BBP_Converter_Base::convert_table( $to_type,  $start )

	public function convert_table( $to_type, $start ) {

		// Are we usig a sync table, or postmeta?
		if ( $this->wpdb->get_var( "SHOW TABLES LIKE '" . $this->sync_table_name . "'" ) == $this->sync_table_name ) {
			$this->sync_table = true;
		} else {
			$this->sync_table = false;
		}

		// Set some defaults
		$has_insert     = false;
		$from_tablename = '';
		$field_list     = $from_tables = $tablefield_array = array();

		// Toggle Table Name based on $to_type (destination)
		switch ( $to_type ) {
			case 'user' :
				$tablename = $this->wpdb->users;
				break;

			case 'tags' :
				$tablename = '';
				break;

			default :
				$tablename = $this->wpdb->posts;
		}

		// Get the fields from the destination table
		if ( !empty( $tablename ) ) {
			$tablefield_array = $this->get_fields( $tablename );
		}

		/** Step 1 ************************************************************/

		// Loop through the field maps, and look for to_type matches
		foreach ( $this->field_map as $item ) {

			// Yay a match, and we have a from table, too
			if ( ( $item['to_type'] == $to_type ) && !empty( $item['from_tablename'] ) ) {

				// $from_tablename was set from a previous loop iteration
				if ( ! empty( $from_tablename ) ) {

					// Doing some joining
					if ( !in_array( $item['from_tablename'], $from_tables ) && in_array( $item['join_tablename'], $from_tables ) ) {
						$from_tablename .= ' ' . $item['join_type'] . ' JOIN ' . $this->opdb->prefix . $item['from_tablename'] . ' AS ' . $item['from_tablename'] . ' ' . $item['join_expression'];
					}

				// $from_tablename needs to be set
				} else {
					$from_tablename = $item['from_tablename'] . ' AS ' . $item['from_tablename'];
				}

				// Specific FROM expression data used
				if ( !empty( $item['from_expression'] ) ) {

					// No 'WHERE' in expression
					if ( stripos( $from_tablename, "WHERE" ) === false ) {
						$from_tablename .= ' ' . $item['from_expression'];

					// 'WHERE' in expression, so replace with 'AND'
					} else {
						$from_tablename .= ' ' . str_replace( "WHERE", "AND", $item['from_expression'] );
					}
				}

				// Add tablename and fieldname to arrays, formatted for querying
				$from_tables[] = $item['from_tablename'];
				$field_list[]  = 'convert(' . $item['from_tablename'] . '.' . $item['from_fieldname'] . ' USING "' . $this->charset . '") AS ' . $item['from_fieldname'];
			}
		}

		/** Step 2 ************************************************************/

		// We have a $from_tablename, so we want to get some data to convert
		if ( !empty( $from_tablename ) ) {

			// Get some data from the old forums
			$field_list  = array_unique( $field_list );
			$forum_query = 'SELECT ' . implode( ',', $field_list ) . ' FROM ' . $this->opdb->prefix . $from_tablename . ' LIMIT ' . $start . ', ' . $this->max_rows;
			$forum_array = $this->opdb->get_results( $forum_query, ARRAY_A );

			// Set this query as the last one ran
			update_option( '_bbp_converter_query', $forum_query );

			// Query returned some results
			if ( !empty( $forum_array ) ) {

				// Loop through results
				foreach ( (array) $forum_array as $forum ) {

					// Reset some defaults
					$insert_post = $insert_postmeta = $insert_data = array();

					// Loop through field map, again...
					foreach ( $this->field_map as $row ) {

						// Types matchand to_fieldname is present. This means
						// we have some work to do here.
						if ( ( $row['to_type'] == $to_type ) && ! is_null( $row['to_fieldname'] ) ) {

							// This row has a destination that matches one of the
							// columns in this table.
							if ( in_array( $row['to_fieldname'], $tablefield_array ) ) {

								// Allows us to set default fields.
								if ( isset( $row['default'] ) ) {
									$insert_post[$row['to_fieldname']] = $row['default'];

								// Translates a field from the old forum.
								} elseif ( isset( $row['callback_method'] ) ) {
									if ( ( 'callback_userid' == $row['callback_method'] ) && empty( $_POST['_bbp_converter_convert_users'] ) ) {
										$insert_post[$row['to_fieldname']] = $forum[$row['from_fieldname']];
									} else {
										$insert_post[$row['to_fieldname']] = call_user_func_array( array( $this, $row['callback_method'] ), array( $forum[$row['from_fieldname']], $forum ) );
									}

								// Maps the field from the old forum.
								} else {
									$insert_post[$row['to_fieldname']] = $forum[$row['from_fieldname']];
								}

							// Destination field is not empty, so we might need
							// to do some extra work or set a default.
							} elseif ( !empty( $row['to_fieldname'] ) ) {

								// Allows us to set default fields.
								if ( isset( $row['default'] ) ) {
									$insert_postmeta[$row['to_fieldname']] = $row['default'];

								// Translates a field from the old forum.
								} elseif ( isset( $row['callback_method'] ) ) {
									if ( ( $row['callback_method'] == 'callback_userid' ) && ( 0 == $_POST['_bbp_converter_convert_users'] ) ) {
										$insert_postmeta[$row['to_fieldname']] = $forum[$row['from_fieldname']];
									} else {
										$insert_postmeta[$row['to_fieldname']] = call_user_func_array( array( $this, $row['callback_method'] ), array( $forum[$row['from_fieldname']], $forum ) );
									}

								// Maps the field from the old forum.
								} else {
									$insert_postmeta[$row['to_fieldname']] = $forum[$row['from_fieldname']];
								}
							}
						}
					}

					/** Step 3 ************************************************/

					// Something to insert into the destination field
					if ( count( $insert_post ) > 0 || ( $to_type == 'tags' && count( $insert_postmeta ) > 0 ) ) {

						switch ( $to_type ) {

							/** New user **************************************/

							case 'user':
								if ( username_exists( $insert_post['user_login'] ) ) {
									$insert_post['user_login'] = 'imported_' . $insert_post['user_login'];
								}

								if ( email_exists( $insert_post['user_email'] ) ) {
									$insert_post['user_email'] = 'imported_' . $insert_post['user_email'];
								}

								$post_id = wp_insert_user( $insert_post );

								if ( is_numeric( $post_id ) ) {

									foreach ( $insert_postmeta as $key => $value ) {

										add_user_meta( $post_id, $key, $value, true );

										if ( '_id' == substr( $key, -3 ) && ( true === $this->sync_table ) ) {
											$this->wpdb->insert( $this->sync_table_name, array( 'value_type' => 'user', 'value_id' => $post_id, 'meta_key' => $key, 'meta_value' => $value ) );
										}
									}
								}
								break;

							/** New Topic-Tag *********************************/

							case 'tags':
								$post_id = wp_set_object_terms( $insert_postmeta['objectid'], $insert_postmeta['name'], 'topic-tag', true );
								$term = get_term_by( 'name', $insert_postmeta['name'], 'topic-tag');
								if ( false !== $term ) {
									wp_update_term( $term->term_id, 'topic-tag', array(
										'description' => $insert_postmeta['description'],
										'slug'        => $insert_postmeta['slug']
									) );
								}
 								break;

							/** Forum, Topic, Reply ***************************/

							default:
								$post_id = wp_insert_post( $insert_post );

								if ( is_numeric( $post_id ) ) {

									foreach ( $insert_postmeta as $key => $value ) {

										add_post_meta( $post_id, $key, $value, true );

										// Forums need to save their old ID for group forum association
										if ( ( 'forum' == $to_type ) && ( '_bbp_forum_id' == $key ) )
											add_post_meta( $post_id, '_bbp_old_forum_id', $value );

										// Topics need an extra bit of metadata
										// to be keyed to the new post_id
										if ( ( 'topic' == $to_type ) && ( '_bbp_topic_id' == $key ) ) {

											// Update the live topic ID
											update_post_meta( $post_id, $key, $post_id );

											// Save the old topic ID
											add_post_meta( $post_id, '_bbp_old_topic_id', $value );
											if ( '_id' == substr( $key, -3 ) && ( true === $this->sync_table ) ) {
												$this->wpdb->insert( $this->sync_table_name, array( 'value_type' => 'post', 'value_id' => $post_id, 'meta_key' => '_bbp_topic_id',     'meta_value' => $post_id ) );
												$this->wpdb->insert( $this->sync_table_name, array( 'value_type' => 'post', 'value_id' => $post_id, 'meta_key' => '_bbp_old_topic_id', 'meta_value' => $value   ) );
											}

										} elseif ( '_id' == substr( $key, -3 ) && ( true === $this->sync_table ) ) {
											$this->wpdb->insert( $this->sync_table_name, array( 'value_type' => 'post', 'value_id' => $post_id, 'meta_key' => $key, 'meta_value' => $value ) );
										}

										// Replies need to save their old reply_to ID for hierarchical replies association
										if ( ( 'reply' == $to_type ) && ( '_bbp_reply_to' == $key ) ) {
											add_post_meta( $post_id, '_bbp_old_reply_to', $value );
										}
									}
								}
								break;
						}
						$has_insert = true;
					}
				}
			}
		}

		return ! $has_insert;
	}