Update Document

src/main/java/me/mrletsplay/shareclientcore/document/ArrayCharBag.java

@@ -26,6 +26,16 @@ public class ArrayCharBag implements CharBag {
 		return i;
 	}
 
+	@Override
+	public Char get(int index) {
+		return chars.get(index);
+	}
+
+	@Override
+	public int size() {
+		return chars.size();
+	}
+
 	@Override
 	public String toString() {
 		return chars.stream()

src/main/java/me/mrletsplay/shareclientcore/document/Char.java

@@ -1,3 +1,8 @@
 package me.mrletsplay.shareclientcore.document;
 
-public record Char(Identifier[] position, int lamport, String value) {}
+public record Char(Identifier[] position, int lamport, char value) {
+
+	public static final Char START_OF_DOCUMENT = new Char(new Identifier[] { new Identifier(1, 0) }, 0, '^');
+	public static final Char END_OF_DOCUMENT = new Char(new Identifier[] { new Identifier(Util.BASE - 1, 0) }, 0, '$');
+
+}

src/main/java/me/mrletsplay/shareclientcore/document/CharBag.java

@@ -20,4 +20,24 @@ public interface CharBag {
 	 */
 	public int remove(Char character);
 
+	/**
+	 * Finds the character at the given index and returns it
+	 * @param index The index of the character
+	 * @return The character
+	 */
+	public Char get(int index);
+
+	/**
+	 * Returns the number of chars in this bag
+	 * @return The number of chars
+	 */
+	public int size();
+
+	/**
+	 * Collects the chars in this bag ordered by their position into a string
+	 * @return A string containing the chars
+	 */
+	@Override
+	public String toString();
+
 }

src/main/java/me/mrletsplay/shareclientcore/document/Document.java

@@ -3,8 +3,39 @@ package me.mrletsplay.shareclientcore.document;
 public class Document {
 
 	private CharBag charBag;
+	private int site;
+	private int lamport;
 
-	public Document() {
+	public Document(int site) {
+		this.charBag = new ArrayCharBag();
+		charBag.add(Char.START_OF_DOCUMENT);
+		charBag.add(Char.END_OF_DOCUMENT);
+
+		this.site = site;
+	}
+
+	public void localInsert(int index, String str) {
+		if(index < 0 || index >= charBag.size() - 1) throw new IllegalArgumentException("Index out of bounds");
+
+		Char charBefore = charBag.get(index);
+		Char charAfter = charBag.get(index +1);
+
+		for(char c : str.toCharArray()) {
+			Identifier[] newPos = Util.generatePositionBetween(charBefore.position(), charAfter.position(), site);
+			lamport++;
+			Char ch = new Char(newPos, lamport, c);
+			charBag.add(ch);
+			charBefore = ch;
+		}
+	}
+
+	public CharBag getCharBag() {
+		return charBag;
+	}
+
+	public String getContents() {
+		String contents = charBag.toString();
+		return contents.substring(1, contents.length() - 1);
 	}
 
 }

src/main/java/me/mrletsplay/shareclientcore/document/Util.java

@@ -47,7 +47,7 @@ public class Util {
 			throw new RuntimeException("Invalid site order");
 		}
 
-		return null;
+		return newPosition.toArray(Identifier[]::new);
 	}
 
 	public static int[] getIncremented(Identifier[] before, Identifier[] after, int offset) {

src/test/java/me/mrletsplay/shareclientcore/DocumentTest.java

@@ -0,0 +1,31 @@
+package me.mrletsplay.shareclientcore;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+import me.mrletsplay.shareclientcore.document.Document;
+
+public class DocumentTest {
+
+	@Test
+	public void testLocalInsert() {
+		Document doc = new Document(1);
+		doc.localInsert(0, "Hello");
+		assertEquals("Hello", doc.getContents());
+		doc.localInsert(5, " World");
+		assertEquals("Hello World", doc.getContents());
+		doc.localInsert(5, " Test");
+		assertEquals("Hello Test World", doc.getContents());
+	}
+
+	@Test
+	public void testLocalInsertInvalidIndexFails() {
+		Document doc = new Document(1);
+		doc.localInsert(0, "Hello");
+		assertThrows(IllegalArgumentException.class, () -> doc.localInsert(-1, "Test"));
+		assertThrows(IllegalArgumentException.class, () -> doc.localInsert(6, "Test"));
+	}
+
+}