Adds EventContext

src/EventContext.php

@@ -0,0 +1,152 @@
+<?php
+declare(strict_types=1);
+
+namespace LotGD\Core;
+use LotGD\Core\Exceptions\ArgumentException;
+
+
+/**
+ * Class EventContext
+ * @package LotGD\Core
+ * @immutable
+ */
+class EventContext
+{
+    private $matchingPattern;
+    private $event;
+    private $data;
+
+    /**
+     * EventContext constructor.
+     * @param string $event The published event
+     * @param string $matchingPattern The matching pattern
+     * @param array $data
+     */
+    public function __construct(
+        string $event,
+        string $matchingPattern,
+        array $data
+    ) {
+        $this->event = $event;
+        $this->matchingPattern = $matchingPattern;
+        $this->data = $data;
+    }
+
+    /**
+     * Returns the event of this context.
+     * @return string
+     */
+    public function getEvent(): string
+    {
+        return $this->event;
+    }
+
+    /**
+     * Returns the matching pattern of this context.
+     * @return string
+     */
+    public function getMatchingPattern(): string
+    {
+        return $this->matchingPattern;
+    }
+
+    /**
+     * Returns a list of fields in this context
+     * @return array
+     */
+    public function getListOfFields(): array
+    {
+        return array_keys($this->data);
+    }
+
+    /**
+     * Returns a comma separated string with all allowed fields, for debugging reasons.
+     * @return string
+     */
+    private function getFormattedListOfFields(): string
+    {
+        return substr(
+            implode(", ", $this->getListOfFields()),
+            0,
+            -2
+        );
+    }
+
+    /**
+     * Sets a field and returns the changed object.
+     * @param $field
+     * @param $value
+     * @return EventContext
+     */
+    public function setField($field, $value): self
+    {
+        if ($this->hasField($field)) {
+            $data = $this->data;
+            $data[$field] = $value;
+        } else {
+            $this->throwException($field);
+        }
+
+        return new static($this->event, $this->matchingPattern, $data);
+    }
+
+    /**
+     * Sets multiple fields at once and returns the changed object.
+     * @param $data array of field => value
+     * @return EventContext
+     */
+    public function setFields($data): self
+    {
+        $oldData = $this->data;
+
+        foreach ($data as $key => $value) {
+            if ($this->hasField($field)) {
+                $oldData[$key] = $value;
+            } else {
+                $this->throwException($field);
+            }
+        }
+
+        return new static($this->event, $this->matchingPattern, $oldData);
+    }
+
+    /**
+     * Returns the data to a field.
+     * @param $field
+     * @return mixed
+     */
+    public function getField($field)
+    {
+        if ($this->hasField($field)) {
+            return $this->data[$field];
+        } else {
+            $this->throwException($field);
+        }
+    }
+
+    /**
+     * Returns true if the context has a specific field.
+     * @param $field
+     * @return bool
+     */
+    public function hasField($field)
+    {
+        if (isset($this->data[$field])) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * internal use only - throws an ArgumentException a field is given that's not valid.
+     * @param $field
+     * @throws ArgumentException
+     */
+    private function throwException($field)
+    {
+        throw new ArgumentException(
+            "{$field} is not valid in this context, only {$this->getFormattedListOfFields()} are allowed."
+        );
+    }
+}