import {logger} from "../../utils/logger";
import type * as Zcl from "../../zspec/zcl";
import type {Endpoint} from "../model";
import type Request from "./request";

const NS = "zh:controller:requestqueue";

type Mutable<T> = {-readonly [P in keyof T]: T[P]};

export class RequestQueue extends Set<Request> {
    private sendInProgress: boolean;
    private id: number;
    private deviceIeeeAddress: string;

    constructor(endpoint: Endpoint) {
        super();
        this.sendInProgress = false;
        this.id = endpoint.ID;
        this.deviceIeeeAddress = endpoint.deviceIeeeAddress;
    }

    public async send(fastPolling: boolean): Promise<void> {
        if (this.size === 0) return;

        if (!fastPolling && this.sendInProgress) {
            logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): sendPendingRequests already in progress`, NS);
            return;
        }
        this.sendInProgress = true;

        // Remove expired requests first
        const now = Date.now();
        for (const request of this) {
            if (now > request.expires) {
                logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): discard after timeout. Size before: ${this.size}`, NS);
                request.reject();
                this.delete(request);
            }
        }

        logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): send pending requests (${this.size}, ${fastPolling})`, NS);

        for (const request of this) {
            if (fastPolling || request.sendPolicy !== "bulk") {
                try {
                    const result = await request.send();
                    logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): send success`, NS);
                    request.resolve(result);
                    this.delete(request);
                } catch (error) {
                    logger.debug(
                        `Request Queue (${this.deviceIeeeAddress}/${this.id}): send failed, expires in ` +
                            `${(request.expires - now) / 1000} seconds (${(error as Error).message})`,
                        NS,
                    );
                }
            }
        }
        this.sendInProgress = false;
    }

    public async queue<Type>(request: Request<Type>): Promise<Type> {
        logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): Sending when active. Expires: ${request.expires}`, NS);
        return await new Promise((resolve, reject): void => {
            request.addCallbacks(resolve, reject);
            this.add(request);
        });
    }

    public filter(newRequest: Request): void {
        if (this.size === 0 || !newRequest.frame.command) {
            return;
        }
        const clusterID = newRequest.frame.cluster.ID;
        const payload = newRequest.frame.payload;
        const commandID = newRequest.frame.command.ID;

        logger.debug(
            `Request Queue (${this.deviceIeeeAddress}/${this.id}): ZCL ${newRequest.frame.command.name} ` +
                `command, filter requests. Before: ${this.size}`,
            NS,
        );

        for (const request of this) {
            if (request?.frame?.cluster?.ID === undefined || !request.frame.command) {
                continue;
            }

            if (request.sendPolicy === "bulk" || request.sendPolicy === "queue" || request.sendPolicy === "immediate") {
                continue;
            }

            if (request.frame.cluster.ID === clusterID && request.frame.command.ID === commandID) {
                if (newRequest.sendPolicy === "keep-payload" && JSON.stringify(request.frame.payload) === JSON.stringify(payload)) {
                    logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): Merge duplicate request`, NS);
                    this.delete(request);
                    newRequest.moveCallbacks(request);
                } else if (
                    (newRequest.sendPolicy === "keep-command" || newRequest.sendPolicy === "keep-cmd-undiv") &&
                    Array.isArray(request.frame.payload)
                ) {
                    const filteredPayload = request.frame.payload.filter(
                        (oldEl: {attrId: number}) => !payload.find((newEl: {attrId: number}) => oldEl.attrId === newEl.attrId),
                    );
                    if (filteredPayload.length === 0) {
                        logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): Remove & reject request`, NS);
                        if (JSON.stringify(request.frame.payload) === JSON.stringify(payload)) {
                            newRequest.moveCallbacks(request);
                        } else {
                            request.reject();
                        }
                        this.delete(request);
                    } else if (newRequest.sendPolicy !== "keep-cmd-undiv") {
                        // remove all duplicate attributes if we shall not write undivided
                        (request.frame as Mutable<Zcl.Frame>).payload = filteredPayload;
                        logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): Remove commands from request`, NS);
                    }
                }
            }
        }
        logger.debug(`Request Queue (${this.deviceIeeeAddress}/${this.id}): After: ${this.size}`, NS);
    }
}

export default RequestQueue;