cryptogame

--Message Stuff
local alphabet = {}
local alphabetCount = {}
local cipher = {}
local stopChars = {["."] = true, [","] = true, ["!"] = true, ["?"] = true, ["("] = true,
  [")"] = true, ["'"] = true, ["\""] = true, [";"] = true, [" "] = true, [""] = true}
local message = ""
local emessage = ""

--Interface Stuff
local w,h = term.getSize()
local listscroll,msgscroll = 0,0
local lines = {}
local playerCipher = {}
local selChar = ""
local decrypting = true

function split(str, pattern)
  local t = { }
  local fpat = "(.-)" .. pattern
  local last_end = 1
  local s, e, cap = str:find(fpat, 1)
  while s do
    if s ~= 1 or cap ~= "" then
      table.insert(t,cap)
    end
    last_end = e+1
    s, e, cap = str:find(fpat, last_end)
  end
  if last_end <= #str then
    cap = str:sub(last_end)
    table.insert(t, cap)
  end
  return t
end

local function openMessage(path)
  local file = nil
  if string.sub(path, 1, 1) == "/" then
    file = fs.open(path, "r")
  else
    file = fs.open(shell.resolve(".").."/"..path,
      "r")
  end
  if not file then error(path.." not found") end

  local submsg = file:readLine()
  while submsg do
    message = message..submsg
    submsg = file:readLine()
  end
  file:close()

  for i=1,#message do
    local char = string.upper(string.sub(message, i, i))
    local unique = true
    if not char or char == "" then unique = false end
    if stopChars[char] then
        unique = false
    end
    for a=1,#alphabet do
      if alphabet[a] == char then
        unique = false
        break
      end
    end
    if unique then
        table.insert(alphabet, char)
        alphabetCount[char] = 0
    end
  end
  table.sort(alphabet)
end

function createCipher()
  local locA = { }
  for i=1,#alphabet do
    locA[i] = alphabet[i]
  end
  while #locA > 0 do
    local index = math.random(1,#locA)
    --this is to ensure every letter in the cipher is different to the original
    if locA[index] ~= alphabet[#cipher+1] then
        table.insert(cipher, locA[index])
        table.remove(locA, index)
    end
  end
end

function encryptMessage()
  emessage = ""
  for i=1,#message do
    local msgChar = string.upper(string.sub(message,i,i))
    local index = -1
    for a=1,#alphabet do
      if alphabet[a] == msgChar then
        index = a
        break
      end
    end
    if index == -1 then
        emessage = emessage..msgChar
    else
        emessage = emessage..cipher[index]
        alphabetCount[cipher[index]] = alphabetCount[cipher[index]] + 1
    end
  end
end

function printDebug()
    print(message.."\n")
    local fullA = ""
    for i=1,#alphabet-1 do
        fullA = fullA..alphabet[i]..","
    end
    print("["..fullA..alphabet[#alphabet].."]")
    fullA = ""
    for i=1,#cipher-1 do
        fullA = fullA..cipher[i]..","
    end
    print("["..fullA..cipher[#cipher].."]")
    print("\n"..emessage.."\n")

    local cipherUnique = true
    for i=1,#cipher do
        if cipher[i] == alphabet[i] then
            print("Duplicate at "..i..": "..cipher[i].."/"..alphabet[i])
            cipherUnique = false
        end
    end
    if cipherUnique then print("Cipher unique")
    else print("Cipher not unique") end
end

function prepareDecryptInterface()
    local words = split(emessage, " ")
    local lineIndex = 1
    lines[lineIndex] = {}
    while #words > 0 do
        if #lines[lineIndex] + #words[1] >  w - 11 then
            lineIndex = lineIndex + 1
            lines[lineIndex] = {}
        end
        for i=1,#words[1] do
            table.insert(lines[lineIndex], string.sub(words[1], i, i))
        end
        table.insert(lines[lineIndex], " ")
        table.remove(words, 1)
    end
end

function drawDecryptInterface()
    term.setBackgroundColour(colours.black)
    term.clear()
    --Header
    term.setCursorPos(1,1)
    term.setBackgroundColour(colours.lime)
    term.setTextColour(colours.black)
    local msg = "Message Decrypter"
    term.write(string.rep(" ", w/2 - #msg/2)..msg..string.rep(" ", w/2 - #msg/2))
    for i=2,h do
        term.setCursorPos(8, i)
        if i < 5 and listscroll > 0 then
            term.write("^")
        elseif i > h-3 and listscroll < #alphabet - h - 1 then
            term.write("V")
        else
            term.write(" ")
        end
    end
    --Sidebar
    term.setBackgroundColour(colours.black)
    for i=1,h-1 do
        local index = i + listscroll
        term.setCursorPos(1, i+1)
        local char = " "
        if playerCipher[alphabet[index]] then char = playerCipher[alphabet[index]] end
        if selChar == alphabet[index] then
            term.setBackgroundColour(colours.grey)
        else
            term.setBackgroundColour(colours.black)
        end
        term.setTextColour(colours.orange)
        term.write(char)
        term.setBackgroundColour(colours.black)
        term.setTextColour(colours.lime)
        term.write(" "..alphabet[index].."-"..alphabetCount[alphabet[index]])
    end
    --Lines
    for i=1,#lines do
        for c=1,#lines[i] do
            term.setCursorPos(10 + c - 1, i * 3)
            term.setBackgroundColour(colours.black)
            term.setTextColour(colours.lime)
            term.write(lines[i][c])
            term.setCursorPos(10 + c - 1, i * 3 + 1)
            if selChar == lines[i][c] then
                term.setBackgroundColour(colours.grey)
            end
            term.setTextColour(colours.orange)
            if playerCipher[lines[i][c]] then
                term.write(playerCipher[lines[i][c]])
            elseif stopChars[lines[i][c]] then
                term.write(lines[i][c])
            else term.write(" ") end
        end
    end
end

function handleInput()
    local id,key,x,y = os.pullEvent()

    if id == "mouse_scroll" then
        if x <=8 then
            scroll = scroll + key * 3
            if scroll < 0 then scroll = 0
            elseif scroll > #alphabet-h then scroll = #alphabet-h
            end
        else

        end
    elseif id == "mouse_click" then
        if y % 3 == 1 and y > 3 and y <= #lines*3+1 and x >= 10 and
                x < #lines[math.floor(y/3)]+10 then
            selChar = lines[math.floor(y/3)][x-9]
            if stopChars[selChar] then
                selChar = ""
            end
        elseif x < 8 and y > 1 then
            selChar = alphabet[y-1+scroll]
        elseif x == 8 and y < 4 and y > 1 then
            scroll = scroll - 3
            if scroll < 0 then scroll = 0 end
        elseif x == 8 and y > h-3 then
            scroll = scroll + 3
            if scroll > #alphabet-h then scroll = #alphabet-h end
        else
            selChar = ""
        end
    elseif id == "char" then
        if selChar ~= "" then
            for k,v in pairs(playerCipher) do
                if v == string.upper(key) then
                    playerCipher[k] = " "
                end
            end
            playerCipher[selChar] = string.upper(key)
        end
    elseif id == "key" and key == keys.enter then
        decrypting = false
    end
end

local tArgs = {...}
if #tArgs < 1 then
  error("Usage : encrypt <path>")
end

openMessage(tArgs[1])
createCipher()
encryptMessage()
prepareDecryptInterface()
while decrypting do
    drawDecryptInterface()
    handleInput()
end