import { Component, OnInit, OnDestroy, ViewChild, ElementRef, AfterViewChecked } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormBuilder, ReactiveFormsModule, Validators, FormsModule } from '@angular/forms';
import { MatButtonModule } from '@angular/material/button';
import { MatIconModule } from '@angular/material/icon';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatInputModule } from '@angular/material/input';
import { MatCardModule } from '@angular/material/card';
import { MatSelectModule } from '@angular/material/select';
import { MatDividerModule } from '@angular/material/divider';
import { MatTooltipModule } from '@angular/material/tooltip';
import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
import { Subscription } from 'rxjs';

import { ApiService } from '../../services/api.service';

interface ChatMessage {
  author: 'user' | 'assistant';
  text: string;
  timestamp?: Date;
}

@Component({
  selector: 'app-chat',
  standalone: true,
  imports: [
    CommonModule,
    FormsModule,
    ReactiveFormsModule,
    MatButtonModule,
    MatIconModule,
    MatFormFieldModule,
    MatInputModule,
    MatCardModule,
    MatSelectModule,
    MatDividerModule,
    MatTooltipModule,
    MatProgressSpinnerModule
  ],
  templateUrl: './chat.component.html',
  styleUrls: ['./chat.component.scss']
})
export class ChatComponent implements OnInit, OnDestroy, AfterViewChecked {
  @ViewChild('scrollMe') private myScrollContainer!: ElementRef;

  projects: string[] = [];
  selectedProject: string | null = null;  // Düzeltildi: ! kaldırıldı, null değer atandı

  sessionId: string | null = null;
  messages: ChatMessage[] = [];
  input = this.fb.control('', Validators.required);
  
  loading = false;
  error = '';
  
  private subs = new Subscription();
  private shouldScroll = false;

  constructor(
    private fb: FormBuilder, 
    private api: ApiService
  ) {}

  ngOnInit(): void {
    this.loadProjects();
  }

  ngAfterViewChecked() {
    if (this.shouldScroll) {
      this.scrollToBottom();
      this.shouldScroll = false;
    }
  }

  ngOnDestroy(): void {
    this.subs.unsubscribe();
  }

  loadProjects(): void {
    this.loading = true;
    const sub = this.api.getChatProjects().subscribe({
      next: projects => {
        this.projects = projects;
        this.loading = false;
        if (projects.length === 0) {
          this.error = 'No enabled projects found. Please enable a project with published version.';
        }
      },
      error: (err) => {
        this.error = 'Failed to load projects';
        this.loading = false;
        console.error('Load projects error:', err);
      }
    });
    this.subs.add(sub);
  }

  startChat(): void {
    if (!this.selectedProject) return;
    
    this.loading = true;
    this.error = '';
    
    const sub = this.api.startChat(this.selectedProject).subscribe({
      next: res => {
        this.sessionId = res.session_id;
        this.messages = [{ 
          author: 'assistant', 
          text: res.answer,
          timestamp: new Date()
        }];
        this.loading = false;
        this.shouldScroll = true;
      },
      error: (err) => {
        this.error = err.error?.detail || 'Failed to start session';
        this.loading = false;
        console.error('Start chat error:', err);
      }
    });
    this.subs.add(sub);
  }

  send(): void {
    if (!this.sessionId || this.input.invalid) return;
    
    const text = this.input.value!.trim();
    if (!text) return;

    // Add user message
    this.messages.push({ 
      author: 'user', 
      text,
      timestamp: new Date()
    });
    
    this.input.reset();
    this.loading = true;
    this.shouldScroll = true;

    // Send to backend
    const sub = this.api.chat(this.sessionId, text).subscribe({
      next: res => {
        this.messages.push({ 
          author: 'assistant', 
          text: res.answer,
          timestamp: new Date()
        });
        this.loading = false;
        this.shouldScroll = true;
      },
      error: (err) => {
        this.messages.push({
          author: 'assistant',
          text: '⚠️ ' + (err.error?.detail || 'Failed to send message. Please try again.'),
          timestamp: new Date()
        });
        this.loading = false;
        this.shouldScroll = true;
        console.error('Chat error:', err);
      }
    });
    this.subs.add(sub);
  }

  endSession(): void {
    this.sessionId = null;
    this.messages = [];
    this.selectedProject = null;
    this.input.reset();
    this.error = '';
  }

  private scrollToBottom(): void {
    try {
      if (this.myScrollContainer) {
        this.myScrollContainer.nativeElement.scrollTop = 
          this.myScrollContainer.nativeElement.scrollHeight;
      }
    } catch(err) {
      console.error('Scroll error:', err);
    }
  }
}