using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ShiftOS.Engine
{
    /// <summary>
    /// Provides functionality for parsing a Terminal command string
    /// </summary>
    public sealed class CommandParser
    {
        public IList<CommandFormat> parts = new List<CommandFormat>();

        /// <summary>
        /// Adds a command format to the parser
        /// </summary>
        /// <param name="part">The format to add</param>
        public void AddPart(CommandFormat part)
        {
            parts.Add(part);
        }

        /// <summary>
        /// Imports the command parser formats from a list.
        /// </summary>
        /// <param name="parts">The list of formats.</param>
        public void ImportPart(IList<CommandFormat> parts)
        {
            this.parts = parts;
        }

        /// <summary>
        /// Saves the parser to a JSON string.
        /// </summary>
        /// <returns></returns>
        public string Save()
        {
            return JsonConvert.SerializeObject(parts, Formatting.Indented);
        }

        /// <summary>
        /// Loads a new <see cref="CommandParser"/> from a file. 
        /// </summary>
        /// <param name="val">The file to load</param>
        /// <returns>The parser constructed from the file</returns>
        public static CommandParser Load(string val)
        {
            CommandParser parser = new CommandParser();
            JArray data = JArray.Parse(val);

            IList<CFValue> values = data.Select(obj => new CFValue(
                (string)obj["type"],
                (string)obj["text"]
            )).ToList();

            foreach (CFValue value in values)
            {
                parser.AddPart(value.GetCommandFormat());
            }

            return parser;
        }

        /// <summary>
        /// Parses a command string.
        /// </summary>
        /// <param name="cdd">The command string to parse.</param>
        /// <returns>The parsed command, ready to be invoked.</returns>
        public KeyValuePair<string, Dictionary<string, string>> ParseCommand(string cdd)
        {
            string command = "";
            Dictionary<string, string> arguments = new Dictionary<string, string>();

            string text = cdd;
            int position = 0;

            int commandPos;
            int firstValuePos = -1;
            int lastValuePos = -1;

            for (int ii = 0; ii < parts.Count; ii++)
            {
                CommandFormat part = parts[ii];
                if (part is CommandFormatMarker)
                {
                    if (part is CommandFormatCommand)
                    {
                        commandPos = ii;
                    }
                    else if (part is CommandFormatValue)
                    {
                        if (firstValuePos > -1)
                            lastValuePos = ii;
                        else
                            firstValuePos = ii;
                    }
                }
            }

            int i = 0;
            string currentArgument = "";
            int help = -1;
            bool id_found = false;
            string id_text = "";

            while (position < text.Length)
            {

                if (i >= parts.Count)
                {
                    position = text.Length;
                    command = "+FALSE+";
                    i = 0;
                }

                CommandFormat part = parts[i];
                string inp = text.Substring(position);
                string res = part.CheckValidity(inp);
                if(part is CommandFormatText)
                {
                    if(res == "+FALSE+")
                    {
                        if(id_found == false)
                        {
                            id_found = true;
                            id_text = inp.Remove(0,1);
                            res = "";
                            arguments.Add("id", id_text);
                        }
                    }
                }

                // ok so:

                // example
                // COMMAND text[ --] ARGUMENT VALUE text[ --] ARGUMENT VALUE
                // COMMAND text[{] ARGUMENT text[=] VALUE text[, ] ARGUMENT text[=] VALUE text[}]

                if (part is CommandFormatMarker)
                {
                    if (part is CommandFormatCommand)
                    {
                        command = res;
                        help = -1;
                    }
                    else if (part is CommandFormatArgument)
                    {
                        if (arguments.ContainsKey(res))
                        {
                            Console.WriteLine("Duplicate command-line argument detected: " + res);
                            command = "+FALSE+";
                            position = text.Length;
                        }
                        else
                        {
                            currentArgument = res;
                            help = -1;
                        }
                    }
                    else if (part is CommandFormatValue)
                    {
                        arguments[currentArgument] = string.Join("", res.Split('"'));

                        if (i == firstValuePos)
                            help = lastValuePos;
                        if (i == lastValuePos)
                            help = firstValuePos;
                    }
                }

                if (res == "+FALSE+")
                {
                    if (help > -1)
                    {
                        i = help;
                        if (i >= parts.Count)
                        {
                            position = text.Length;
                            command = "+FALSE+";
                        }
                    }
                    else
                    {
                        position = text.Length;
                        command = "+FALSE+";
                    }
                    help = -1;
                }
                else
                {
                    position += res.Length;
                }

                i++;
            }

            if (command == "+FALSE+")
            {
                //lblExampleCommand.Text = "Syntax Error";
                return new KeyValuePair<string, Dictionary<string, string>>();
            }
            else
            {
                /*string argvs = "{";

                foreach (KeyValuePair<string, string> entry in arguments) {
                    argvs += entry.Key + "=" + entry.Value + ", ";
                }

                argvs += "}";

                lblExampleCommand.Text = command + argvs;*/
                return new KeyValuePair<string, Dictionary<string, string>>(command, arguments);
            }
        }

        public static CommandParser GenerateSample()
        {
            var parser = new CommandParser();
            parser.AddPart(new CommandFormatCommand());
            parser.AddPart(new CommandFormatText(" --"));
            parser.AddPart(new CommandFormatArgument());
            parser.AddPart(new CommandFormatText(" "));
            parser.AddPart(new CommandFormatValue());
            parser.AddPart(new CommandFormatText(" --"));
            parser.AddPart(new CommandFormatArgument());
            parser.AddPart(new CommandFormatText(" "));
            parser.AddPart(new CommandFormatValue());
            return parser;
        }
    }

    public class CFValue
    {
        public string type { get; set; }

        public string text { get; set; }

        public CFValue(string type, string text)
        {
            this.type = type;
            this.text = text;
        }

        public CFValue(CommandFormat format)
        {
            type = "";
            text = "";
            if (format is CommandFormatText)
            {
                text = ((CommandFormatText)format).str;
                if (format is CommandFormatOptionalText)
                {
                    type = "optionalText";
                }
                else if (format is CommandFormatRegex)
                {
                    type = "regexText";
                }
                else
                {
                    type = "text";
                }
            }
            else if (format is CommandFormatMarker)
            {
                if (format is CommandFormatCommand)
                {
                    type = "command";
                }
                else if (format is CommandFormatArgument)
                {
                    type = "argument";
                }
                else if (format is CommandFormatValue)
                {
                    type = "value";
                }
            }
        }

        public CommandFormat GetCommandFormat()
        { // TODO update with better code
            switch (type)
            {
                case "text":
                    return new CommandFormatText(text);
                case "optionalText":
                    return new CommandFormatOptionalText(text);
                case "regexText":
                    return new CommandFormatRegex(text);
                case "command":
                    return new CommandFormatCommand();
                case "argument":
                    return new CommandFormatArgument();
                case "value":
                    return new CommandFormatValue();
                case "color":
                    throw new NotImplementedException(); // fix this (make it not a notimplementedexception)
            }
            return new CommandFormatMarker();
        }
    }


    public class CommandFormat
    {
        public virtual string CheckValidity(string check)
        {
            return check;
        }


        //winforms use in engine - coding standard violation.
        //Control Draw(); 
    }
    public class CommandFormatText : CommandFormat
    {
        public string str = "";
        TextBox textBox;

        public CommandFormatText()
        {

        }

        public CommandFormatText(string str)
        {
            this.str = str;
        }

        public override string CheckValidity(string check)
        {
            return check.StartsWith(str) ? str : "+FALSE+";
        }

        void TextChanged(object sender, EventArgs e)
        {
            str = textBox.Text;
        }
    }

    public class CommandFormatOptionalText : CommandFormatText
    {
        public CommandFormatOptionalText() : base()
        {
        }
        public CommandFormatOptionalText(string str) : base(str)
        {
        }

        public override string CheckValidity(string check)
        {
            return check.StartsWith(str) ? str : "";
        }
    }

    public class CommandFormatRegex : CommandFormatText
    {
        public CommandFormatRegex() : base()
        {
        }
        public CommandFormatRegex(string str) : base(str)
        {
        }

        public override string CheckValidity(string check)
        {
            Match match = (new Regex("^" + str)).Match(check);
            return match.Success ? match.Value : "+FALSE+";
        }
    }

    public class CommandFormatMarker : CommandFormat
    {
        protected string str;
        Button button;

        public CommandFormatMarker()
        {
        }

        public override string CheckValidity(string check)
        {
            string res = string.Empty;
            string alphanumeric = "QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm-_0123456789"; // not using regex for performance reasons
            //You said "alphanumeric" for that variable name... but it only had the alphabet in it. Rectified. - Michael
            foreach (char c in check)
            {
                if (alphanumeric.IndexOf(c) > -1)
                {
                    res += c;
                }
                else
                {
                    break;
                }
            }

            return res;
        }
    }

    public class CommandFormatCommand : CommandFormatMarker
    {
        //stub
    }

    public class CommandFormatArgument : CommandFormatMarker
    {
        //stub
    }

    public class CommandFormatValue : CommandFormatMarker
    {
        public override string CheckValidity(string cd)
        {
            string res = string.Empty;
            var check = "";
            bool done = false;

            if (cd.StartsWith("\""))
            {
                check = cd.Substring(1);

                foreach (char c in check)
                {
                    if (c != '"')
                    {
                        res += c;
                    }
                    else
                    {
                        done = true;
                        res = "\"" + res + "\"";
                        break;
                    }
                }
            }
            else
            {
                res = base.CheckValidity(cd);
                done = true;
            }
            return done ? res : "+FALSE+";
        }
    }
}