using System;
using System.Linq;
using Sprache;
using XNeedle.Parser;
using XNeedle.Parser.Elements;

namespace XNeedle.Transformation
{
    public class ContextFunctions
    {
        public static string hex(Context ctx, double value)
        {
            uint v = (uint)value;
            return $"#x{v:X8}";
        }

        public static double GetLevel(Context ctx)
        {
            int level = 0;
            System.Xml.Linq.XElement? n = ctx.Node;
            while (null != (n = n?.Parent))
                level++;
            return level;
        }
        public static double crc(Context ctx)
        {
            if (ctx.Node is null)
            {
                return 0;
            }
            int crc = 0xAFFE;

            return (double)crc;
        }

        public static string text(Context ctx)
        {
            if (ctx.Node is null) return "";
            return ctx.Node.Value;
        }

        public static string text(Context ctx, string txt)
        {
            if (ctx.Node is null) return "";
            ctx.Node.SetValue(txt);
            return txt;
        }

        public static string cdata(Context ctx)
        {
            if (ctx.Node is null) return "";
            var cdataNode = ctx.Node.Nodes().OfType<System.Xml.Linq.XCData>().FirstOrDefault();
            return cdataNode?.Value ?? "";
        }

        public static string cdata(Context ctx, string txt)
        {
            if (ctx.Node is null) return "";
            var cdataNode = ctx.Node.Nodes().OfType<System.Xml.Linq.XCData>().FirstOrDefault();
            if (cdataNode != null)
            {
                cdataNode.Value = txt;
            }
            else
            {
                ctx.Node.Add(new System.Xml.Linq.XCData(txt));
            }
            return txt;
        }

        public static string attr(Context ctx, string name, string value)
        {
            if (ctx.Node is null) return "";
            var attr = ctx.Node.Attribute(name);
            if (attr != null)
            {
                attr.Value = value;
            }
            else
            {
                ctx.Node.SetAttributeValue(name, value);
            }
            return "";
        }

        public static string attr(Context ctx, string name)
        {
            var attr = ctx.Node?.Attribute(name);
            if (attr != null)
            {
                return attr.Value;
            }
            return "";
        }
    }
}