using RazorEngine;
using RazorEngine.Templating;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace Tango.CodeGeneration
{
    /// <summary>
    /// Contains several code generation helper methods.
    /// </summary>
    internal static class Helper
    {
        /// <summary>
        /// Gets a code template by the code object type.
        /// </summary>
        /// <param name="type">The type.</param>
        /// <returns></returns>
        public static String GetTemplate(Type type)
        {
            return GetTemplate(type.Name);
        }

        /// <summary>
        /// Gets a code template by name.
        /// </summary>
        /// <param name="name">The name.</param>
        /// <returns></returns>
        public static String GetTemplate(String name)
        {
            var assembly = Assembly.GetAssembly(typeof(Helper));
            var resourceName = typeof(Helper).Namespace + ".Templates." + name + ".cshtml";

            using (Stream stream = assembly.GetManifestResourceStream(resourceName))
            {
                using (StreamReader reader = new StreamReader(stream))
                {
                    return reader.ReadToEnd();
                }
            }
        }

        /// <summary>
        /// Parses the template using Razor Engine.
        /// </summary>
        /// <param name="template">The template.</param>
        /// <param name="model">The model.</param>
        /// <returns></returns>
        public static String ParseTemplate(String template, object model)
        {
            return Engine.Razor.RunCompile(template, Guid.NewGuid().ToString(), model.GetType(), model).Replace("<div>", "").Replace("</div>", "");
        }

        /// <summary>
        /// Indents the c sharp code.
        /// </summary>
        /// <param name="code">The code.</param>
        /// <returns></returns>
        public static string IndentCSharpCode(string code)
        {
            const string INDENT_STEP = "    ";

            if (string.IsNullOrWhiteSpace(code))
            {
                return code;
            }

            var result = new StringBuilder();
            var indent = string.Empty;
            var lineContent = false;
            var stringDefinition = false;

            for (var i = 0; i < code.Length; i++)
            {
                var ch = code[i];

                if (ch == '"' && !stringDefinition)
                {
                    result.Append(ch);
                    stringDefinition = true;
                    continue;
                }

                if (ch == '"' && stringDefinition)
                {
                    result.Append(ch);
                    stringDefinition = false;
                    continue;
                }

                if (stringDefinition)
                {
                    result.Append(ch);
                    continue;
                }

                if (ch == '{' && !stringDefinition)
                {
                    if (lineContent)
                    {
                        result.AppendLine();
                    }

                    result.Append(indent).Append("{");

                    if (lineContent)
                    {
                        result.AppendLine();
                    }

                    indent += INDENT_STEP;
                    lineContent = false;

                    continue;
                }

                if (ch == '}' && !stringDefinition)
                {
                    if (indent.Length != 0)
                    {
                        indent = indent.Substring(0, indent.Length - INDENT_STEP.Length);
                    }

                    if (lineContent)
                    {
                        result.AppendLine();
                    }

                    result.Append(indent).Append("}");

                    if (lineContent)
                    {
                        result.AppendLine();
                    }


                    lineContent = false;

                    continue;
                }

                if (ch == '\r')
                {
                    continue;
                }

                if ((ch == ' ' || ch == '\t') && !lineContent)
                {
                    continue;
                }

                if (ch == '\n')
                {
                    lineContent = false;
                    result.AppendLine();

                    continue;
                }

                if (!lineContent)
                {
                    result.Append(indent);
                    lineContent = true;
                }

                result.Append(ch);
            }

            return result.ToString();
        }
    }
}