Quarry

local tArgs = { ... }
if #tArgs == 0 then
    print( "Usage: clearRoomLarge <radius> <(optional, if not go until bedrock)depth>" )
    return
end

-- Mine in a quarry pattern until we hit something we can't
local size = tonumber( tArgs[1] )
if size < 1 then
    print( "Excavate radius must be positive" )
    return
end

targetDepth = 256
if #tArgs > 1 then
    targetDepth = tonumber( tArgs[2] )
    if targetDepth < 1 then
        print( "Depth provided too shallow" )
        return
    end
    targetDepth = targetDepth - 1
end
collected = 0
depth = 0
tripDepth = 0
stopCause = 0

local xPos,zPos = 0,0
local xDir,zDir = 0,1

local function collect()
    collected = collected + 1
    if math.fmod(collected, 25) == 0 then
        print( "Mined "..collected.." blocks." )
    end

    for n=1,9 do
        if turtle.getItemCount(n) == 0 then
            return true
        end
    end

    print( "No empty slots left." )
    return false
end

local function tryForwards()
    while not turtle.forward() do
        if turtle.dig() then
            if not collect() then
                stopCause = 2
                return false
            end
        else
            -- give sand a chance to fall
            sleep(0.8)
            if turtle.dig() then
                if not collect() then
                    stopCause = 2
                    return false
                end
            else
                stopCause = 1
                return false
            end
        end
    end
    xPos = xPos + xDir
    zPos = zPos + zDir
    return true
end

local function tryDown()
    if depth == targetDepth then
        return false
    end
    if not turtle.down() then
        if turtle.digDown() then
            if not collect() then
                return false
            end
        end
        if not turtle.down() then
            return false
        end
    end
    depth = depth + 1
    if math.fmod( depth, 10 ) == 0 then
        print( "Descended "..depth.." metres." )
    end
    return true
end

local function turnLeft()
    turtle.turnLeft()
    xDir, zDir = -zDir, xDir
end

local function turnRight()
    turtle.turnRight()
    xDir, zDir = zDir, -xDir
end

local function main() -- ===================START MAIN LOOP FUNCTION

    print( "Excavating..." )

    local reseal = false
    if turtle.digDown() then
        reseal = true
    end

    if tripDepth == 0 then
        while turtle.down() do
            depth = depth + 1
        end
    end

    local alternate = 0
    local done = false
    while not done do
        for n=1,size do
            for m=1,size-1 do
                if not tryForwards() then
                    done = true
                    break
                end
            end
            if done then
                break
            end
            if n<size then
                if math.fmod(n + alternate,2) == 0 then
                    turnLeft()
                    if not tryForwards() then
                        done = true
                        break
                    end
                    turnLeft()
                else
                    turnRight()
                    if not tryForwards() then
                        done = true
                        break
                    end
                    turnRight()
                end
            end
        end
        if done then
            break
        end

        if size > 1 then
            if math.fmod(size,2) == 0 then
                turnRight()
            else
                if alternate == 0 then
                    turnLeft()
                else
                    turnRight()
                end
                alternate = 1 - alternate
            end
        end

        if not tryDown() then
            done = true
            break
        end
    end

tripDepth = depth

    print( "Returning to surface..." )
    -- Return to where we started
    while depth > 0 do
        if turtle.up() then
            depth = depth - 1
        elseif turtle.digUp() then
            collect()
        else
            sleep( 0.5 )
        end
    end

    if xPos > 0 then
        while xDir ~= -1 do
            turnLeft()
        end
        while xPos > 0 do
            if turtle.forward() then
                xPos = xPos - 1
            elseif turtle.dig() then
                collect()
            else
                sleep( 0.5 )
            end
        end
    end

    if zPos > 0 then
        while zDir ~= -1 do
            turnLeft()
        end
        while zPos > 0 do
            if turtle.forward() then
                zPos = zPos - 1
            elseif turtle.dig() then
                collected = collected + 1
            else
                sleep( 0.5 )
            end
        end
    end
    while zDir ~= 1 do
        turnLeft()
    end

    -- Seal the hole
    if reseal then
        turtle.placeDown()
        turtle.forward()
        turtle.placeDown()
        turtle.back()
    end

    turtle.turnLeft()
    turtle.forward()
    for n=1,9 do
        turtle.drop()
    end
    turtle.back()
    turtle.turnRight()
end -- ===========================================END MAIN LOOP FUNCTION

local done = false
while not done do
    if (tripDepth == targetDepth) or (stopCause == 1) then
        done = true
    else
        stopCause = 0
        xPos,zPos = 0,0
        xDir,zDir = 0,1
        turtle.digDown()
        for n=1,tripDepth do
            if turtle.down() then
                depth = depth + 1
            end
        end
        main()
    end
end

print( "Mined "..collected.." blocks total." )