<?php

declare(strict_types=1);

namespace App\Services\FormBuilder;

use App\Models\FormBuilder\FormField;
use App\Models\FormBuilder\FormSubmission;
use App\Models\User;
use Illuminate\Support\Collection;

/**
 * Per-field RBAC for form rendering, value writes, and filter access.
 * Implements ARCH §24 (role_restrictions matrix) + §18.3 (subject-self
 * always has access).
 */
final class FieldAccessService
{
    public function canRead(?User $user, FormField $field, ?FormSubmission $submission = null): bool
    {
        if ($this->isSubjectSelf($user, $submission)) {
            return true;
        }

        $restrictions = $this->effectiveRestrictions($field);
        $readRule = $restrictions['read'] ?? true;

        return $this->matches($user, $readRule);
    }

    public function canWrite(?User $user, FormField $field, ?FormSubmission $submission = null): bool
    {
        if ($this->isSubjectSelf($user, $submission)) {
            return true;
        }

        $restrictions = $this->effectiveRestrictions($field);
        $writeRule = $restrictions['write'] ?? ['any_of_roles' => ['org_admin', 'event_manager']];

        return $this->matches($user, $writeRule);
    }

    /**
     * @param  Collection<int, FormField>  $fields
     * @return Collection<int, FormField>
     */
    public function filterVisibleFields(?User $user, Collection $fields, ?FormSubmission $submission = null): Collection
    {
        return $fields->filter(fn (FormField $f) => $this->canRead($user, $f, $submission))->values();
    }

    /**
     * @return array<string, mixed>
     */
    private function effectiveRestrictions(FormField $field): array
    {
        $r = $field->role_restrictions ?? null;
        if (is_array($r) && $r !== []) {
            return $r;
        }

        if ($field->is_admin_only) {
            return [
                'read' => ['any_of_roles' => ['org_admin']],
                'write' => ['any_of_roles' => ['org_admin']],
            ];
        }

        return [
            'read' => true,
            'write' => ['any_of_roles' => ['org_admin', 'event_manager']],
        ];
    }

    private function isSubjectSelf(?User $user, ?FormSubmission $submission): bool
    {
        if ($user === null || $submission === null) {
            return false;
        }

        if ($submission->submitted_by_user_id === $user->id) {
            return true;
        }

        if ($submission->subject_type === 'user' && $submission->subject_id === $user->id) {
            return true;
        }

        if ($submission->subject_type === 'user_profile' && $submission->subject_id !== null) {
            $profile = \App\Models\UserProfile::query()->find($submission->subject_id);
            if ($profile !== null && $profile->user_id === $user->id) {
                return true;
            }
        }

        if ($submission->subject_type === 'person' && $submission->subject_id !== null) {
            $personUserId = \App\Models\Person::withoutGlobalScopes()
                ->whereKey($submission->subject_id)
                ->value('user_id');
            if ($personUserId !== null && $personUserId === $user->id) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param  mixed  $rule
     */
    private function matches(?User $user, $rule): bool
    {
        if ($rule === true) {
            return true;
        }
        if ($rule === false) {
            return false;
        }
        if (! is_array($rule)) {
            return false;
        }

        if ($user === null) {
            return false;
        }

        if (isset($rule['subject_self']) && $rule['subject_self'] === true) {
            return true;
        }

        if (isset($rule['any_of_roles']) && is_array($rule['any_of_roles'])) {
            foreach ($rule['any_of_roles'] as $role) {
                if ($user->hasRole((string) $role)) {
                    return true;
                }
            }

            return false;
        }

        if (isset($rule['all_of_roles']) && is_array($rule['all_of_roles'])) {
            foreach ($rule['all_of_roles'] as $role) {
                if (! $user->hasRole((string) $role)) {
                    return false;
                }
            }

            return true;
        }

        if (isset($rule['not_roles']) && is_array($rule['not_roles'])) {
            foreach ($rule['not_roles'] as $role) {
                if ($user->hasRole((string) $role)) {
                    return false;
                }
            }

            return true;
        }

        return false;
    }
}