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

namespace AniNIX.Crypto {

    public abstract class Cipher {


        //Cipher description to be set by each individual cipher.
        public abstract String Description();
        public abstract String Command();

        /// <summary>
        /// Create a new Cipher
        /// </summary>
        /// <returns>Cipher</returns>
        public Cipher (Workbench w) {
            string helpString = String.Format("{0} -- {1}\n",this.Command().PadRight(16),this.Description().Split('\n')[0]); 
            if (!w.HelpText.ToString().Contains(helpString)) {
                w.HelpText.Append(helpString);
            }
            if (!w.SwitchCases.ContainsKey(this.Command())) {
                w.SwitchCases.Add(this.Command(),this);
            }
        }
        public Cipher() {
        }

        /// <summary> 
        /// We should be able to act on a workspace and command line. Most ciphers will use the same syntax. Those that don't can override.
        /// </summary>
        /// <param name=workSpace>The current version of the text being worked on.</param>
        /// <param name=line>The command sequence.</param>
        /// <returns>The updated version of the workSpace</returns> 
        public virtual String RunCommand(String workSpace,String inputText,String[] line) {
            if (workSpace == null || line == null || line.Length < 2) {
                Console.Error.WriteLine("Malformed request.");
                return workSpace;
            }
            switch (line[1]) {
                case "encrypt": 
                    return Encrypt(workSpace,inputText,line);
                case "decrypt":
                    return Decrypt(workSpace,inputText,line);
                case "help": 
                case "": 
                    GetHelp();
                    return workSpace;
                default:
                    Console.Error.WriteLine("Invalid command. Type help for more.");
                    return workSpace;
            }
        }

        /// <summary>
        /// Show the helptext for this cipher. By default, most ciphers will only have encrypt, decrypt, and help functions.
        /// </summary>
        /// <param name=line>This is the incoming line and we use it to get the cipher name</param>
        public virtual void GetHelp() {
            String command = Command();
            Console.WriteLine(String.Format("Help for the {0} cipher suite.\n{1}\n",command,Description()));
            Console.WriteLine("Usage:");
            Console.Write(command);
            Console.WriteLine(" encrypt key         -- encrypt with the key");
            Console.Write(command);
            Console.WriteLine(" decrypt key         -- decrypt with the key"); 
            Console.Write(command);
            Console.WriteLine(" help                -- show this helptext.");
        }

        /// <summary> 
        /// All ciphers must be able to encrypt a string.
        /// </summary>
        /// <param name=workSpace>The current version of the text being worked on.</param>
        /// <param name=line>The command sequence.</param>
        /// <returns>The updated version of the workSpace</returns> 
        public abstract String Encrypt(string workSpace,String ciphetText,String[] line);

        /// <summary> 
        /// All ciphers must be able to decrypt a string.
        /// </summary>
        /// <param name=workSpace>The current version of the text being worked on.</param>
        /// <param name=line>The command sequence.</param>
        /// <returns>The updated version of the workSpace</returns> 
        public abstract String Decrypt(String workSpace,String inputText,String[] line);

    }
}