From 3de02566bf199f3a49fcfe2b2d4119a287eb26bb Mon Sep 17 00:00:00 2001
From: Dan Brown <ssddanbrown@googlemail.com>
Date: Wed, 19 May 2021 23:37:23 +0100
Subject: [PATCH] Started building system for cross-model queries

---
 app/Auth/Permissions/PermissionService.php    |   3 +-
 .../Tools/RelationMultiModelQuery.php         | 154 ++++++++++++++++++
 2 files changed, 156 insertions(+), 1 deletion(-)
 create mode 100644 app/Entities/Tools/RelationMultiModelQuery.php

diff --git a/app/Auth/Permissions/PermissionService.php b/app/Auth/Permissions/PermissionService.php
index c5bdc8070..1c82f8e08 100644
--- a/app/Auth/Permissions/PermissionService.php
+++ b/app/Auth/Permissions/PermissionService.php
@@ -580,8 +580,9 @@ class PermissionService
 
     /**
      * Filter items that have entities set as a polymorphic relation.
+     * @param Builder|\Illuminate\Database\Query\Builder $query
      */
-    public function filterRestrictedEntityRelations(Builder $query, string $tableName, string $entityIdColumn, string $entityTypeColumn, string $action = 'view'): Builder
+    public function filterRestrictedEntityRelations($query, string $tableName, string $entityIdColumn, string $entityTypeColumn, string $action = 'view')
     {
         $tableDetails = ['tableName' => $tableName, 'entityIdColumn' => $entityIdColumn, 'entityTypeColumn' => $entityTypeColumn];
 
diff --git a/app/Entities/Tools/RelationMultiModelQuery.php b/app/Entities/Tools/RelationMultiModelQuery.php
new file mode 100644
index 000000000..68a90acd0
--- /dev/null
+++ b/app/Entities/Tools/RelationMultiModelQuery.php
@@ -0,0 +1,154 @@
+<?php namespace BookStack\Entities\Tools;
+
+use BookStack\Auth\Permissions\PermissionService;
+use BookStack\Entities\Models\Book;
+use BookStack\Entities\Models\Bookshelf;
+use BookStack\Entities\Models\Chapter;
+use BookStack\Entities\Models\Entity;
+use BookStack\Entities\Models\Page;
+use BookStack\Model;
+use Illuminate\Database\Query\Builder;
+use Illuminate\Database\Query\JoinClause;
+use Illuminate\Support\Collection;
+
+/**
+ * Create a query for a polymorphic relation
+ * that looks up all entity models in a single query
+ * returning a collection or various hydrated models.
+ */
+class RelationMultiModelQuery
+{
+
+    // TODO - Hydrate results to models
+    // TODO - Allow setting additional wheres and all-model columns (From the core relation - eg, last_viewed_at)
+
+//select views.updated_at as last_viewed_at,
+//b.id as book_id, b.name as book_name, b.slug as book_slug, b.description as book_description,
+//s.id as bookshelf_id, s.name as bookshelf_name, s.slug as bookshelf_slug, s.description as bookshelf_description,
+//c.id as chapter_id, c.name as chapter_name, c.slug as chapter_slug, c.description as chapter_description,
+//p.id as page_id, p.name as page_name, p.slug as page_slug, p.text as page_description
+//from views
+//left join bookshelves s on (s.id = views.viewable_id and views.viewable_type = 'BookStack\\Bookshelf' and s.deleted_at is null)
+//left join books b on (b.id = views.viewable_id and views.viewable_type = 'BookStack\\Book' and b.deleted_at is null)
+//left join chapters c on (c.id = views.viewable_id and views.viewable_type = 'BookStack\\Chapter' and c.deleted_at is null)
+//left join pages p on (p.id = views.viewable_id and views.viewable_type = 'BookStack\\Page' and p.deleted_at is null)
+//#     Permissions
+//where exists(
+//select * from joint_permissions jp where jp.entity_id = views.viewable_id and jp.entity_type = views.viewable_type
+//and jp.action = 'view' and jp.role_id in (1, 2, 3, 6, 12) and (jp.has_permission = 1 or (jp.has_permission_own = 1 and jp.owned_by = 1))
+//)
+//and (s.id is not null or b.id is not null or c.id is not null or p.id is not null)
+//and views.user_id = 1
+
+    /** @var array<string, array> */
+    protected $lookupModels = [];
+
+    /** @var Model */
+    protected $relation;
+
+    /** @var string */
+    protected $polymorphicFieldName;
+
+    public function __construct(Model $relation, string $polymorphicFieldName)
+    {
+        $this->relation = $relation;
+        $this->polymorphicFieldName = $polymorphicFieldName;
+    }
+
+    /**
+     * Set the query to look up the given entity type.
+     */
+    public function forEntity(string $class, array $columns): self
+    {
+        $this->lookupModels[$class] = $columns;
+        return $this;
+    }
+
+    /**
+     * Set the query to look up all entity types.
+     */
+    public function forAllEntities(): self
+    {
+        $this->lookupModels[Page::class] = ['id', 'name', 'slug', 'book_id', 'chapter_id', 'text'];
+        $this->lookupModels[Chapter::class] = ['id', 'name', 'slug', 'book_id', 'description'];
+        $this->lookupModels[Book::class] = ['id', 'name', 'slug', 'description', 'image_id'];
+        $this->lookupModels[Bookshelf::class] = ['id', 'name', 'slug', 'description', 'image_id'];
+        return $this;
+    }
+
+    /**
+     * Build the core query to run.
+     */
+    protected function build(): Builder
+    {
+        $query = $this->relation->newQuery()->toBase();
+        $relationTable = $this->relation->getTable();
+        $modelTables = [];
+
+        // Load model selects & joins
+        foreach ($this->lookupModels as $lookupModel => $columns) {
+            /** @var Entity $model */
+            $model = (new $lookupModel);
+            $table = $model->getTable();
+            $modelTables[] = $table;
+            $query->addSelect($this->tableColumnsToSelectArray($table, $columns));
+            $query->leftJoin($table, function (JoinClause $join) use ($table, $relationTable, $model) {
+                $polyPrefix = $relationTable . '.' . $this->polymorphicFieldName;
+                $join->on($polyPrefix . '_id', '=', $table . '.id');
+                $join->where($polyPrefix . '_type', '=', $model->getMorphClass());
+                $join->whereNull($table . '.deleted_at');
+            });
+        }
+
+        // Where we have a model result
+        $query->where(function (Builder $query) use ($modelTables) {
+            foreach ($modelTables as $table) {
+                $query->orWhereNotNull($table . '.id');
+            }
+        });
+
+        $this->applyPermissionsToQuery($query, 'view');
+
+        return $query;
+    }
+
+    protected function applyPermissionsToQuery(Builder $query, string $action)
+    {
+        $permissions = app()->make(PermissionService::class);
+        $permissions->filterRestrictedEntityRelations(
+            $query,
+            $this->relation->getTable(),
+            $this->polymorphicFieldName . '_id',
+            $this->polymorphicFieldName . '_type',
+            $action,
+        );
+    }
+
+    /**
+     * Create an array of select statements from the given table and column.
+     */
+    protected function tableColumnsToSelectArray(string $table, array $columns): array
+    {
+        $selectArray = [];
+        foreach ($columns as $column) {
+            $selectArray[] = $table . '.' . $column . ' as '.  $table . '_' . $column;
+        }
+        return $selectArray;
+    }
+
+    /**
+     * Get the SQL from the core query being ran.
+     */
+    public function toSql(): string
+    {
+        return $this->build()->toSql();
+    }
+
+    /**
+     * Run the query and get the results.
+     */
+    public function run(): Collection
+    {
+        return $this->build()->get();
+    }
+}
\ No newline at end of file