<?php

namespace App\Support;

use Illuminate\Support\Facades\Validator;
use Illuminate\Validation\Rule;
use Illuminate\Validation\ValidationException;

/** Shared announcement/activity link contract. */
final class ContentLink
{
    public const FIELDS = ['click_type', 'link', 'link_pc', 'link_h5'];

    public static function normalize(array $row): array
    {
        $type = $row['click_type'] ?? 'none';
        $type = in_array($type, ['none', 'external', 'internal'], true) ? $type : 'none';
        return [
            'click_type' => $type,
            'link' => $type !== 'none' ? ($row['link'] ?? null) : null,
            'link_pc' => $type === 'internal' ? ($row['link_pc'] ?? $row['link'] ?? null) : null,
            'link_h5' => $type === 'internal' ? ($row['link_h5'] ?? $row['link'] ?? null) : null,
        ];
    }

    public static function forSave(array $input, array $previous = []): array
    {
        $before = self::normalize($previous);
        $type = $input['click_type'] ?? $before['click_type'];
        // An explicitly empty click type is invalid, rather than an omitted field.
        if (array_key_exists('click_type', $input)) $type = $input['click_type'];
        Validator::make(['click_type' => $type], ['click_type' => ['required', 'string', Rule::in(array_keys(AnnouncementCatalog::CLICKS))]],
            ['click_type.in' => '点击方式仅支持无链接、外站链接、站内路径'])->validate();
        $result = ['click_type' => $type, 'link' => null, 'link_pc' => null, 'link_h5' => null];
        if ($type === 'none') return $result;
        if ($type === 'external') {
            $result['link'] = array_key_exists('link', $input) ? $input['link'] : ($before['click_type'] === $type ? $before['link'] : null);
            self::validateLink('link', $result['link'], $type);
            return $result;
        }
        $legacy = array_key_exists('link', $input) && !array_key_exists('link_pc', $input) && !array_key_exists('link_h5', $input);
        foreach (['link_pc' => 'PC', 'link_h5' => 'H5'] as $field => $label) {
            $result[$field] = $legacy ? $input['link'] : (array_key_exists($field, $input) ? $input[$field] : ($before['click_type'] === $type ? $before[$field] : null));
            self::validateLink($field, $result[$field], $type, $label);
        }
        // Keep old callers functional; new dual-path submissions have no shared internal target.
        if ($legacy) $result['link'] = $input['link'];
        elseif (!array_key_exists('link_pc', $input) && !array_key_exists('link_h5', $input) && $before['click_type'] === $type) $result['link'] = $before['link'];
        return $result;
    }

    public static function forPlatform(array $row, ?string $platform): array
    {
        $links = self::normalize($row);
        if ($links['click_type'] === 'internal') {
            $links['link'] = match ($platform) {
                'PC' => $links['link_pc'], 'H5', 'APP' => $links['link_h5'],
                default => $links['link_pc'] === $links['link_h5'] ? $links['link_pc'] : null,
            };
        }
        return array_intersect_key($links, ['click_type' => true, 'link' => true]);
    }

    public static function requestPlatform(): string
    {
        $platform = request()->header('Platform');
        return is_string($platform) ? (ActivityEligibility::normalizePlatform($platform) ?? 'PC') : 'PC';
    }

    public static function valid(string $value, string $type): bool
    {
        if ($value === '' || preg_match('/[\x00-\x20\x7f\\\\]/', $value)) return false;
        if ($type === 'internal') return str_starts_with($value, '/') && !str_starts_with($value, '//');
        $parts = parse_url($value);
        return filter_var($value, FILTER_VALIDATE_URL) && $parts && in_array(strtolower($parts['scheme'] ?? ''), ['http', 'https'], true)
            && !isset($parts['user']) && !isset($parts['pass']);
    }

    private static function validateLink(string $field, $value, string $type, string $label = ''): void
    {
        Validator::make([$field => $value], [$field => ['required', 'string', 'max:2048']],
            [$field . '.required' => $type === 'internal' ? '请填写' . $label . '站内相对路径' : '请填写跳转链接'])->validate();
        if (!self::valid($value, $type)) throw ValidationException::withMessages([
            $field => $type === 'internal' ? '请填写有效的' . $label . '站内相对路径' : '请填写有效的HTTP/HTTPS外站链接',
        ]);
    }
}