1 files changed, 140 insertions, 0 deletions
diff --git a/www/crm/wp-content/plugins/civicrm/civicrm/ext/api4/Civi/Api4/Service/Schema/SchemaMap.php b/www/crm/wp-content/plugins/civicrm/civicrm/ext/api4/Civi/Api4/Service/Schema/SchemaMap.php
new file mode 100644
index 00000000..3989afeb
--- /dev/null
+++ b/www/crm/wp-content/plugins/civicrm/civicrm/ext/api4/Civi/Api4/Service/Schema/SchemaMap.php
@@ -0,0 +1,140 @@
+<?php
+
+namespace Civi\Api4\Service\Schema;
+
+use Civi\Api4\Service\Schema\Joinable\BridgeJoinable;
+use Civi\Api4\Service\Schema\Joinable\Joinable;
+
+class SchemaMap {
+
+  const MAX_JOIN_DEPTH = 3;
+
+  /**
+   * @var Table[]
+   */
+  protected $tables = [];
+
+  /**
+   * @param $baseTableName
+   * @param $targetTableAlias
+   *
+   * @return Joinable[]
+   *   Array of links to the target table, empty if no path found
+   */
+  public function getPath($baseTableName, $targetTableAlias) {
+    $table = $this->getTableByName($baseTableName);
+    $path = [];
+
+    if (!$table) {
+      return $path;
+    }
+
+    $this->findPaths($table, $targetTableAlias, 1, $path);
+
+    foreach ($path as $index => $pathLink) {
+      if ($pathLink instanceof BridgeJoinable) {
+        $start = array_slice($path, 0, $index);
+        $middle = [$pathLink->getMiddleLink()];
+        $end = array_slice($path, $index, count($path) - $index);
+        $path = array_merge($start, $middle, $end);
+      }
+    }
+
+    return $path;
+  }
+
+  /**
+   * @return Table[]
+   */
+  public function getTables() {
+    return $this->tables;
+  }
+
+  /**
+   * @param $name
+   *
+   * @return Table|null
+   */
+  public function getTableByName($name) {
+    foreach ($this->tables as $table) {
+      if ($table->getName() === $name) {
+        return $table;
+      }
+    }
+
+    return NULL;
+  }
+
+  /**
+   * Adds a table to the schema map if it has not already been added
+   *
+   * @param Table $table
+   *
+   * @return $this
+   */
+  public function addTable(Table $table) {
+    if (!$this->getTableByName($table->getName())) {
+      $this->tables[] = $table;
+    }
+
+    return $this;
+  }
+
+  /**
+   * @param array $tables
+   */
+  public function addTables(array $tables) {
+    foreach ($tables as $table) {
+      $this->addTable($table);
+    }
+  }
+
+  /**
+   * Recursive function to traverse the schema looking for a path
+   *
+   * @param Table $table
+   *   The current table to base fromm
+   * @param string $target
+   *   The target joinable table alias
+   * @param int $depth
+   *   The current level of recursion which reflects the number of joins needed
+   * @param Joinable[] $path
+   *   (By-reference) The possible paths to the target table
+   * @param Joinable[] $currentPath
+   *   For internal use only to track the path to reach the target table
+   */
+  private function findPaths(Table $table, $target, $depth, &$path, $currentPath = []
+  ) {
+    static $visited = [];
+
+    // reset if new call
+    if ($depth === 1) {
+      $visited = [];
+    }
+
+    $canBeShorter = empty($path) || count($currentPath) + 1 < count($path);
+    $tooFar = $depth > self::MAX_JOIN_DEPTH;
+    $beenHere = in_array($table->getName(), $visited);
+
+    if ($tooFar || $beenHere || !$canBeShorter) {
+      return;
+    }
+
+    // prevent circular reference
+    $visited[] = $table->getName();
+
+    foreach ($table->getExternalLinks() as $link) {
+      if ($link->getAlias() === $target) {
+        $path = array_merge($currentPath, [$link]);
+      }
+      else {
+        $linkTable = $this->getTableByName($link->getTargetTable());
+        if ($linkTable) {
+          $nextStep = array_merge($currentPath, [$link]);
+          $this->findPaths($linkTable, $target, $depth + 1, $path, $nextStep);
+        }
+      }
+    }
+  }
+
+}