// /**
//  * File: TemplateElement.cs
//  * Author: haraldwolff
//  *
//  * This file and it's content is copyrighted by the Author and / or copyright holder.
//  * Any use wihtout proper permission is illegal and may lead to legal actions.
//  *
//  *
//  **/
using System;
using System.Collections;
using System.Collections.Generic;
using ln.templates.script;

namespace ln.templates.html
{
    public class TemplateElement : Element
    {
        Dictionary<string, NewExpression> expressions = new Dictionary<string, NewExpression>();
        Dictionary<string, NewExpression> loops = new Dictionary<string, NewExpression>();
        List<NewExpression> conditions = new List<NewExpression>();

        NewExpression includeExpression;

        bool hideTag;

        public TemplateElement(string tagName)
            :base(tagName)
        {
            hideTag = "template".Equals(tagName.ToLower());
        }

        public override void SetAttribute(string attributeName, string attributeValue)
        {
            if (attributeName.StartsWith("v-for:", StringComparison.InvariantCultureIgnoreCase))
                loops.Add(attributeName.Substring(6), new NewExpression(attributeValue));
            else if (attributeName.Equals("v-if", StringComparison.InvariantCultureIgnoreCase))
                conditions.Add(new NewExpression(attributeValue));
            else if (attributeName.Equals("v-include", StringComparison.InvariantCultureIgnoreCase))
                includeExpression = new NewExpression(attributeValue);
            else if (attributeName[0] == ':')
                expressions.Add(attributeName.Substring(1), new NewExpression(attributeValue));
            else
                base.SetAttribute(attributeName, attributeValue);
        }

        public virtual void RenderTemplate(RenderContext renderContext)
        {
            if (loops.Count == 0)
            {
                RenderElement(renderContext);
            } else
            {
                Stack<KeyValuePair<string, NewExpression>> loopStack = new Stack<KeyValuePair<string, NewExpression>>(loops);
                DoLoop(renderContext, loopStack);
            }
        }

        void DoLoop(RenderContext renderContext, Stack<KeyValuePair<string, NewExpression>> loopStack)
        {
            if (loopStack.Count == 0)
            {
                RenderElement(renderContext);
            } else
            {
                KeyValuePair<string, NewExpression> loop = loopStack.Pop();
                IEnumerable enumerable = (IEnumerable)loop.Value.Resolve(renderContext);
                foreach (object o in enumerable)
                {
                    renderContext.SetScriptObject(loop.Key, o);
                    DoLoop(renderContext, loopStack);
                }
                loopStack.Push(loop);
            }
        }

        void RenderElement(RenderContext renderContext)
        {
            if (checkConditions(renderContext))
            {
                if (includeExpression != null)
                {
                    object includeValue = includeExpression.Resolve(renderContext);
                    if (!(includeValue is TemplateDocument includeTemplate))
                    {
                        includeTemplate = renderContext.TemplateSource.GetTemplateByPath((string)includeValue);
                    }
                    includeTemplate.RenderTemplate(renderContext, true);
                }
                else
                {
                    if (!hideTag)
                    {
                        renderContext.ContentWriter.Write("<{0}", Name);
                        foreach (KeyValuePair<String, String> attributePair in Attributes)
                            renderContext.ContentWriter.Write(" {0}=\"{1}\"", attributePair.Key, attributePair.Value);

                        foreach (KeyValuePair<string,NewExpression> keyValuePair in expressions)
                        {
                            object value = keyValuePair.Value.Resolve(renderContext);
                            if (value != null)
                            {
                                renderContext.ContentWriter.Write(" {0}=\"{1}\"", keyValuePair.Key, value);
                            }
                        }

                        renderContext.ContentWriter.Write(">");
                    }

                    if (!IsVoid)
                    {
                        foreach (Element element in Children)
                        {
                            if (element is TemplateElement templateElement)
                            {
                                templateElement.RenderTemplate(renderContext);
                            }
                            else
                            {
                                renderContext.ContentWriter.Write(element.ToString());
                            }
                        }

                        if (!hideTag)
                            renderContext.ContentWriter.Write("</{0}>", Name);
                    }
                }
            }
        }

        bool checkConditions(RenderContext renderContext)
        {
            foreach (NewExpression condition in conditions)
                if (!condition.IsTrue(renderContext))
                    return false;
            return true;
        }

    }
}