crop_farm.lua

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-- TURTLE MUST BE PLACED IN CENTRE OF 9x9 FARM. BY DEFAULT, IT FACES SOUTH. SET face_north TO true IF YOU WANT IT ROTATED --
-- ITEMS WILL BE OUTPUTTED AT THE CENTRE OF THE OPPOSITE WALL TO ITS STARTING FACING DIRECTION -----------------------------
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-- API --------------------------------------------------
FUEL_ITEMS = {"minecraft:coal", "minecraft:charcoal"}
FUEL_SLOT = -1
FUEL_COUNT = 0

function hasValue (tab, val)
    for index, value in ipairs(tab) do
        if value == val then
            return true
        end
    end

    return false
end

function printKeys(tab)
    -- Source - https://stackoverflow.com/a/12674376
    -- Posted by lhf
    -- Retrieved 2026-06-11, License - CC BY-SA 3.0

    local keyset={}
    local n=0

    for k,v in pairs(tab) do
        n=n+1
        keyset[n]=k
    end

    print(textutils.serialise(keyset))
end

function turnAround()
    turtle.turnRight()
    turtle.turnRight()
end

function findItemInInventory(item_name)
    for i=1,16 do
        local item = turtle.getItemDetail(i)
        if item ~= nil then
            if item["name"] == item_name then
                return i, item["count"]
            end
        end
    end

    return -1, 0
end

function itemIsFuel(item_name)
    return hasValue(FUEL_ITEMS, item_name)
end

function refuelIfNeeded()
    local level = turtle.getFuelLevel()
    if level == "unlimited" then print("Turtle does not need fuel") return end

    if FUEL_COUNT == 0 then
       FUEL_SLOT = -1
    end

    if FUEL_SLOT == -1 then
        for i=1,16 do
            local item = turtle.getItemDetail(i)
            if item ~= nil then
               if itemIsFuel(item["name"]) then
                    FUEL_SLOT = i
                    FUEL_COUNT = item["count"]
               end
            end
        end
    end

    if FUEL_SLOT ~= -1 then
        turtle.select(FUEL_SLOT)
        if level == 0 then
            turtle.refuel(1)
            FUEL_COUNT = FUEL_COUNT - 1
        end
        return true
    else
        print("No fuel found!")
        return false
    end
end

function calculateFacingDirection()
    refuelIfNeeded()

    local start_x, _, start_z = gps.locate()
    turtle.forward()
    local end_x, _, end_z = gps.locate()
    turtle.back()

    if start_x == end_x then
        -- Moved in Z direction
        local difference = end_z - start_z
        if difference > 0 then
            return "south"
        else
            return "north"
        end
    else
        -- Moved in X direction
        local difference = end_x - start_x
        if difference > 0 then
            return "east"
        else
            return "west"
        end
    end
end

function faceTargetDirection(target_direction, current_direction)
    local directions = {
        north = 0,
        east  = 1,
        south = 2,
        west  = 3
    }

    local target = directions[target_direction]
    local current = directions[current_direction]

    if not target or not current then
        error("Invalid direction")
    end

    local difference = (target - current) % 4

    if difference == 1 then
        turtle.turnRight()
    elseif difference == 2 then
        turnAround()
    elseif difference == 3 then
        turtle.turnLeft()
    end
    -- difference == 0 means we're already facing the correct direction
end

function moveToTargetPosition(pos_x, pos_y, pos_z)
    print("Moving to: " .. pos_x .. ", " .. pos_y .. ", " .. pos_z)

    local current_x, current_y, current_z = gps.locate()
    local facing_direction = calculateFacingDirection()

    -- Move along X
    if current_x < pos_x then
        faceTargetDirection("east", facing_direction)

        while current_x < pos_x do
            turtle.forward()
            current_x = current_x + 1
        end

        facing_direction = "east"
    elseif current_x > pos_x then
        faceTargetDirection("west", facing_direction)

        while current_x > pos_x do
            turtle.forward()
            current_x = current_x - 1
        end

        facing_direction = "west"
    end

    -- Move along Z
    if current_z < pos_z then
        faceTargetDirection("south", facing_direction)

        while current_z < pos_z do
            turtle.forward()
            current_z = current_z + 1
        end

        facing_direction = "south"
    elseif current_z > pos_z then
        faceTargetDirection("north", facing_direction)

        while current_z > pos_z do
            turtle.forward()
            current_z = current_z - 1
        end

        facing_direction = "north"
    end

    -- Move along Y
    while current_y < pos_y do
        turtle.up()
        current_y = current_y + 1
    end

    while current_y > pos_y do
        turtle.down()
        current_y = current_y - 1
    end

    return facing_direction
end

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SEED_SLOT = -1
SEED_COUNT = 0

CROP_CONTROLLER_ID = -1

FACING_NORTH = false

local function turnLeft()
    if FACING_NORTH then
        turtle.turnRight()
    else
        turtle.turnLeft()
    end
end

local function turnRight()
    if FACING_NORTH then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end
end

local function moveAndFarm(crop_name)
    if refuelIfNeeded() ~= true then
        return
    end

    turtle.forward()
    local exists, block = turtle.inspectDown()

    if exists == true then
        if block["name"] == crop_name then
            if block["state"]["age"] == 7 then
                turtle.digDown()
            end
        end
    end

    turtle.suckDown()
end

local function moveAndPlant(seed_item)
    if refuelIfNeeded() ~= true then
        rednet.send(CROP_CONTROLLER_ID, "crop_worker_no_fuel")
        return
    end

    turtle.forward()
    local exists, block = turtle.inspectDown()

    if exists == false then
        if SEED_COUNT == 0 then
            SEED_SLOT = -1
        end

        if SEED_SLOT == -1 then
            local seed_slot, seed_count = findItemInInventory(seed_item)
            if seed_slot == -1 then
                print("No seeds!!!")
                rednet.send(CROP_CONTROLLER_ID, "crop_worker_no_seeds")
            end

            SEED_SLOT = seed_slot
            SEED_COUNT = seed_count
        end

        if SEED_SLOT ~= -1 then
            turtle.select(SEED_SLOT)
            turtle.placeDown()
            SEED_COUNT = SEED_COUNT - 1
        end
    end

    turtle.suckDown()
end

local function harvest(crop_name)
    -- Move to South edge
    for i=1,4 do
       moveAndFarm(crop_name)
    end

    for j=1,2 do
        -- Turn
        turnLeft()
        moveAndFarm(crop_name)
        turnLeft()

        -- Move to North edge
        for i=1,8 do
            moveAndFarm(crop_name)
        end

        -- Turn
        turnRight()
        moveAndFarm(crop_name)
        turnRight()

        -- Move to South edge
        for i=1,8 do
            moveAndFarm(crop_name)
        end
    end

    turnRight()

    for i=1,8 do
        moveAndFarm(crop_name)
    end

    turnRight()

    for j=1,2 do
        -- Move to North edge
        for i=1,8 do
            moveAndFarm(crop_name)
        end

        -- Turn
        turnRight()
        moveAndFarm(crop_name)
        turnRight()

        -- Move to South edge
        for i=1,8 do
            moveAndFarm(crop_name)
        end

        -- Turn
        turnLeft()
        moveAndFarm(crop_name)
        turnLeft()
    end

    -- Move to North edge
    for i=1,8 do
        moveAndFarm(crop_name)
    end

    -- Move back to origin
    turnAround()

    for i=1,4 do
        moveAndFarm(crop_name)
    end
end

local function plant(seed_name)
    -- Move to South edge
    for i=1,4 do
       moveAndPlant(seed_name)
    end

    for j=1,2 do
        -- Turn
        turnLeft()
        moveAndPlant(seed_name)
        turnLeft()

        -- Move to North edge
        for i=1,8 do
            moveAndPlant(seed_name)
        end

        -- Turn
        turnRight()
        moveAndPlant(seed_name)
        turnRight()

        -- Move to South edge
        for i=1,8 do
            moveAndPlant(seed_name)
        end
    end

    turnRight()

    for i=1,8 do
        moveAndPlant(seed_name)
    end

    turnRight()

    for j=1,2 do
        -- Move to North edge
        for i=1,8 do
            moveAndPlant(seed_name)
        end

        -- Turn
        turnRight()
        moveAndPlant(seed_name)
        turnRight()

        -- Move to South edge
        for i=1,8 do
            moveAndPlant(seed_name)
        end

        -- Turn
        turnLeft()
        moveAndPlant(seed_name)
        turnLeft()
    end

    -- Move to North edge
    for i=1,8 do
        moveAndPlant(seed_name)
    end

    -- Dump to chest
    for i=1,16 do
        turtle.select(i)
        local item = turtle.getItemDetail()
        if item ~= nil then
            if itemIsFuel(item["name"]) ~= true then
                turtle.drop(item["count"])
            end
        end
    end

    -- Move back to origin
    turnAround()

    for i=1,4 do
        moveAndPlant(seed_name)
    end
end

local function main(...)
    local turtle_name, crop_name, seed_name = ...
    print(turtle_name)
    print(crop_name)
    print(seed_name)

    if fs.exists("/start_position.txt") == true then
        -- Move towards the intended start position
        local file = fs.open("/start_position.txt", "r")
        local target_x = file.readLine()
        local target_y = file.readLine()
        local target_z = file.readLine()
        local target_facing = file.readLine()
        file.close()

        local facing_direction = moveToTargetPosition(tonumber(target_x), tonumber(target_y), tonumber(target_z))
        faceTargetDirection(target_facing, facing_direction)
    else
        local start_x, start_y, start_z = gps.locate()
        local facing_direction = calculateFacingDirection()

        local file = fs.open("/start_position.txt", "w")
        file.writeLine(start_x)
        file.writeLine(start_y)
        file.writeLine(start_z)
        file.writeLine(facing_direction)
        file.close()
    end

    peripheral.find("modem", rednet.open)

    repeat
        local id, message = rednet.receive()
        if message == "crop_controller_ping" then
            CROP_CONTROLLER_ID = id
            rednet.send(CROP_CONTROLLER_ID, "crop_worker_pong")
        end
    until CROP_CONTROLLER_ID ~= -1

    print("Connected")

    while true do
        local id, message = rednet.receive()
        if id == CROP_CONTROLLER_ID then
            if message == "crop_controller_identify" then
                rednet.send(CROP_CONTROLLER_ID, turtle_name)
            end
            if message == "crop_controller_harvest" then
                harvest(crop_name)
                plant(seed_name)
                rednet.send(CROP_CONTROLLER_ID, "crop_worker_finished")
            end
        end
    end
end

main(...)