stripmine

modem = peripheral.wrap("right")

function cycle(length)
    turtle.turnLeft()
    digBranch(length)
    turtle.turnRight()
    turtle.turnRight()
    digBranch(length)
    turtle.turnLeft()
    seekOre()
    storeItems()
    forward()
    forward()
    forward()
end

function digBranch(length)
    for i = 1, length do
        digOnce()
    end
    for i = 1, length do
        back()
    end
end

function digOnce()
    forward()
    seekOre()
end

function seekOre()
    local r = 0
    turtle.select(1)
    tryStoreItems()
    if turtle.detectUp() then
        if not compareUp() then
            up()
            seekOre()
            down()
        end
    end
    if turtle.detectDown() then
        if not compareDown() then
            down()
            seekOre()
            up()
        end
    end
    for i = 1, 4 do
        turtle.turnRight()
        if turtle.detect() and not compare() then
            forward()
            seekOre()
            back()
        end
    end
end

function compareUp()
    matches = false
    turtle.select(1)
    matches = matches or turtle.compareUp()
    turtle.select(2)
    matches = matches or turtle.compareUp()
    turtle.select(3)
    matches = matches or turtle.compareUp()
    return matches
end

function compareDown()
    matches = false
    turtle.select(1)
    matches = matches or turtle.compareDown()
    turtle.select(2)
    matches = matches or turtle.compareDown()
    turtle.select(3)
    matches = matches or turtle.compareDown()
    return matches
end

function compare()
    matches = false
    turtle.select(1)
    matches = matches or turtle.compare()
    turtle.select(2)
    matches = matches or turtle.compare()
    turtle.select(3)
    matches = matches or turtle.compare()
    return matches
end

function tryStoreItems()
    store = false
    for i = 4, 15 do
        if turtle.getItemSpace(i) < 4 then
            store = true
        end
    end
    if store then
        storeItems()
    end
end

function storeItems()
    turtle.digUp()
    turtle.select(16)
    turtle.placeUp()
    for i = 4, 15 do
        turtle.select(i)
        turtle.dropUp(turtle.getItemCount())
    end
    turtle.select(16)
    turtle.digUp()
end

function dig()
    while true do
        turtle.dig()
        os.sleep(0.2)
        if not turtle.detect() then
            break
        end
    end
end

function digUp()
    while true do
        turtle.digUp()
        os.sleep(0.2)
        if not turtle.detectUp() then
            break
        end
    end
end

function forward()
    while true do
        if turtle.forward() then
            return
        else
            print"obstructed in: forward"
            dig()
            turtle.attack()
            turtle.attack()
            turtle.attack()
        end
    end
end

function back()
    while true do
        if turtle.back() then
            return
        else
            print"obstructed in: back"
            turtle.turnRight()
            turtle.turnRight()
            dig()
            kill()
            turtle.turnRight()
            turtle.turnRight()
        end
    end
end

function kill()
    loop = true
    while loop do
        loop = turtle.attack()
        if loop then
            os.sleep(1)
        end
    end
end

function killUp()
    loop = true
    while loop do
        loop = turtle.attackUp()
        if loop then
            os.sleep(1)
        end
    end
end

function killDown()
    loop = true
    while loop do
        loop = turtle.attackDown()
        if loop then
            os.sleep(1)
        end
    end
end

function up()
    while true do
        if turtle.up() then
            return
        else
            print"obstructed in: up"
            digUp()
            killUp()
        end
    end
end

function down()
    while true do
        if turtle.down() then
            return
        else
            print"obstructed in: down"
            turtle.digDown()
            killDown()
        end
    end
end

function grid(depth, side, length, layers)
    layers = layers or 1
    for l = 1, layers do
        for s = 1, side do
            for i = 1, depth do
                cycle(length)
            end
            print"waiting..."
            print"ok."
            for i = 1, depth do
                back()
                back()
                back()
            end
            print"waiting..."
            print"ok."
            if s < side then
                turtle.turnRight()
                for i = 1, length * 2 + 1 do
                    forward()
                end
                turtle.turnLeft()
            end
        end
        turtle.turnLeft()
        for s = 2, side do
            for i = 1, length * 2 + 1 do
                forward()
            end
        end
        turtle.turnRight()
        if l < layers then
            up()
            up()
        end
    end
    for i = 2, layers do
        down()
        down()
    end
end

grid(2, 1, 4, 2)