--[[
This script will make a turtle into a mower!
It will drive in a zigzag pattern in the field and remove weeds.
You can choose which objects it will destroy by changing the 
appropriate string below. In order to dig, you also need to place a tool 
in slot 1 of the turtle.

Copyright 2016, George Kaklamanos <gkaklas1@gmail.com>
You may use this script under the terms of the 
GNU General Public License version 3 or later.
For more info please read the LICENSE, which is included in this repository.
--]]


-- Select the item in slot 1 and equip the right hand side with it.
turtle.select(1)
turtle.equipRight(1)

goRight = true
while true do
    success = moveAndDestroy()
    if not success then
        changeRow()
    end
end

-- Is the block in front of us of the kind we want to destroy?
function wantedBlock()
    local s,data = turtle.inspect()
    return data["name"] == "minecraft:yellow_flower"
end

-- Move forward one block, dig if necessary.
function moveAndDestroy()
    local success
    if wantedBlock() then
        turtle.dig()
    end
    if not turtle.detect() then
        success = turtle.forward()
    end
    return success
end

function turn()
    if goRight then
        turtle.turnRight()
    else 
        turtle.turnLeft()
    end
end

function antiturn()
    if goRight then
        turtle.turnLeft()
    else 
        turtle.turnRight()
    end
end


-- Move to the next row of the zigzag pattern.
function changeRow()
    local success
    -- Turn towards the right direction
    turn()
    -- If something is blocking the way, go around it.
    while not moveAndDestroy() do  
        turn()
        moveAndDestroy()
        antiturn()
    end
    -- Now we are in the next row, let's go to the beginning of it.
    antiturn()
    repeat
        success = moveAndDestroy()
    until not success

    -- Turn around, towards the end of the row.
    turn()
    turn()

    goRight = not goRight
end