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import { DateTime } from 'luxon';
import { marked } from 'marked';
import DOMPurify from 'dompurify';
const RUN_COALESCE_MAX_INTERVAL = 10 /* min */ * 60 /* sec */ * 1000; /* ms */
export class Messages {
channels = $state({}); // Mapping<ChannelId, Message>
inChannel(channel) {
return this.channels[channel] || [];
}
addMessage(channel, id, { at, sender, body }) {
let parsedAt = DateTime.fromISO(at);
let renderedBody = DOMPurify.sanitize(marked.parse(body, { breaks: true }));
const message = { id, at: parsedAt, body, renderedBody };
// You might be thinking, can't this be
//
// let runs = (this.channels[channel] ||= []);
//
// Let me tell you, I thought that too. Javascript's semantics allow it. It
// didn't work - the first message in each channel was getting lost as the
// update to `this.channels` wasn't actually happening. I suspect this is
// due to the implementation of Svelte's `$state` rune, but I don't know it
// for sure.
//
// In any case, splitting the read and write up like this has the same
// semantics, and _works_. (This time, for sure!)
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);
}
}
this.channels[channel] = runs;
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;
}
}
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