computercraft/turtles/mine.lua

-- 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

-- Start at this position to find the next shaft
next_shaft_side = 0
next_shaft_height = 0

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

-- Dumps the current turtle position
function _dump_pos()
    print("Current position: H "..height.." S "..side.." D "..depth)
end

-- Updates the turtle position for a move in the given direction
function _count_move_dir(dir)
    dir = dir % 4
    if      dir == 0 then depth = depth + 1
    elseif  dir == 1 then side = side + 1
    elseif  dir == 2 then depth = depth - 1
    elseif  dir == 3 then side = side - 1
    end
end

function move_forward()
    rc, desc = turtle.forward()
    if not rc then abort("Move: "..desc) end
    _count_move_dir(facing)
end
function move_back()
    rc, desc = turtle.back()
    if not rc then abort("Move: "..desc) end
    _count_move_dir(facing + 2)
end
function move_up()
    rc, desc = turtle.up()
    if not rc then abort("Move: "..desc) end
    height = height + 1
end
function move_down()
    rc, desc = turtle.down()
    if not rc then abort("Move: "..desc) end
    height = height - 1
end

function go_to_depth(dd)
    turn_abs(0)
    while depth > dd do
        move_back()
    end
    while depth < dd do
        move_forward()
    end
end


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

    if height ~= dh then
        while height > dh do
            move_down()
        end
        while height < dh do
            move_up()
        end
    end

    if side ~= ds then
        turn_abs(1)

        while side > ds do
            move_back()
        end
        while side < ds do
            move_forward()
        end
    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()
    function is_shaft_pos()
        if side % 2 == 1 then
            return false
        elseif side % 4 == 0 then
            return height % 3 == 0
        elseif side % 4 == 2 then
            return height % 3 ~= 0
        end
    end
    function is_shaft()
        return is_shaft_pos() and turtle.detect()
    end

    go_to(next_shaft_height, 0, next_shaft_side)

    while true do
        if side % 2 == 0 then
            while height < MAX_HEIGHT - 1 do
                if is_shaft() then
                    return
                end

                if turtle.detectUp() then
                    turtle.digUp()
                end
                move_up()
            end
            if is_shaft() then
                return
            end
        else
            while height > 0 do
                if is_shaft() then
                    return
                end

                if turtle.detectDown() then
                    turtle.digDown()
                end
                move_down()
            end
            if is_shaft() then
                return
            end
        end

        turn_abs(1)
        if turtle.detect() then
            turtle.dig()
        end
        move_forward()
        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()
        next_shaft_height = height
        next_shaft_side = side
        print("Mining shaft at position:")
        _dump_pos()
        mine_shaft()

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

main()