add Tag->toSNBT

src/Tag/ByteArrayTag.php

@@ -75,4 +75,16 @@ protected function getValueString(): string
         }
         return $this->count() . " byte" . ($this->count() === 1 ? "" : "s") . " [" . implode(" ", $values) . "]";
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        $values = [];
+        foreach ($this->valueArray as $val) {
+            $values[] = $val . "b";
+        }
+        return "[B;" . implode(", ", $values) . "]";
+    }
 }

src/Tag/ByteTag.php

@@ -34,4 +34,12 @@ protected static function readContentRaw(Reader $reader, TagOptions $options): s
     {
         return $reader->getDeserializer()->readByte()->getRawData();
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return $this->value . "b";
+    }
 }

src/Tag/CompoundTag.php

@@ -413,4 +413,16 @@ function equals(Tag $tag): bool
         }
         return true;
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        $data = [];
+        foreach ($this->valueArray as $value) {
+            $data[] = json_encode($value->getName()) . ": " . $value->toSNBT();
+        }
+        return "{" . implode(", ", $data) . "}";
+    }
 }

src/Tag/DoubleTag.php

@@ -51,4 +51,12 @@ public function setValue(float $value): static
         $this->resetRawValue();
         return parent::setValue($value);
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return $this->value . "d";
+    }
 }

src/Tag/EndTag.php

@@ -64,4 +64,12 @@ function equals(Tag $tag): bool
     {
         return $tag->getType() === $this->getType();
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return "";
+    }
 }

src/Tag/FloatTag.php

@@ -51,4 +51,12 @@ public function setValue(float $value): static
         $this->resetRawValue();
         return parent::setValue($value);
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return $this->value . "f";
+    }
 }

src/Tag/IntArrayTag.php

@@ -59,4 +59,16 @@ protected function checkArrayKey($offset): bool
     {
         return is_int($offset);
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        $values = [];
+        foreach ($this->valueArray as $val) {
+            $values[] = $val;
+        }
+        return "[I;" . implode(", ", $values) . "]";
+    }
 }

src/Tag/IntTag.php

@@ -34,4 +34,12 @@ protected static function readContentRaw(Reader $reader, TagOptions $options): s
     {
         return $reader->getDeserializer()->readInt()->getRawData();
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return strval($this->value);
+    }
 }

src/Tag/ListTag.php

@@ -255,4 +255,16 @@ protected function getValueString(): string
         }
         return parent::getValueString();
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        $values = [];
+        foreach ($this->valueArray as $value) {
+            $values[] = $value->toSNBT();
+        }
+        return "[" . implode(", ", $values) . "]";
+    }
 }

src/Tag/LongArrayTag.php

@@ -88,4 +88,16 @@ protected function checkArrayKey($offset): bool
     {
         return is_int($offset);
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        $values = [];
+        foreach ($this->valueArray as $val) {
+            $values[] = $val . "L";
+        }
+        return "[L;" . implode(", ", $values) . "]";
+    }
 }

src/Tag/LongTag.php

@@ -53,4 +53,12 @@ public function setValue(int $value): static
         $this->resetRawValue();
         return parent::setValue($value);
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return $this->value . "L";
+    }
 }

src/Tag/ShortTag.php

@@ -34,4 +34,12 @@ protected static function readContentRaw(Reader $reader, TagOptions $options): s
     {
         return $reader->getDeserializer()->readShort()->getRawData();
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return $this->value . "s";
+    }
 }

src/Tag/StringTag.php

@@ -94,4 +94,12 @@ public function equals(Tag $tag): bool
         return $tag instanceof StringTag && $this->getType() === $tag->getType() &&
             $tag->getValue() === $this->getValue();
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function toSNBT(): string
+    {
+        return json_encode($this->value);
+    }
 }

src/Tag/Tag.php

@@ -233,11 +233,12 @@ public function write(Writer $writer): static
 
     /**
      * @param string $str
+     * @param int $width
      * @return string
      */
-    protected function indent(string $str): string
+    protected function indent(string $str, int $width = 2): string
     {
-        return "  " . str_replace("\n", "\n  ", $str);
+        return str_repeat(" ", $width) . str_replace("\n", "\n  ", $str);
     }
 
     /**
@@ -256,6 +257,14 @@ public function __toString(): string
         return $this->getTagTypeString() . "('" . ($this->getName() ?: "None") . "'): " . $this->getValueString();
     }
 
+    /**
+     * Convert tag to SNBT
+     * See https://minecraft.wiki/w/NBT_format#Conversion_to_SNBT
+     *
+     * @return string
+     */
+    abstract public function toSNBT(): string;
+
     /**
      * @param Tag $tag
      * @return bool