/**
 * 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/.
 */

import { Component, inject, ViewChild, ElementRef, AfterViewInit } from '@angular/core';
import { MAT_DIALOG_DATA, MatDialogRef, MatDialogContent, MatDialogActions } from '@angular/material/dialog';
import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';
import { FaIconComponent } from '@fortawesome/angular-fontawesome';

export interface ImageCropData {
  file: File;
  title: string;
  aspectRatio: number; // width/height, e.g. 1 for square, 1.5 for 3:2
  maxWidth: number;
  maxHeight: number;
}

@Component({
  selector: 'mifosx-image-crop-dialog',
  templateUrl: './image-crop-dialog.component.html',
  styleUrls: ['./image-crop-dialog.component.scss'],
  imports: [
    ...STANDALONE_SHARED_IMPORTS,
    FaIconComponent,
    MatDialogContent,
    MatDialogActions
  ]
})
export class ImageCropDialogComponent implements AfterViewInit {
  @ViewChild('sourceCanvas') sourceCanvas!: ElementRef<HTMLCanvasElement>;
  @ViewChild('previewCanvas') previewCanvas!: ElementRef<HTMLCanvasElement>;

  imageLoaded = false;
  private img = new Image();
  private imgWidth = 0;
  private imgHeight = 0;

  // Crop box (relative to displayed image)
  cropX = 0;
  cropY = 0;
  cropW = 200;
  cropH = 200;

  // Drag state
  private dragging = false;
  private dragStartX = 0;
  private dragStartY = 0;
  private dragStartCropX = 0;
  private dragStartCropY = 0;

  // Resize state
  private resizing = false;

  // Canvas display dimensions
  private canvasDisplayW = 0;
  private canvasDisplayH = 0;
  private scaleX = 1;
  private scaleY = 1;

  zoom = 1;

  dialogRef = inject(MatDialogRef<ImageCropDialogComponent>);
  data = inject<ImageCropData>(MAT_DIALOG_DATA);

  ngAfterViewInit() {
    const reader = new FileReader();
    reader.onload = (e: any) => {
      this.img.onload = () => {
        this.imageLoaded = true;
        setTimeout(() => this.initCanvas());
      };
      this.img.src = e.target.result;
    };
    reader.readAsDataURL(this.data.file);
  }

  private initCanvas() {
    const canvas = this.sourceCanvas.nativeElement;
    const ctx = canvas.getContext('2d')!;
    const container = canvas.parentElement!;

    const maxW = container.clientWidth || 500;
    const maxH = 400;

    // Scale image to fit container
    const ratio = Math.min(maxW / this.img.width, maxH / this.img.height, 1);
    this.canvasDisplayW = Math.floor(this.img.width * ratio);
    this.canvasDisplayH = Math.floor(this.img.height * ratio);
    this.imgWidth = this.img.width;
    this.imgHeight = this.img.height;

    canvas.width = this.canvasDisplayW;
    canvas.height = this.canvasDisplayH;
    this.scaleX = this.img.width / this.canvasDisplayW;
    this.scaleY = this.img.height / this.canvasDisplayH;

    // Init crop box centered
    const cropSize = Math.min(this.canvasDisplayW, this.canvasDisplayH) * 0.6;
    if (this.data.aspectRatio >= 1) {
      this.cropW = cropSize;
      this.cropH = cropSize / this.data.aspectRatio;
    } else {
      this.cropH = cropSize;
      this.cropW = cropSize * this.data.aspectRatio;
    }
    this.cropX = (this.canvasDisplayW - this.cropW) / 2;
    this.cropY = (this.canvasDisplayH - this.cropH) / 2;

    this.drawCanvas();
    this.updatePreview();
  }

  private drawCanvas() {
    const canvas = this.sourceCanvas.nativeElement;
    const ctx = canvas.getContext('2d')!;

    ctx.clearRect(0, 0, canvas.width, canvas.height);
    ctx.drawImage(this.img, 0, 0, canvas.width, canvas.height);

    // Dark overlay outside crop
    ctx.fillStyle = 'rgba(0,0,0,0.5)';
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    // Clear crop area
    ctx.clearRect(this.cropX, this.cropY, this.cropW, this.cropH);
    ctx.drawImage(
      this.img,
      this.cropX * this.scaleX,
      this.cropY * this.scaleY,
      this.cropW * this.scaleX,
      this.cropH * this.scaleY,
      this.cropX,
      this.cropY,
      this.cropW,
      this.cropH
    );

    // Crop border
    ctx.strokeStyle = '#1353a0';
    ctx.lineWidth = 2;
    ctx.strokeRect(this.cropX, this.cropY, this.cropW, this.cropH);

    // Corner handles
    const hs = 8;
    ctx.fillStyle = '#1353a0';
    const corners = [
      [
        this.cropX,
        this.cropY
      ],
      [
        this.cropX + this.cropW,
        this.cropY
      ],
      [
        this.cropX,
        this.cropY + this.cropH
      ],
      [
        this.cropX + this.cropW,
        this.cropY + this.cropH
      ]
    ];
    corners.forEach(
      ([
        x,
        y
      ]) => {
        ctx.fillRect(x - hs / 2, y - hs / 2, hs, hs);
      }
    );
  }

  private updatePreview() {
    if (!this.previewCanvas) return;
    const pCanvas = this.previewCanvas.nativeElement;
    const pCtx = pCanvas.getContext('2d')!;
    const pw = this.data.maxWidth || 150;
    const ph = this.data.maxHeight || 150;
    pCanvas.width = pw;
    pCanvas.height = ph;

    pCtx.clearRect(0, 0, pw, ph);
    pCtx.drawImage(
      this.img,
      this.cropX * this.scaleX,
      this.cropY * this.scaleY,
      this.cropW * this.scaleX,
      this.cropH * this.scaleY,
      0,
      0,
      pw,
      ph
    );
  }

  onMouseDown(event: MouseEvent) {
    const rect = this.sourceCanvas.nativeElement.getBoundingClientRect();
    const x = event.clientX - rect.left;
    const y = event.clientY - rect.top;

    // Check if near bottom-right corner for resize
    const cornerX = this.cropX + this.cropW;
    const cornerY = this.cropY + this.cropH;
    if (Math.abs(x - cornerX) < 12 && Math.abs(y - cornerY) < 12) {
      this.resizing = true;
      return;
    }

    // Check if inside crop box for drag
    if (x >= this.cropX && x <= this.cropX + this.cropW && y >= this.cropY && y <= this.cropY + this.cropH) {
      this.dragging = true;
      this.dragStartX = x;
      this.dragStartY = y;
      this.dragStartCropX = this.cropX;
      this.dragStartCropY = this.cropY;
    }
  }

  onMouseMove(event: MouseEvent) {
    if (!this.dragging && !this.resizing) return;
    const rect = this.sourceCanvas.nativeElement.getBoundingClientRect();
    const x = event.clientX - rect.left;
    const y = event.clientY - rect.top;

    if (this.dragging) {
      this.cropX = Math.max(0, Math.min(this.canvasDisplayW - this.cropW, this.dragStartCropX + (x - this.dragStartX)));
      this.cropY = Math.max(0, Math.min(this.canvasDisplayH - this.cropH, this.dragStartCropY + (y - this.dragStartY)));
    }

    if (this.resizing) {
      const newW = Math.max(40, Math.min(this.canvasDisplayW - this.cropX, x - this.cropX));
      const newH = newW / this.data.aspectRatio;
      if (this.cropY + newH <= this.canvasDisplayH) {
        this.cropW = newW;
        this.cropH = newH;
      }
    }

    this.drawCanvas();
    this.updatePreview();
  }

  onMouseUp() {
    this.dragging = false;
    this.resizing = false;
  }

  confirm() {
    // Create cropped image as blob
    const offscreen = document.createElement('canvas');
    offscreen.width = this.data.maxWidth || 300;
    offscreen.height = this.data.maxHeight || 300;
    const ctx = offscreen.getContext('2d')!;
    ctx.drawImage(
      this.img,
      this.cropX * this.scaleX,
      this.cropY * this.scaleY,
      this.cropW * this.scaleX,
      this.cropH * this.scaleY,
      0,
      0,
      offscreen.width,
      offscreen.height
    );

    offscreen.toBlob((blob) => {
      if (blob) {
        const croppedFile = new File([blob], this.data.file.name, { type: 'image/png' });
        this.dialogRef.close({ croppedFile, previewUrl: offscreen.toDataURL('image/png') });
      }
    }, 'image/png');
  }
}