<?php

namespace App\Services;

use App\Models\Commons\Menu;
use App\Models\Permission;
use App\Models\Role;
use Illuminate\Support\Facades\DB;

class RolePermissionService
{
    /**
     * 권한 유형 목록
     */
    private array $permissionTypes = ['view', 'create', 'update', 'delete', 'approve', 'export', 'manage'];

    /**
     * 역할의 권한 매트릭스 조회
     *
     * @param  int  $roleId  역할 ID
     * @param  int|null  $tenantId  테넌트 ID
     * @return array 메뉴별 권한 상태 매트릭스
     */
    public function getRolePermissionMatrix(int $roleId, ?int $tenantId = null): array
    {
        $query = DB::table('role_has_permissions')
            ->join('permissions', 'role_has_permissions.permission_id', '=', 'permissions.id')
            ->where('role_has_permissions.role_id', $roleId)
            ->where('permissions.name', 'like', 'menu:%');

        if ($tenantId) {
            $query->where('permissions.tenant_id', $tenantId);
        }

        $rolePermissions = $query->pluck('permissions.name')->toArray();

        $permissions = [];
        foreach ($rolePermissions as $permName) {
            if (preg_match('/^menu:(\d+)\.(\w+)$/', $permName, $matches)) {
                $menuId = (int) $matches[1];
                $type = $matches[2];

                if (! isset($permissions[$menuId])) {
                    $permissions[$menuId] = [];
                }

                $permissions[$menuId][$type] = true;
            }
        }

        return $permissions;
    }

    /**
     * 특정 메뉴의 특정 권한 토글
     *
     * @param  int  $roleId  역할 ID
     * @param  int  $menuId  메뉴 ID
     * @param  string  $permissionType  권한 유형
     * @param  int|null  $tenantId  테넌트 ID
     * @return bool 토글 후 상태 (true: 허용, false: 거부)
     */
    public function togglePermission(int $roleId, int $menuId, string $permissionType, ?int $tenantId = null): bool
    {
        $permissionName = "menu:{$menuId}.{$permissionType}";

        // 권한 생성 또는 조회
        $permission = Permission::firstOrCreate(
            ['name' => $permissionName, 'guard_name' => 'web', 'tenant_id' => $tenantId],
            ['created_by' => auth()->id()]
        );

        // 현재 권한 상태 확인
        $exists = DB::table('role_has_permissions')
            ->where('role_id', $roleId)
            ->where('permission_id', $permission->id)
            ->exists();

        if ($exists) {
            // 권한 제거
            DB::table('role_has_permissions')
                ->where('role_id', $roleId)
                ->where('permission_id', $permission->id)
                ->delete();

            $newValue = false;
        } else {
            // 권한 부여
            DB::table('role_has_permissions')->insert([
                'role_id' => $roleId,
                'permission_id' => $permission->id,
            ]);

            $newValue = true;
        }

        // 하위 메뉴에 권한 전파
        $this->propagateToChildren($roleId, $menuId, $permissionType, $newValue, $tenantId);

        return $newValue;
    }

    /**
     * 하위 메뉴에 권한 전파
     *
     * @param  int  $roleId  역할 ID
     * @param  int  $parentMenuId  부모 메뉴 ID
     * @param  string  $permissionType  권한 유형
     * @param  bool  $value  권한 값 (true: 허용, false: 거부)
     * @param  int|null  $tenantId  테넌트 ID
     */
    protected function propagateToChildren(int $roleId, int $parentMenuId, string $permissionType, bool $value, ?int $tenantId = null): void
    {
        $children = Menu::where('parent_id', $parentMenuId)->get();

        foreach ($children as $child) {
            $permissionName = "menu:{$child->id}.{$permissionType}";
            $permission = Permission::firstOrCreate(
                ['name' => $permissionName, 'guard_name' => 'web', 'tenant_id' => $tenantId],
                ['created_by' => auth()->id()]
            );

            if ($value) {
                // 권한 부여
                $exists = DB::table('role_has_permissions')
                    ->where('role_id', $roleId)
                    ->where('permission_id', $permission->id)
                    ->exists();

                if (! $exists) {
                    DB::table('role_has_permissions')->insert([
                        'role_id' => $roleId,
                        'permission_id' => $permission->id,
                    ]);
                }
            } else {
                // 권한 제거
                DB::table('role_has_permissions')
                    ->where('role_id', $roleId)
                    ->where('permission_id', $permission->id)
                    ->delete();
            }

            // 재귀적으로 하위 메뉴 처리
            $this->propagateToChildren($roleId, $child->id, $permissionType, $value, $tenantId);
        }
    }

    /**
     * 모든 권한 허용
     *
     * @param  int  $roleId  역할 ID
     * @param  int|null  $tenantId  테넌트 ID
     */
    public function allowAllPermissions(int $roleId, ?int $tenantId = null): void
    {
        $query = Menu::where('is_active', 1);
        if ($tenantId) {
            $query->where('tenant_id', $tenantId);
        }
        $menus = $query->get();

        foreach ($menus as $menu) {
            foreach ($this->permissionTypes as $type) {
                $permissionName = "menu:{$menu->id}.{$type}";
                $permission = Permission::firstOrCreate(
                    ['name' => $permissionName, 'guard_name' => 'web', 'tenant_id' => $tenantId],
                    ['created_by' => auth()->id()]
                );

                // 권한 부여
                $exists = DB::table('role_has_permissions')
                    ->where('role_id', $roleId)
                    ->where('permission_id', $permission->id)
                    ->exists();

                if (! $exists) {
                    DB::table('role_has_permissions')->insert([
                        'role_id' => $roleId,
                        'permission_id' => $permission->id,
                    ]);
                }
            }
        }
    }

    /**
     * 모든 권한 거부
     *
     * @param  int  $roleId  역할 ID
     * @param  int|null  $tenantId  테넌트 ID
     */
    public function denyAllPermissions(int $roleId, ?int $tenantId = null): void
    {
        $query = Menu::where('is_active', 1);
        if ($tenantId) {
            $query->where('tenant_id', $tenantId);
        }
        $menus = $query->get();

        foreach ($menus as $menu) {
            foreach ($this->permissionTypes as $type) {
                $permissionName = "menu:{$menu->id}.{$type}";
                $permission = Permission::where('name', $permissionName)->first();

                if ($permission) {
                    DB::table('role_has_permissions')
                        ->where('role_id', $roleId)
                        ->where('permission_id', $permission->id)
                        ->delete();
                }
            }
        }
    }

    /**
     * 메뉴 트리 조회 (권한 매트릭스 표시용)
     *
     * @param  int|null  $tenantId  테넌트 ID
     * @return \Illuminate\Support\Collection 메뉴 트리
     */
    public function getMenuTree(?int $tenantId = null): \Illuminate\Support\Collection
    {
        $query = Menu::with('parent')
            ->where('is_active', 1);

        if ($tenantId) {
            $query->where('tenant_id', $tenantId);
        }

        $allMenus = $query->orderBy('sort_order', 'asc')
            ->orderBy('id', 'asc')
            ->get();

        // depth 계산하여 플랫한 구조로 변환
        return $this->flattenMenuTree($allMenus);
    }

    /**
     * 트리 구조를 플랫한 배열로 변환 (depth 정보 포함)
     *
     * @param  \Illuminate\Support\Collection  $menus  메뉴 컬렉션
     * @param  int|null  $parentId  부모 메뉴 ID
     * @param  int  $depth  현재 깊이
     * @return \Illuminate\Support\Collection
     */
    private function flattenMenuTree(\Illuminate\Support\Collection $menus, ?int $parentId = null, int $depth = 0): \Illuminate\Support\Collection
    {
        $result = collect();

        $filteredMenus = $menus->where('parent_id', $parentId)->sortBy('sort_order');

        foreach ($filteredMenus as $menu) {
            $menu->depth = $depth;

            // 자식 메뉴 존재 여부 확인
            $menu->has_children = $menus->where('parent_id', $menu->id)->count() > 0;

            $result->push($menu);

            // 자식 메뉴 재귀적으로 추가
            $children = $this->flattenMenuTree($menus, $menu->id, $depth + 1);
            $result = $result->merge($children);
        }

        return $result;
    }

    /**
     * 특정 역할의 활성 메뉴 권한 확인
     *
     * @param  int  $roleId  역할 ID
     * @param  int  $menuId  메뉴 ID
     * @param  string  $permissionType  권한 유형
     * @return bool 권한 존재 여부
     */
    public function hasPermission(int $roleId, int $menuId, string $permissionType): bool
    {
        $permissionName = "menu:{$menuId}.{$permissionType}";

        return DB::table('role_has_permissions')
            ->join('permissions', 'role_has_permissions.permission_id', '=', 'permissions.id')
            ->where('role_has_permissions.role_id', $roleId)
            ->where('permissions.name', $permissionName)
            ->exists();
    }
}