/*
 * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import 'dart:typed_data';

import 'package:image/image.dart' as im;

import '../../pdf.dart';
import 'widget.dart';

/// Identifies an image without committing to the precise final asset
abstract class ImageProvider {
  ImageProvider(
    this._width,
    this._height,
    this.orientation,
    this.dpi,
  );

  final double? dpi;

  final int? _width;

  /// Image width
  int? get width => orientation.index >= 4 ? _height : _width;

  final int _height;

  /// Image height
  int? get height => orientation.index < 4 ? _height : _width;

  /// The internal orientation of the image
  final PdfImageOrientation orientation;

  final _cache = <int, PdfImage>{};

  PdfImage buildImage(Context context, {int? width, int? height});

  /// Resolves this image provider using the given context, returning a PdfImage
  /// The image is automatically added to the document
  PdfImage resolve(Context context, PdfPoint size, {double? dpi}) {
    final effectiveDpi = dpi ?? this.dpi;

    if (effectiveDpi == null || _cache[0] != null) {
      _cache[0] ??= buildImage(context);

      if (_cache[0]!.pdfDocument != context.document) {
        _cache[0] = buildImage(context);
      }

      return _cache[0]!;
    }

    final width = (size.x / PdfPageFormat.inch * effectiveDpi).toInt();
    final height = (size.y / PdfPageFormat.inch * effectiveDpi).toInt();

    if (!_cache.containsKey(width)) {
      _cache[width] ??= buildImage(context, width: width, height: height);
    }

    if (_cache[width]!.pdfDocument != context.document) {
      _cache[width] = buildImage(context, width: width, height: height);
    }

    return _cache[width]!;
  }
}

class ImageProxy extends ImageProvider {
  ImageProxy(
    this._image, {
    double? dpi,
  }) : super(_image.width, _image.height, _image.orientation, dpi);

  /// The proxy image
  final PdfImage _image;

  @override
  PdfImage buildImage(Context context, {int? width, int? height}) => _image;
}

class MemoryImage extends ImageProvider {
  factory MemoryImage(
    Uint8List bytes, {
    PdfImageOrientation? orientation,
    double? dpi,
  }) {
    final decoder = im.findDecoderForData(bytes);
    if (decoder == null) {
      throw Exception('Unable to guess the image type ${bytes.length} bytes');
    }

    if (decoder is im.JpegDecoder) {
      final info = PdfJpegInfo(bytes);

      return MemoryImage._(
        bytes,
        info.width,
        info.height,
        orientation ?? info.orientation,
        dpi,
      );
    }

    final info = decoder.startDecode(bytes);

    if (info == null) {
      throw Exception('Unable decode the image');
    }

    return MemoryImage._(
      bytes,
      info.width,
      info.height,
      orientation ?? PdfImageOrientation.topLeft,
      dpi,
    );
  }

  MemoryImage._(
    this.bytes,
    int? width,
    int height,
    PdfImageOrientation orientation,
    double? dpi,
  ) : super(width, height, orientation, dpi);

  /// The image data
  final Uint8List bytes;

  @override
  PdfImage buildImage(Context context, {int? width, int? height}) {
    if (width == null) {
      return PdfImage.file(context.document, bytes: bytes);
    }

    final image = im.decodeImage(bytes);

    if (image == null) {
      throw Exception('Unable decode the image');
    }

    final resized = im.copyResize(image, width: width);
    return PdfImage.fromImage(context.document, image: resized);
  }
}

class ImageImage extends ImageProvider {
  ImageImage(
    this._image, {
    double? dpi,
    PdfImageOrientation? orientation,
  }) : super(_image.width, _image.height,
            orientation ?? PdfImageOrientation.topLeft, dpi);

  /// The image data
  final im.Image _image;

  @override
  PdfImage buildImage(Context context, {int? width, int? height}) {
    if (width == null) {
      return PdfImage.fromImage(context.document, image: _image);
    }

    final resized = im.copyResize(_image, width: width);
    return PdfImage.fromImage(context.document, image: resized);
  }
}

class RawImage extends ImageImage {
  RawImage({
    required Uint8List bytes,
    required int width,
    required int height,
    PdfImageOrientation? orientation,
    double? dpi,
  }) : super(PdfRasterBase(width, height, true, bytes).asImage(),
            orientation: orientation, dpi: dpi);
}