-- Short URL to raw: https://tiny.tobast.fr/cc_mineturtle

facing = 0  -- Direction towards mining shafts. Incr. clockwise.

height = 0  -- At ground level, lowest mining level
MAX_HEIGHT = 7  -- Will not mine higher than this.
depth = -2  -- Out of the mining shafts
side = 6  -- Increases towards the right when facing shafts

DOCK_POINT_H = 0
DOCK_POINT_D = -2
DOCK_POINT_S = 6

DROP_POINT_H = 0
DROP_POINT_D = -2
DROP_POINT_S = 0

FUEL_POINT_H = 0
FUEL_POINT_D = -2
FUEL_POINT_S = 3

FUEL_EXPECTATION = 2000
FUEL_LOW = 1000

SHAFT_DEPTH = 100

function distance_to_drop()
    return math.abs(depth - DROP_POINT_D)
    + math.abs(height - DROP_POINT_H)
    + math.abs(side - DROP_POINT_S);
end

function distance_to_refuel()
    local drop_to_fuel = math.abs(FUEL_POINT_D - DROP_POINT_D)
    + math.abs(FUEL_POINT_H - DROP_POINT_H)
    + math.abs(FUEL_POINT_S - DROP_POINT_S);
    return distance_to_drop() + drop_to_fuel;
end

function turn_abs(dir)
    local diff = (dir - facing) % 4
    if diff == 3 then
        turtle.turnLeft()
    else
        for i=1,diff do turtle.turnRight() end
    end
    facing = dir
end

function turn_rel(dir)
    turn_abs((facing + dir) % 4)
end

function go_to_depth(dd)
    turn_abs(0)
    while depth > dd do
        turtle.back()
        depth = depth - 1
    end
    while depth < dd do
        turtle.forward()
        depth = depth + 1
    end
end


-- Go to a target position, assuming no excavation is needed
function go_to(dh, dd, ds)
    go_to_depth(0)

    while height > dh do
        turtle.down()
        height = height - 1
    end
    while height < dh do
        turtle.up()
        height = height + 1
    end

    turn_abs(1)

    while side > ds do
        turtle.back()
        side = side - 1
    end
    while side < ds do
        turtle.forward()
        side = side + 1
    end

    go_to_depth(dd)
end

-- enter failed/done state
function abort(msg)
    print("ABORTING: ")
    print(msg)
    go_to(DOCK_POINT_H, DOCK_POINT_D, DOCK_POINT_S)
    making_a_fatal_error_awdadwdaw()
end


-- Discharge the inventory in the drop chest
function discharge_inventory()
    go_to(DROP_POINT_H, DROP_POINT_D, DROP_POINT_S)
    for slot=1,16 do
        turtle.select(slot)
        turtle.dropUp()
    end
end

-- Refuel from fuel point
function refuel_turtle()
    turtle.select(1)
    if turtle.getItemCount() > 0 then
        return false
    end

    go_to(FUEL_POINT_H, FUEL_POINT_D, FUEL_POINT_S)
    while turtle.getFuelLevel() < FUEL_EXPECTATION do
        local rc, desc = turtle.suckUp()
        if not rc then
            abort("No more fuel available")
        end
        local rc, desc = turtle.refuel()
        if not rc then
            abort("Found some non-fuel in the fuel")
        end
    end
end

-- Find the next unmined shaft and end up in front of it
function find_next_shaft()
    go_to(0, 0, 0)

    while true do
        print("Climb")
        for hei=0,MAX_HEIGHT-1 do
            if (hei % 3) == 0 then
                if turtle.detect() then
                    return
                end
            end

            if turtle.detectUp() then
                turtle.digUp()
            end
            if not turtle.up() then abort("Misshaped lobby") end
            height = height + 1
        end

        turn_abs(1)
        for i=0,1 do
            if turtle.detect() then
                turtle.dig()
            end
            if not turtle.forward() then abort("Misshaped lobby") end
            side = side + 1
        end
        turn_abs(0)

        print("Down")
        for hei=MAX_HEIGHT-1,0,-1 do
            if (hei % 3) ~= 0 then
                if turtle.detect() then
                    return
                end
            end

            if turtle.detectDown() then
                turtle.digDown()
            end
            if not turtle.down() then abort("Misshaped lobby") end
            height = height - 1
        end

        turn_abs(1)
        for i=0,1 do
            if turtle.detect() then
                turtle.dig()
            end
            if not turtle.forward() then abort("Misshaped lobby") end
            side = side + 1
        end
        turn_abs(0)
    end
end

-- Mine a new shaft in front of the turtle
function mine_shaft()
    turtle.dig()
end

-- Main function
function main()
    if turtle.getFuelLevel() < distance_to_refuel() then
        print("Not enough fuel to begin with.")
        return
    elseif turtle.getFuelLevel() < FUEL_LOW then
        refuel_turtle()
    end

    while true do
        print("Finding shaft")
        find_next_shaft()
        print("Mining shaft")
        mine_shaft()

        print("Discharging")
        discharge_inventory()
        if turtle.getFuelLevel() < FUEL_LOW then
            refuel_turtle()
        end
    end
end

main()