snort/src/Nostr/Thread.ts

import { u256 } from "Nostr";
import { default as NEvent } from "Nostr/Event";
import EventKind from "Nostr/EventKind";
import Tag from "Nostr/Tag";

export default class Thread {
    Root?: Tag;
    ReplyTo?: Tag;
    Mentions: Array<Tag>;
    PubKeys: Array<u256>;

    constructor() {
        this.Mentions = [];
        this.PubKeys = [];
    }

    /**
     * Extract thread information from an Event
     * @param ev Event to extract thread from
     */
    static ExtractThread(ev: NEvent) {
        let isThread = ev.Tags.some(a => a.Key === "e");
        if (!isThread) {
            return null;
        }

        let shouldWriteMarkers = ev.Kind === EventKind.TextNote;
        let ret = new Thread();
        let eTags = ev.Tags.filter(a => a.Key === "e");
        let marked = eTags.some(a => a.Marker !== undefined);
        if (!marked) {
            ret.Root = eTags[0];
            ret.Root.Marker = shouldWriteMarkers ? "root" : undefined;
            if (eTags.length > 1) {
                ret.ReplyTo = eTags[1];
                ret.ReplyTo.Marker = shouldWriteMarkers ? "reply" : undefined;
            }
            if (eTags.length > 2) {
                ret.Mentions = eTags.slice(2);
                if (shouldWriteMarkers) {
                    ret.Mentions.forEach(a => a.Marker = "mention");
                }
            }
        } else {
            let root = eTags.find(a => a.Marker === "root");
            let reply = eTags.find(a => a.Marker === "reply");
            ret.Root = root;
            ret.ReplyTo = reply;
            ret.Mentions = eTags.filter(a => a.Marker === "mention");
        }
        ret.PubKeys = Array.from(new Set(ev.Tags.filter(a => a.Key === "p").map(a => <u256>a.PubKey)));
        return ret;
    }
}