neoban/frontend/src/app/chat/chat.ts

import { Component, ElementRef, ViewChild, effect, inject } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormControl, ReactiveFormsModule } from '@angular/forms';
import { ChatStore } from './chat.store';
import { ActivatedRoute } from '@angular/router';

@Component({
  selector: 'app-chat',
  standalone: true,
  imports: [CommonModule, ReactiveFormsModule],
  templateUrl: './chat.html',
  styleUrl: './chat.css',
})
export class Chat {
  readonly chatStore = inject(ChatStore);
  private route = inject(ActivatedRoute);

  @ViewChild('scrollContainer') private scrollContainer!: ElementRef;

  messageControl = new FormControl('');

  constructor() {
    // Scroll to bottom when messages change
    effect(() => {
      // Accessing messages will trigger effect on change
      const msgs = this.chatStore.messages();
      const loading = this.chatStore.isLoading();

      setTimeout(() => {
        this.scrollToBottom();
      }, 50);
    });
  }

  ngOnInit() {
    this.route.paramMap.subscribe((params) => {
      const urlId = params.get('id');
      if (urlId) {
        // If an ID exists in the URL, populate it in the store
        this.chatStore.setChatId(urlId);
        this.chatStore.fetchChatHistory();
      }
    });
  }

  errorMessage = '';

  sendMessage() {
    const value = this.messageControl.value;
    if (value && value.trim() && !this.chatStore.isLoading()) {
      const words = value.trim().split(/\s+/).length;
      if (words > 400) {
        this.errorMessage = `Input must be under 400 words (currently ${words} words).`;
        return;
      }
      this.errorMessage = '';
      this.chatStore.sendMessage(value.trim());
      this.messageControl.setValue('');
    }
  }

  private scrollToBottom(): void {
    try {
      const el = this.scrollContainer.nativeElement;
      el.scrollTop = el.scrollHeight;
    } catch (err) {}
  }
}