/**
 * 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, ViewChild, ElementRef, AfterViewInit, Renderer2, OnDestroy, inject } from '@angular/core';
import {
  MatDialogRef,
  MAT_DIALOG_DATA,
  MatDialogTitle,
  MatDialogActions,
  MatDialogClose
} from '@angular/material/dialog';
import { NgStyle } from '@angular/common';
import { FaIconComponent } from '@fortawesome/angular-fontawesome';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';

/** What the captured image is for — drives the dialog's title/instructions and lets the
 * caller decide (based on how it opened the dialog) which upload method to invoke on the
 * resulting data URL. Defaults to 'profile' so existing callers that don't pass `data`
 * keep working unchanged. */
export type CaptureImageTarget = 'profile' | 'signature';

/**
 * Capture image dialog component
 */
@Component({
  selector: 'mifosx-capture-image-dialog',
  templateUrl: './capture-image-dialog.component.html',
  styleUrls: ['./capture-image-dialog.component.scss'],
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    MatDialogTitle,
    NgStyle,
    FaIconComponent,
    MatDialogActions,
    MatDialogClose
  ]
})
export class CaptureImageDialogComponent implements AfterViewInit, OnDestroy {
  dialogRef = inject<MatDialogRef<CaptureImageDialogComponent>>(MatDialogRef);
  private renderer = inject(Renderer2);
  private data = inject<{ captureTarget?: CaptureImageTarget } | null>(MAT_DIALOG_DATA, { optional: true });

  /** 'profile' (default, unchanged behaviour) or 'signature' — photographing a paper signature. */
  captureTarget: CaptureImageTarget = this.data?.captureTarget || 'profile';

  get isSignatureCapture(): boolean {
    return this.captureTarget === 'signature';
  }

  get dialogTitle(): string {
    return this.isSignatureCapture ? 'Capture Client Signature' : 'Capture Client Image';
  }

  get dialogInstructions(): string {
    return this.isSignatureCapture
      ? 'Photograph the customer’s signed paper — line up the signature within the frame before capturing.'
      : 'Line up the customer’s face within the frame before capturing.';
  }

  /** Video element reference */
  @ViewChild('video', { static: true }) video: ElementRef;
  /** Canvas element reference */
  @ViewChild('canvas', { static: true }) canvas: ElementRef;
  /** Fallback element reference */
  @ViewChild('fallback', { static: true }) fallback: ElementRef;
  /** Capture button element reference */
  @ViewChild('captureButton') captureButton: ElementRef;

  /** Toggles button states */
  isCaptured = false;
  /** Client image file */
  clientImageDataURL: string;

  ngAfterViewInit() {
    this.startCamera();
  }

  ngOnDestroy() {
    this.stopCamera();
  }

  /**
   * Initializes camera video stream once user grants permission.
   * Sets fallback if permission not granted.
   * See https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices for configuration details.
   */
  startCamera() {
    if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
      // Signature capture asks for a wide/short (16:9) stream to match the frame it's shown
      // in — requesting an aspect ratio close to what the CSS box actually renders avoids the
      // camera negotiating a 4:3 stream that then gets pillarboxed (black bars) inside a 16:9 box.
      const videoConstraints: MediaTrackConstraints = this.isSignatureCapture
        ? { width: { ideal: 1280 }, height: { ideal: 720 }, facingMode: 'user' }
        : { width: { ideal: 640 }, height: { ideal: 480 }, facingMode: 'user' };
      navigator.mediaDevices
        .getUserMedia({ video: videoConstraints })
        .then((stream: MediaStream) => {
          this.renderer.setProperty(this.video.nativeElement, 'srcObject', stream);
          this.video.nativeElement.play();
        })
        .catch((error: Error) => {
          this.handleError(error);
        });
    } else {
      throw new Error('Cannot connect to camera');
    }
  }

  /**
   * Shows fallback message.
   * @param {Error} error Error
   */
  handleError(error: Error) {
    this.renderer.removeStyle(this.fallback.nativeElement, 'display');
    const fallbackMessage = this.renderer.createText(`${error.name}: ${error.message}`);
    this.renderer.appendChild(this.fallback.nativeElement, fallbackMessage);
    this.renderer.setStyle(this.video.nativeElement, 'display', 'none');
    this.renderer.setProperty(this.captureButton, 'disabled', 'true');
  }

  /**
   * Stops video stream and closes the camera.
   * See https://developer.mozilla.org/en-US/docs/Web/API/MediaStreamTrack for `MediaStreamTrack` properties.
   */
  stopCamera() {
    const stream: MediaStream = this.video.nativeElement.srcObject;
    if (stream) {
      const videoStream: MediaStreamTrack = stream.getTracks()[0];
      videoStream.stop();
    }
    this.renderer.setProperty(this.video.nativeElement, 'srcObject', null);
  }

  /**
   * Captures the image by drawing video state on canvas, then converts canvas state to data URL.
   * Uses actual video dimensions to prevent aspect ratio distortion.
   * See https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toDataURL for details.
   */
  capture() {
    this.isCaptured = true;
    this.video.nativeElement.pause();

    // Get actual video stream dimensions to preserve aspect ratio
    const videoWidth = this.video.nativeElement.videoWidth;
    const videoHeight = this.video.nativeElement.videoHeight;

    // Set canvas dimensions to match video stream
    this.canvas.nativeElement.width = videoWidth;
    this.canvas.nativeElement.height = videoHeight;

    // Draw the video frame at full resolution without distortion
    this.canvas.nativeElement.getContext('2d').drawImage(this.video.nativeElement, 0, 0, videoWidth, videoHeight);

    // Convert to data URL with JPEG format for smaller file size
    this.clientImageDataURL = this.canvas.nativeElement.toDataURL('image/jpeg', 0.9);
  }

  /**
   * Allows user to capture image again.
   */
  recapture() {
    this.isCaptured = false;
    this.video.nativeElement.play();
  }
}