import { writable } from "svelte/store";
import gateway, { GatewayEventType } from "./gateway";

class Store {
    constructor() {
        this._handlers = [];
        this._didInit = false;
    }

    _tryInit() {
        if (!this._didInit && this._init) {
            this._init();
            this._didInit = true;
        }
    }

    subscribe(handler) {
        this._tryInit();

        const newLength = this._handlers.push(handler);
        const handlerIndex = newLength - 1;
        handler(this._value);
        return () => {
            this._handlers.splice(handlerIndex, 1);
        };
    }

    _dispatchUpdate() {
        this._handlers.forEach(e => {
            e(this._value);
        });
    }
}

class ChannelsStore extends Store {
    constructor() {
        super();

        this._value = [];
    }

    _init() {
        const channels = gateway.channels;
        if (channels) {
            this._value = channels;
        }

        gateway.subscribe(GatewayEventType.Ready, ({ channels }) => {
            if (channels) {
                this._value = channels;
            }

            this._dispatchUpdate();
        });
        gateway.subscribe(GatewayEventType.ChannelCreate, (channel) => {
            this._value.push(channel);

            this._dispatchUpdate();
        });
        gateway.subscribe(GatewayEventType.ChannelDelete, ({ id }) => {
            const index = this._value.findIndex(e => e.id === id);
            if (!index)
                return;

            this._value.splice(index, 1);

            this._dispatchUpdate();
        });
        gateway.subscribe(GatewayEventType.ChannelUpdate, (data) => {
            const index = this._value.findIndex(e => e.id === data.id);
            if (!index)
                return;

            if (!this._value[index])
                return;

            this._value[index] = data;

            this._dispatchUpdate();
        });
    }
}

class GatewayStatusStore extends Store {
    constructor() {
        super();
        this._value = { open: false, ready: false };
    }

    _init() {
        this._value.open = gateway.open;
        this._value.ready = gateway.authenticated;

        gateway.subscribe(GatewayEventType.Open, () => {
            this._value.open = true;
            this._dispatchUpdate();
        });

        gateway.subscribe(GatewayEventType.Close, () => {
            this._value.open = false;
            this._value.ready = false;
            this._dispatchUpdate();
        });

        gateway.subscribe(GatewayEventType.Ready, () => {
            this._value.ready = true;
            this._dispatchUpdate();
        });
    }
}

export const channels = new ChannelsStore();
export const gatewayStatus = new GatewayStatusStore();
export const selectedChannel = writable({ id: -1, name: "none", creator_id: -1 });