Misc Changes

app/src/main/java/solutions/tretter/githugandroid/levels/RevertLevel.kt

@@ -0,0 +1,21 @@
+package solutions.tretter.githugandroid
+
+/**
+ * Port of the upstream ruby-githug `revert` level.
+ *
+ * Setup documents the repository shape the learner explores. Evaluation is kept
+ * state-based whenever the exercise changes repository objects; answer-only
+ * levels intentionally validate the answer entered at the prompt.
+ */
+internal fun revertLevel(): Level = level(
+    id = "revert",
+    title = "Revert",
+    description = "You have committed several times but want to undo the middle commit. All commits have been pushed, so you can't change existing history.",
+    hints = listOf("Try the revert command."),
+    commandSuggestions = listOf("git revert HEAD~1"),
+    setup = { RepoState(initialized = true, commits = listOf(CommitNode("1", "First commit"), CommitNode("2", "Bad commit"), CommitNode("3", "Second commit")), branches = mapOf("master" to 3), pushedBranches = setOf("origin/master")) },
+    validator = repoPredicate { repo -> repo.commits.any { it.message.startsWith("Revert") } },
+    testCases = listOf(
+        levelTestCase("revert middle commit", "git revert HEAD~1"),
+    ),
+)