<?php

namespace App\Services;

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

class DepartmentService
{
    private static function v(array $params, array $rules)
    {
        $v = Validator::make($params, $rules);
        if ($v->fails()) abort(422, $v->errors()->first());
        return $v->validated();
    }

    /** 목록 */
    public static function index(array $params)
    {
        $p = self::v($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',
        ]);

        $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'].'%');
            });
        }

        return $q->orderBy('sort_order')->orderBy('name')->paginate($p['per_page'] ?? 20);
    }

    /** 생성 */
    public static function store(array $params)
    {
        $p = self::v($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 (!empty($p['code'])) {
            $exists = Department::query()->where('code', $p['code'])->exists();
            if ($exists) abort(409, '이미 존재하는 부서 코드입니다.');
        }

        $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 self::show($dept->id, []);
    }

    /** 단건 */
    public static function show(int $id, array $params)
    {
        $dept = Department::query()->find($id);
        if (!$dept) abort(404, '부서를 찾을 수 없습니다.');
        return $dept;
    }

    /** 수정 */
    public static function update(int $id, array $params)
    {
        $p = self::v($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',
        ]);

        $dept = Department::query()->find($id);
        if (!$dept) abort(404, '부서를 찾을 수 없습니다.');

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

        $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 static function destroy(int $id, array $params)
    {
        $p = self::v($params, [
            'deleted_by' => 'nullable|integer|min:1',
        ]);

        $dept = Department::query()->find($id);
        if (!$dept) abort(404, '부서를 찾을 수 없습니다.');

        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 static function listUsers(int $deptId, array $params)
    {
        $p = self::v($params, [
            'page'      => 'nullable|integer|min:1',
            'per_page'  => 'nullable|integer|min:1|max:200',
        ]);

        $dept = Department::query()->find($deptId);
        if (!$dept) abort(404, '부서를 찾을 수 없습니다.');

        return $dept->departmentUsers()
            ->with('user')
            ->orderByDesc('is_primary')
            ->orderBy('id')
            ->paginate($p['per_page'] ?? 20);
    }

    /** 사용자 배정 (단건) */
    public static function attachUser(int $deptId, array $params)
    {
        $p = self::v($params, [
            'user_id'    => 'required|integer|min:1',
            'is_primary' => 'nullable|in:0,1',
            'joined_at'  => 'nullable|date',
        ]);

        $dept = Department::query()->find($deptId);
        if (!$dept) abort(404, '부서를 찾을 수 없습니다.');

        return 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)) {
                abort(409, '이미 배정된 사용자입니다.');
            }

            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']];
        });
    }

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

        if (!$du) abort(404, '배정된 사용자를 찾을 수 없습니다.');
        $du->delete();

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

    /** 주부서 설정/해제 */
    public static function setPrimary(int $deptId, int $userId, array $params)
    {
        $p = self::v($params, [
            'is_primary' => 'required|in:0,1',
        ]);

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

            if (!$du) abort(404, '배정된 사용자를 찾을 수 없습니다.');

            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];
        });
    }

    /** 부서 권한 목록 */
    public static function listPermissions(int $deptId, array $params)
    {
        $p = self::v($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',
        ]);

        $dept = Department::query()->find($deptId);
        if (!$dept) abort(404, '부서를 찾을 수 없습니다.');

        $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']);

        return $q->orderByDesc('is_allowed')->orderBy('permission_id')->paginate($p['per_page'] ?? 20);
    }

    /** 권한 부여/차단 upsert */
    public static function upsertPermission(int $deptId, array $params)
    {
        $p = self::v($params, [
            'permission_id' => 'required|integer|min:1',
            'menu_id'       => 'nullable|integer|min:1',
            'is_allowed'    => 'nullable|in:0,1',
        ]);

        $dept = Department::query()->find($deptId);
        if (!$dept) abort(404, '부서를 찾을 수 없습니다.');

        $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();

        return self::listPermissions($deptId, []);
    }

    /** 권한 제거 (menu_id 없으면 전체 제거) */
    public static function revokePermission(int $deptId, int $permissionId, array $params)
    {
        $p = self::v($params, [
            'menu_id' => 'nullable|integer|min:1',
        ]);

        $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()) abort(404, '대상 권한을 찾을 수 없습니다.');

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

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