/* eslint-disable @typescript-eslint/require-await */
import { ShortChannelId } from "@node-lightning/core";
import { shortChannelIdFromNumber } from "@node-lightning/core";
import { OutPoint } from "@node-lightning/core";
import { ChannelAnnouncementMessage } from "../messages/ChannelAnnouncementMessage";
import { ChannelUpdateMessage } from "../messages/ChannelUpdateMessage";
import { ExtendedChannelAnnouncementMessage } from "../messages/ExtendedChannelAnnouncementMessage";
import { NodeAnnouncementMessage } from "../messages/NodeAnnouncementMessage";
import { IGossipStore } from "./GossipStore";

/**
 * In-memory implementation of the IGossipStore.
 */
export class GossipMemoryStore implements IGossipStore {
    private _channelAnn = new Map<bigint, ChannelAnnouncementMessage>();
    private _channelByOutPoint = new Map<string, bigint>();
    private _channelUpd = new Map<bigint, ChannelUpdateMessage>();
    private _nodeAnn = new Map<string, NodeAnnouncementMessage>();
    private _nodeChannels = new Map<string, Set<bigint>>();

    public get channelAnnouncementCount() {
        return this._channelAnn.size;
    }

    public get channelUpdateCount() {
        return this._channelUpd.size;
    }

    public get nodeAnnouncementCount() {
        return this._nodeAnn.size;
    }

    public async saveChannelAnnouncement(msg: ChannelAnnouncementMessage): Promise<void> {
        const chanKey = getChanKey(msg.shortChannelId);
        this._channelAnn.set(chanKey, msg);
        if (msg instanceof ExtendedChannelAnnouncementMessage) {
            this._channelByOutPoint.set(msg.outpoint.toString(), msg.shortChannelId.toNumber());
        }
        await this._saveNodeChannel(msg.nodeId1, chanKey);
        await this._saveNodeChannel(msg.nodeId2, chanKey);
    }

    public async saveChannelUpdate(msg: ChannelUpdateMessage): Promise<void> {
        this._channelUpd.set(getChanUpdKey(getChanKey(msg.shortChannelId), msg.direction), msg);
    }

    public async saveNodeAnnouncement(msg: NodeAnnouncementMessage): Promise<void> {
        this._nodeAnn.set(getNodeKey(msg.nodeId), msg);
    }

    public async findChannelsForNode(nodeId: Buffer): Promise<ShortChannelId[]> {
        const scidInts = this._nodeChannels.get(getNodeKey(nodeId));
        const results: ShortChannelId[] = [];
        if (!scidInts) return results;
        for (const scidInt of scidInts) {
            results.push(shortChannelIdFromNumber(scidInt));
        }
        return results;
    }

    public async findNodeAnnouncement(nodeId: Buffer): Promise<NodeAnnouncementMessage> {
        return this._nodeAnn.get(getNodeKey(nodeId));
    }

    public async findNodeAnnouncements(): Promise<NodeAnnouncementMessage[]> {
        return Array.from(this._nodeAnn.values());
    }

    public async findChannelAnnouncemnts(): Promise<ChannelAnnouncementMessage[]> {
        return Array.from(this._channelAnn.values());
    }

    public async findChannelAnnouncement(
        scid: ShortChannelId,
    ): Promise<ChannelAnnouncementMessage> {
        return this._channelAnn.get(getChanKey(scid));
    }

    public async findChannelAnnouncementByOutpoint(
        outpoint: OutPoint,
    ): Promise<ChannelAnnouncementMessage> {
        const scidNum = this._channelByOutPoint.get(outpoint.toString());
        return this._channelAnn.get(scidNum);
    }

    public async findChannelUpdate(
        scid: ShortChannelId,
        dir: number,
    ): Promise<ChannelUpdateMessage> {
        return this._channelUpd.get(getChanUpdKey(getChanKey(scid), dir));
    }

    public async deleteChannelAnnouncement(scid: ShortChannelId): Promise<void> {
        const msg = await this.findChannelAnnouncement(scid);
        if (!msg) return;
        const chanKey = getChanKey(scid);

        // delete channel
        this._channelAnn.delete(getChanKey(scid));

        // delete outpoint link
        if (msg instanceof ExtendedChannelAnnouncementMessage) {
            this._channelByOutPoint.delete(msg.outpoint.toString());
        }

        // delete channel_updates
        this._channelUpd.delete(getChanUpdKey(scid.toNumber(), 0));
        this._channelUpd.delete(getChanUpdKey(scid.toNumber(), 0));

        // delete node links
        this._nodeChannels.get(getNodeKey(msg.nodeId1)).delete(chanKey);
        this._nodeChannels.get(getNodeKey(msg.nodeId2)).delete(chanKey);
    }

    public async deleteChannelUpdate(scid: ShortChannelId, dir: number) {
        this._channelUpd.delete(getChanUpdKey(getChanKey(scid), dir));
    }

    public async deleteNodeAnnouncement(nodeId: Buffer) {
        this._nodeAnn.delete(getNodeKey(nodeId));
        this._nodeChannels.get(getNodeKey(nodeId));
    }

    private async _saveNodeChannel(nodeId: Buffer, chanKey: bigint) {
        const nodeKey = getNodeKey(nodeId);
        this._nodeChannels.set(nodeKey, this._nodeChannels.get(nodeKey) || new Set<bigint>());
        this._nodeChannels.get(nodeKey).add(chanKey);
    }
}

function getNodeKey(nodeId: Buffer): string {
    return nodeId.toString("hex");
}

function getChanKey(scid: ShortChannelId): bigint {
    return scid.toNumber();
}

function getChanUpdKey(chanKey: bigint, direction: number): bigint {
    return (chanKey << BigInt(8)) | BigInt(direction);
}