import { ChangeDetectionStrategy, Component, inject, OnInit, ViewChild } from '@angular/core';
import { HttpErrorResponse } from '@angular/common/http';
import { MatDialog } from '@angular/material/dialog';
import { MatPaginator } from '@angular/material/paginator';
import { MatSnackBar } from '@angular/material/snack-bar';
import { MatSort } from '@angular/material/sort';
import { MatTableDataSource } from '@angular/material/table';

import { httpErrorMessage } from 'src/app/helpers/http-error';
import { Role, roleLabel } from 'src/app/models/role';
import { User } from 'src/app/models/user.model';
import { RolesService } from 'src/app/services/roles.service';
import { TokenStorageService } from 'src/app/services/token-storage.service';
import { UserService } from 'src/app/services/user.service';
import { RolesDialogComponent, RolesDialogData } from '../roles-dialog/roles-dialog.component';

@Component({
  selector: 'app-board-admin',
  templateUrl: './board-admin.component.html',
  styleUrls: ['./board-admin.component.scss'],
  changeDetection: ChangeDetectionStrategy.Eager,
  standalone: false
})
export class BoardAdminComponent implements OnInit {
  private readonly userService = inject(UserService);
  private readonly rolesService = inject(RolesService);
  private readonly tokenStorage = inject(TokenStorageService);
  private readonly dialog = inject(MatDialog);
  private readonly snackBar = inject(MatSnackBar);

  readonly displayedColumns = ['username', 'email', 'roles', 'actions'];
  readonly dataSource = new MatTableDataSource<User>([]);
  readonly roleLabel = roleLabel;
  readonly currentUserId = this.tokenStorage.getUser().id;

  private allRoles: Role[] = [];

  @ViewChild(MatSort) set sort(sort: MatSort) {
    this.dataSource.sort = sort;
  }

  @ViewChild(MatPaginator) set paginator(paginator: MatPaginator) {
    this.dataSource.paginator = paginator;
  }

  ngOnInit(): void {
    this.dataSource.sortingDataAccessor = (user, column) =>
      column === 'roles' ? (user.roles ?? []).length : String((user as any)[column] ?? '').toLowerCase();
    this.dataSource.filterPredicate = (user, filter) =>
      [user.username, user.email, ...(user.roles ?? []).map(role => roleLabel(role.name))]
        .some(value => value?.toLowerCase().includes(filter));

    this.userService.getAll().subscribe({
      // На пустой результат сервер отвечает 204 без тела
      next: users => this.dataSource.data = users ?? [],
      error: err => this.showError(err)
    });
    this.rolesService.getAllRoles().subscribe({
      next: roles => this.allRoles = roles ?? [],
      error: err => this.showError(err)
    });
  }

  applyFilter(value: string): void {
    this.dataSource.filter = value.trim().toLowerCase();
    this.dataSource.paginator?.firstPage();
  }

  initials(user: User): string {
    return (user.username ?? '?').slice(0, 2);
  }

  editRoles(user: User): void {
    const data: RolesDialogData = { user, allRoles: this.allRoles };
    this.dialog.open(RolesDialogComponent, { width: '360px', data })
      .afterClosed()
      .subscribe((roles?: string[]) => {
        if (roles) {
          this.saveRoles(user, roles);
        }
      });
  }

  private saveRoles(user: User, roles: string[]): void {
    this.userService.updateRoles(user.id, roles).subscribe({
      next: updated => {
        this.dataSource.data = this.dataSource.data.map(u => u.id === updated.id ? updated : u);
        if (updated.id === this.currentUserId) {
          // Собственные роли хранятся в сессии — обновляем, чтобы меню и доступы совпадали с сервером
          this.tokenStorage.saveUser({ ...this.tokenStorage.getUser(), roles });
        }
        this.snackBar.open(`Roles of ${updated.username} were updated`, 'OK', { duration: 3000 });
      },
      error: err => this.showError(err)
    });
  }

  private showError(err: HttpErrorResponse): void {
    this.snackBar.open(httpErrorMessage(err), 'OK', { duration: 5000 });
  }
}