using Sarand.Net.Standard.Base.Core;
using Sarand.Net.Standard.Base.Utils;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;

namespace Sarand.Net.Standard.Proc.Xml
{
	//=======================================================================
	public class SaXmlNamespace
	{
		public SaXmlNamespace (String prefix, String uri)
		{
			Prefix = prefix;
			Uri = uri;
		}
		public String Prefix { get; }
		public String Uri { get; }
	}

	//=======================================================================
	public static class SaMsXmlUtil
	{
		//-------------------------------------------------------------------
		// Data members.
		public static Encoding DefaultEncoding { get; } = Encoding.UTF8;

		//-------------------------------------------------------------------
		/// <summary>Retrieve the Xml Declaration from the XML document.</summary>
		public static XmlDeclaration GetXmlDeclaration (this XmlDocument xmlDoc)
		{
			return xmlDoc.ChildNodes.OfType<XmlDeclaration>().FirstOrDefault();
		}

		//-------------------------------------------------------------------
		// Convert XML document to string.
		public static String GetXml (this XmlDocument xmlDoc, Encoding encoding = null)
		{
			// Ensure correct encoding for generated XML data.
			if (encoding == null) encoding = DefaultEncoding;
			XmlWriterSettings settings = new XmlWriterSettings() { Encoding = encoding };
			using (var stringWriter = new StringWriter())
			using (var xmlTextWriter = XmlWriter.Create(stringWriter, settings))
			{
				// Ensure that the document has the requested encoding in its XML declaration.
				XmlDeclaration xmlDeclaration = xmlDoc.GetXmlDeclaration();
				if (xmlDeclaration == null)
				{
					xmlDeclaration = xmlDoc.CreateXmlDeclaration("1.0", encoding.WebName, null);
					xmlDoc.InsertBefore(xmlDeclaration, xmlDoc.DocumentElement);
				}
				else xmlDeclaration.Encoding = encoding.WebName;
				// Write the document to String.
				xmlDoc.WriteTo(xmlTextWriter);
				xmlTextWriter.Flush();
				return stringWriter.GetStringBuilder().ToString();
			}
		}
		public static String FormatXml (this XmlDocument xmlDoc, Encoding encoding = null)
		{
			// Ensure correct encoding for generated XML data.
			if (encoding == null) encoding = DefaultEncoding;
			XmlWriterSettings settings = new XmlWriterSettings() { Encoding = encoding, Indent = true };
			using (MemoryStream memoryStream = new MemoryStream())
			using (var xmlTextWriter = new XmlTextWriter(memoryStream, encoding))
			{
				// XML output format.
				xmlTextWriter.Formatting = Formatting.Indented;
				// Ensure that the document has the requested encoding in its XML declaration.
				XmlDeclaration xmlDeclaration = xmlDoc.GetXmlDeclaration();
				if (xmlDeclaration == null)
				{
					xmlDeclaration = xmlDoc.CreateXmlDeclaration("1.0", encoding.WebName, null);
					xmlDoc.InsertBefore(xmlDeclaration, xmlDoc.DocumentElement);
				}
				else xmlDeclaration.Encoding = encoding.WebName;
				// Write the document to String.
				xmlDoc.WriteTo(xmlTextWriter);
				xmlTextWriter.Flush();
				memoryStream.Flush();
				memoryStream.Position = 0;
				using (StreamReader streamReader = new StreamReader(memoryStream))
				{
					return streamReader.ReadToEnd();
				}
			}
		}

		//-------------------------------------------------------------------
		// Append element to node.
		public static XmlElement AppendElement (this XmlNode node, String name, String text = "")
		{
			XmlDocument doc = (node is XmlDocument ? node as XmlDocument : node.OwnerDocument);
			XmlElement child = (XmlElement)node.AppendChild(doc.CreateElement(name));
			if (!StringUtil.IsEmpty(text))
				child.AppendChild(doc.CreateTextNode(text));
			return child;
		}
		public static XmlElement AppendElement (this XmlNode node, SaXmlNamespace xmlNamespace, String name, String text = "")
		{
			XmlDocument doc = (node is XmlDocument ? node as XmlDocument : node.OwnerDocument);
			XmlElement child = (XmlElement)node.AppendChild(doc.CreateElement(xmlNamespace.Prefix, name, xmlNamespace.Uri));
			if (!StringUtil.IsEmpty(text))
				child.AppendChild(doc.CreateTextNode(text));
			return child;
		}

		//-------------------------------------------------------------------
		// Get child text.
		public static String GetChildText (this XmlNode node, String name)
		{
			foreach (XmlNode child in node.ChildNodes)
				if (child.Name.EqualsCI(name))
					return child.InnerText;
			return String.Empty;
		}

		//-------------------------------------------------------------------
	}
	//=======================================================================
}