Introduction to Bellevue View Engine - Part 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Ope.Bellevue.Renderers.General;

namespace Ope.Bellevue.Parsing
{
    public class DeclarationHandler
    {        
        public bool Handle(HtmlAgilityPack.HtmlNode node, ElementDeclaration declr, Ope.Bellevue.Parsing.ParsedViewBase parseResult)
        {
            var instruction = new Ope.Bellevue.Rendering.RenderingInstruction(declr);

            switch (instruction.DeclarationName)
            {
                // Elements
                case "apply-template":
                    instruction.SetRenderer(typeof(ApplyTemplate));
                    instruction.AddParameter("value", declr.Expression, 0);
                    instruction.AddParameter("template-id", declr.Expression, 1);
                    parseResult.AddRendering(node, instruction);
                    return true;                
                case "debugger":
                    instruction.SetRenderer(typeof(Ope.Bellevue.Renderers.Infra.PrintDebugger));
                    parseResult.AddRendering(node, instruction);
                    return true;
                case "text":
                    instruction.SetRenderer(typeof(Text));
                    instruction.AddParameter("value", declr.Expression, 0);
                    parseResult.AddRendering(node, instruction);
                    return true;
                case "text-replace":
                    instruction.SetRenderer(typeof(TextReplace));
                    instruction.AddParameter("replace-text", declr.Expression, 0);
                    instruction.AddParameter("value", declr.Expression, 1);
                    instruction.AddParameter("original-text", node.InnerText);
                    parseResult.AddRendering(node, instruction);
                    return true;
                case "text-format":
                    instruction.SetRenderer(typeof(TextFormat));
                    instruction.AddParameter("value", declr.Expression, 0);
                    if (declr.Expression.Terms.Count > 1)
                    {
                        instruction.AddParameter("format-text", declr.Expression, 1);
                    }
                    else
                    {
                        instruction.AddParameter("format-text", node.InnerText);
                    }
                    parseResult.AddRendering(node, instruction);
                    return true;
                case "html":
                    instruction.SetRenderer(typeof(Text));
                    instruction.AddParameter("value", declr.Expression, 0);
                    instruction.AddParameter("noEncoding", "true");
                    parseResult.AddRendering(node, instruction);
                    return true;
                case "render-control":
                    instruction.SetRenderer(typeof(RenderControl));
                    instruction.AddParameter("value", declr.Expression, 0);
                    parseResult.AddRendering(node, instruction);
                    return true;
                case "action-link":
                    instruction.SetRenderer(typeof(Ope.Bellevue.Renderers.MvcHtmlHelper));
                    for (int i = 0; i < declr.Expression.Terms.Count; i++)
                    {
                        instruction.AddParameter("parameter" + i, declr.Expression, i);
                    }
                    parseResult.AddRendering(node, instruction);
                    return true;
                case "placeholder-id":
                    instruction.SetRenderer(typeof(Ope.Bellevue.Renderers.Infra.ContentPlaceholder));
                    instruction.AddParameter("id", declr.Expression, 0);
                    // HACK: Rewrite rendering of the inner HTML
                    instruction.AddParameter("original-value", node.InnerHtml);
                    parseResult.AddRendering(node, instruction);
                    return true;

                // Attributes
                case "attr":
                    instruction.SetRenderer(typeof(Text));
                    // TODO: More robust way to get the term
                    string attrName = declr.Expression.Terms[0].Value;
                    instruction.AddParameter("attr-name", attrName);
                    instruction.AddParameter("original-value", node.GetAttributeValue(attrName, ""));
                    instruction.AddParameter("value", declr.Expression, 1);
                    parseResult.AddRendering(attrName, node, instruction);
                    return true;
                case "style":
                    instruction.SetRenderer(typeof(Text));
                    instruction.AddParameter("attr-name", "style");
                    string originalValue = node.GetAttributeValue("style", "");
                    if (originalValue != "")
                    {
                        if (instruction.Position == Ope.Bellevue.Rendering.RelativePosition.Append)
                        {
                            originalValue = originalValue + ";";
                        }
                        if (instruction.Position == Ope.Bellevue.Rendering.RelativePosition.Insert)
                        {
                            originalValue = ";" + originalValue;
                        }
                    }
                    instruction.AddParameter("original-value", originalValue);
                    instruction.AddParameter("value", declr.Expression, 0);
                    parseResult.AddRendering("style", node, instruction);
                    return true;
                case "class":
                    instruction.SetRenderer(typeof(Text));
                    instruction.AddParameter("attr-name", "class");
                    string originalClass = node.GetAttributeValue("class", "");
                    if (originalClass != "")
                    {
                        if (instruction.Position == Ope.Bellevue.Rendering.RelativePosition.Append)
                        {
                            originalClass = originalClass + " ";
                        }
                        if (instruction.Position == Ope.Bellevue.Rendering.RelativePosition.Insert)
                        {
                            originalClass = " " + originalClass;
                        }
                    }
                    instruction.AddParameter("original-value", originalClass);
                    instruction.AddParameter("value", declr.Expression, 0);
                    parseResult.AddRendering("class", node, instruction);
                    return true;
                case "value":
                    instruction.SetRenderer(typeof(Text));
                    instruction.AddParameter("attr-name", "value");
                    instruction.AddParameter("original-value", node.GetAttributeValue("value", ""));
                    instruction.AddParameter("value", declr.Expression, 0);
                    parseResult.AddRendering("value", node, instruction);
                    return true;
                case "checked":
                    instruction.SetRenderer(typeof(Checked));
                    instruction.AddParameter("value", declr.Expression, 0);
                    parseResult.AddRendering("checked", node, instruction);
                    return true;
                default:
                    return false;
            }
        }
    }
}