<?php

namespace SilverStripe\Forms\GridField;

use SilverStripe\Admin\LeftAndMain;
use SilverStripe\Control\Controller;
use SilverStripe\Control\PjaxResponseNegotiator;
use SilverStripe\Control\RequestHandler;
use SilverStripe\Control\HTTPRequest;
use SilverStripe\Control\HTTPResponse;
use SilverStripe\Control\HTTPResponse_Exception;
use SilverStripe\Forms\FieldList;
use SilverStripe\Forms\Form;
use SilverStripe\Forms\FormAction;
use SilverStripe\Forms\LiteralField;
use SilverStripe\ORM\ArrayList;
use SilverStripe\ORM\DataObject;
use SilverStripe\ORM\FieldType\DBHTMLText;
use SilverStripe\ORM\HasManyList;
use SilverStripe\ORM\ManyManyList;
use SilverStripe\ORM\SS_List;
use SilverStripe\ORM\ValidationException;
use SilverStripe\View\ArrayData;
use SilverStripe\View\SSViewer;

class GridFieldDetailForm_ItemRequest extends RequestHandler
{

	private static $allowed_actions = array(
		'edit',
		'view',
		'ItemEditForm'
	);

	/**
	 *
	 * @var GridField
	 */
	protected $gridField;

	/**
	 *
	 * @var GridFieldDetailForm
	 */
	protected $component;

	/**
	 *
	 * @var DataObject
	 */
	protected $record;

	/**
	 * This represents the current parent RequestHandler (which does not necessarily need to be a Controller).
	 * It allows us to traverse the RequestHandler chain upwards to reach the Controller stack.
	 *
	 * @var RequestHandler
	 */
	protected $popupController;

	/**
	 *
	 * @var string
	 */
	protected $popupFormName;

	/**
	 * @var String
	 */
	protected $template = null;

	private static $url_handlers = array(
		'$Action!' => '$Action',
		'' => 'edit',
	);

	/**
	 *
	 * @param GridField $gridField
	 * @param GridFieldDetailForm $component
	 * @param DataObject $record
	 * @param RequestHandler $requestHandler
	 * @param string $popupFormName
	 */
	public function __construct($gridField, $component, $record, $requestHandler, $popupFormName)
	{
		$this->gridField = $gridField;
		$this->component = $component;
		$this->record = $record;
		$this->popupController = $requestHandler;
		$this->popupFormName = $popupFormName;
		parent::__construct();
	}

	public function Link($action = null)
	{
		return Controller::join_links($this->gridField->Link('item'),
			$this->record->ID ? $this->record->ID : 'new', $action);
	}

	/**
	 * @param HTTPRequest $request
	 * @return mixed
	 */
	public function view($request)
	{
		if (!$this->record->canView()) {
			$this->httpError(403);
		}

		$controller = $this->getToplevelController();

		$form = $this->ItemEditForm();
		$form->makeReadonly();

		$data = new ArrayData(array(
			'Backlink' => $controller->Link(),
			'ItemEditForm' => $form
		));
		$return = $data->renderWith($this->getTemplates());

		if ($request->isAjax()) {
			return $return;
		} else {
			return $controller->customise(array('Content' => $return));
		}
	}

	/**
	 * @param HTTPRequest $request
	 * @return mixed
	 */
	public function edit($request)
	{
		$controller = $this->getToplevelController();
		$form = $this->ItemEditForm();

		$return = $this->customise(array(
			'Backlink' => $controller->hasMethod('Backlink') ? $controller->Backlink() : $controller->Link(),
			'ItemEditForm' => $form,
		))->renderWith($this->getTemplates());

		if ($request->isAjax()) {
			return $return;
		} else {
			// If not requested by ajax, we need to render it within the controller context+template
			return $controller->customise(array(
				// TODO CMS coupling
				'Content' => $return,
			));
		}
	}

	/**
	 * Builds an item edit form.  The arguments to getCMSFields() are the popupController and
	 * popupFormName, however this is an experimental API and may change.
	 *
	 * @todo In the future, we will probably need to come up with a tigher object representing a partially
	 * complete controller with gaps for extra functionality.  This, for example, would be a better way
	 * of letting Security/login put its log-in form inside a UI specified elsewhere.
	 *
	 * @return Form
	 */
	public function ItemEditForm()
	{
		$list = $this->gridField->getList();

		if (empty($this->record)) {
			$controller = $this->getToplevelController();
			$url = $controller->getRequest()->getURL();
			$noActionURL = $controller->removeAction($url);
			$controller->getResponse()->removeHeader('Location');   //clear the existing redirect
			return $controller->redirect($noActionURL, 302);
		}

		$canView = $this->record->canView();
		$canEdit = $this->record->canEdit();
		$canDelete = $this->record->canDelete();
		$canCreate = $this->record->canCreate();

		if (!$canView) {
			$controller = $this->getToplevelController();
			// TODO More friendly error
			return $controller->httpError(403);
		}

		// Build actions
		$actions = $this->getFormActions();

		// If we are creating a new record in a has-many list, then
		// pre-populate the record's foreign key.
		if ($list instanceof HasManyList && !$this->record->isInDB()) {
			$key = $list->getForeignKey();
			$id = $list->getForeignID();
			$this->record->$key = $id;
		}

		$fields = $this->component->getFields();
		if (!$fields) {
			$fields = $this->record->getCMSFields();
		}

		// If we are creating a new record in a has-many list, then
		// Disable the form field as it has no effect.
		if ($list instanceof HasManyList) {
			$key = $list->getForeignKey();

			if ($field = $fields->dataFieldByName($key)) {
				$fields->makeFieldReadonly($field);
			}
		}


		// Caution: API violation. Form expects a Controller, but we are giving it a RequestHandler instead.
		// Thanks to this however, we are able to nest GridFields, and also access the initial Controller by
		// dereferencing GridFieldDetailForm_ItemRequest->getController() multiple times. See getToplevelController
		// below.
		$form = new Form(
			$this,
			'ItemEditForm',
			$fields,
			$actions,
			$this->component->getValidator()
		);

		$form->loadDataFrom($this->record, $this->record->ID == 0 ? Form::MERGE_IGNORE_FALSEISH : Form::MERGE_DEFAULT);

		if ($this->record->ID && !$canEdit) {
			// Restrict editing of existing records
			$form->makeReadonly();
			// Hack to re-enable delete button if user can delete
			if ($canDelete) {
				$form->Actions()->fieldByName('action_doDelete')->setReadonly(false);
			}
		} elseif (!$this->record->ID && !$canCreate) {
			// Restrict creation of new records
			$form->makeReadonly();
		}

		// Load many_many extraData for record.
		// Fields with the correct 'ManyMany' namespace need to be added manually through getCMSFields().
		if ($list instanceof ManyManyList) {
			$extraData = $list->getExtraData('', $this->record->ID);
			$form->loadDataFrom(array('ManyMany' => $extraData));
		}

		// TODO Coupling with CMS
		$toplevelController = $this->getToplevelController();
		if ($toplevelController && $toplevelController instanceof LeftAndMain) {
			// Always show with base template (full width, no other panels),
			// regardless of overloaded CMS controller templates.
			// TODO Allow customization, e.g. to display an edit form alongside a search form from the CMS controller
			$form->setTemplate([
				'type' => 'Includes',
				'SilverStripe\\Admin\\LeftAndMain_EditForm',
			]);
			$form->addExtraClass('cms-content cms-edit-form center flexbox-area-grow');
			$form->setAttribute('data-pjax-fragment', 'CurrentForm Content');
			if ($form->Fields()->hasTabSet()) {
				$form->Fields()->findOrMakeTab('Root')->setTemplate('SilverStripe\\Forms\\CMSTabSet');
				$form->addExtraClass('cms-tabset');
			}

			$form->Backlink = $this->getBackLink();
		}

		$cb = $this->component->getItemEditFormCallback();
		if ($cb) {
			$cb($form, $this);
		}
		$this->extend("updateItemEditForm", $form);
		return $form;
	}

	/**
	 * Build the set of form field actions for this DataObject
	 *
	 * @return FieldList
	 */
	protected function getFormActions()
	{
		$canEdit = $this->record->canEdit();
		$canDelete = $this->record->canDelete();
		$actions = new FieldList();
		if ($this->record->ID !== 0) {
			if ($canEdit) {
				$actions->push(FormAction::create('doSave', _t('GridFieldDetailForm.Save', 'Save'))
					->setUseButtonTag(true)
					->addExtraClass('ss-ui-action-constructive')
					->setAttribute('data-icon', 'accept'));
			}

			if ($canDelete) {
				$actions->push(FormAction::create('doDelete', _t('GridFieldDetailForm.Delete', 'Delete'))
					->setUseButtonTag(true)
					->addExtraClass('ss-ui-action-destructive action-delete'));
			}

		} else { // adding new record
			//Change the Save label to 'Create'
			$actions->push(FormAction::create('doSave', _t('GridFieldDetailForm.Create', 'Create'))
				->setUseButtonTag(true)
				->addExtraClass('ss-ui-action-constructive')
				->setAttribute('data-icon', 'add'));

			// Add a Cancel link which is a button-like link and link back to one level up.
			$crumbs = $this->Breadcrumbs();
			if ($crumbs && $crumbs->count() >= 2) {
				$oneLevelUp = $crumbs->offsetGet($crumbs->count() - 2);
				$text = sprintf(
					"<a class=\"%s\" href=\"%s\">%s</a>",
					"crumb ss-ui-button ss-ui-action-destructive cms-panel-link ui-corner-all", // CSS classes
					$oneLevelUp->Link, // url
					_t('GridFieldDetailForm.CancelBtn', 'Cancel') // label
				);
				$actions->push(new LiteralField('cancelbutton', $text));
			}
		}
		$this->extend('updateFormActions', $actions);
		return $actions;
	}

	/**
	 * Traverse the nested RequestHandlers until we reach something that's not GridFieldDetailForm_ItemRequest.
	 * This allows us to access the Controller responsible for invoking the top-level GridField.
	 * This should be equivalent to getting the controller off the top of the controller stack via Controller::curr(),
	 * but allows us to avoid accessing the global state.
	 *
	 * GridFieldDetailForm_ItemRequests are RequestHandlers, and as such they are not part of the controller stack.
	 *
	 * @return Controller
	 */
	protected function getToplevelController()
	{
		$c = $this->popupController;
		while ($c && $c instanceof GridFieldDetailForm_ItemRequest) {
			$c = $c->getController();
		}
		return $c;
	}

	protected function getBackLink()
	{
		// TODO Coupling with CMS
		$backlink = '';
		$toplevelController = $this->getToplevelController();
		if ($toplevelController && $toplevelController instanceof LeftAndMain) {
			if ($toplevelController->hasMethod('Backlink')) {
				$backlink = $toplevelController->Backlink();
			} elseif ($this->popupController->hasMethod('Breadcrumbs')) {
				$parents = $this->popupController->Breadcrumbs(false)->items;
				$backlink = array_pop($parents)->Link;
			}
		}
		if (!$backlink) {
			$backlink = $toplevelController->Link();
		}

		return $backlink;
	}

	/**
	 * Get the list of extra data from the $record as saved into it by
	 * {@see Form::saveInto()}
	 *
	 * Handles detection of falsey values explicitly saved into the
	 * DataObject by formfields
	 *
	 * @param DataObject $record
	 * @param SS_List $list
	 * @return array List of data to write to the relation
	 */
	protected function getExtraSavedData($record, $list)
	{
		// Skip extra data if not ManyManyList
		if (!($list instanceof ManyManyList)) {
			return null;
		}

		$data = array();
		foreach ($list->getExtraFields() as $field => $dbSpec) {
			$savedField = "ManyMany[{$field}]";
			if ($record->hasField($savedField)) {
				$data[$field] = $record->getField($savedField);
			}
		}
		return $data;
	}

	public function doSave($data, $form)
	{
		$isNewRecord = $this->record->ID == 0;

		// Check permission
		if (!$this->record->canEdit()) {
			return $this->httpError(403);
		}

		// Save from form data
		try {
			$this->saveFormIntoRecord($data, $form);
		} catch (ValidationException $e) {
			return $this->generateValidationResponse($form, $e);
		}

		$link = '<a href="' . $this->Link('edit') . '">"'
			. htmlspecialchars($this->record->Title, ENT_QUOTES)
			. '"</a>';
		$message = _t(
			'GridFieldDetailForm.Saved',
			'Saved {name} {link}',
			array(
				'name' => $this->record->i18n_singular_name(),
				'link' => $link
			)
		);

		$form->sessionMessage($message, 'good', false);

		// Redirect after save
		return $this->redirectAfterSave($isNewRecord);
	}

	/**
	 * Response object for this request after a successful save
	 *
	 * @param bool $isNewRecord True if this record was just created
	 * @return HTTPResponse|DBHTMLText
	 */
	protected function redirectAfterSave($isNewRecord)
	{
		$controller = $this->getToplevelController();
		if ($isNewRecord) {
			return $controller->redirect($this->Link());
		} elseif ($this->gridField->getList()->byID($this->record->ID)) {
			// Return new view, as we can't do a "virtual redirect" via the CMS Ajax
			// to the same URL (it assumes that its content is already current, and doesn't reload)
			return $this->edit($controller->getRequest());
		} else {
			// Changes to the record properties might've excluded the record from
			// a filtered list, so return back to the main view if it can't be found
			$url = $controller->getRequest()->getURL();
			$noActionURL = $controller->removeAction($url);
			$controller->getRequest()->addHeader('X-Pjax', 'Content');
			return $controller->redirect($noActionURL, 302);
		}
	}

	public function httpError($errorCode, $errorMessage = null)
	{
		$controller = $this->getToplevelController();
		return $controller->httpError($errorCode, $errorMessage);
	}

	/**
	 * Loads the given form data into the underlying dataobject and relation
	 *
	 * @param array $data
	 * @param Form $form
	 * @throws ValidationException On error
	 * @return DataObject Saved record
	 */
	protected function saveFormIntoRecord($data, $form)
	{
		$list = $this->gridField->getList();

		// Check object matches the correct classname
		if (isset($data['ClassName']) && $data['ClassName'] != $this->record->ClassName) {
			$newClassName = $data['ClassName'];
			// The records originally saved attribute was overwritten by $form->saveInto($record) before.
			// This is necessary for newClassInstance() to work as expected, and trigger change detection
			// on the ClassName attribute
			$this->record->setClassName($this->record->ClassName);
			// Replace $record with a new instance
			$this->record = $this->record->newClassInstance($newClassName);
		}

		// Save form and any extra saved data into this dataobject
		$form->saveInto($this->record);
		$this->record->write();
		$extraData = $this->getExtraSavedData($this->record, $list);
		$list->add($this->record, $extraData);

		return $this->record;
	}

	/**
	 * Generate a response object for a form validation error
	 *
	 * @param Form $form The source form
	 * @param ValidationException $e The validation error message
	 * @return HTTPResponse
	 * @throws HTTPResponse_Exception
	 */
	protected function generateValidationResponse($form, $e)
	{
		$controller = $this->getToplevelController();

		$form->sessionMessage($e->getResult()->message(), 'bad', false);
		$responseNegotiator = new PjaxResponseNegotiator(array(
			'CurrentForm' => function () use (&$form) {
				return $form->forTemplate();
			},
			'default' => function () use (&$controller) {
				return $controller->redirectBack();
			}
		));
		if ($controller->getRequest()->isAjax()) {
			$controller->getRequest()->addHeader('X-Pjax', 'CurrentForm');
		}
		return $responseNegotiator->respond($controller->getRequest());
	}

	/**
	 * @param array $data
	 * @param Form $form
	 * @return HTTPResponse
	 */
	public function doDelete($data, $form)
	{
		$title = $this->record->Title;
		try {
			if (!$this->record->canDelete()) {
				throw new ValidationException(
					_t('GridFieldDetailForm.DeletePermissionsFailure', "No delete permissions"), 0);
			}

			$this->record->delete();
		} catch (ValidationException $e) {
			$form->sessionMessage($e->getResult()->message(), 'bad', false);
			return $this->getToplevelController()->redirectBack();
		}

		$message = sprintf(
			_t('GridFieldDetailForm.Deleted', 'Deleted %s %s'),
			$this->record->i18n_singular_name(),
			htmlspecialchars($title, ENT_QUOTES)
		);

		$toplevelController = $this->getToplevelController();
		if ($toplevelController && $toplevelController instanceof LeftAndMain) {
			$backForm = $toplevelController->getEditForm();
			$backForm->sessionMessage($message, 'good', false);
		} else {
			$form->sessionMessage($message, 'good', false);
		}

		//when an item is deleted, redirect to the parent controller
		$controller = $this->getToplevelController();
		$controller->getRequest()->addHeader('X-Pjax', 'Content'); // Force a content refresh

		return $controller->redirect($this->getBackLink(), 302); //redirect back to admin section
	}

	/**
	 * @param string $template
	 * @return $this
	 */
	public function setTemplate($template)
	{
		$this->template = $template;
		return $this;
	}

	/**
	 * @return string
	 */
	public function getTemplate()
	{
		return $this->template;
	}

	/**
	 * Get list of templates to use
	 *
	 * @return array
	 */
	public function getTemplates()
	{
		$templates = SSViewer::get_templates_by_class($this, '', __CLASS__);
		// Prefer any custom template
		if($this->getTemplate()) {
			array_unshift($templates, $this->getTemplate());
		}
		return $templates;
	}

	/**
	 * @return Controller
	 */
	public function getController()
	{
		return $this->popupController;
	}

	/**
	 * @return GridField
	 */
	public function getGridField()
	{
		return $this->gridField;
	}

	/**
	 * @return DataObject
	 */
	public function getRecord()
	{
		return $this->record;
	}

	/**
	 * CMS-specific functionality: Passes through navigation breadcrumbs
	 * to the template, and includes the currently edited record (if any).
	 * see {@link LeftAndMain->Breadcrumbs()} for details.
	 *
	 * @param boolean $unlinked
	 * @return ArrayList
	 */
	public function Breadcrumbs($unlinked = false)
	{
		if (!$this->popupController->hasMethod('Breadcrumbs')) {
			return null;
		}

		/** @var ArrayList $items */
		$items = $this->popupController->Breadcrumbs($unlinked);
		if ($this->record && $this->record->ID) {
			$title = ($this->record->Title) ? $this->record->Title : "#{$this->record->ID}";
			$items->push(new ArrayData(array(
				'Title' => $title,
				'Link' => $this->Link()
			)));
		} else {
			$items->push(new ArrayData(array(
				'Title' => sprintf(_t('GridField.NewRecord', 'New %s'), $this->record->i18n_singular_name()),
				'Link' => false
			)));
		}

		return $items;
	}
}