<?php

namespace App\Services;

use App\Models\Commons\Department;
use App\Models\Commons\DepartmentPermission;
use App\Models\Commons\DepartmentUser;
use Carbon\Carbon;
use Illuminate\Http\JsonResponse;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Validator;

class DepartmentService extends Service
{
    /**
     * 공통 검증 헬퍼: 실패 시 ['error'=>..., 'code'=>...] 형태로 반환
     */
    protected function v(array $params, array $rules)
    {
        $v = Validator::make($params, $rules);
        if ($v->fails()) {
            return ['error' => $v->errors()->first(), 'code' => 422];
        }
        return $v->validated();
    }

    /** 목록 */
    public function index(array $params)
    {
        $p = $this->v($params, [
            'q'         => 'nullable|string|max:100',
            'is_active' => 'nullable|in:0,1',
            'page'      => 'nullable|integer|min:1',
            'per_page'  => 'nullable|integer|min:1|max:200',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $q = Department::query();

        if (isset($p['is_active'])) {
            $q->where('is_active', (int)$p['is_active']);
        }
        if (!empty($p['q'])) {
            $q->where(function ($w) use ($p) {
                $w->where('name', 'like', '%' . $p['q'] . '%')
                    ->orWhere('code', 'like', '%' . $p['q'] . '%');
            });
        }

        $q->orderBy('sort_order')->orderBy('name');

        $perPage = $p['per_page'] ?? 20;
        $page    = $p['page'] ?? null;

        return $q->paginate($perPage, ['*'], 'page', $page);
    }

    /** 생성 */
    public function store(array $params)
    {
        // 테넌트 강제가 필요하면 아래 라인 사용:
        // $this->tenantIdOrFail();

        $p = $this->v($params, [
            'code'        => 'nullable|string|max:50',
            'name'        => 'required|string|max:100',
            'description' => 'nullable|string|max:255',
            'is_active'   => 'nullable|in:0,1',
            'sort_order'  => 'nullable|integer',
            'created_by'  => 'nullable|integer|min:1',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        if (!empty($p['code'])) {
            $exists = Department::query()->where('code', $p['code'])->exists();
            if ($exists) return ['error' => '이미 존재하는 부서 코드입니다.', 'code' => 409];
        }

        $dept = Department::create([
            'code'        => $p['code']        ?? null,
            'name'        => $p['name'],
            'description' => $p['description'] ?? null,
            'is_active'   => isset($p['is_active']) ? (int)$p['is_active'] : 1,
            'sort_order'  => $p['sort_order']  ?? 0,
            'created_by'  => $p['created_by']  ?? null,
            'updated_by'  => $p['created_by']  ?? null,
        ]);

        return $dept->fresh();
    }

    /** 단건 */
    public function show(int $id, array $params = [])
    {
        if (!$id) return ['error' => 'id가 필요합니다.', 'code' => 400];

        $res = Department::query()->find($id);
        if (!$res) {
            return ['error' => '부서를 찾을 수 없습니다.', 'code' => 404];
        }
        return $res;
    }

    /** 수정 */
    public function update(int $id, array $params)
    {
        if (!$id) return ['error' => 'id가 필요합니다.', 'code' => 400];

        $p = $this->v($params, [
            'code'        => 'nullable|string|max:50',
            'name'        => 'nullable|string|max:100',
            'description' => 'nullable|string|max:255',
            'is_active'   => 'nullable|in:0,1',
            'sort_order'  => 'nullable|integer',
            'updated_by'  => 'nullable|integer|min:1',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $dept = Department::query()->find($id);
        if (!$dept) return ['error' => '부서를 찾을 수 없습니다.', 'code' => 404];

        if (array_key_exists('code', $p) && !is_null($p['code'])) {
            $exists = Department::query()
                ->where('code', $p['code'])
                ->where('id', '!=', $id)
                ->exists();
            if ($exists) return ['error' => '이미 존재하는 부서 코드입니다.', 'code' => 409];
        }

        $dept->fill([
            'code'        => array_key_exists('code', $p) ? $p['code'] : $dept->code,
            'name'        => $p['name']        ?? $dept->name,
            'description' => $p['description'] ?? $dept->description,
            'is_active'   => isset($p['is_active']) ? (int)$p['is_active'] : $dept->is_active,
            'sort_order'  => $p['sort_order']  ?? $dept->sort_order,
            'updated_by'  => $p['updated_by']  ?? $dept->updated_by,
        ])->save();

        return $dept->fresh();
    }

    /** 삭제(soft) */
    public function destroy(int $id, array $params)
    {
        if (!$id) return ['error' => 'id가 필요합니다.', 'code' => 400];

        $p = $this->v($params, [
            'deleted_by' => 'nullable|integer|min:1',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $dept = Department::query()->find($id);
        if (!$dept) return ['error' => '부서를 찾을 수 없습니다.', 'code' => 404];

        if (!empty($p['deleted_by'])) {
            $dept->deleted_by = $p['deleted_by'];
            $dept->save();
        }
        $dept->delete();

        return ['id' => $id, 'deleted_at' => now()->toDateTimeString()];
    }

    /** 부서 사용자 목록 */
    public function listUsers(int $deptId, array $params)
    {
        $p = $this->v($params, [
            'page'      => 'nullable|integer|min:1',
            'per_page'  => 'nullable|integer|min:1|max:200',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $dept = Department::query()->find($deptId);
        if (!$dept) return ['error' => '부서를 찾을 수 없습니다.', 'code' => 404];

        $builder = $dept->departmentUsers()->with('user')
            ->orderByDesc('is_primary')->orderBy('id');

        $perPage = $p['per_page'] ?? 20;
        $page    = $p['page'] ?? null;

        return $builder->paginate($perPage, ['*'], 'page', $page);
    }

    /** 사용자 배정 (단건) */
    public function attachUser(int $deptId, array $params)
    {
        $p = $this->v($params, [
            'user_id'    => 'required|integer|min:1',
            'is_primary' => 'nullable|in:0,1',
            'joined_at'  => 'nullable|date',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $dept = Department::query()->find($deptId);
        if (!$dept) return ['error' => '부서를 찾을 수 없습니다.', 'code' => 404];

        $result = DB::transaction(function () use ($dept, $p) {
            $du = DepartmentUser::withTrashed()
                ->where('department_id', $dept->id)
                ->where('user_id', $p['user_id'])
                ->first();

            if ($du && is_null($du->deleted_at)) {
                return ['error' => '이미 배정된 사용자입니다.', 'code' => 409];
            }

            if (!empty($p['is_primary']) && (int)$p['is_primary'] === 1) {
                DepartmentUser::whereNull('deleted_at')
                    ->where('user_id', $p['user_id'])
                    ->update(['is_primary' => 0]);
            }

            $payload = [
                'department_id' => $dept->id,
                'user_id'       => $p['user_id'],
                'is_primary'    => isset($p['is_primary']) ? (int)$p['is_primary'] : 0,
                'joined_at'     => !empty($p['joined_at']) ? Carbon::parse($p['joined_at']) : now(),
            ];

            if ($du) {
                $du->fill($payload);
                $du->restore();
                $du->save();
            } else {
                DepartmentUser::create($payload);
            }

            return ['department_id' => $dept->id, 'user_id' => $p['user_id']];
        });

        if ($result instanceof JsonResponse) return $result;
        return $result;
    }

    /** 사용자 제거(soft) */
    public function detachUser(int $deptId, int $userId, array $params)
    {
        $du = DepartmentUser::whereNull('deleted_at')
            ->where('department_id', $deptId)
            ->where('user_id', $userId)
            ->first();

        if (!$du) return ['error' => '배정된 사용자를 찾을 수 없습니다.', 'code' => 404];

        $du->delete();

        return [
            'user_id'    => $userId,
            'deleted_at' => now()->toDateTimeString(),
        ];
    }

    /** 주부서 설정/해제 */
    public function setPrimary(int $deptId, int $userId, array $params)
    {
        $p = $this->v($params, [
            'is_primary' => 'required|in:0,1',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $result = DB::transaction(function () use ($deptId, $userId, $p) {
            $du = DepartmentUser::whereNull('deleted_at')
                ->where('department_id', $deptId)
                ->where('user_id', $userId)
                ->first();

            if (!$du) {
                return ['error' => '배정된 사용자를 찾을 수 없습니다.', 'code' => 404];
            }

            if ((int)$p['is_primary'] === 1) {
                DepartmentUser::whereNull('deleted_at')
                    ->where('user_id', $userId)
                    ->update(['is_primary' => 0]);
            }

            $du->is_primary = (int)$p['is_primary'];
            $du->save();

            return ['user_id' => $userId, 'department_id' => $deptId, 'is_primary' => $du->is_primary];
        });

        if ($result instanceof JsonResponse) return $result;
        return $result;
    }

    /** 부서 권한 목록 */
    public function listPermissions(int $deptId, array $params)
    {
        $p = $this->v($params, [
            'menu_id'     => 'nullable|integer|min:1',
            'is_allowed'  => 'nullable|in:0,1',
            'page'        => 'nullable|integer|min:1',
            'per_page'    => 'nullable|integer|min:1|max:200',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $dept = Department::query()->find($deptId);
        if (!$dept) return ['error' => '부서를 찾을 수 없습니다.', 'code' => 404];

        $q = DepartmentPermission::query()
            ->whereNull('deleted_at')
            ->where('department_id', $deptId);

        if (isset($p['menu_id']))    $q->where('menu_id', $p['menu_id']);
        if (isset($p['is_allowed'])) $q->where('is_allowed', (int)$p['is_allowed']);

        $q->orderByDesc('is_allowed')->orderBy('permission_id');

        $perPage = $p['per_page'] ?? 20;
        $page    = $p['page'] ?? null;

        return $q->paginate($perPage, ['*'], 'page', $page);
    }

    /** 권한 부여/차단 upsert */
    public function upsertPermission(int $deptId, array $params)
    {
        $p = $this->v($params, [
            'permission_id' => 'required|integer|min:1',
            'menu_id'       => 'nullable|integer|min:1',
            'is_allowed'    => 'nullable|in:0,1',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $dept = Department::query()->find($deptId);
        if (!$dept) return ['error' => '부서를 찾을 수 없습니다.', 'code' => 404];

        $payload = [
            'department_id' => $deptId,
            'permission_id' => $p['permission_id'],
            'menu_id'       => $p['menu_id'] ?? null,
        ];

        $model = DepartmentPermission::withTrashed()->firstOrNew($payload);
        $model->is_allowed = isset($p['is_allowed']) ? (int)$p['is_allowed'] : 1;
        $model->deleted_at = null;
        $model->save();

        // 변경 후 목록 반환
        return $this->listPermissions($deptId, []);
    }

    /** 권한 제거 (menu_id 없으면 전체 제거) */
    public function revokePermission(int $deptId, int $permissionId, array $params)
    {
        $p = $this->v($params, [
            'menu_id' => 'nullable|integer|min:1',
        ]);
        if ($p instanceof JsonResponse) return $p;
        if (isset($p['error'])) return $p;

        $q = DepartmentPermission::whereNull('deleted_at')
            ->where('department_id', $deptId)
            ->where('permission_id', $permissionId);

        if (isset($p['menu_id'])) $q->where('menu_id', $p['menu_id']);

        $rows = $q->get();
        if ($rows->isEmpty()) return ['error' => '대상 권한을 찾을 수 없습니다.', 'code' => 404];

        foreach ($rows as $row) $row->delete();

        return [
            'permission_id' => $permissionId,
            'menu_id'       => $p['menu_id'] ?? null,
            'deleted_count' => $rows->count(),
        ];
    }
}