using System;
using System.IO;
using Commons.Collections;
using NVelocity;
using NVelocity.App;
using NVelocity.Runtime.Directive;
using NVelocity.Runtime.Resource;
using NVelocity.Runtime.Resource.Loader;
using Taloyhtio.GeneralApi.Common;
using Taloyhtio.GeneralApi.Common.Extensions;
using Taloyhtio.GeneralApi.Core.Common;

namespace Taloyhtio.GeneralApi.Core.Services.Impl
{
    public class TemplateEngine : ITemplateEngine
    {
        public string Merge(string templateText, params Pair<string, object>[] args)
        {
            if (string.IsNullOrEmpty(templateText))
            {
                return templateText;
            }

            var context = new VelocityContext();
            if (!args.IsNullOrEmpty())
            {
                foreach (var t in args)
                {
                    context.Put(t.Item1, t.Item2);
                }
            }

            var velocity = new VelocityEngine();
            var props = new ExtendedProperties();
//            string templateFolder = "";
//            props.AddProperty("file.resource.loader.path",
//                templateFolder);
            props.AddProperty("resource.manager.class",
                typeof(ResourceManagerImpl).AssemblyQualifiedName);
            props.AddProperty("file.resource.loader.class",
                typeof(FileResourceLoader).AssemblyQualifiedName);
            props.AddProperty("directive.manager",
                typeof(DirectiveManager).AssemblyQualifiedName);
            velocity.Init(props);
            using (var sw = new StringWriter())
            {
                velocity.Evaluate(context, sw, "", templateText);
                sw.Flush();
                return sw.ToString();
            }
        }

        public string Merge(string templateFileName, string templateFolder, params Pair<string, object>[] args)
        {
            if (string.IsNullOrEmpty(templateFileName) || string.IsNullOrEmpty(templateFolder))
            {
                return string.Empty;
            }

            var context = new VelocityContext();
            if (!args.IsNullOrEmpty())
            {
                foreach (var t in args)
                {
                    context.Put(t.Item1, t.Item2);
                }
            }

            var velocity = new VelocityEngine();
            var props = new ExtendedProperties();
            props.AddProperty("file.resource.loader.path",
                templateFolder);
            props.AddProperty("resource.manager.class",
                typeof(ResourceManagerImpl).AssemblyQualifiedName);
            props.AddProperty("file.resource.loader.class",
                typeof(FileResourceLoader).AssemblyQualifiedName);
            props.AddProperty("directive.manager",
                typeof(DirectiveManager).AssemblyQualifiedName);
            velocity.Init(props);

            var template = velocity.GetTemplate(templateFileName);

            using (var sw = new StringWriter())
            {
                template.Merge(context, sw);
                sw.Flush();
                return sw.ToString();
            }

        }
    }
}