using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tango.Scripting.Editors.Indentation.CSharp
{
    class CSharpIndentationHelper
    {
        public static string IndentCSharpCode(string code)
        {
            const string INDENT_STEP = "\t";

            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();
        }
    }
}