-- Based on excavate from the original computercraft distribution
-- written by hildenae
local rubberwood=1
local tool=2
-- electric hat has 200 uses.
-- my size is 2 rows of 6 threes
-- with a maxheight of 7 - this leves 4 uses
local width = 6
local rows = 2
local MAX_USES=200
local uses = 0
local depth = 0
local xPos,zPos = 0,0
local xDir,zDir = 0,1

local function turnLeft()
    turtle.turnLeft()
    xDir, zDir = -zDir, xDir
end

local function turnRight()
    turtle.turnRight()
    xDir, zDir = zDir, -xDir
end

function goTo( x, y, z, xd, zd )
    while depth > y do
        if turtle.up() then
            depth = depth - 1
        else
            return false
        end
    end

    if xPos > x then
        while xDir ~= -1 do
            turnLeft()
        end
        while xPos > x do
            if turtle.forward() then
                xPos = xPos - 1
            else
                return false
            end
        end
    elseif xPos < x then
        while xDir ~= 1 do
            turnLeft()
        end
        while xPos < x do
            if turtle.forward() then
                xPos = xPos + 1
            else
                return false
            end
        end
    end

    if zPos > z then
        while zDir ~= -1 do
            turnLeft()
        end
        while zPos > z do
            if turtle.forward() then
                zPos = zPos - 1
            else
                return false
            end
        end
    elseif zPos < z then
        while zDir ~= 1 do
            turnLeft()
        end
        while zPos < z do
            if turtle.forward() then
                zPos = zPos + 1
            else
                return false
            end
        end
    end
    while depth < y do
        if turtle.down() then
            depth = depth + 1
        else
            return false
        end
    end
    while zDir ~= zd or xDir ~= xd do
        turnLeft()
    end
    return true
end

local function forward()
    turtle.forward()
    xPos = xPos + xDir
    zPos = zPos + zDir
    return true
end

local function down()
    if turtle.down() then
        depth = depth + 1
        return true
    else
        return false
    end
end

local function harvest()
    turtle.select(rubberwood)
    if turtle.compare() then
        turtle.select(tool)
        turtle.place()
        uses = uses + 1
    else
        print("not wood")
    end
end

local function downTree()
    local x,y,z,xd,zd = xPos,depth,zPos,xDir,zDir
    repeat
        harvest()
    until not down()
    goTo( x,y,z,xd,zd )
end

local function moveRight()
    turnRight()
    forward()
    turnLeft()
end
local function moveLeft()
    turnLeft()
    forward()
    turnRight()
end
local function turn180()
    turnRight()
    turnRight()
end
local function harvestRow()
    local w = width
    while(w > 0) do
        downTree()
        moveRight()
        w = w -1
    end
    forward()
    turnLeft()
    downTree() -- check side for resin
    moveRight()
    turnLeft()
    w = width
    while(w > 0) do
        moveRight()
        downTree()
        w = w -1
    end
    moveRight()
    forward()
    turnLeft()
    downTree() -- check side for resin
end

run = true
while run do

    local r = rows
    forward()
    while (r > 0) do
        harvestRow()
        moveLeft()
        forward()
        turnLeft()
        r = r -1
    end

    moveLeft() -- move out to the side
    turn180()
    for i = 0, rows, 2 do
        print ("moving forward 2")
        forward()
        forward()
    end
    print("uses: ")
    print (uses)

    -- go to charge station
    goTo(0,0,0,0,1)
    run = false
end