<?php
namespace FluidTYPO3\Vhs\ViewHelpers\Menu;

/*
 * This file is part of the FluidTYPO3/Vhs project under GPLv2 or later.
 *
 * For the full copyright and license information, please read the
 * LICENSE.md file that was distributed with this source code.
 */

use FluidTYPO3\Vhs\Service\PageService;
use FluidTYPO3\Vhs\Traits\PageRecordViewHelperTrait;
use FluidTYPO3\Vhs\Traits\TagViewHelperTrait;
use TYPO3\CMS\Core\Domain\Repository\PageRepository;
use TYPO3\CMS\Core\Utility\GeneralUtility;
use TYPO3Fluid\Fluid\Core\ViewHelper\AbstractTagBasedViewHelper;

/**
 * Base class for menu rendering ViewHelpers.
 */
abstract class AbstractMenuViewHelper extends AbstractTagBasedViewHelper
{
    use PageRecordViewHelperTrait;
    use TagViewHelperTrait;

    /**
     * @var string
     */
    protected $tagName = 'ul';

    /**
     * @var boolean
     */
    protected $escapeOutput = false;

    /**
     * @var PageService
     */
    protected $pageService;

    private bool $original = true;
    private array $backupValues = [];

    public function injectPageService(PageService $pageService): void
    {
        $this->pageService = $pageService;
    }

    public function initializeArguments(): void
    {
        parent::initializeArguments();
        $this->registerUniversalTagAttributes();
        $this->registerPageRecordArguments();
        $this->registerArgument('tagName', 'string', 'Tag name to use for enclosing container', false, 'ul');
        $this->registerArgument(
            'tagNameChildren',
            'string',
            'Tag name to use for child nodes surrounding links. If set to "a" enables non-wrapping mode.',
            false,
            'li'
        );
        $this->registerArgument('entryLevel', 'integer', 'Optional entryLevel TS equivalent of the menu', false, 0);
        $this->registerArgument(
            'levels',
            'integer',
            'Number of levels to render - setting this to a number higher than 1 (one) will expand menu ' .
            'items that are active, to a depth of $levels starting from $entryLevel',
            false,
            1
        );
        $this->registerArgument(
            'expandAll',
            'boolean',
            'If TRUE and $levels > 1 then expands all (not just the active) menu items which have submenus',
            false,
            false
        );
        $this->registerArgument('classFirst', 'string', 'Optional class name for the first menu elment', false, '');
        $this->registerArgument('classLast', 'string', 'Optional class name for the last menu elment', false, '');
        $this->registerArgument('classActive', 'string', 'Optional class name to add to active links', false, 'active');
        $this->registerArgument(
            'classCurrent',
            'string',
            'Optional class name to add to current link',
            false,
            'current'
        );
        $this->registerArgument(
            'substElementUid',
            'boolean',
            'Optional parameter for wrapping the link with the uid of the page',
            false,
            false
        );
        $this->registerArgument(
            'showHiddenInMenu',
            'boolean',
            'Include pages that are set to be hidden in menus',
            false,
            false
        );
        $this->registerArgument('showCurrent', 'boolean', 'If FALSE, does not display the current page', false, true);
        $this->registerArgument(
            'linkCurrent',
            'boolean',
            'If FALSE, does not wrap the current page in a link',
            false,
            true
        );
        $this->registerArgument(
            'linkActive',
            'boolean',
            'If FALSE, does not wrap with links the titles of pages that are active in the rootline',
            false,
            true
        );
        $this->registerArgument(
            'titleFields',
            'string',
            'CSV list of fields to use as link label - default is "nav_title,title", change to for example ' .
            '"tx_myext_somefield,subtitle,nav_title,title". The first field that contains text will be used. ' .
            'Field value resolved AFTER page field overlays.',
            false,
            'nav_title,title'
        );
        $this->registerArgument(
            'includeAnchorTitle',
            'boolean',
            'If TRUE, includes the page title as title attribute on the anchor.',
            false,
            true
        );
        $this->registerArgument(
            'includeSpacers',
            'boolean',
            'Wether or not to include menu spacers in the page select query',
            false,
            false
        );
        $this->registerArgument(
            'deferred',
            'boolean',
            'If TRUE, does not output the tag content UNLESS a v:page.menu.deferred child ViewHelper is both used ' .
            'and triggered. This allows you to create advanced conditions while still using automatic rendering',
            false,
            false
        );
        $this->registerArgument(
            'as',
            'string',
            'If used, stores the menu pages as an array in a variable named after this value and renders the tag ' .
            'content. If the tag content is empty automatic rendering is triggered.',
            false,
            'menu'
        );
        $this->registerArgument(
            'rootLineAs',
            'string',
            'If used, stores the menu root line as an array in a variable named according to this value and renders ' .
            'the tag content - which means automatic rendering is disabled if this attribute is used',
            false,
            'rootLine'
        );
        $this->registerArgument(
            'excludePages',
            'mixed',
            'Page UIDs to exclude from the menu. Can be CSV, array or an object implementing Traversable.',
            false,
            ''
        );
        $this->registerArgument(
            'forceAbsoluteUrl',
            'boolean',
            'If TRUE, the menu will be rendered with absolute URLs',
            false,
            false
        );
        $this->registerArgument(
            'doktypes',
            'mixed',
            'DEPRECATED: Please use typical doktypes for starting points like shortcuts.',
            false,
            ''
        );
        $this->registerArgument(
            'divider',
            'string',
            'Optional divider to insert between each menu item. Note that this does not mix well with automatic ' .
            'rendering due to the use of an ul > li structure'
        );
    }

    /**
     * @return string
     */
    public function render()
    {
        /** @var int|null $entryLevel */
        $entryLevel = $this->arguments['entryLevel'];
        /** @var int|null $pageUid */
        $pageUid = $this->arguments['pageUid'];
        $pageUid = $pageUid > 0 ? (int) $pageUid : null;
        $pages = $this->getMenu($pageUid, (int) $entryLevel);
        $menu = $this->parseMenu($pages);
        $rootLine = $this->pageService->getRootLine(
            $pageUid,
            (bool) ($this->arguments['reverse'] ?? false)
        );
        $this->cleanupSubmenuVariables();
        $this->cleanTemplateVariableContainer();
        $this->backupVariables();
        $variableProvider = $this->renderingContext->getVariableProvider();
        /** @var string $as */
        $as = $this->arguments['as'];
        /** @var string $rootLineAs */
        $rootLineAs = $this->arguments['rootLineAs'];
        $variableProvider->add($as, $menu);
        $variableProvider->add($rootLineAs, $rootLine);
        $this->initalizeSubmenuVariables();
        $output = $this->renderContent($menu);
        $this->cleanupSubmenuVariables();
        $variableProvider->remove($as);
        $variableProvider->remove($rootLineAs);
        $this->restoreVariables();

        return $output;
    }

    /**
     * Renders the tag's content or if omitted auto
     * renders the menu for the provided arguments.
     */
    public function renderContent(array $menu): string
    {
        $deferredRendering = (boolean) $this->arguments['deferred'];
        if (0 === count($menu) && !$deferredRendering) {
            return '';
        }
        if ($deferredRendering) {
            $tagContent = $this->autoRender($menu);
            $this->tag->setContent($tagContent);
            $deferredContent = $this->tag->render();
            $this->renderingContext->getViewHelperVariableContainer()->addOrUpdate(
                'FluidTYPO3\Vhs\ViewHelpers\Menu\AbstractMenuViewHelper',
                'deferredString',
                $deferredContent
            );
            $this->renderingContext->getViewHelperVariableContainer()->addOrUpdate(
                'FluidTYPO3\Vhs\ViewHelpers\Menu\AbstractMenuViewHelper',
                'deferredArray',
                $menu
            );
            $output = $this->renderChildren();
            $this->unsetDeferredVariableStorage();
        } else {
            $content = $this->renderChildren();
            if (!is_scalar($content)) {
                $content = '';
            } else {
                $content = (string) $content;
            }
            if (0 < mb_strlen(trim($content))) {
                $output = $content;
            } elseif ($this->arguments['hideIfEmpty']) {
                $output = '';
            } else {
                $output = $this->renderTag($this->getWrappingTagName(), $this->autoRender($menu));
            }
        }

        return is_scalar($output) ? (string) $output : '';
    }

    protected function autoRender(array $menu, int $level = 1): string
    {
        /** @var string $tagName */
        $tagName = $this->arguments['tagNameChildren'];
        $this->tag->setTagName($this->getWrappingTagName());
        $html = [];
        /** @var int $levels */
        $levels = $this->arguments['levels'];
        $levels = (integer) $levels;
        $showCurrent = (boolean) $this->arguments['showCurrent'];
        $expandAll = (boolean) $this->arguments['expandAll'];
        $itemsRendered = 0;
        $numberOfItems = count($menu);
        foreach ($menu as $page) {
            if ($page['current'] && !$showCurrent) {
                continue;
            }
            $class = (trim($page['class']) !== '') ? ' class="' . trim($page['class']) . '"' : '';
            $elementId = ($this->arguments['substElementUid']) ? ' id="elem_' . $page['uid'] . '"' : '';
            if (!$this->isNonWrappingMode()) {
                $html[] = '<' . $tagName . $elementId . $class . '>';
            }
            $html[] = $this->renderItemLink($page);
            if (($page['active'] || $expandAll) && $page['hasSubPages'] && $level < $levels) {
                $subPages = $this->getMenu($page['uid']);
                $subMenu = $this->parseMenu($subPages);
                if (0 < count($subMenu)) {
                    /** @var string|null $className */
                    $className = $this->arguments['class'];
                    $renderedSubMenu = $this->autoRender($subMenu, $level + 1);
                    /** @var string|null $parentTagId */
                    $parentTagId = $this->tag->getAttribute('id') ?? $this->arguments['id'] ?? null;
                    if (!empty($parentTagId)) {
                        $this->tag->addAttribute('id', $parentTagId . '-lvl-' . $level);
                    }
                    $this->tag->setTagName($this->getWrappingTagName());
                    $this->tag->setContent($renderedSubMenu);
                    $this->tag->addAttribute(
                        'class',
                        (!empty($className) ? $className . ' lvl-' : 'lvl-') . $level
                    );
                    $html[] = $this->tag->render();
                    if (!empty($parentTagId)) {
                        $this->tag->addAttribute('id', $parentTagId);
                    }
                }
            }
            if (!$this->isNonWrappingMode()) {
                $html[] = '</' . $tagName . '>';
            }
            $itemsRendered++;
            if (isset($this->arguments['divider']) && $itemsRendered < $numberOfItems) {
                $divider = $this->arguments['divider'];
                if (!$this->isNonWrappingMode()) {
                    $html[] = '<' . $tagName . '>' . $divider . '</' . $tagName . '>';
                } else {
                    $html[] = $divider;
                }
            }
        }

        return implode(LF, $html);
    }

    protected function renderItemLink(array $page): string
    {
        $isSpacer = $page['doktype'] === PageRepository::DOKTYPE_SPACER;
        $isCurrent = (boolean) $page['current'];
        $isActive = (boolean) $page['active'];
        $linkCurrent = (boolean) $this->arguments['linkCurrent'];
        $linkActive = (boolean) $this->arguments['linkActive'];
        $includeAnchorTitle = (boolean) $this->arguments['includeAnchorTitle'];
        $target = (!empty($page['target'])) ? ' target="' . $page['target'] . '"' : '';
        $class = (trim($page['class']) !== '') ? ' class="' . trim($page['class']) . '"' : '';
        if ($isSpacer || ($isCurrent && !$linkCurrent) || ($isActive && !$linkActive)) {
            $html = htmlspecialchars($page['linktext']);
        } elseif ($includeAnchorTitle) {
            $html = sprintf(
                '<a href="%s" title="%s"%s%s>%s</a>',
                $page['link'],
                htmlspecialchars($page['title']),
                $class,
                $target,
                htmlspecialchars($page['linktext'])
            );
        } else {
            $html = sprintf(
                '<a href="%s"%s%s>%s</a>',
                $page['link'],
                $class,
                $target,
                htmlspecialchars($page['linktext'])
            );
        }

        return $html;
    }

    protected function determineParentPageUid(?int $pageUid = null, ?int $entryLevel = 0): ?int
    {
        $rootLineData = $this->pageService->getRootLine();
        if (null === $pageUid) {
            if (null !== $entryLevel) {
                if ($entryLevel < 0) {
                    $entryLevel = count($rootLineData) - 1 + $entryLevel;
                }
                if (is_array($rootLineData[$entryLevel] ?? null)) {
                    $pageUid = $rootLineData[$entryLevel]['uid'] ?? null;
                }
            } else {
                $pageUid = $GLOBALS['TSFE']->id;
            }
        }

        return $pageUid;
    }

    public function getMenu(?int $pageUid = null, ?int $entryLevel = 0): array
    {
        $pageUid = $this->determineParentPageUid($pageUid, $entryLevel);
        if ($pageUid === null) {
            return [];
        }
        $showHiddenInMenu = (boolean) $this->arguments['showHiddenInMenu'];
        $showAccessProtected = (boolean) $this->arguments['showAccessProtected'];
        $includeSpacers = (boolean) $this->arguments['includeSpacers'];
        $excludePages = $this->processPagesArgument($this->arguments['excludePages']);

        return $this->pageService->getMenu(
            $pageUid,
            $excludePages,
            $showHiddenInMenu,
            $includeSpacers,
            $showAccessProtected
        );
    }

    public function parseMenu(array $pages): array
    {
        $count = 0;
        $total = count($pages);
        $processedPages = [];
        foreach ($pages as $index => $page) {
            if (!is_array($page) || !isset($page['uid'])) {
                continue;
            }
            $count++;
            $class = [];
            $originalPageUid = $page['uid'];
            $showAccessProtected = (boolean) $this->arguments['showAccessProtected'];
            if ($showAccessProtected) {
                $pages[$index]['accessProtected'] = $this->pageService->isAccessProtected($page);
                if ($pages[$index]['accessProtected']) {
                    $class[] = $this->arguments['classAccessProtected'];
                }
                $pages[$index]['accessGranted'] = $this->pageService->isAccessGranted($page);
                if ($pages[$index]['accessGranted'] && $this->pageService->isAccessProtected($page)) {
                    $class[] = $this->arguments['classAccessGranted'];
                }
            }
            $targetPage = $this->pageService->getShortcutTargetPage($page);
            if ($targetPage !== null) {
                if ($this->pageService->shouldUseShortcutTarget($this->arguments)) {
                    $pages[$index] = $targetPage;
                }
                if ($this->pageService->shouldUseShortcutUid($this->arguments)) {
                    $pages[$index]['uid'] = $targetPage['uid'];
                }
            }
            if ($this->pageService->isActive($originalPageUid)) {
                $pages[$index]['active'] = true;
                $class[] = $this->arguments['classActive'];
            } else {
                $pages[$index]['active'] = false;
            }
            if ($this->pageService->isCurrent($targetPage['uid'] ?? $page['uid'])) {
                $pages[$index]['current'] = true;
                $class[] = $this->arguments['classCurrent'];
            } else {
                 $pages[$index]['current'] = false;
            }
            $pages[$index]['hasSubPages'] = false;
            if (0 < count($this->getMenu($originalPageUid))) {
                $pages[$index]['hasSubPages'] = true;
            }
            if (1 === $count) {
                $class[] = $this->arguments['classFirst'];
            }
            if ($count === $total) {
                $class[] = $this->arguments['classLast'];
            }
            $pages[$index]['class'] = implode(' ', $class);
            $pages[$index]['linktext'] = $this->getItemTitle($pages[$index]);
            $forceAbsoluteUrl = (boolean) $this->arguments['forceAbsoluteUrl'];
            $pages[$index]['link'] = $this->pageService->getItemLink($pages[$index], $forceAbsoluteUrl);
            $processedPages[$index] = $pages[$index];
        }

        return $processedPages;
    }

    protected function getItemTitle(array $page): string
    {
        /** @var string $titleFieldsArgument */
        $titleFieldsArgument = $this->arguments['titleFields'];
        $titleFieldList = GeneralUtility::trimExplode(',', $titleFieldsArgument);
        foreach ($titleFieldList as $titleFieldName) {
            if (!empty($page[$titleFieldName])) {
                return $page[$titleFieldName];
            }
        }

        return $page['title'];
    }

    /**
     * Initialize variables used by the submenu instance recycler. Variables set here
     * may be read by the Page / Menu / Sub ViewHelper which then automatically repeats
     * rendering using the exact same arguments but with a new page UID as starting page.
     * Note that the submenu VieWHelper is only capable of recycling one type of menu at
     * a time - for example, a List menu nested inside a regular Menu ViewHelper will
     * simply start another menu rendering completely separate from the parent menu.
     */
    protected function initalizeSubmenuVariables(): void
    {
        if (!$this->original) {
            return;
        }
        $viewHelperVariableContainer = $this->renderingContext->getViewHelperVariableContainer();
        $variables = $this->renderingContext->getVariableProvider()->getAll();
        $viewHelperVariableContainer->addOrUpdate(
            'FluidTYPO3\Vhs\ViewHelpers\Menu\AbstractMenuViewHelper',
            'parentInstance',
            $this
        );
        $viewHelperVariableContainer->addOrUpdate(
            'FluidTYPO3\Vhs\ViewHelpers\Menu\AbstractMenuViewHelper',
            'variables',
            $variables
        );
    }

    public function setOriginal(bool $original): void
    {
        $this->original = $original;
    }

    protected function cleanupSubmenuVariables(): void
    {
        if (!$this->original) {
            return;
        }
        $viewHelperVariableContainer = $this->renderingContext->getViewHelperVariableContainer();
        if (!$viewHelperVariableContainer->exists(AbstractMenuViewHelper::class, 'parentInstance')) {
            return;
        }
        $viewHelperVariableContainer->remove(AbstractMenuViewHelper::class, 'parentInstance');
        $viewHelperVariableContainer->remove(AbstractMenuViewHelper::class, 'variables');
    }

    /**
     * Saves copies of all template variables while rendering
     * the menu.
     */
    public function backupVariables(): void
    {
        /** @var string $as */
        $as = $this->arguments['as'];
        /** @var string $rootLineAs */
        $rootLineAs = $this->arguments['rootLineAs'];
        $variableProvider = $this->renderingContext->getVariableProvider();
        $backups = [$as, $rootLineAs];
        foreach ($backups as $var) {
            if ($variableProvider->exists($var)) {
                $this->backupValues[$var] = $variableProvider->get($var);
                $variableProvider->remove($var);
            }
        }
    }

    /**
     * Restores all saved template variables.
     */
    public function restoreVariables(): void
    {
        $variableProvider = $this->renderingContext->getVariableProvider();
        if (0 < count($this->backupValues)) {
            foreach ($this->backupValues as $var => $value) {
                if (!$variableProvider->exists($var)) {
                    $variableProvider->add($var, $value);
                }
            }
        }
    }

    /**
     * Retrieves a stored, if any, parent instance of a menu. Although only implemented by
     * the Page / Menu / Sub ViewHelper, placing this method in this abstract class instead
     * will allow custom menu ViewHelpers to work as sub menu ViewHelpers without being
     * forced to implement their own variable retrieval or subclass Page / Menu / Sub.
     * Returns NULL if no parent exists.
     *
     * @param integer $pageUid UID of page that's the new parent page, overridden in arguments of cloned and
     *                         recycled menu ViewHelper instance.
     */
    protected function retrieveReconfiguredParentMenuInstance(int $pageUid): ?self
    {
        if (!$this->renderingContext->getViewHelperVariableContainer()->exists(
            AbstractMenuViewHelper::class,
            'parentInstance'
        )) {
            return null;
        }
        /** @var AbstractMenuViewHelper $parentInstance */
        $parentInstance = $this->renderingContext->getViewHelperVariableContainer()->get(
            AbstractMenuViewHelper::class,
            'parentInstance'
        );
        $arguments = $parentInstance->getMenuArguments();
        $arguments['pageUid'] = $pageUid;
        $parentInstance->setArguments($arguments);

        return $parentInstance;
    }

    protected function cleanTemplateVariableContainer(): void
    {
        if (!$this->renderingContext->getViewHelperVariableContainer()->exists(
            AbstractMenuViewHelper::class,
            'variables'
        )) {
            return;
        }
        /** @var iterable $storedVariables */
        $storedVariables = $this->renderingContext->getViewHelperVariableContainer()->get(
            AbstractMenuViewHelper::class,
            'variables'
        );
        $variableProvider = $this->renderingContext->getVariableProvider();
        /** @var iterable $allVariables */
        $allVariables = $variableProvider->getAll();
        foreach ($allVariables as $variableName => $value) {
            $this->backupValues[$variableName] = $value;
            $variableProvider->remove($variableName);
        }
        foreach ($storedVariables as $variableName => $value) {
            /** @var string $variableName */
            $variableProvider->add($variableName, $value);
        }
    }

    public function getMenuArguments(): array
    {
        if (!is_array($this->arguments)) {
            return $this->arguments->toArray();
        }
        return $this->arguments;
    }

    protected function unsetDeferredVariableStorage(): void
    {
        $viewHelperVariableContainer = $this->renderingContext->getViewHelperVariableContainer();
        if ($viewHelperVariableContainer->exists(AbstractMenuViewHelper::class, 'deferredString')) {
            $viewHelperVariableContainer->remove(AbstractMenuViewHelper::class, 'deferredString');
            $viewHelperVariableContainer->remove(AbstractMenuViewHelper::class, 'deferredArray');
        }
    }

    public function getWrappingTagName(): string
    {
        /** @var string $tagName */
        $tagName = $this->arguments['tagName'];
        return $this->isNonWrappingMode() ? 'nav' : $tagName;
    }

    /**
     * Returns TRUE for non-wrapping mode which is triggered
     * by setting tagNameChildren to 'a'.
     */
    public function isNonWrappingMode(): bool
    {
        /** @var string $tagName */
        $tagName = $this->arguments['tagNameChildren'];
        return ('a' === strtolower($tagName));
    }

    /**
     * Returns array of page UIDs from provided pages
     *
     * @param mixed|null $pages
     */
    public function processPagesArgument($pages = null): array
    {
        if (null === $pages) {
            $pages = $this->arguments['pages'];
        }
        if ($pages instanceof \Traversable) {
            $pages = iterator_to_array($pages);
        } elseif (is_string($pages)) {
            $pages = GeneralUtility::trimExplode(',', $pages, true);
        } elseif (is_int($pages)) {
            $pages = (array) $pages;
        }
        if (!is_array($pages)) {
            return [];
        }

        return $pages;
    }
}