/**
 * 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, OnDestroy, inject } from '@angular/core';
import { CommonModule } from '@angular/common';
import { UntypedFormBuilder, UntypedFormGroup, Validators, ReactiveFormsModule } from '@angular/forms';
import { MAT_DIALOG_DATA, MatDialogModule, MatDialogRef } from '@angular/material/dialog';
import { MatButtonModule } from '@angular/material/button';
import { MatDatepickerModule } from '@angular/material/datepicker';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatIconModule } from '@angular/material/icon';
import { MatInputModule } from '@angular/material/input';
import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
import { MatTooltipModule } from '@angular/material/tooltip';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';

/** What the caller hands in: the document as it stands, and the scans already on file. */
export interface KycDocumentUpdateData {
  documentName: string;
  documentNumber: string;
  issueDate: Date | string | null;
  expiryDate: Date | string | null;
  /** Why the document is being asked for, shown at the top so the officer sees the reason. */
  reason: string;
  /** Previews of what is currently held, so the officer can see what they are replacing. */
  currentFront: string | null;
  currentBack: string | null;
  /**
   * True when the KYC record is already verified. Changing data on one of those needs a reason on
   * the record, which the server enforces - so the dialog asks for it rather than letting the
   * officer fill the whole form in and be refused on submit.
   */
  requiresRemarks: boolean;
}

/** What the caller gets back: the corrected details, plus whichever sides were re-scanned. */
export interface KycDocumentUpdateResult {
  documentNumber: string;
  issueDate: Date | null;
  expiryDate: Date | null;
  front: File | null;
  back: File | null;
  /** Why the document was re-collected. Blank unless the record was already verified. */
  remarks: string;
}

/**
 * Re-collects an officially valid document without leaving the KYC record.
 *
 * PAN and Aadhaar are each dealt with on their own row of the verification table. The OVD was the
 * exception: its Update button put the whole KYC form into edit mode, so re-collecting one expiring
 * document meant scrolling a form of unrelated fields and finding the same document again. The work
 * is the same either way - a new number, new dates, a fresh scan of each side - so it is asked for
 * in one place.
 */
@Component({
  selector: 'mifosx-kyc-document-update-dialog',
  templateUrl: './kyc-document-update-dialog.component.html',
  styleUrls: ['./kyc-document-update-dialog.component.scss'],
  standalone: true,
  // The shared set carries the date adapter the two datepickers below need; the sibling dialogs
  // pull it in the same way.
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    CommonModule,
    ReactiveFormsModule,
    MatDialogModule,
    MatButtonModule,
    MatDatepickerModule,
    MatFormFieldModule,
    MatIconModule,
    MatInputModule,
    MatProgressSpinnerModule,
    MatTooltipModule
  ]
})
export class KycDocumentUpdateDialogComponent implements OnDestroy {
  private formBuilder = inject(UntypedFormBuilder);
  private dialogRef = inject<MatDialogRef<KycDocumentUpdateDialogComponent>>(MatDialogRef);
  data = inject<KycDocumentUpdateData>(MAT_DIALOG_DATA);

  form: UntypedFormGroup;

  /** Newly chosen files, with a local preview so the officer sees what they picked. */
  picked: { front: File | null; back: File | null } = { front: null, back: null };
  pickedPreview: { front: string | null; back: string | null } = { front: null, back: null };

  readonly slots: ('front' | 'back')[] = [
    'front',
    'back'
  ];

  constructor() {
    this.form = this.formBuilder.group({
      documentNumber: [
        this.data.documentNumber || '',
        [Validators.required]
      ],
      issueDate: [this.toDate(this.data.issueDate)],
      // Left free rather than required: a passport expires, a PAN card does not.
      expiryDate: [this.toDate(this.data.expiryDate)],
      // Required only where the server requires it, so completing a record that was never verified
      // does not demand a justification for filling in blanks.
      remarks: [
        '',
        this.data.requiresRemarks ? [Validators.required] : []
      ]
    });
  }

  private toDate(value: Date | string | null): Date | null {
    if (!value) {
      return null;
    }
    const d = value instanceof Date ? value : new Date(value);
    return isNaN(d.getTime()) ? null : d;
  }

  previewOf(slot: 'front' | 'back'): string | null {
    return this.pickedPreview[slot] || (slot === 'front' ? this.data.currentFront : this.data.currentBack);
  }

  /** True once this side has been re-scanned in this dialog, so the label can say so. */
  isReplaced(slot: 'front' | 'back'): boolean {
    return !!this.picked[slot];
  }

  pickedName(slot: 'front' | 'back'): string {
    return this.picked[slot]?.name || '';
  }

  onFilePicked(event: Event, slot: 'front' | 'back'): void {
    const input = event.target as HTMLInputElement;
    const file = input.files?.[0] || null;
    // Cleared so re-picking the same filename still fires a change event.
    input.value = '';
    if (!file) {
      return;
    }
    if (this.pickedPreview[slot]) {
      URL.revokeObjectURL(this.pickedPreview[slot]!);
    }
    this.picked[slot] = file;
    this.pickedPreview[slot] = file.type.startsWith('image/') ? URL.createObjectURL(file) : null;
  }

  clearPick(slot: 'front' | 'back'): void {
    if (this.pickedPreview[slot]) {
      URL.revokeObjectURL(this.pickedPreview[slot]!);
    }
    this.picked[slot] = null;
    this.pickedPreview[slot] = null;
  }

  /**
   * Something has to change for the update to mean anything - either a corrected detail or a fresh
   * scan. Submitting an untouched form would reopen a verified KYC record for no reason.
   */
  get hasChanges(): boolean {
    if (this.picked.front || this.picked.back) {
      return true;
    }
    const v = this.form.value;
    const sameNumber = (v.documentNumber || '').trim() === (this.data.documentNumber || '').trim();
    const sameIssue = this.sameDay(v.issueDate, this.toDate(this.data.issueDate));
    const sameExpiry = this.sameDay(v.expiryDate, this.toDate(this.data.expiryDate));
    return !(sameNumber && sameIssue && sameExpiry);
  }

  private sameDay(a: Date | null, b: Date | null): boolean {
    if (!a && !b) {
      return true;
    }
    if (!a || !b) {
      return false;
    }
    return a.getFullYear() === b.getFullYear() && a.getMonth() === b.getMonth() && a.getDate() === b.getDate();
  }

  submit(): void {
    if (this.form.invalid || !this.hasChanges) {
      this.form.markAllAsTouched();
      return;
    }
    const v = this.form.value;
    const result: KycDocumentUpdateResult = {
      documentNumber: (v.documentNumber || '').trim(),
      issueDate: v.issueDate || null,
      expiryDate: v.expiryDate || null,
      front: this.picked.front,
      back: this.picked.back,
      remarks: (v.remarks || '').trim()
    };
    this.dialogRef.close(result);
  }

  cancel(): void {
    this.dialogRef.close();
  }

  ngOnDestroy(): void {
    // Only the previews this dialog created; the caller owns the ones it passed in.
    for (const slot of this.slots) {
      if (this.pickedPreview[slot]) {
        URL.revokeObjectURL(this.pickedPreview[slot]!);
      }
    }
  }
}