Refactor time splitter, support computing of dates for time entries

src/NodaTimeBeforeAfterIndicator.php

@@ -0,0 +1,67 @@
+<?PHP
+/**
+ * Represents a time indicator (CE / BCE).
+ *
+ * @author Joshua Ramon Enslin <joshua@museum-digital.de>
+ */
+declare(strict_types = 1);
+
+/**
+ * Represents a time indicator (CE / BCE).
+ */
+enum NodaTimeBeforeAfterIndicator implements JsonSerializable {
+
+    case none;
+    case after;
+    case before;
+    case since;
+    case until;
+
+    /**
+     * Returns a value of this type based on a string.
+     *
+     * @param string $input Input to get a value from.
+     *
+     * @return NodaTimeBeforeAfterIndicator
+     */
+    public static function fromString(string $input):NodaTimeBeforeAfterIndicator {
+
+        return match($input) {
+            '' => self::none,
+            'Nach' => self::after,
+            'Vor' => self::before,
+            'Seit' => self::since,
+            'Bis' => self::until,
+            default => throw new MDpageParameterNotFromListException("Unknown before / after indicator"),
+        };
+
+    }
+
+    /**
+     * Returns a canonical string representation.
+     *
+     * @return string
+     */
+    public function toString():string {
+
+        return match($this) {
+            self::none  => '',
+            self::after => 'Nach',
+            self::before => 'Vor',
+            self::since => 'Seit',
+            self::until => 'Bis',
+        };
+
+    }
+
+    /**
+     * Provides the option to serialize as a string during json_encode().
+     *
+     * @return string
+     */
+    public function jsonSerialize():string {
+
+        return $this->name;
+
+    }
+}