<?php

declare(strict_types=1);

namespace App\Services\WebStories;

use App\Models\WorldWebStory;
use App\Models\WorldWebStoryPage;
use Illuminate\Support\Arr;
use Illuminate\Support\Str;
use Illuminate\Validation\ValidationException;

final class WorldWebStoryValidationService
{
    /**
     * @return array{valid: bool, errors: list<string>, warnings: list<string>, page_count: int}
     */
    public function validate(WorldWebStory $story): array
    {
        $story->loadMissing('orderedPages');
        $pages = $story->orderedPages->where('active', true)->values();

        $errors = [];
        $warnings = [];

        if (trim((string) $story->title) === '') {
            $errors[] = 'Story title is required.';
        }

        if (trim((string) $story->slug) === '') {
            $errors[] = 'Story slug is required.';
        }

        if (trim((string) $story->poster_portrait_path) === '') {
            $errors[] = 'Poster portrait image is required.';
        }

        if (trim((string) $story->publisher_logo_path) === '') {
            $errors[] = 'Publisher logo is required.';
        }

        if ($pages->count() < 5) {
            $errors[] = 'A published web story must have at least 5 active pages.';
        }

        if ($pages->count() > 10) {
            $errors[] = 'A published web story may not have more than 10 active pages.';
        }

        foreach ($pages as $page) {
            $pageNumber = (int) $page->position;
            $body = trim((string) $page->body);
            $headline = trim((string) $page->headline);

            if (in_array((string) $page->background_type, [WorldWebStoryPage::BACKGROUND_IMAGE, WorldWebStoryPage::BACKGROUND_VIDEO], true)
                && trim((string) ($page->background_mobile_path ?: $page->background_path)) === '') {
                $errors[] = sprintf('Page %d is missing required background media.', $pageNumber);
            }

            if (mb_strlen($body) > 180) {
                $errors[] = sprintf('Page %d body exceeds 180 characters.', $pageNumber);
            }

            if (trim((string) $page->alt_text) === '') {
                $errors[] = sprintf('Page %d is missing alt text.', $pageNumber);
            }

            if ($headline === '' && $body === '') {
                $warnings[] = sprintf('Page %d has no story text.', $pageNumber);
            }

            if (filled($page->cta_label) || filled($page->cta_url)) {
                if (! filled($page->cta_label) || ! filled($page->cta_url)) {
                    $errors[] = sprintf('Page %d CTA requires both label and URL.', $pageNumber);
                } elseif (! $this->isAllowedCtaUrl((string) $page->cta_url)) {
                    $errors[] = sprintf('Page %d CTA URL is not allowed.', $pageNumber);
                }
            }
        }

        return [
            'valid' => $errors === [],
            'errors' => array_values(array_unique($errors)),
            'warnings' => array_values(array_unique($warnings)),
            'page_count' => $pages->count(),
        ];
    }

    /**
     * @param  array<string, mixed>  $page
     */
    public function validatePagePayload(array $page): array
    {
        $errors = [];
        $position = (int) ($page['position'] ?? 0);
        $body = trim((string) ($page['body'] ?? ''));
        $backgroundType = (string) ($page['background_type'] ?? WorldWebStoryPage::BACKGROUND_IMAGE);
        $backgroundPath = trim((string) ($page['background_mobile_path'] ?? $page['background_path'] ?? ''));
        $altText = trim((string) ($page['alt_text'] ?? ''));
        $ctaUrl = trim((string) ($page['cta_url'] ?? ''));
        $ctaLabel = trim((string) ($page['cta_label'] ?? ''));

        if ($body !== '' && mb_strlen($body) > 180) {
            $errors['body'] = sprintf('Page %d body exceeds 180 characters.', max(1, $position));
        }

        if (in_array($backgroundType, [WorldWebStoryPage::BACKGROUND_IMAGE, WorldWebStoryPage::BACKGROUND_VIDEO], true) && $backgroundPath === '') {
            $errors['background_path'] = 'Background media is required for image and video pages.';
        }

        if ($altText === '') {
            $errors['alt_text'] = 'Alt text is required.';
        }

        if (($ctaUrl !== '' || $ctaLabel !== '') && ($ctaUrl === '' || $ctaLabel === '')) {
            $errors['cta'] = 'CTA label and URL must both be present.';
        }

        if ($ctaUrl !== '' && ! $this->isAllowedCtaUrl($ctaUrl)) {
            $errors['cta_url'] = 'CTA URL must stay on Skinbase or use a relative path.';
        }

        return $errors;
    }

    public function assertPublishable(WorldWebStory $story): void
    {
        $result = $this->validate($story);

        if ($result['valid']) {
            return;
        }

        throw ValidationException::withMessages([
            'story' => $result['errors'],
        ]);
    }

    public function isAllowedCtaUrl(string $url): bool
    {
        $value = trim($url);

        if ($value === '') {
            return false;
        }

        if (Str::startsWith($value, ['/'])) {
            return true;
        }

        $parts = parse_url($value);
        $host = strtolower((string) Arr::get($parts, 'host', ''));

        if ($host === '') {
            return false;
        }

        $allowedHosts = array_filter([
            strtolower((string) parse_url((string) config('app.url'), PHP_URL_HOST)),
            'skinbase.org',
            'www.skinbase.org',
            'skinbase.top',
            'www.skinbase.top',
        ]);

        foreach ($allowedHosts as $allowedHost) {
            if ($host === $allowedHost || Str::endsWith($host, '.' . $allowedHost)) {
                return true;
            }
        }

        return false;
    }
}