1 files changed, 105 insertions, 0 deletions
diff --git a/app/javascript/flavours/glitch/reducers/contexts.js b/app/javascript/flavours/glitch/reducers/contexts.js
new file mode 100644
index 000000000..aea77ae41
--- /dev/null
+++ b/app/javascript/flavours/glitch/reducers/contexts.js
@@ -0,0 +1,105 @@
+import {
+  ACCOUNT_BLOCK_SUCCESS,
+  ACCOUNT_MUTE_SUCCESS,
+} from 'flavours/glitch/actions/accounts';
+import { CONTEXT_FETCH_SUCCESS } from 'flavours/glitch/actions/statuses';
+import { TIMELINE_DELETE, TIMELINE_UPDATE } from 'flavours/glitch/actions/timelines';
+import { Map as ImmutableMap, List as ImmutableList } from 'immutable';
+import compareId from '../compare_id';
+
+const initialState = ImmutableMap({
+  inReplyTos: ImmutableMap(),
+  replies: ImmutableMap(),
+});
+
+const normalizeContext = (immutableState, id, ancestors, descendants) => immutableState.withMutations(state => {
+  state.update('inReplyTos', immutableAncestors => immutableAncestors.withMutations(inReplyTos => {
+    state.update('replies', immutableDescendants => immutableDescendants.withMutations(replies => {
+      function addReply({ id, in_reply_to_id }) {
+        if (in_reply_to_id && !inReplyTos.has(id)) {
+
+          replies.update(in_reply_to_id, ImmutableList(), siblings => {
+            const index = siblings.findLastIndex(sibling => compareId(sibling, id) < 0);
+            return siblings.insert(index + 1, id);
+          });
+
+          inReplyTos.set(id, in_reply_to_id);
+        }
+      }
+
+      // We know in_reply_to_id of statuses but `id` itself.
+      // So we assume that the status of the id replies to last ancestors.
+
+      ancestors.forEach(addReply);
+
+      if (ancestors[0]) {
+        addReply({ id, in_reply_to_id: ancestors[ancestors.length - 1].id });
+      }
+
+      descendants.forEach(addReply);
+    }));
+  }));
+});
+
+const deleteFromContexts = (immutableState, ids) => immutableState.withMutations(state => {
+  state.update('inReplyTos', immutableAncestors => immutableAncestors.withMutations(inReplyTos => {
+    state.update('replies', immutableDescendants => immutableDescendants.withMutations(replies => {
+      ids.forEach(id => {
+        const inReplyToIdOfId = inReplyTos.get(id);
+        const repliesOfId = replies.get(id);
+        const siblings = replies.get(inReplyToIdOfId);
+
+        if (siblings) {
+          replies.set(inReplyToIdOfId, siblings.filterNot(sibling => sibling === id));
+        }
+
+
+        if (repliesOfId) {
+          repliesOfId.forEach(reply => inReplyTos.delete(reply));
+        }
+
+        inReplyTos.delete(id);
+        replies.delete(id);
+      });
+    }));
+  }));
+});
+
+const filterContexts = (state, relationship, statuses) => {
+  const ownedStatusIds = statuses.filter(status => status.get('account') === relationship.id)
+    .map(status => status.get('id'));
+
+  return deleteFromContexts(state, ownedStatusIds);
+};
+
+const updateContext = (state, status) => {
+  if (status.in_reply_to_id) {
+    return state.withMutations(mutable => {
+      const replies = mutable.getIn(['replies', status.in_reply_to_id], ImmutableList());
+
+      mutable.setIn(['inReplyTos', status.id], status.in_reply_to_id);
+
+      if (!replies.includes(status.id)) {
+        mutable.setIn(['replies', status.in_reply_to_id], replies.push(status.id));
+      }
+    });
+  }
+
+  return state;
+};
+
+export default function replies(state = initialState, action) {
+  switch(action.type) {
+  case ACCOUNT_BLOCK_SUCCESS:
+  case ACCOUNT_MUTE_SUCCESS:
+    return filterContexts(state, action.relationship, action.statuses);
+  case CONTEXT_FETCH_SUCCESS:
+    return normalizeContext(state, action.id, action.ancestors, action.descendants);
+  case TIMELINE_DELETE:
+    return deleteFromContexts(state, [action.id]);
+  case TIMELINE_UPDATE:
+    return updateContext(state, action.status);
+  default:
+    return state;
+  }
+}