import { HttpClient } from '@angular/common/http';
import { Component, OnDestroy, OnInit } from '@angular/core';
import { lastValueFrom, Subscription } from 'rxjs';

import {
    ParticipantModel,
    ParticipantService,
    OpenViduComponentsModule,
} from 'openvidu-components-angular';

@Component({
    selector: 'app-root',
    template: `
        <!-- OpenVidu Video Conference Component -->
        <ov-videoconference
            [token]="token"
            [livekitUrl]="LIVEKIT_URL"
            (onTokenRequested)="onTokenRequested($event)"
        >
            <!-- Custom Participants Panel -->
            <div *ovParticipantsPanel id="my-panel">
                <ul id="local">
                    <li>{{ localParticipant.name }}</li>
                </ul>
                <ul id="remote">
                    @for (p of remoteParticipants; track p) {
                    <li>{{ p.name }}</li>
                    }
                </ul>
            </div>
        </ov-videoconference>
    `,
    styles: `
        #my-panel {
            background: #faff7f;
            height: 100%;
            overflow: hidden;
        }
        #my-panel > #local {
            background: #a184ff;
        }
        #my-panel > #remote {
            background: #7fb8ff;
        }
    `,
    standalone: true,
    imports: [OpenViduComponentsModule],
})
export class AppComponent implements OnInit, OnDestroy {
    // For local development, leave these variables empty
    // For production, configure them with correct URLs depending on your deployment
    APPLICATION_SERVER_URL = '';
    LIVEKIT_URL = '';

    // Define the name of the room and initialize the token variable
    roomName = 'custom-participants-panel';
    token!: string;

    // Participant-related properties
    localParticipant!: ParticipantModel;
    remoteParticipants!: ParticipantModel[];
    localParticipantSubs!: Subscription;
    remoteParticipantsSubs!: Subscription;

    constructor(
        private httpClient: HttpClient,
        private participantService: ParticipantService
    ) {
        this.configureUrls();
    }

    private configureUrls() {
        // If APPLICATION_SERVER_URL is not configured, use default value from local development
        if (!this.APPLICATION_SERVER_URL) {
            if (window.location.hostname === 'localhost') {
                this.APPLICATION_SERVER_URL = 'http://localhost:6080/';
            } else {
                this.APPLICATION_SERVER_URL =
                    'https://' + window.location.hostname + ':6443/';
            }
        }

        // If LIVEKIT_URL is not configured, use default value from local development
        if (!this.LIVEKIT_URL) {
            if (window.location.hostname === 'localhost') {
                this.LIVEKIT_URL = 'ws://localhost:7880/';
            } else {
                this.LIVEKIT_URL = 'wss://' + window.location.hostname + ':7443/';
            }
        }
    }

    // Subscribes to updates for local and remote participants.
    ngOnInit() {
        this.subscribeToParticipants();
    }

    // Unsubscribes from updates for local and remote participants to prevent memory leaks.
    ngOnDestroy() {
        this.localParticipantSubs.unsubscribe();
        this.remoteParticipantsSubs.unsubscribe();
    }

    // Function called when a participant requests a token to join the room.
    async onTokenRequested(participantName: string) {
        const { token } = await this.getToken(this.roomName, participantName);
        this.token = token;
    }

    // Subscribes to updates for local and remote participants.
    subscribeToParticipants() {
        this.localParticipantSubs =
            this.participantService.localParticipant$.subscribe((p) => {
                if (p) this.localParticipant = p;
            });

        this.remoteParticipantsSubs =
            this.participantService.remoteParticipants$.subscribe(
                (participants) => {
                    this.remoteParticipants = participants;
                }
            );
    }

    // Sends a request to the server to obtain a token for a participant.
    async getToken(roomName: string, participantName: string): Promise<any> {
        try {
            // Send a POST request to the server to obtain a token
            return lastValueFrom(
                this.httpClient.post<any>(this.APPLICATION_SERVER_URL + 'token', {
                    roomName,
                    participantName,
                })
            );
        } catch (error: any) {
            // Handle errors, e.g., if the server is not reachable
            if (error.status === 404) {
                throw {
                    status: error.status,
                    message:
                        'Cannot connect with the backend. ' + error.url + ' not found',
                };
            }
            throw error;
        }
    }
}