using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web;

namespace Tango.CodeGeneration
{
    /// <summary>
    /// Represents a code object base class.
    /// </summary>
    /// <seealso cref="Tango.CodeGeneration.ICodeObject" />
    public abstract class CodeObject : ICodeObject
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="CodeObject"/> class.
        /// </summary>
        public CodeObject()
        {
            Attributes = new List<string>();
            IndentResult = true;
        }

        /// <summary>
        /// Gets or sets the code object modifier.
        /// </summary>
        public CodeObjectModifier Modifier { get; set; }

        /// <summary>
        /// Gets or sets the attributes associated with this code object.
        /// </summary>
        public List<String> Attributes { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether to indent the resulting code.
        /// </summary>
        public bool IndentResult { get; set; }

        /// <summary>
        /// Generates the code represented by this code object.
        /// </summary>
        /// <returns></returns>
        public virtual string GenerateCode()
        {
            var code = Helper.ParseTemplate(GetTemplate(), this);

            if (IndentResult)
            {
                code = Helper.IndentCSharpCode(code);
                code = RemoveDoubleLines(code);
            }

            code = code.Replace("&amp;amp;quot;", "\"");
            code = HttpUtility.HtmlDecode(code);

            return code;
        }

        /// <summary>
        /// Removes the double lines.
        /// </summary>
        /// <param name="str">The string.</param>
        /// <returns></returns>
        private String RemoveDoubleLines(string str)
        {
            String result = String.Empty;

            using (var streamReader = new StringReader(str))
            {
                string line = null;
                bool previousLineWasBlank = false;
                while ((line = streamReader.ReadLine()) != null)
                {
                    if (!string.IsNullOrEmpty(line) || !previousLineWasBlank)
                    {
                        result += line +Environment.NewLine;
                    }

                    previousLineWasBlank = string.IsNullOrEmpty(line);
                }
            }

            return result;
        }

        /// <summary>
        /// Gets the template associated with this code object.
        /// </summary>
        /// <returns></returns>
        public virtual string GetTemplate()
        {
            return Helper.GetTemplate(this.GetType());
        }

        /// <summary>
        /// Returns a <see cref="System.String" /> that represents this instance.
        /// </summary>
        /// <returns>
        /// A <see cref="System.String" /> that represents this instance.
        /// </returns>
        public override string ToString()
        {
            return GenerateCode();
        }

        /// <summary>
        /// Gets the modifier string.
        /// </summary>
        /// <returns></returns>
        public String GetModifierString()
        {
            return Modifier.ToString().ToLower();
        }

        /// <summary>
        /// Gets the attributes string.
        /// </summary>
        /// <returns></returns>
        public String GetAttributesString()
        {
            if (Attributes != null && Attributes.Count > 0)
            {
                return String.Join(Environment.NewLine, Attributes);
            }
            else
            {
                return null;
            }
        }
    }
}