/*
 * 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 'package:meta/meta.dart';
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart';
import 'package:vector_math/vector_math_64.dart';
import 'package:xml/xml.dart';

import '../svg/painter.dart';
import '../svg/parser.dart';

class SvgImage extends Widget {
  factory SvgImage({
    @required String svg,
    BoxFit fit = BoxFit.contain,
    Alignment alignment = Alignment.center,
    bool clip = true,
    double width,
    double height,
  }) {
    assert(clip != null);
    assert(alignment != null);

    final xml = XmlDocument.parse(svg);
    final parser = SvgParser(xml: xml);

    return SvgImage._fromParser(
      parser,
      fit,
      alignment,
      clip,
      width,
      height,
    );
  }

  SvgImage._fromParser(
    this._svgParser,
    this.fit,
    this.alignment,
    this.clip,
    this.width,
    this.height,
  )   : assert(_svgParser != null),
        assert(fit != null),
        assert(alignment != null);

  final SvgParser _svgParser;

  final BoxFit fit;

  final Alignment alignment;

  final bool clip;

  final double width;

  final double height;

  FittedSizes sizes;

  @override
  void layout(Context context, BoxConstraints constraints,
      {bool parentUsesSize = false}) {
    final w = width != null || _svgParser.width != null
        ? constraints.constrainWidth(width ?? _svgParser.width)
        : constraints.hasBoundedWidth
            ? constraints.maxWidth
            : constraints.constrainWidth(_svgParser.viewBox.width);
    final h = height != null || _svgParser.height != null
        ? constraints.constrainHeight(height ?? _svgParser.height)
        : constraints.hasBoundedHeight
            ? constraints.maxHeight
            : constraints.constrainHeight(_svgParser.viewBox.height);

    sizes = applyBoxFit(fit, _svgParser.viewBox.size, PdfPoint(w, h));
    box = PdfRect.fromPoints(PdfPoint.zero, sizes.destination);
  }

  @override
  void paint(Context context) {
    super.paint(context);

    final _alignment = Alignment(alignment.x, -alignment.y);
    final sourceRect = _alignment.inscribe(sizes.source, _svgParser.viewBox);
    final sx = sizes.destination.x / sizes.source.x;
    final sy = sizes.destination.y / sizes.source.y;
    final dx = sourceRect.x * sx;
    final dy = sourceRect.y * sy;

    final mat = Matrix4.identity()
      ..translate(
        box.x - dx,
        box.y + dy + box.height,
      )
      ..scale(sx, -sy);

    context.canvas.saveContext();
    if (clip) {
      context.canvas
        ..drawBox(box)
        ..clipPath();
    }
    context.canvas.setTransform(mat);

    final painter = SvgPainter(
      _svgParser,
      context.canvas,
      context.document,
      PdfRect(
        0,
        0,
        context.page.pageFormat.width,
        context.page.pageFormat.height,
      ),
    );
    painter.paint();
    context.canvas.restoreContext();
  }
}