//Title: Customizeable Caesar Cipher
//Credit to: DivineO'peanut
//Contributed by: DivineO'peanut
//Special thanks to: Inuyashaisbest (tracking a bug)

/*
http://en.wikipedia.org/wiki/Caesar_cipher

This is a highly-customizable implantation of the Caesar cipher. You can
leave the code as is, to get the "classic" Caesar cipher, or you can modify
caesar_lower and caesar_upper to partly revise the encryption.

The proc caesarcipher(text here,number of shifts) will encipher the text and return
the result, and caesardecipher(text here,number of shifts) will decipher it.

The lists "caesar_lower" and "caesar_upper" serve as the repertoire of characters the snippet uses, and can be 
changed to result in different version of the cipher.
*/



//[MAIN SNIPPET CODE GOES HERE]
var/list/caesar_lower = list("a","b","c","d","e","f","g","h","i","j","k",
                        "l","m","n","o","p","q","r","s","t","u","v","w","x","y","z")
var/list/caesar_upper = list("A","B","C","D","E","F","G","H","I","J","K",
                        "L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z")

proc/caesarencipher(t,n=3)
    . = ""
    var/length = length(t)
    for(var/c in 1 to length)
        var/char = copytext(t,c,c+1)
        if(char in caesar_lower)
            var/find = caesar_lower.Find(char)
            if(find+n > caesar_lower.len)
                . += caesar_lower[find+n-(caesar_lower.len)]
                continue
            else
                . += caesar_lower[find+n]
                continue
        else if(char in caesar_upper)
            var/find = caesar_upper.Find(char)
            if(find+n > caesar_upper.len)
                . += caesar_upper[find+n-(caesar_upper.len)]
                continue
            else
                . += caesar_upper[find+n]
                continue
                
proc/caesardecipher(t,n=3)
    . = ""
    var/length = length(t)
    for(var/c in 1 to length)
        var/char = copytext(t,c,c+1)
        if(char in caesar_lower)
            var/find = caesar_lower.Find(char)
            if(find-n < 0)
                . += caesar_lower[(caesar_lower.len-1)-find-(n-1)]
                continue
            else
                . += caesar_lower[find-n]
                continue
        else if(char in caesar_upper)
            var/find = caesar_upper.Find(char)
            if(find-n < 0)
                . += caesar_upper[(caesar_upper.len-1)-find-(n-1)]
                continue
            else
                . += caesar_upper[find-n]
                continue


///*
//Testing Code/Sample Implementation:

/*** Once you are done playing with the code, uncomment this and try
    enciphering something again: ***/

/*
world
    New()
        caesar_lower = list("1","2","3","4","5","6","7","8","9")
        caesar_upper = list("!","@","#","$","%","^","&","*","(")
*/

client/verb/encipher(txt as text,shifts=3 as num)    // encipher a certain text
    src << caesarencipher(txt,shifts)

client/verb/decipher(txt as text,shifts=3 as num)    // decipher that text
    src << caesardecipher(txt,shifts)
//*/