#789: implement uninstall of IDEasy

cli/src/main/java/com/devonfw/tools/ide/commandlet/UninstallCommandlet.java

@@ -2,6 +2,7 @@
 
 import com.devonfw.tools.ide.context.IdeContext;
 import com.devonfw.tools.ide.property.ToolProperty;
+import com.devonfw.tools.ide.tool.IdeasyCommandlet;
 import com.devonfw.tools.ide.tool.ToolCommandlet;
 
 /**
@@ -21,7 +22,7 @@ public UninstallCommandlet(IdeContext context) {
 
     super(context);
     addKeyword(getName());
-    this.tools = add(new ToolProperty("", true, true, "tool"));
+    this.tools = add(new ToolProperty("", false, true, "tool"));
   }
 
   @Override
@@ -30,10 +31,27 @@ public String getName() {
     return "uninstall";
   }
 
+  @Override
+  public boolean isIdeRootRequired() {
+
+    return this.tools.getValueCount() > 0;
+  }
+
   @Override
   public void run() {
 
-    for (int i = 0; i < this.tools.getValueCount(); i++) {
+    int valueCount = this.tools.getValueCount();
+    if (valueCount == 0) {
+      if (!this.context.isForceMode()) {
+        this.context.askToContinue("Sub-command uninstall without any further arguments will perform the entire uninstallation of IDEasy.\n"
+            + "Since this is typically not to be called manually, you may have forgotten to specify the tool to install as extra argument.\n"
+            + "The current command will uninstall IDEasy from your computer. Are you sure?");
+      }
+      IdeasyCommandlet ideasy = new IdeasyCommandlet(this.context);
+      ideasy.uninstallIdeasy();
+      return;
+    }
+    for (int i = 0; i < valueCount; i++) {
       ToolCommandlet toolCommandlet = this.tools.getValue(i);
       if (toolCommandlet.getInstalledVersion() != null) {
         toolCommandlet.uninstall();

cli/src/main/java/com/devonfw/tools/ide/common/SimpleSystemPath.java

@@ -0,0 +1,85 @@
+package com.devonfw.tools.ide.common;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.function.Predicate;
+
+/**
+ * Represents the PATH variable in a structured way. Similar to {@link SystemPath} but much simper: It just tokenizes the PATH into a {@link java.util.List} of
+ * {@link String}s.
+ */
+public class SimpleSystemPath {
+
+  private final char separator;
+
+  private final List<String> entries;
+
+  private SimpleSystemPath(char separator, List<String> entries) {
+
+    super();
+    this.separator = separator;
+    this.entries = entries;
+  }
+
+  /**
+   * @return the entries of this PATH as a mutable {@link List}.
+   */
+  public List<String> getEntries() {
+
+    return this.entries;
+  }
+
+  /**
+   * Remove all entries from this PATH that match the given {@link Predicate}.
+   *
+   * @param filter the {@link Predicate} {@link Predicate#test(Object) deciding} what to filter and remove.
+   */
+  public void removeEntries(Predicate<String> filter) {
+
+    Iterator<String> iterator = this.entries.iterator();
+    while (iterator.hasNext()) {
+      String entry = iterator.next();
+      if (filter.test(entry)) {
+        iterator.remove();
+      }
+    }
+  }
+
+  @Override
+  public String toString() {
+
+    StringBuilder sb = new StringBuilder();
+    boolean first = true;
+    for (String entry : this.entries) {
+      if (first) {
+        first = false;
+      } else {
+        sb.append(this.separator);
+      }
+      sb.append(entry);
+    }
+    return sb.toString();
+  }
+
+  /**
+   * @param path the entire PATH as {@link String},
+   * @param separator the separator character.
+   * @return the {@link SimpleSystemPath}.
+   */
+  public static SimpleSystemPath of(String path, char separator) {
+
+    List<String> entries = new ArrayList<>();
+    int start = 0;
+    int len = path.length();
+    while (start < len) {
+      int end = path.indexOf(separator, start);
+      if (end < 0) {
+        end = len;
+      }
+      entries.add(path.substring(start, end));
+      start = end + 1;
+    }
+    return new SimpleSystemPath(separator, entries);
+  }
+}

cli/src/main/java/com/devonfw/tools/ide/os/WindowsHelper.java

@@ -14,6 +14,11 @@ public interface WindowsHelper {
    */
   void setUserEnvironmentValue(String key, String value);
 
+  /**
+   * @param key the name of the environment variable to remove.
+   */
+  void removeUserEnvironmentValue(String key);
+
   /**
    * @param key the name of the environment variable.
    * @return the value of the environment variable in the users context.

cli/src/main/java/com/devonfw/tools/ide/os/WindowsHelperImpl.java

@@ -3,6 +3,7 @@
 import java.util.List;
 
 import com.devonfw.tools.ide.context.IdeContext;
+import com.devonfw.tools.ide.log.IdeLogLevel;
 import com.devonfw.tools.ide.process.ProcessMode;
 import com.devonfw.tools.ide.process.ProcessResult;
 
@@ -33,6 +34,16 @@ public void setUserEnvironmentValue(String key, String value) {
     assert (result.isSuccessful());
   }
 
+  @Override
+  public void removeUserEnvironmentValue(String key) {
+    ProcessResult result = this.context.newProcess().executable("reg").addArgs("delete", HKCU_ENVIRONMENT, "/v", key, "/f").run(ProcessMode.DEFAULT_CAPTURE);
+    if (result.isSuccessful()) {
+      this.context.debug("Removed environment variable {}", key);
+    } else {
+      result.log(IdeLogLevel.WARNING, this.context);
+    }
+  }
+
   @Override
   public String getUserEnvironmentValue(String key) {