From 9b38cb1a62ede4900fde4ba47a7b065db329e994 Mon Sep 17 00:00:00 2001
From: Owen Jacobson <owen@grimoire.ca>
Date: Tue, 1 Jul 2025 15:40:11 -0400
Subject: Rename "channel" to "conversation" throughout the client.

Existing client state, stored in local storage, is migrated to new keys (that mention "conversation" instead of "channel" where appropriate) the first time the client loads.
---
 ui/lib/state/local/conversations.svelte.js | 119 +++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 ui/lib/state/local/conversations.svelte.js

(limited to 'ui/lib/state/local/conversations.svelte.js')

diff --git a/ui/lib/state/local/conversations.svelte.js b/ui/lib/state/local/conversations.svelte.js
new file mode 100644
index 0000000..835c237
--- /dev/null
+++ b/ui/lib/state/local/conversations.svelte.js
@@ -0,0 +1,119 @@
+import { DateTime } from 'luxon';
+import { SvelteMap } from 'svelte/reactivity';
+
+import * as iter from '$lib/iterator.js';
+
+// Conversations were called "channels" in previous iterations. Support loading
+// data saved under that name to prevent the change from resetting everyone's
+// unread tracking.
+export const STORE_KEY_CHANNELS = 'pilcrow:channelsData';
+export const STORE_KEY_CONVERSATIONS = 'pilcrow:conversations';
+
+class Conversation {
+  draft = $state();
+  lastReadAt = $state(null);
+  scrollPosition = $state(null);
+
+  static fromStored({ draft, lastReadAt, scrollPosition }) {
+    return new Conversation({
+      draft,
+      lastReadAt: lastReadAt == null ? null : DateTime.fromISO(lastReadAt),
+      scrollPosition,
+    });
+  }
+
+  constructor({ draft = '', lastReadAt = null, scrollPosition = null } = {}) {
+    this.draft = draft;
+    this.lastReadAt = lastReadAt;
+    this.scrollPosition = scrollPosition;
+  }
+
+  toStored() {
+    const { draft, lastReadAt, scrollPosition } = this;
+    return {
+      draft,
+      lastReadAt: lastReadAt?.toISO(),
+      scrollPosition,
+    };
+  }
+}
+
+export class Conversations {
+  // Store conversationId -> { draft = '', lastReadAt = null, scrollPosition = null }
+  all = $state();
+
+  static fromLocalStorage() {
+    const stored =
+      localStorage.getItem(STORE_KEY_CONVERSATIONS) ?? localStorage.getItem(STORE_KEY_CHANNELS);
+    if (stored !== null) {
+      return Conversations.fromStored(JSON.parse(stored));
+    }
+    return Conversations.empty();
+  }
+
+  static fromStored(stored) {
+    const loaded = Object.keys(stored).map((conversationId) => [
+      conversationId,
+      Conversation.fromStored(stored[conversationId]),
+    ]);
+    const all = new SvelteMap(loaded);
+    return new Conversations({ all });
+  }
+
+  static empty() {
+    return new Conversations({ all: new SvelteMap() });
+  }
+
+  constructor({ all }) {
+    this.all = all;
+  }
+
+  conversation(conversationId) {
+    let conversation = this.all.get(conversationId);
+    if (conversation === undefined) {
+      conversation = new Conversation();
+      this.all.set(conversationId, conversation);
+    }
+    return conversation;
+  }
+
+  updateLastReadAt(conversationId, at) {
+    const conversation = this.conversation(conversationId);
+    // Do it this way, rather than with Math.max tricks, to avoid assignment
+    // when we don't need it, to minimize reactive changes:
+    if (conversation.lastReadAt === null || at > conversation.lastReadAt) {
+      conversation.lastReadAt = at;
+      this.save();
+    }
+  }
+
+  retainConversations(conversations) {
+    const conversationIds = conversations.map((conversation) => conversation.id);
+    const retain = new Set(conversationIds);
+    for (const conversationId of Array.from(this.all.keys())) {
+      if (!retain.has(conversationId)) {
+        this.all.delete(conversationId);
+      }
+    }
+    this.save();
+  }
+
+  toStored() {
+    return iter.reduce(
+      this.all.entries(),
+      (stored, [conversationId, conversation]) => ({
+        ...stored,
+        [conversationId]: conversation.toStored(),
+      }),
+      {},
+    );
+  }
+
+  save() {
+    let stored = this.toStored();
+    localStorage.setItem(STORE_KEY_CONVERSATIONS, JSON.stringify(stored));
+    // If we were able to save the data under `pilcrow:conversations`, then remove the old data;
+    // it is no longer needed and wouldn't be loaded anyways.
+    localStorage.removeItem(STORE_KEY_CHANNELS);
+  }
+}
-- 
cgit v1.2.3