import { Component, OnInit, Input, ViewChild, AfterViewInit } from '@angular/core';
import { FormControl, UntypedFormControl, FormsModule, ReactiveFormsModule } from '@angular/forms';
import {Observable} from 'rxjs';
import {startWith, map} from 'rxjs/operators';
import { MatAutocompleteTrigger, MatAutocomplete } from '@angular/material/autocomplete';
import { PlotService, PlotType, AutocompleteResult, Suggestion, ResultMode } from '../plot.service';
import { MatInput } from '@angular/material/input';
import { NgFor, AsyncPipe } from '@angular/common';
import { MatOption } from '@angular/material/core';

@Component({
    selector: 'pdb-query-autocomplete',
    templateUrl: './query-autocomplete.component.html',
    styleUrls: ['./query-autocomplete.component.scss'],
    standalone: true,
    imports: [MatInput, FormsModule, MatAutocompleteTrigger, ReactiveFormsModule, MatAutocomplete, NgFor, MatOption, AsyncPipe]
})
export class QueryAutocompleteComponent implements OnInit {

  queryField = new FormControl<Suggestion>(new Suggestion("","",0));

  suggestions = new UntypedFormControl();
    
  filteredSuggestions!: Observable<Suggestion[]>;
  
  query : string = ""; 

  suggestionFetcherEnabled = true;
  
  @ViewChild(MatAutocompleteTrigger)
  autocomplete!: MatAutocompleteTrigger;
  
  
  constructor(private plotService: PlotService) {
  }

  ngOnInit() {
    this.query = "";
    this.queryField.valueChanges.subscribe((value) =>{
      if (value != null) {
        if (typeof value == "string") {
          this.query = value;
        }else{
          this.query = value.newQuery;
          
          const el : HTMLInputElement = <HTMLInputElement>document.getElementById('query-autocomplete-input');
          el.selectionStart=value.newCaretPosition;
          el.selectionEnd=value.newCaretPosition;
        }
        
        
        if (this.suggestionFetcherEnabled) {
          this.fetchSuggestions(value.newCaretPosition);
        }
      }
    });
    this.filteredSuggestions = this.suggestions.valueChanges.pipe(
      map(value => value)
    );
  }
  
  onKey(event: any) {    
    //console.log(event);
    if (event.key == "ArrowDown" || event.key == "ArrowUp"){
      return;
    }
    const caretIndex = event.srcElement.selectionStart +1;
    
    this.fetchSuggestions(caretIndex);
  }
  
  fetchSuggestions(caretIndex: number){
    const that = this;
    const query = typeof this.queryField.value == "string" 
      ? this.queryField.value
      : this.queryField.value!.newQuery;
    
    this.plotService
      .autocomplete(query, caretIndex, ResultMode.CUT_AT_DOT)
      .subscribe({
        next: (data: AutocompleteResult) => {
          that.suggestions.setValue(data.proposals);
          that.autocomplete.openPanel();
        }, 
        error: (error:any) => console.log(error)
      }
      );
  }
  
  displaySuggestion(suggestion?: Suggestion): string {
    return suggestion ? suggestion.newQuery : '';
  }
}