/**
 * Copyright since 2025 Mifos Initiative
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/** Angular Imports */
import {
  Component,
  DestroyRef,
  EventEmitter,
  Input,
  OnChanges,
  OnInit,
  Output,
  SimpleChanges,
  inject
} from '@angular/core';
import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
import { FormControl, ReactiveFormsModule } from '@angular/forms';
import { MatAutocompleteModule, MatAutocompleteSelectedEvent } from '@angular/material/autocomplete';
import { of } from 'rxjs';
import { catchError, debounceTime, distinctUntilChanged, filter, map, switchMap } from 'rxjs/operators';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';

/** Custom Services */
import { LockerService } from '../../locker.service';

/** What a pick hands back — enough to show the client and link them. */
export interface PickedClient {
  clientId: number;
  displayName: string;
  mobileNo?: string | null;
  officeName?: string | null;
}

/**
 * Client name box with type-ahead (case-insensitive, from 2 letters) over existing clients. Emits the picked client,
 * and emits null as soon as the text is changed away from it, so a stale client id is never kept for another name.
 */
@Component({
  selector: 'mifosx-locker-client-picker',
  template: `
    <mat-form-field appearance="fill" class="picker-field">
      <mat-label>{{ label | translate }}</mat-label>
      <input
        matInput
        [formControl]="nameControl"
        [matAutocomplete]="auto"
        [required]="required"
        autocomplete="off"
        [readonly]="disabled"
      />
      <mat-autocomplete #auto="matAutocomplete" [displayWith]="displayName" (optionSelected)="onSelected($event)">
        @for (c of suggestions; track c.clientId) {
          <mat-option [value]="c">
            <span class="opt-name">{{ c.displayName }}</span>
            <span class="opt-meta">
              {{ 'ID' | translate }} {{ c.clientId }}
              @if (c.mobileNo) {
                · {{ c.mobileNo }}
              }
              @if (c.officeName) {
                · {{ c.officeName }}
              }
            </span>
          </mat-option>
        }
      </mat-autocomplete>
      @if (pickedId) {
        <mat-hint class="picked">{{ 'Client ID' | translate }} {{ pickedId }}</mat-hint>
      } @else if (!disabled) {
        <mat-hint>{{ 'Type 2+ letters and pick a client' | translate }}</mat-hint>
      }
    </mat-form-field>
  `,
  styles: [
    `
      .picker-field {
        width: 100%;
      }
      .opt-name {
        display: block;
        font-weight: 500;
        line-height: 1.2;
      }
      .opt-meta {
        display: block;
        font-size: 0.75rem;
        color: rgb(0 0 0 / 55%);
        line-height: 1.2;
      }
      .picked {
        color: #1976d2;
        font-weight: 600;
      }
    `
  ],
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    ReactiveFormsModule,
    MatAutocompleteModule
  ]
})
export class LockerClientPickerComponent implements OnInit, OnChanges {
  private lockerService = inject(LockerService);
  private destroyRef = inject(DestroyRef);

  @Input() label = 'Client';
  @Input() required = false;
  @Input() disabled = false;
  /** Pre-selected client, e.g. when an existing application is opened. */
  @Input() clientId: number | null = null;
  @Input() clientName: string | null = null;
  /** Client ids that may not be picked here (e.g. the main applicant in the joint-holder list). */
  @Input() excludeIds: number[] = [];

  @Output() picked = new EventEmitter<PickedClient | null>();

  nameControl = new FormControl<any>('');
  suggestions: PickedClient[] = [];
  pickedId: number | null = null;
  private pickedName = '';

  ngOnInit(): void {
    this.nameControl.valueChanges
      .pipe(
        // A picked option puts the object in the box; only typed text counts as a change.
        filter((value: any): value is string => typeof value === 'string'),
        debounceTime(300),
        map((value: string) => value.trim()),
        distinctUntilChanged(),
        switchMap((name: string) => {
          if (this.pickedId && name !== this.pickedName) {
            this.pickedId = null;
            this.pickedName = '';
            this.picked.emit(null);
          }
          if (name.length < 2 || this.pickedId) {
            return of([]);
          }
          return this.lockerService.searchClientsByName(name).pipe(catchError(() => of([])));
        }),
        takeUntilDestroyed(this.destroyRef)
      )
      .subscribe((rows: any[]) => {
        // The search returns one row per account; keep one per client.
        const seen = new Set<number>();
        this.suggestions = (rows ?? [])
          .filter(
            (r: any) =>
              r?.clientId && !this.excludeIds.includes(r.clientId) && !seen.has(r.clientId) && seen.add(r.clientId)
          )
          .slice(0, 10);
      });
  }

  ngOnChanges(changes: SimpleChanges): void {
    if (changes['clientId'] || changes['clientName']) {
      this.pickedId = this.clientId ?? null;
      this.pickedName = this.clientName ?? '';
      this.nameControl.setValue(this.pickedName, { emitEvent: false });
    }
  }

  onSelected(event: MatAutocompleteSelectedEvent): void {
    const client: PickedClient = event.option.value;
    this.pickedId = client.clientId;
    this.pickedName = client.displayName;
    this.suggestions = [];
    this.nameControl.setValue(client.displayName, { emitEvent: false });
    this.picked.emit(client);
  }

  displayName = (value: any): string => (typeof value === 'string' ? value : (value?.displayName ?? ''));
}