Fix completion in multi word commands

Fixes #150

spring-shell-core/src/main/java/org/springframework/shell/Shell.java

@@ -58,7 +58,8 @@ public class Shell implements CommandRegistry {
 	private final ResultHandler resultHandler;
 
 	/**
-	 * Marker object returned to signify that there was no input to turn into a command execution.
+	 * Marker object returned to signify that there was no input to turn into a command
+	 * execution.
 	 */
 	public static final Object NO_INPUT = new Object();
 
@@ -243,9 +244,12 @@ public class Shell implements CommandRegistry {
 	}
 
 	private List<CompletionProposal> commandsStartingWith(String prefix) {
+		// Workaround for https://github.com/spring-projects/spring-shell/issues/150
+		// (sadly, this ties this class to JLine somehow)
+		int lastWordStart = prefix.lastIndexOf(' ') + 1;
 		return methodTargets.entrySet().stream()
 				.filter(e -> e.getKey().startsWith(prefix))
-				.map(e -> toCommandProposal(e.getKey(), e.getValue()))
+				.map(e -> toCommandProposal(e.getKey().substring(lastWordStart), e.getValue()))
 				.collect(Collectors.toList());
 	}
 

spring-shell-core/src/test/java/org/springframework/shell/ShellTest.java

@@ -19,6 +19,8 @@ package org.springframework.shell;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
 
 import org.junit.Assert;
 import org.junit.Before;
@@ -31,6 +33,7 @@ import org.mockito.junit.MockitoJUnit;
 import org.mockito.junit.MockitoRule;
 import org.springframework.context.ApplicationContext;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.isA;
@@ -189,6 +192,53 @@ public class ShellTest {
 		shell.gatherMethodTargets();
 	}
 
+	@Test
+	public void commandNameCompletion() throws Exception {
+		shell.applicationContext = mock(ApplicationContext.class);
+		when(parameterResolver.supports(any())).thenReturn(true);
+		when(shell.applicationContext.getBeansOfType(MethodTargetRegistrar.class))
+				.thenReturn(Collections.singletonMap("foo", r -> {
+					r.register("hello world", MethodTarget.of("helloWorld", this, "hellow world"));
+					r.register("another command", MethodTarget.of("helloWorld", this, "another command"));
+				}));
+		shell.gatherMethodTargets();
+
+		// Invoke at very start
+		List<String> proposals = shell.complete(new CompletionContext(Arrays.asList(""), 0, "".length()))
+				.stream().map(CompletionProposal::value).collect(Collectors.toList());
+		assertThat(proposals).containsExactly("another command", "hello world");
+
+		// Invoke in middle of first word
+		proposals = shell.complete(new CompletionContext(Arrays.asList("hel"), 0, "hel".length()))
+				.stream().map(CompletionProposal::value).collect(Collectors.toList());
+		assertThat(proposals).containsExactly("hello world");
+
+		// Invoke at end of first word (no space after yet)
+		proposals = shell.complete(new CompletionContext(Arrays.asList("hello"), 0, "hello".length()))
+				.stream().map(CompletionProposal::value).collect(Collectors.toList());
+		assertThat(proposals).containsExactly("hello world");
+
+		// Invoke after first word / start of second word
+		proposals = shell.complete(new CompletionContext(Arrays.asList("hello", ""), 1, "".length()))
+				.stream().map(CompletionProposal::value).collect(Collectors.toList());
+		assertThat(proposals).containsExactly("world");
+
+		// Invoke in middle of second word
+		proposals = shell.complete(new CompletionContext(Arrays.asList("hello", "wo"), 1, "wo".length()))
+				.stream().map(CompletionProposal::value).collect(Collectors.toList());
+		assertThat(proposals).containsExactly("world");
+
+		// Invoke at end of whole command (no space after yet)
+		proposals = shell.complete(new CompletionContext(Arrays.asList("hello", "world"), 1, "world".length()))
+				.stream().map(CompletionProposal::value).collect(Collectors.toList());
+		assertThat(proposals).containsExactly("world");
+
+		// Invoke in middle of second word
+		proposals = shell.complete(new CompletionContext(Arrays.asList("hello", "world", ""), 2, "".length()))
+				.stream().map(CompletionProposal::value).collect(Collectors.toList());
+		assertThat(proposals).isEmpty();
+	}
+
 	private void helloWorld(String a) {
 		invoked = true;
 	}