Populate form fields with values from a previous form entry

GF_Easy_Form_Population.php

<?php
/**
 * Gravity Forms Easy Form Population
 *
 * Populate form fields with values from a previous form entry.
 *
 * @version   1.0
 * @author    Travis Lopes <[email protected]>
 * @license   GPL-2.0+
 * @link      http://travislop.es/
 */

class Gravity_Forms_Easy_Form_Population {
	
	public function __construct() {
		
		add_filter( 'gform_pre_render', array( $this, 'populate_form' ) );
		
	}
	
	public function populate_form( $form ) {
		
		/* If the entry ID parameter is not set, return the form. */
		if ( ! rgget( 'entry_id' ) ) {
			return $form;
		}
		
		/* Get the entry and its form. */
		$original_entry = GFAPI::get_entry( rgget( 'entry_id' ) );
		$original_form  = GFAPI::get_form( $original_entry['form_id'] );
		$field_values   = array();
		
		/* Loop through the original form's fields and push set values to field values array. */
		foreach ( $original_form['fields'] as $field ) {
			
			/* If this field has multiple inputs, loop through them. */
			if ( $field->inputs ) {
				
				foreach ( $field->inputs as $input ) {
					if ( $input['name'] ) {
						$field_values[ $input['name'] ] = rgar( $original_entry, $input['id'] );
					}
				}
				
			} else {
				
				if ( $field->inputName ) {
					$field_values[ $field->inputName ] = rgar( $original_entry, $field->id );
				}
				
			}
			
		}
		
		/* Add field values to current form. */
		foreach ( $form['fields'] as &$field ) {
			
			/* If this field has multiple inputs, loop through them. */
			if ( $field->inputs ) {
				
				foreach ( $field->inputs as &$input ) {
					if ( $input['name'] && rgar( $field_values, $input['name'] ) ) {
						$input['defaultValue'] = rgar( $field_values, $input['name'] );
					}
				}
				
			} else {
				
				if ( $field->inputName && rgar( $field_values, $field->inputName ) ) {
					$field->defaultValue = rgar( $field_values, $field->inputName );
				}
				
			}
			
			
		}
		
		/* Return the form. */
		return $form;
		
	}
	
}

if ( class_exists( 'GFForms' ) ) {
	new Gravity_Forms_Easy_Form_Population();
}