Split message runs after ten minutes' silence.

I've also refactored how runs are processed, to avoid re-splitting runs every time the channel view is rendered. They're generated when messages are ingested into the `$messages` store, instead.

1 files changed, 59 insertions, 0 deletions

diff --git a/ui/lib/store/messages.svelte.js b/ui/lib/store/messages.svelte.js
new file mode 100644
index 0000000..1c59599
--- /dev/null
+++ b/ui/lib/store/messages.svelte.js
@@ -0,0 +1,59 @@
+const RUN_COALESCE_MAX_INTERVAL = 10 /* min */ * 60 /* sec */ * 1000; /* ms */
+
+export class Messages {
+  channels = $state({});
+
+  inChannel(channel) {
+    return this.channels[channel];
+  }
+
+  addMessage(channel, id, at, sender, body) {
+    let parsedAt = new Date(at);
+    const message = { id, at: parsedAt, body };
+
+    let runs = (this.channels[channel] ||= []);
+    let currentRun = runs.slice(-1)[0];
+    if (currentRun === undefined) {
+      currentRun = { sender, messages: [message] };
+      runs.push(currentRun);
+    } else {
+      let lastMessage = currentRun.messages.slice(-1)[0];
+      let newRun =
+        currentRun.sender !== sender || parsedAt - lastMessage.at > RUN_COALESCE_MAX_INTERVAL;
+
+      if (newRun) {
+        currentRun = { sender, messages: [message] };
+        runs.push(currentRun);
+      } else {
+        currentRun.messages.push(message);
+      }
+    }
+
+    return this;
+  }
+
+  setMessages(messages) {
+    this.channels = {};
+    for (let { channel, id, at, sender, body } of messages) {
+      this.addMessage(channel, id, at, sender, body);
+    }
+    return this;
+  }
+
+  deleteMessage(messageId) {
+    for (let channel in this.channels) {
+      this.channels[channel] = this.channels[channel]
+        .map(({ sender, messages }) => ({
+          sender,
+          messages: messages.filter(({ id }) => id != messageId)
+        }))
+        .filter(({ messages }) => messages.length > 0);
+    }
+    return this;
+  }
+
+  deleteChannel(id) {
+    delete this.channels[id];
+    return this;
+  }
+}