using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using HtmlAgilityPack;
namespace InABox.Core
{
public static class HTMLUtils
{
///
/// Takes a HTML Snippet and converts it to full HTML.
/// This is used to convert Fast-Reports "html-enabled" text to Syncfusion RichTextEditor html.
///
/// The html snippet (no or tags, paragraphs represented by line breaks
/// Properly formed HTM suitable for editing
public static string TextToHtml(string text)
{
var result = text;
if (!result.Contains(""))
{
var lines = result.Split("\n").Select(l => $"{(string.IsNullOrWhiteSpace(l) ? " " : l)}
").ToList();
while (string.Equals(lines.LastOrDefault(),$"
"))
lines.RemoveAt(lines.Count-1);
result = $"{string.Join("\n",lines)}";
}
var doc = new HtmlDocument();
doc.LoadHtml(result);
HtmlNode? head = null;
var htmlnode = doc.DocumentNode.SelectSingleNode("//html");
if (!htmlnode.ChildNodes.Any(x => string.Equals(x.Name, "head", StringComparison.CurrentCultureIgnoreCase)))
{
head = doc.CreateElement("head");
htmlnode.PrependChild(head);
}
head = doc.DocumentNode.SelectSingleNode("//head");
if (head != null)
{
HtmlNode? style = null;
if (!head.ChildNodes.Any(x =>
string.Equals(x.Name, "style", StringComparison.CurrentCultureIgnoreCase)))
{
style = doc.CreateElement("style");
head.PrependChild(style);
}
else
style = head.ChildNodes["style"];
style.InnerHtml = "p { margin: 0px 0px 0px 0px; }";
}
return doc.DocumentNode.OuterHtml;
}
///
/// Converts HTML data to Fast-Reports compatible "html-enabled" text
/// Will dump tags that Fast-Reports cannot display
///
/// The HTML data to be processed
/// Text Suitable for printing using Fast-Reports
public static string HtmlToText(string html)
{
Dictionary _replacements = new Dictionary()
{
{ "\n", "" },
{ "\r", "" },
{ "]*>", "" },
{ "]*>", "\r\n" },
};
var doc = new HtmlDocument();
doc.LoadHtml(html);
ProcessNode(doc.DocumentNode, (n) => ReplaceAttribute(n, "font-style","italic", "i"));
ProcessNode(doc.DocumentNode, (n) => ReplaceAttribute(n, "text-decoration","underline", "u"));
ProcessNode(doc.DocumentNode, (n) => ReplaceAttribute(n, "font-weight","bold", "b"));
ProcessNode(doc.DocumentNode, (n) => ReplaceAttribute(n, "font-size","(.*?)", ""));
ProcessNode(doc.DocumentNode, (n) => ReplaceAttribute(n, "font-family","(.*?)", ""));
ProcessNode(doc.DocumentNode, (n) => ReplaceAttribute(n, "background","(.*?)", ""));
string result = doc.DocumentNode.SelectSingleNode("//body").InnerHtml;
foreach (var _key in _replacements.Keys)
result = Regex.Replace(result, _key, _replacements[_key]);
var lines = result.Split("\r\n").ToList();
while (string.IsNullOrWhiteSpace(lines.LastOrDefault()))
lines.RemoveAt(lines.Count-1);
return string.Join("\r\n", lines);
}
private static void ProcessNode(HtmlNode node, Action action)
{
if (node.Name.ToLower() == "span")
action(node);
foreach (var _child in node.ChildNodes)
ProcessNode(_child,action);
}
private static void ReplaceAttribute(HtmlNode node, string attribute, string value, string tag)
{
var _value = $"{attribute}:{value};";
var _style = node.Attributes.Contains("style") ? node.Attributes["style"] : null;
if (_style != null)
{
var _oldvalue = _style.Value;
_style.Value = Regex.Replace(_style.Value, _value, "");
if (!string.Equals(_style.Value, _oldvalue))
{
if (string.IsNullOrWhiteSpace(_style.Value))
node.Attributes.Remove("style");
if (!string.IsNullOrWhiteSpace(tag))
{
var text = node.OuterHtml;
node.Name = tag;
node.Attributes.RemoveAll();
node.InnerHtml = text;
}
}
}
}
}
}