import { Brackets } from "typeorm";
import { fetchMeta } from "./fetch-meta.js";
import { Instances } from "../models/index.js";
import { DAY } from "../const.js";
import { shouldBlockInstance } from "./should-block-instance.js";
// Threshold from last contact after which an instance will be considered
// "dead" and should no longer get activities delivered to it.
const deadThreshold = 7 * DAY;
/**
 * Returns the subset of hosts which should be skipped.
 *
 * @param hosts array of punycoded instance hosts
 * @returns array of punycoed instance hosts that should be skipped (subset of hosts parameter)
 */ export async function skippedInstances(hosts) {
    // first check for blocked instances since that info may already be in memory
    const meta = await fetchMeta();
    const shouldSkip = await Promise.all(hosts.map((host)=>shouldBlockInstance(host, meta)));
    const skipped = hosts.filter((_, i)=>shouldSkip[i]);
    // if possible return early and skip accessing the database
    if (skipped.length === hosts.length) return hosts;
    const deadTime = new Date(Date.now() - deadThreshold);
    return skipped.concat(await Instances.createQueryBuilder("instance").where("instance.host in (:...hosts)", {
        // don't check hosts again that we already know are suspended
        // also avoids adding duplicates to the list
        hosts: hosts.filter((host)=>!skipped.includes(host))
    }).andWhere(new Brackets((qb)=>{
        qb.where("instance.isSuspended").orWhere(new Brackets((qb)=>{
            qb.where("instance.isNotResponding").andWhere("instance.lastCommunicatedAt < :deadTime", {
                deadTime
            });
        }));
    })).select("host").getRawMany());
}
/**
 * Returns whether a specific host (punycoded) should be skipped.
 * Convenience wrapper around skippedInstances which should only be used if there is a single host to check.
 * If you have multiple hosts, consider using skippedInstances instead to do a bulk check.
 *
 * @param host punycoded instance host
 * @returns whether the given host should be skipped
 */ export async function shouldSkipInstance(host) {
    const skipped = await skippedInstances([
        host
    ]);
    return skipped.length > 0;
}
