GPS_ERROR_MESSAGE = "GPS SYSTEM DOES NOT WORK"
PARAM_ERROR = "INVALID PARAMETER HAS BEEN PASSED"
ACCEPTABLE_COLORS = { colors.white, colors.orange, colors.magenta, colors.lightBlue, colors.yellow, colors.lime, colors.pink, colors.gray, colors.lightGray, colors.cyan, colors.purple, colors.blue, colors.brown, colors.green, colors.red, colors.black }
ACCEPTABLE_DIRECTIONS = { "North", "East", "South", "West" }

-- One line color print
function printColor(color, text)
    for index, value in ipairs(ACCEPTABLE_COLORS) do
        if (color == value) then break end
        if (index == tableLength(ACCEPTABLE_COLORS) and color ~= value) then
            print(text)
            return
        end
    end
    term.setTextColor(color)
    print(text)
    term.setTextColor(colors.white)
end

-- Safer and simpler way of getting coordinates in library
function getCoordinates()
    local startX, startY, startZ = gps.locate(1)
    if (not startX) then
        printError(GPS_ERROR_MESSAGE)
    else
        return startX, startY, startZ
    end
end

-- While detecting a block in front, keep digging it away
function keepDigging()
    while (turtle.detect()) do
        turtle.dig()
    end
end

-- returns the length of the entire table
function tableLength(table)
    local count = 0
    for _ in pairs(table) do count = count + 1 end
    return count
end

--
-- Figure out if the turtle is looking at North, South, West, or East
function getDirection()
    local direction
    local startX, _, startZ = getCoordinates()
    keepDigging()
    if (turtle.forward()) then
        local endX, _, endZ = getCoordinates()
        if (startX > endX) then
            direction = "West"
        elseif (startX < endX) then
            direction = "East"
        elseif (startZ > endZ) then
            direction = "North"
        elseif (startZ < endZ) then
            direction = "South"
        end
        turtle.back()
    end
    return direction
end

-- Recalibrates turtle to face North, South, West, or East (but with knowledge of given direction)
function faceDirectionP(directionToFace, facedDirection)
    if (facedDirection == directionToFace) then return true end
    for key, value in ipairs(ACCEPTABLE_DIRECTIONS) do
        if (facedDirection == value) then
            facedDirection = key
        elseif (directionToFace == value) then
            directionToFace = key
        end
    end
    local difference = math.abs(facedDirection - directionToFace)
    local command
    if (facedDirection < directionToFace) then
        command = turtle.turnRight
    else
        command = turtle.turnLeft
    end
    while (difference > 0) do
        command()
        difference = difference - 1
    end
end

-- Recalibrates turtle to face North, South, West, or East
function faceDirection(directionToFace)
    local facing = getDirection()
    faceDirectionP(directionToFace, facing)
end

-- Moves the turtle to the given coordinates and gives verification at the end
function moveTo(endX, endY, endZ)
    local startX, startY, startZ = getCoordinates()
    local distX = math.abs(startX - endX)
    local distZ = math.abs(startZ - endZ)
    local distY = math.abs(startY - endY)
    local changeY
    local detectorY
    local diggerY
    if (endY > startY) then
        changeY   = turtle.up
        detectorY = turtle.detectUp
        diggerY   = turtle.digUp
    elseif (endY < startY) then
        changeY = turtle.down
        detectorY = turtle.detectDown
        diggerY = turtle.digDown
    end
    while (distY > 0) do
        changeY()
        while (detectorY()) do
            diggerY()
        end
        distY = distY - 1
    end
    if (endX > startX) then
        faceDirection("East")
    elseif (endX < startX) then
        faceDirection("West")
    end
    while (distX > 0) do
        keepDigging()
        turtle.forward()
        distX = distX - 1
    end
    if (endZ > startZ) then
        faceDirection("South")
    elseif (endZ < startZ) then
        faceDirection("North")
    end
    while (distZ > 0) do
        keepDigging()
        turtle.forward()
        distZ = distZ - 1
    end
end

-- Goes through the turtles inventory, slots 1-16, refueling as much as it can
function refuelAll()
    for slot = 1, 16, 1 do
        turtle.select(slot)
        turtle.refuel(turtle.getItemCount(slot))
    end
end

-- Goes through the turtles inventory from slots 1-16 and find the first empty slot...returns -1 if no empty slots
function findEmptySpace()
    for slot = 1, 16, 1 do
        turtle.select(slot)
        if (turtle.getItemDetail() == nil) then
            return slot
        end
    end
    return -1
end

-- Same as last one, just 1-16 slots...returns -1 if no slot
function findSlot(...)
    for slot = 1, 16, 1 do
        turtle.select(slot)
        local item = turtle.getItemDetail()
        if (item ~= nil) then
            for v in ipairs(arg) do
                if (string.match(item.name, v)) then
                    return slot
                end
            end
        end
    end
    return -1
end

-- Does the same thing, just 1-16
function findSlots(...)
    local listOfSlots = {}
    local curIdx = 1
    for slot = 1, 16, 1 do
        turtle.select(slot)
        local item = turtle.getItemDetail()
        if (item ~= nil) then
            for v in ipairs(arg) do
                if (string.match(item.name, v)) then
                    listOfSlots[curIdx] = slot
                    curIdx = curIdx + 1
                end
            end
        end
    end
    return listOfSlots
end

-- Reverses the turn in case it is needed for quarrying or navigating a set pattern
function oppositeTurn(turnType)
    if (turnType == turtle.turnLeft) then
        return turtle.turnRight
    elseif (turnType == turtle.turnRight) then
        return turtle.turnLeft
    else
        return error("WAS NOT GIVEN A TURTLE TURN METHOD!")
    end
end

-- Assume turtle is in backleft corner of Quarry, one block behind.
function quarryP(length, width, height, facedDirection)
    local startX, startY, startZ = getCoordinates()
    local firstTurn = turtle.turnRight
    local changeY
    if (height >= 0) then
        changeY = turtle.up
    else
        changeY = turtle.down
    endX
    keepDigging()
    turtle.forward()
    for d = height,
        for l = 1, length do
            firstTurn()
            keepDigging()
            turtle.forward()
        end
end

-- Assume turtle is in backleft corner again, one block behind
function quarry(length, width, height)
    local facedDirection = getDirection()
    quarryP(length, width, height, facedDirection)
end