<?php

declare(strict_types=1);

namespace Esun\Translation\Model\Entity;

use Esun\Translation\Api\TranslatableEntityInterface;
use Esun\Translation\Model\Html\HtmlTranslationValidator;
use Magento\Cms\Api\PageRepositoryInterface;
use Magento\Cms\Model\Page;
use Magento\Cms\Model\PageFactory;
use Magento\Cms\Model\ResourceModel\Page\CollectionFactory;

class CmsPageEntity implements TranslatableEntityInterface
{
    private const FIELDS = [
        'title' => ['label' => 'Page Title', 'is_html' => false],
        'content_heading' => ['label' => 'Content Heading', 'is_html' => false],
        'content' => ['label' => 'Content', 'is_html' => true],
        'meta_title' => ['label' => 'Meta Title', 'is_html' => false],
        'meta_keywords' => ['label' => 'Meta Keywords', 'is_html' => false],
        'meta_description' => ['label' => 'Meta Description', 'is_html' => false],
    ];

    public function __construct(
        private readonly PageRepositoryInterface $pageRepository,
        private readonly PageFactory $pageFactory,
        private readonly CollectionFactory $collectionFactory,
        private readonly HtmlTranslationValidator $htmlValidator
    ) {
    }

    public function getType(): string
    {
        return 'cms_page';
    }

    public function getLabel(): string
    {
        return 'CMS Page';
    }

    public function getTitle(int $entityId): string
    {
        return (string)$this->getPage($entityId)->getTitle();
    }

    public function getEditUrlPath(): string
    {
        return 'cms/page/edit';
    }

    public function getEditIdParam(): string
    {
        return 'page_id';
    }

    public function getFields(int $entityId, array $targetStoreIds = []): array
    {
        $source = $this->getPage($entityId);
        $target = $this->findTargetPage($source, $targetStoreIds);
        $fields = [];

        foreach (self::FIELDS as $code => $metadata) {
            $fields[] = [
                'code' => $code,
                'label' => $metadata['label'],
                'source_value' => (string)($source->getData($code) ?? ''),
                'target_value' => $target ? (string)($target->getData($code) ?? '') : '',
                'is_html' => (bool)$metadata['is_html'],
            ];
        }

        return $fields;
    }

    public function apply(int $entityId, array $storeIds, array $fields): array
    {
        $source = $this->getPage($entityId);
        $fields = $this->filterAndValidateFields($fields);
        if ($fields === []) {
            throw new \RuntimeException('No translatable CMS page fields were provided.');
        }

        $updated = 0;
        $created = 0;
        foreach (array_unique(array_map('intval', $storeIds)) as $storeId) {
            if ($storeId <= 0) {
                continue;
            }

            $page = $this->findByIdentifierAndStore((string)$source->getIdentifier(), $storeId);
            if ($page) {
                $this->applyFields($page, $fields);
                $page->setStores([$storeId]);
                $this->pageRepository->save($page);
                $updated++;
                continue;
            }

            if (in_array(0, array_map('intval', (array)$source->getStores()), true)) {
                throw new \RuntimeException(
                    'This CMS page is assigned to All Store Views. Create store-specific pages first or remove All Store Views before creating localized copies.'
                );
            }

            $copy = $this->cloneForStore($source, $storeId);
            $this->applyFields($copy, $fields);
            $this->pageRepository->save($copy);
            $created++;
        }

        if ($updated + $created === 0) {
            throw new \RuntimeException('No valid target store views were provided.');
        }

        return [
            'updated' => $updated,
            'created' => $created,
            'message' => __('CMS page translations applied. Updated: %1, Created: %2.', $updated, $created)->render(),
        ];
    }

    private function getPage(int $pageId): Page
    {
        $page = $this->pageRepository->getById($pageId);
        if (!$page instanceof Page) {
            throw new \RuntimeException('CMS page model type is not supported.');
        }

        return $page;
    }

    /**
     * @param int[] $targetStoreIds
     */
    private function findTargetPage(Page $source, array $targetStoreIds): ?Page
    {
        foreach ($targetStoreIds as $storeId) {
            $page = $this->findByIdentifierAndStore((string)$source->getIdentifier(), (int)$storeId);
            if ($page && (int)$page->getId() !== (int)$source->getId()) {
                return $page;
            }
        }

        return null;
    }

    private function findByIdentifierAndStore(string $identifier, int $storeId): ?Page
    {
        if ($storeId <= 0) {
            return null;
        }

        $collection = $this->collectionFactory->create();
        $collection->addFieldToFilter('identifier', $identifier);
        $collection->addStoreFilter($storeId, false);
        $collection->setPageSize(1);
        $page = $collection->getFirstItem();

        return $page && $page->getId() ? $page : null;
    }

    /**
     * @param array<string, mixed> $fields
     * @return array<string, string>
     */
    private function filterAndValidateFields(array $fields): array
    {
        $result = [];
        foreach ($fields as $code => $value) {
            $code = (string)$code;
            if (!isset(self::FIELDS[$code])) {
                continue;
            }

            $value = (string)$value;
            if ((bool)self::FIELDS[$code]['is_html']) {
                $errors = $this->htmlValidator->validate($value);
                if ($errors !== []) {
                    throw new \RuntimeException(sprintf(
                        'HTML for "%s" is invalid: %s',
                        $code,
                        implode('; ', $errors)
                    ));
                }
            }
            $result[$code] = $value;
        }

        return $result;
    }

    /**
     * @param array<string, string> $fields
     */
    private function applyFields(Page $page, array $fields): void
    {
        foreach ($fields as $code => $value) {
            $page->setData($code, $value);
        }
    }

    private function cloneForStore(Page $source, int $storeId): Page
    {
        $data = $source->getData();
        unset($data['page_id'], $data['store_id']);

        $copy = $this->pageFactory->create();
        $copy->setData($data);
        $copy->setStores([$storeId]);
        $copy->setData('store_id', [$storeId]);

        return $copy;
    }
}