1 files changed, 85 insertions, 0 deletions
diff --git a/app/assets/javascripts/ide/lib/create_diff.js b/app/assets/javascripts/ide/lib/create_diff.js
new file mode 100644
index 00000000000..3e915afdbcb
--- /dev/null
+++ b/app/assets/javascripts/ide/lib/create_diff.js
@@ -0,0 +1,85 @@
+import { commitActionForFile } from '~/ide/stores/utils';
+import { commitActionTypes } from '~/ide/constants';
+import createFileDiff from './create_file_diff';
+
+const getDeletedParents = (entries, file) => {
+  const parent = file.parentPath && entries[file.parentPath];
+
+  if (parent && parent.deleted) {
+    return [parent, ...getDeletedParents(entries, parent)];
+  }
+
+  return [];
+};
+
+const filesWithChanges = ({ stagedFiles = [], changedFiles = [], entries = {} }) => {
+  // We need changed files to overwrite staged, so put them at the end.
+  const changes = stagedFiles.concat(changedFiles).reduce((acc, file) => {
+    const key = file.path;
+    const action = commitActionForFile(file);
+    const prev = acc[key];
+
+    // If a file was deleted, which was previously added, then we should do nothing.
+    if (action === commitActionTypes.delete && prev && prev.action === commitActionTypes.create) {
+      delete acc[key];
+    } else {
+      acc[key] = { action, file };
+    }
+
+    return acc;
+  }, {});
+
+  // We need to clean "move" actions, because we can only support 100% similarity moves at the moment.
+  // This is because the previous file's content might not be loaded.
+  Object.values(changes)
+    .filter(change => change.action === commitActionTypes.move)
+    .forEach(change => {
+      const prev = changes[change.file.prevPath];
+
+      if (!prev) {
+        return;
+      }
+
+      if (change.file.content === prev.file.content) {
+        // If content is the same, continue with the move but don't do the prevPath's delete.
+        delete changes[change.file.prevPath];
+      } else {
+        // Otherwise, treat the move as a delete / create.
+        Object.assign(change, { action: commitActionTypes.create });
+      }
+    });
+
+  // Next, we need to add deleted directories by looking at the parents
+  Object.values(changes)
+    .filter(change => change.action === commitActionTypes.delete && change.file.parentPath)
+    .forEach(({ file }) => {
+      // Do nothing if we've already visited this directory.
+      if (changes[file.parentPath]) {
+        return;
+      }
+
+      getDeletedParents(entries, file).forEach(parent => {
+        changes[parent.path] = { action: commitActionTypes.delete, file: parent };
+      });
+    });
+
+  return Object.values(changes);
+};
+
+const createDiff = state => {
+  const changes = filesWithChanges(state);
+
+  const toDelete = changes.filter(x => x.action === commitActionTypes.delete).map(x => x.file.path);
+
+  const patch = changes
+    .filter(x => x.action !== commitActionTypes.delete)
+    .map(({ file, action }) => createFileDiff(file, action))
+    .join('');
+
+  return {
+    patch,
+    toDelete,
+  };
+};
+
+export default createDiff;