<?php

namespace App\Services;

use App\Models\AdminUser;
use App\Models\ResearchDirection;
use App\Models\Teacher;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Http\Exceptions\HttpResponseException;
use Illuminate\Http\Request;

class GridMemberScopeService
{
    public function isSuperAdmin(AdminUser $user): bool
    {
        return $user->isSuperAdmin();
    }

    public function isGridMember(AdminUser $user): bool
    {
        if ($this->isSuperAdmin($user)) {
            return false;
        }

        return $user->roles()->where('code', 'grid_member')->exists();
    }

    public function hasScope(AdminUser $user): bool
    {
        if ($this->isSuperAdmin($user)) {
            return false;
        }

        if (! $this->isGridMember($user)) {
            return false;
        }

        return $this->universityIds($user) !== [] || $this->researchDirectionNames($user) !== [];
    }

    /**
     * @return array<int>
     */
    public function universityIds(AdminUser $user): array
    {
        return $user->universities()->pluck('universities.id')->map(fn ($id) => (int) $id)->all();
    }

    /**
     * @return array<int>
     */
    public function researchDirectionIds(AdminUser $user): array
    {
        return $user->researchDirections()
            ->where('research_directions.status', 1)
            ->pluck('research_directions.id')
            ->map(fn ($id) => (int) $id)
            ->all();
    }

    /**
     * @return array<int, string>
     */
    public function researchDirectionNames(AdminUser $user): array
    {
        return $user->researchDirections()
            ->where('research_directions.status', 1)
            ->orderBy('research_directions.sort')
            ->pluck('research_directions.name')
            ->all();
    }

    /**
     * @return array{university_ids: int[], research_direction_ids: int[], research_direction_names: string[]}
     */
    public function scopePayload(AdminUser $user): array
    {
        return [
            'university_ids' => $this->universityIds($user),
            'research_direction_ids' => $this->researchDirectionIds($user),
            'research_direction_names' => $this->researchDirectionNames($user),
        ];
    }

    public function applyTeacherScope(Builder $query, AdminUser $user): void
    {
        if (! $this->isGridMember($user)) {
            return;
        }

        $uniIds = $this->universityIds($user);
        $dirIds = $this->researchDirectionIds($user);

        if ($uniIds === [] || $dirIds === []) {
            $query->whereRaw('1 = 0');

            return;
        }

        $query->whereIn('university_id', $uniIds)
            ->whereHas('researchDirections', fn ($q) => $q->whereIn('research_directions.id', $dirIds));
    }

    public function assertTeacherAccessible(AdminUser $user, Teacher $teacher): void
    {
        if (! $this->isGridMember($user)) {
            return;
        }

        $uniIds = $this->universityIds($user);
        $dirIds = $this->researchDirectionIds($user);

        if ($uniIds === [] || $dirIds === []) {
            $this->deny();
        }

        if (! in_array((int) $teacher->university_id, $uniIds, true)) {
            $this->deny();
        }

        $teacher->loadMissing('researchDirections');
        $overlap = $teacher->researchDirections->pluck('id')->intersect($dirIds);
        if ($overlap->isEmpty()) {
            $this->deny();
        }
    }

    public function assertCanMutateTeachers(AdminUser $user): void
    {
        if ($this->isGridMember($user)) {
            $this->deny('网格员仅可编辑与跟进已配置范围内的老师');
        }
    }

    /**
     * @param  array<string, mixed>  $data
     */
    public function assertTeacherDataInScope(AdminUser $user, array $data, ?Teacher $existing = null): void
    {
        if (! $this->isGridMember($user)) {
            return;
        }

        $uniIds = $this->universityIds($user);
        $dirIds = $this->researchDirectionIds($user);

        if (isset($data['university_id']) && ! in_array((int) $data['university_id'], $uniIds, true)) {
            $this->deny('所选高校不在您的负责范围内');
        }

        if (isset($data['research_direction_ids'])) {
            foreach ($data['research_direction_ids'] as $dirId) {
                if (! in_array((int) $dirId, $dirIds, true)) {
                    $this->deny('所选研究方向不在您的负责范围内');
                }
            }
        }

        if ($existing) {
            $this->assertTeacherAccessible($user, $existing);
        }
    }

    public function userFromRequest(Request $request): AdminUser
    {
        /** @var AdminUser $user */
        $user = $request->user();

        return $user;
    }

    protected function deny(string $message = '无权访问该老师'): void
    {
        throw new HttpResponseException(
            response()->json([
                'message' => $message,
                'data' => null,
            ], 403)
        );
    }
}