<?php namespace ProcessWire;

/**
 * ProcessWire Cache Fieldtype
 *
 * Provides a field that caches the values of other fields for fewer runtime queries
 *
 * For documentation about the fields used in this class, please see:  
 * /wire/core/Fieldtype.php
 * 
 * ProcessWire 3.x, Copyright 2020 by Ryan Cramer
 * https://processwire.com
 *
 */

class FieldtypeCache extends Fieldtype {

	/**
	 * Get module information
	 * 
	 * @return array
	 * 
	 */
	public static function getModuleInfo() {
		return array(
			'title' => 'Cache',
			'version' => 102,
			'summary' => 'Caches the values of other fields for fewer runtime queries. Can also be used to combine multiple text fields and have them all be searchable under the cached field name.'
		);
	}

	public function getDatabaseSchema(Field $field) {
		$schema = parent::getDatabaseSchema($field); 
		$schema['data'] = 'mediumtext NOT NULL';
		$schema['keys']['data'] = 'FULLTEXT KEY data (data)'; 
		return $schema;
	}

	public function ___getCompatibleFieldtypes(Field $field) {
		$fieldtypes = $this->wire(new Fieldtypes());
		foreach($this->wire('fieldtypes') as $fieldtype) {
			if($fieldtype instanceof FieldtypeCache) $fieldtypes->add($fieldtype); 
		}
		return $fieldtypes; 
	}

	public function sanitizeValue(Page $page, Field $field, $value) {
		if(!is_array($value)) $value = array();
		return $value;
	}

	public function getInputfield(Page $page, Field $field) {
		$page->get($field->name); // forced dereference, in case it's not autojoin
		return null; 
	}

	public function getMatchQuery($query, $table, $subfield, $operator, $value) {
		/** @var DatabaseQuerySelectFulltext $ft */
		$ft = $this->wire(new DatabaseQuerySelectFulltext($query)); 
		$ft->match($table, $subfield, $operator, $value); 
		return $query; 
	}

	public function ___wakeupValue(Page $page, Field $field, $value) {

		if(!$value || $this->cacheDisabled($field)) return $this->cacheFields($field); 
		$value = json_decode($value, true); 
		if(!is_array($value)) $value = array($value);

		foreach($value as $name => $v) {
			$f = $this->fields->get($name); 
			if(!$f) {
				$this->error("Field '$name' referenced by '$field' does not exist."); 
				continue; 
			}
			$v = $f->type->wakeupValue($page, $f, $v); 
			if(!$page->__isset($name)) $page->setFieldValue($name, $v, false); 
		}
		return $this->cacheFields($field); 
	}

	public function ___sleepValue(Page $page, Field $field, $value) {
		$value = array(); // we don't care what value gets passed in here
		foreach($this->cacheFields($field) as $name) {
			$f = $this->fields->get($name); 
			if($f) $value[$name] = $f->type->sleepValue($page, $f, $page->get($name)); 
		}
		if(defined("JSON_UNESCAPED_UNICODE")) {
			return json_encode($value, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES); 
		} else {
			return json_encode($value); 
		}
	}

	public function ___savePageField(Page $page, Field $field) {
	
		if($this->cacheDisabled($field)) return true; 

		// set to an array of the cache fields if there is nothing in the field
		// this is just to make sure that it's populated with something
		if(!$page->get($field->name)) $page->set($field->name, $this->cacheFields($field));

		// ensure that the cache gets updated on every page save
		$page->trackChange($field->name); 

		return parent::___savePageField($page, $field); 
	}

	/**
	 * Get number of pages in the cache
	 * 
	 * @param Field $field FieldtypeCache field to check
	 * @return int Number of cached pages
	 * 
	 */
	public function getNumPagesCached(Field $field) {
		$database = $this->wire('database');
		$table = $database->escapeTable($field->getTable()); 
		$query = $database->prepare("SELECT COUNT(*) FROM `$table`"); 
		try {
			$query->execute();
			$num = (int) $query->fetchColumn();
			$query->closeCursor();
		} catch(\Exception $e) {
			$num = 0;
		}
		return $num; 
	}

	/**
	 * Regenerate the cache for the given Field
	 * 
	 * @param Field $field Field of type FieldtypeCache
	 * @return int Number of pages that were cached
	 * 
	 */
	protected function regenerateCache(Field $field) {

		$numPages = 0;
		$numTemplates = 0; 
		$max = 500;
		$saveOptions = array(
			'quiet' => true, 
			'noHooks' => true, 
		);

		foreach($this->templates as $template) {
			if(!$template->fields->has($field)) continue; 
			$numTemplates++;
			$numTemplatePages = 0;
			$selector = "template=$template, include=all";
			$total = $this->pages->count($selector);
			$pages = $total > $max ? $this->pages->findMany($selector) : $this->pages->find($selector);
			set_time_limit(60 * 5);
			foreach($pages as $page) {
				$this->pages->___saveField($page, $field, $saveOptions);
				$numPages++;
				$numTemplatePages++; 
			}
			$this->message("Cache '{$field->name}' saved for $numTemplatePages pages saved with template '$template'"); 
		}
		if(!$numTemplates) $this->error("Cache '{$field->name}' is not assigned to any templates."); 
		return $numPages; 
	}

	/**
	 * @param Field $field
	 * @return array
	 * 
	 */
	protected function cacheFields(Field $field) {
		$cacheFields = $field->get('cacheFields');
		if(!is_array($cacheFields)) $cacheFields = array();
		return $cacheFields;
	}

	/**
	 * @param Field $field
	 * @return bool
	 * 
	 */
	protected function cacheDisabled(Field $field) {
		return (bool) $field->get('cacheDisabled');
	}

	public function ___getConfigInputfields(Field $field) {

		$inputfields = parent::___getConfigInputfields($field);
	
		/** @var InputfieldAsmSelect $select */
		$select = $this->modules->get("InputfieldAsmSelect"); 
		$select->attr('name', 'cacheFields'); 
		$select->label = 'Fields to cache';
		$select->description = 'Select all fields that you would like to be cached.';
		$select->notes = 
			"If you don't have 'autojoin' checked under this field's advanced settings, then you will have to " . 
			"call \$page->{$field->name} before the cached fields will be loaded.";

		foreach($this->fields as $f) {
			if($f->name == $field->name || $f->type instanceof FieldtypeFieldsetOpen) continue;
			$label = $f->name; 
			if($f->flags & Field::flagAutojoin) $label .= " (autojoin)";
			$select->addOption($f->name, $label); 
		}
		$select->attr('value', $this->cacheFields($field)); 
		$inputfields->append($select);

		/** @var InputfieldCheckbox $checkbox */
		$checkbox = $this->modules->get("InputfieldCheckbox"); 
		$checkbox->attr('name', '_regenerateCache');
		$checkbox->attr('value', 1); 
		$checkbox->attr('checked', ''); 
		$checkbox->label = "Regenerate Cache?";
		$checkbox->description = 
			"The cache for each page is automatically generated when you save a page. But if you are adding a cache to existing pages, " . 
			"then it won't exist until each of those pages is saved. By checking this box, the cache will be generated for all pages that have " . 
			"this cache field (via their template). Depending on how many pages that is, it may take awhile. Typically you only need to do " . 
			"this when creating the cache, or adding/removing fields from it. If you just created this cache field, don't forget to add it to " . 
			"one or more templates before using this cache generation/regeneration tool.";

		$checkbox->notes = "The cache currently contains data from " . $this->getNumPagesCached($field) . " pages.";
		if($this->input->post('_regenerateCache')) $this->regenerateCache($field); 
		$inputfields->append($checkbox); 

		$checkbox = $this->modules->get("InputfieldCheckbox"); 
		$checkbox->attr('name', 'cacheDisabled');
		$checkbox->attr('value', 1); 
		$checkbox->attr('checked', $this->cacheDisabled($field) ? 'checked' : ''); 
		$checkbox->label = "Disable Cache?";
		$checkbox->description = "Temporarily disable the cache for testing, debugging, etc.";
		$inputfields->append($checkbox); 

		return $inputfields; 
	}

}