Turt API

--Computercraft API For turtle control.
--Made by Andrew Lalis; andrewlalisofficial@gmail.com

local orientation = "none"

--Local function to validate cardinal directions.
local function isCardinal(dir)
    return (dir == "n" or dir == "s" or dir == "e" or dir == "w")
end

--Local function to turn around.
local function turnAround()
    turtle.turnRight()
    turtle.turnRight()
end

--Sets the starting orientation of the turtle.
function setOrientation(cardinal)
    if (isCardinal(cardinal)) then
        orientation = cardinal
    else
        error("Unknown cardinal direction. Must be n, s, e, or w.",2)
    end
end

--Changes the turtle's orientation.
function changeOrientation(cardinal)
    if (not isCardinal(cardinal)) then
        error("Unknown cardinal direction. Must be n, s, e, or w.", 2)
        return false
    else
        if (orientation == "n") then
            if (cardinal == "w") then
                turtle.turnLeft()
            elseif (cardinal == "e") then
                turtle.turnRight()
            elseif (cardinal == "s") then
                turnAround()
            end
        elseif (orientation == "s") then
            if (cardinal == "w") then
                turtle.turnRight()
            elseif (cardinal == "e") then
                turtle.turnLeft()
            elseif (cardinal == "n") then
                turnAround()
            end
        elseif (orientation == "e") then
            if (cardinal == "n") then
                turtle.turnLeft()
            elseif (cardinal == "s") then
                turtle.turnRight()
            elseif (cardinal == "w") then
                turnAround()
            end
        else
            if (cardinal == "n") then
                turtle.turnRight()
            elseif (cardinal == "s") then
                turtle.turnLeft()
            elseif (cardinal == "e") then
                turnAround()
            end
        end
        orientation = cardinal
        return true
    end
end

--Determines if the turtle has an item, and if so, returns the following table.
--{count=X, slots={1,2,3,..}}, or nil, if not found.
function getItemCount(name, damage)
    local dmg = damage or 0
    local result = {count=0, slots={}}
    for i=1,16 do
        local data = turtle.getItemDetail(i)
        if (data ~= nil and data.name == name and data.damage == dmg) then
            result.count = result.count + data.count
            table.insert(result.slots, i)
        end
    end
    if (result.count > 0) then
        return result
    else
        return nil
    end
end

--Selects an item by name. Returns success value.
function select(name, damage)
    local item = getItemCount(name, damage)
    if (item ~= nil) then
        turtle.select(item.slots[1])
        return true
    else
        return false
    end
end

--Places an item by name. Returns success value.
function place(name, damage, direction, orient)
    if (not select(name, damage)) then
        return false
    end
    local dir = direction or nil
    local newOrient = orient or nil
    local previousOrient = orientation
    local success
    if (dir == "up") then
        success = changeOrientation(newOrient) and turtle.placeUp()
    elseif (dir == "down") then
        success = changeOrientation(newOrient) and turtle.placeDown()
    elseif (dir == "right") then
        turtle.turnRight()
        success = turtle.place()
        turtle.turnLeft()
    elseif (dir == "left") then
        turtle.turnLeft()
        success = turtle.place()
        turtle.turnRight()
    elseif (dir == "back") then
        turnAround()
        success = turtle.place()
        turnAround()
    else
        success = turtle.place()
    end
    if (orientation ~= previousOrient) then
        changeOrientation(previousOrient)
    end
    return success
end