--#filename:matrix-ss
--#version:0.8
--#author:Advert
-- Matrix screensaver v0.8
-- (C) 2012 User 'Advert' at http://www.computercraft.info/forums2/
-- X11/mit licence (use/modify at your will, but please, leave credit where due)
-- Spacebar to quit cleanly!
local mobj = {}
do -- Standart variables.
        mobj.x = 0
        mobj.y = 0 -- Offscreen
        mobj.lingerMin = 3 -- Minimum time to linger (frames)
        mobj.lingerMax = 10 -- Maximum time to linger
        mobj.linger = 10 -- How long this object will linger
        mobj.tailLenMin = 3 -- Minimum tail length
        mobj.tailLenMax = 10 -- Maximum tail length
        mobj.tailLen = 10
        mobj.chars = "1234567890-=!@#$%^&*()_+qwertyuiop[]QWERTYUIOP{}asdfghjkl;'\\ASDFGHJKL:\"|zxcvbnm,./ZXCVBNM<>?"
        mobj.charsLen = mobj.chars:len()
        mobj.currentTail = {"a", "a", "a", "a", "a", "a", "a", "a", "a", "a"}
        mobj.secretText = {}
        mobj.skipFrame = 0
        mobj.skipFrameMin = 1
        mobj.skipFrameMax = 3
        mobj.skipFrameMod = -1
        mobj.currFrame = 0
end

function mobj:new(o, ...)
        local o = o or {}
        setmetatable(o, self)
        self.__index = self
        o:__init(...)
        return o
end


function mobj:__init(x)
        self.linger = math.random(self.lingerMin, self.lingerMax)
        self.tailLen = math.random(self.tailLenMin, self.tailLenMax)
        self.x = x
        self.y = 1
        self.nFrame = 1
        self.currentTail = {}
        self.skipFrame = math.random(self.skipFrameMin, self.skipFrameMax) + self.skipFrameMod
end
function mobj:randomLinger()
        self.linger = math.random(self.lingerMin, self.lingerMax)
end
function mobj:printPos(x, y, sText)
        term.setCursorPos(x, y)
        term.write(sText)
end
function mobj:printPosT(x, y, sText)
        if self.secretText[y] and self.secretText[y][x] then
                sText = self.secretText[y][x]
        end
        return self:printPos(x, y, sText)
end
function mobj:randomChar()
        local r = math.random(1, self.charsLen)
        return string.sub(self.chars, r, r)
end
function mobj:printTail()
        for i = 1, self.tailLen do
                if not self.currentTail[i] then break end
                self:printPosT(self.x, self.y - i, self.currentTail[i])
        end
end

local termX, termY = term.getSize()
do
        for y = 1, termY do
                mobj.secretText[y] = {}
        end
        function mobj:addSecretText(x, y, sText)
                if sText:len() + x > termX then
                        -- lolno.
                else
                        for i = 1, sText:len() do
                                local chr = sText:sub(i, i)
                                self.secretText[y][x + i-1] = chr
                        end
                end
        end
        function mobj:addSecretTextD(x, y, dir, sText)
                -- 1 = bottomright, 2 = bottomleft, 3 = topright, 4 = topleft
                local xmod = dir %2 == 1 and 1 or -1
                local ymod = (dir == 1 or dir == 2) and 1 or -1
                local finalx, finaly = x + (xmod * sText:len()), y + (ymod *sText:len())
                --print("finalx, finaly", finalx, finaly)
                --read()
                local cx, cy = x, y
                for i = 1, sText:len() do
                        local cx, cy = x + (xmod * (i -1)), y + (ymod * (i -1))
                        if self.secretText[cy] then
                                self.secretText[cy][cx] = sText:sub(i, i)
                        end
                end
        end

end

function mobj:render()
        self:printTail()
        local sSkip = false
        if self.currFrame ~= self.skipFrame then
                self.currFrame = self.currFrame + 1
        else
                self.currFrame = 0
                self.nFrame = self.nFrame + 1
                if self.nFrame == self.linger then
                        table.insert(self.currentTail, 1, self.lastRandomChar)
                        self:printPosT(self.x, self.y, self.currentTail[1])
                        self.y = self.y + 1
                        self.nFrame = 1
                        if self.y > termY + self.tailLen then
                                self:__init(self.x)
                        end
                        sSkip = true
                else
                        self.lastRandomChar = self:randomChar()
                end
        end
        if not sSkip then
                self:printPos(self.x, self.y, self.lastRandomChar)
        end
end

local objects = {}
local eventT

function init()
        for i = 1, termX do
                objects[i] = mobj:new({}, i)
        end
        eventT = os.startTimer(0)
end

function render()
        term.clear()
        for _, k in pairs(objects) do
                k:render()
        end
end

mobj:addSecretTextD(15, 4, 1, "Casper7526")
mobj:addSecretTextD(18, 4, 1, "made me")
mobj:addSecretTextD(21, 4, 1, "do this.")
mobj:addSecretText(15, 15, "Spacebar to exit.")
init()

while true do
        local e, p1, p2 = os.pullEvent()
        if e == "timer" and p1 == eventT then
                eventT = os.startTimer(0.05) -- 20 fps
                render()
        elseif e == "key" and p1 == 57 then
                term.clear()
                term.setCursorPos(1,1)
                break
        end
end