args['data'] ?? [];
		$filter     = $args['filter'] ?? null;
		$table_name = $args['table_name'] ?? '';
		$where_key  = $args['where_key'] ?? '';
		$where_key  = sanitize_key( $where_key );

		/*if ( ! $filter instanceof FilterBase ) {
			throw new Exception( __( 'Invalid filter!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}*/

		if ( empty( $filter->all_fields ) ) {
			throw new Exception( __( 'Filter must have property all_fields!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		if ( empty( $data ) || ! is_array( $data ) ) {
			throw new Exception( __( 'Data must be an array!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		if ( empty( $where_key ) ) {
			throw new Exception( __( 'Invalid where key!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		if ( empty( $table_name ) ) {
			throw new Exception( __( 'Table name is required!', 'learnpress' ) . ' | ' . __FUNCTION__ );
		}

		$filter->collection = $table_name;
		foreach ( $data as $col_name => $value ) {
			if ( ! in_array( $col_name, $filter->all_fields ) ) {
				continue;
			}

			// Key `order` is reserved keyword in MySQL
			if ( $col_name === 'order' ) {
				$col_name = '`order`';
			}

			if ( is_null( $value ) ) {
				$filter->set[] = $col_name . ' = null';
			} else {
				$filter->set[] = $this->wpdb->prepare( $col_name . ' = %s', $value );
			}
		}

		$filter->where[] = $this->wpdb->prepare( "AND $where_key = %d", $data[ $where_key ] );
		$this->update_execute( $filter );

		return true;
	}
}

• [F] class-lp-course-db.php
  Delete
• [F] class-lp-course-json-db.php
  Delete
• [F] class-lp-db.php
  Delete
• [F] class-lp-lesson-db.php
  Delete
• [F] class-lp-material-db.php
  Delete
• [F] class-lp-order-db.php
  Delete
• [F] class-lp-post-db.php
  Delete
• [F] class-lp-post-meta-db.php
  Delete
• [F] class-lp-question-answers-db.php
  Delete
• [F] class-lp-question-db.php
  Delete
• [F] class-lp-quiz-db.php
  Delete
• [F] class-lp-quiz-questions-db.php
  Delete
• [F] class-lp-section-db.php
  Delete
• [F] class-lp-section-items-db.php
  Delete
• [F] class-lp-sessions-db.php
  Delete
• [F] class-lp-statistics-db.php
  Delete
• [F] class-lp-user-db.php
  Delete
• [F] class-lp-user-item-meta-db.php
  Delete
• [F] class-lp-user-item-results-db.php
  Delete
• [F] class-lp-user-items-db.php
  Delete
• [F] class-thim-cache-db.php
  Delete
• [F] CourseSectionDB.php
  Delete
• [F] DataBase.php
  Delete
• [F] PostDB.php
  Delete
• [F] QuestionAnswersDB.php
  Delete
• [F] QuizQuestionsDB.php
  Delete
• [F] UserItemsDB.php
  Delete