import 'package:flutter/material.dart';
import 'package:flutter_html/src/css_parser.dart';
import 'package:flutter_html/style.dart';
import 'package:html/dom.dart' as dom;
//TODO(Sub6Resources): don't use the internal code of the html package as it may change unexpectedly.
//ignore: implementation_imports
import 'package:html/src/query_selector.dart';

/// A [StyledElement] applies a style to all of its children.
class StyledElement {
  final String name;
  final String elementId;
  final List<String> elementClasses;
  List<StyledElement> children;
  Style style;
  final dom.Element? _node;

  StyledElement({
    this.name = "[[No name]]",
    this.elementId = "[[No ID]]",
    this.elementClasses = const [],
    required this.children,
    required this.style,
    required dom.Element? node,
  }) : this._node = node;

  bool matchesSelector(String selector) =>
      (_node != null && matches(_node!, selector)) || name == selector;

  Map<String, String> get attributes =>
      _node?.attributes.map((key, value) {
        return MapEntry(key.toString(), value);
      }) ??
      Map<String, String>();

  dom.Element? get element => _node;

  @override
  String toString() {
    String selfData =
        "[$name] ${children.length} ${elementClasses.isNotEmpty == true ? 'C:${elementClasses.toString()}' : ''}${elementId.isNotEmpty == true ? 'ID: $elementId' : ''}";
    children.forEach((child) {
      selfData += ("\n${child.toString()}")
          .replaceAll(RegExp("^", multiLine: true), "-");
    });
    return selfData;
  }
}

StyledElement parseStyledElement(
    dom.Element element, List<StyledElement> children) {
  StyledElement styledElement = StyledElement(
    name: element.localName!,
    elementId: element.id,
    elementClasses: element.classes.toList(),
    children: children,
    node: element,
    style: Style(),
  );

  switch (element.localName) {
    case "abbr":
    case "acronym":
      styledElement.style = Style(
        textDecoration: TextDecoration.underline,
        textDecorationStyle: TextDecorationStyle.dotted,
      );
      break;
    case "address":
      continue italics;
    case "article":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "aside":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    bold:
    case "b":
      styledElement.style = Style(
        fontWeight: FontWeight.bold,
      );
      break;
    case "bdo":
      TextDirection textDirection =
          ((element.attributes["dir"] ?? "ltr") == "rtl")
              ? TextDirection.rtl
              : TextDirection.ltr;
      styledElement.style = Style(
        direction: textDirection,
      );
      break;
    case "big":
      styledElement.style = Style(
        fontSize: FontSize.larger,
      );
      break;
    case "blockquote":
      //TODO(Sub6Resources) this is a workaround for collapsing margins. Remove.
      if (element.parent!.localName == "blockquote") {
        styledElement.style = Style(
          margin: const EdgeInsets.only(left: 40.0, right: 40.0, bottom: 14.0),
          display: Display.BLOCK,
        );
      } else {
        styledElement.style = Style(
          margin: const EdgeInsets.symmetric(horizontal: 40.0, vertical: 14.0),
          display: Display.BLOCK,
        );
      }
      break;
    case "body":
      styledElement.style = Style(
        margin: EdgeInsets.all(8.0),
        display: Display.BLOCK,
      );
      break;
    case "center":
      styledElement.style = Style(
        alignment: Alignment.center,
        display: Display.BLOCK,
      );
      break;
    case "cite":
      continue italics;
    monospace:
    case "code":
      styledElement.style = Style(
        fontFamily: 'Monospace',
      );
      break;
    case "dd":
      styledElement.style = Style(
        margin: EdgeInsets.only(left: 40.0),
        display: Display.BLOCK,
      );
      break;
    strikeThrough:
    case "del":
      styledElement.style = Style(
        textDecoration: TextDecoration.lineThrough,
      );
      break;
    case "dfn":
      continue italics;
    case "div":
      styledElement.style = Style(
        margin: EdgeInsets.all(0),
        display: Display.BLOCK,
      );
      break;
    case "dl":
      styledElement.style = Style(
        margin: EdgeInsets.symmetric(vertical: 14.0),
        display: Display.BLOCK,
      );
      break;
    case "dt":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "em":
      continue italics;
    case "figcaption":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "figure":
      styledElement.style = Style(
        margin: EdgeInsets.symmetric(vertical: 14.0, horizontal: 40.0),
        display: Display.BLOCK,
      );
      break;
    case "footer":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "font":
      styledElement.style = Style(
        color: element.attributes['color'] != null ?
          element.attributes['color']!.startsWith("#") ?
            ExpressionMapping.stringToColor(element.attributes['color']!) :
            ExpressionMapping.namedColorToColor(element.attributes['color']!) :
          null,
        fontFamily: element.attributes['face']?.split(",").first,
        fontSize: element.attributes['size'] != null ? numberToFontSize(element.attributes['size']!) : null,
      );
      break;
    case "h1":
      styledElement.style = Style(
        fontSize: FontSize.xxLarge,
        fontWeight: FontWeight.bold,
        margin: EdgeInsets.symmetric(vertical: 18.67),
        display: Display.BLOCK,
      );
      break;
    case "h2":
      styledElement.style = Style(
        fontSize: FontSize.xLarge,
        fontWeight: FontWeight.bold,
        margin: EdgeInsets.symmetric(vertical: 17.5),
        display: Display.BLOCK,
      );
      break;
    case "h3":
      styledElement.style = Style(
        fontSize: FontSize(16.38),
        fontWeight: FontWeight.bold,
        margin: EdgeInsets.symmetric(vertical: 16.5),
        display: Display.BLOCK,
      );
      break;
    case "h4":
      styledElement.style = Style(
        fontSize: FontSize.medium,
        fontWeight: FontWeight.bold,
        margin: EdgeInsets.symmetric(vertical: 18.5),
        display: Display.BLOCK,
      );
      break;
    case "h5":
      styledElement.style = Style(
        fontSize: FontSize(11.62),
        fontWeight: FontWeight.bold,
        margin: EdgeInsets.symmetric(vertical: 19.25),
        display: Display.BLOCK,
      );
      break;
    case "h6":
      styledElement.style = Style(
        fontSize: FontSize(9.38),
        fontWeight: FontWeight.bold,
        margin: EdgeInsets.symmetric(vertical: 22),
        display: Display.BLOCK,
      );
      break;
    case "header":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "hr":
      styledElement.style = Style(
        margin: EdgeInsets.symmetric(vertical: 7.0),
        width: double.infinity,
        height: 1,
        backgroundColor: Colors.black,
        display: Display.BLOCK,
      );
      break;
    case "html":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    italics:
    case "i":
      styledElement.style = Style(
        fontStyle: FontStyle.italic,
      );
      break;
    case "ins":
      continue underline;
    case "kbd":
      continue monospace;
    case "li":
      styledElement.style = Style(
        display: Display.LIST_ITEM,
      );
      break;
    case "main":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "mark":
      styledElement.style = Style(
        color: Colors.black,
        backgroundColor: Colors.yellow,
      );
      break;
    case "nav":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "noscript":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "ol":
    case "ul":
      //TODO(Sub6Resources): This is a workaround for collapsed margins. Remove.
      if (element.parent!.localName == "li") {
        styledElement.style = Style(
//          margin: EdgeInsets.only(left: 30.0),
          display: Display.BLOCK,
          listStyleType: element.localName == "ol"
              ? ListStyleType.DECIMAL
              : ListStyleType.DISC,
        );
      } else {
        styledElement.style = Style(
//          margin: EdgeInsets.only(left: 30.0, top: 14.0, bottom: 14.0),
          display: Display.BLOCK,
          listStyleType: element.localName == "ol"
              ? ListStyleType.DECIMAL
              : ListStyleType.DISC,
        );
      }
      break;
    case "p":
      styledElement.style = Style(
        margin: EdgeInsets.symmetric(vertical: 14.0),
        display: Display.BLOCK,
      );
      break;
    case "pre":
      styledElement.style = Style(
        fontFamily: 'monospace',
        margin: EdgeInsets.symmetric(vertical: 14.0),
        whiteSpace: WhiteSpace.PRE,
        display: Display.BLOCK,
      );
      break;
    case "q":
      styledElement.style = Style(
        before: "\"",
        after: "\"",
      );
      break;
    case "s":
      continue strikeThrough;
    case "samp":
      continue monospace;
    case "section":
      styledElement.style = Style(
        display: Display.BLOCK,
      );
      break;
    case "small":
      styledElement.style = Style(
        fontSize: FontSize.smaller,
      );
      break;
    case "strike":
      continue strikeThrough;
    case "strong":
      continue bold;
    case "sub":
      styledElement.style = Style(
        fontSize: FontSize.smaller,
        verticalAlign: VerticalAlign.SUB,
      );
      break;
    case "sup":
      styledElement.style = Style(
        fontSize: FontSize.smaller,
        verticalAlign: VerticalAlign.SUPER,
      );
      break;
    case "tt":
      continue monospace;
    underline:
    case "u":
      styledElement.style = Style(
        textDecoration: TextDecoration.underline,
      );
      break;
    case "var":
      continue italics;
  }

  return styledElement;
}

typedef ListCharacter = String Function(int i);

FontSize numberToFontSize(String num) {
  switch (num) {
    case "1":
      return FontSize.xxSmall;
    case "2":
      return FontSize.xSmall;
    case "3":
      return FontSize.small;
    case "4":
      return FontSize.medium;
    case "5":
      return FontSize.large;
    case "6":
      return FontSize.xLarge;
    case "7":
      return FontSize.xxLarge;
  }
  if (num.startsWith("+")) {
    final relativeNum = double.tryParse(num.substring(1)) ?? 0;
    return numberToFontSize((3 + relativeNum).toString());
  }
  if (num.startsWith("-")) {
    final relativeNum = double.tryParse(num.substring(1)) ?? 0;
    return numberToFontSize((3 - relativeNum).toString());
  }
  return FontSize.medium;
}