import { Component, inject, OnInit } from '@angular/core';
import { CommonModule } from '@angular/common';
import {
  catchError,
  debounceTime,
  distinctUntilChanged,
  Observable,
  of,
  retry,
  Subject,
} from 'rxjs';
import { HttpErrorResponse } from '@angular/common/http';
import { Employee } from '../Employee';

import { MatCardModule } from '@angular/material/card';
import { MatButtonModule } from '@angular/material/button';
import { MatIconModule } from '@angular/material/icon';
import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
import { MatSnackBarModule } from '@angular/material/snack-bar';
import { MatDividerModule } from '@angular/material/divider';
import { MatTooltipModule } from '@angular/material/tooltip';
import { MatMenuModule } from '@angular/material/menu';
import { MatTableModule } from '@angular/material/table';
import { MatSortModule } from '@angular/material/sort';
import { MatDialog } from '@angular/material/dialog';
import { DeleteComponent } from '../delete/delete.component';
import EmployeeApiService from '../../services/employee-api.service';
import { CreateComponent } from '../create/create.component';
import { EditComponent } from '../edit/edit.component';
import { DetailsComponent } from '../details/details.component';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatInputModule } from '@angular/material/input';
import { ErrorHandlerService } from '../../services/error.handler.service';

@Component({
  selector: 'app-employee-list',
  standalone: true,
  imports: [
    CommonModule,
    MatCardModule,
    MatButtonModule,
    MatIconModule,
    MatProgressSpinnerModule,
    MatSnackBarModule,
    MatDividerModule,
    MatTooltipModule,
    MatMenuModule,
    MatTableModule,
    MatSortModule,
    MatFormFieldModule,
    MatInputModule,
  ],
  templateUrl: './table.component.html',
  styleUrl: './table.component.css',
})
export class TableComponent implements OnInit {
  private readonly apiService: EmployeeApiService = inject(EmployeeApiService);
  private readonly matDialog: MatDialog = inject(MatDialog);
  private readonly errorHandlerService: ErrorHandlerService =
    inject(ErrorHandlerService);

  private static readonly MAX_RETRIES = 3;

  private allEmployees: Employee[] = [];
  private searchSubject = new Subject<string>();
  public employees$: Observable<Employee[]> = of([]);
  public isSearching = false;
  public readonly displayedColumns: string[] = ['name', 'actions'];

  public ngOnInit(): void {
    this.loadEmployees();
    this.setupSearch();
  }

  private loadEmployees(): void {
    this.fetchEmployees().subscribe((employees) => {
      this.allEmployees = employees;
      this.employees$ = of(employees);
    });
  }

  private setupSearch(): void {
    this.searchSubject
      .pipe(debounceTime(300), distinctUntilChanged())
      .subscribe((searchTerm) => {
        this.isSearching = true;
        setTimeout(() => {
          const filteredEmployees = this.allEmployees.filter(
            (employee) =>
              employee.firstName?.toLowerCase().includes(searchTerm) ||
              employee.lastName?.toLowerCase().includes(searchTerm),
          );
          this.employees$ = of(filteredEmployees);
          this.isSearching = false;
        }, 150);
      });
  }

  private fetchEmployees(): Observable<Employee[]> {
    return this.apiService.getAll().pipe(
      retry(TableComponent.MAX_RETRIES),
      catchError((error: HttpErrorResponse) => {
        console.error('Error fetching employees:', error);
        this.errorHandlerService.showErrorMessage(
          'Failed to load employees. Please try again.',
        );
        return of([]);
      }),
    );
  }

  protected openDeleteDialogue(employee: Employee): void {
    this.matDialog
      .open(DeleteComponent, { data: employee })
      .afterClosed()
      .subscribe((deleted: boolean) => {
        if (deleted) {
          this.employees$ = this.fetchEmployees();
        }
      });
  }

  protected showCreateEmployeeModal() {
    this.matDialog
      .open(CreateComponent)
      .afterClosed()
      .subscribe((created: boolean) => {
        if (created) {
          this.employees$ = this.fetchEmployees();
        }
      });
  }

  protected showEditEmployeeModal(employee: Employee) {
    this.matDialog
      .open(EditComponent, { data: employee })
      .afterClosed()
      .subscribe((edited: boolean) => {
        if (edited) {
          this.employees$ = this.fetchEmployees();
        }
      });
  }

  protected openDetailModal(employee: Employee) {
    this.matDialog.open(DetailsComponent, { data: employee });
  }

  protected filterEmployees(event: Event): void {
    const searchTerm = (event.target as HTMLInputElement).value.toLowerCase();
    this.searchSubject.next(searchTerm);
  }
}