local robot = require("robot")
local cp = require("component")
local navi = cp.navigation
local inv = cp.inventory_controller
--require specific used libraries

local chest_pos = navi.getFacing() - 2
if(chest_pos < 1) then
    chest_pos = chest_pos + 4
end
--save charger and chest position
--charger is on the left of the robot and chest is behind the robot

local waypoint = navi.findWaypoints(64)
local relX = waypoint[1]["position"][1]
local relZ = waypoint[1]["position"][3]
--save ending position, Y is not needed

local area = (math.abs(relX) + 1) * (math.abs(relZ) + 1)
--calculate total columns

mined = 0
charge_time = 0
--global varibles for mined columns and drill charge time

local function path_finding(m)
    local length = 0
        if(chest_pos % 2 == 1) then
            length = math.abs(relZ) + 1
        --facing z
        else
            length = math.abs(relX) + 1
        --facing x
        end
        local forwards = mined % length
        local rights = math.floor(mined / length)
        --calculate needed moves
    if(m == 0) then
        --return mode
        robot.turnRight()
        local i = 0
        while(i < forwards) do
            robot.forward()
            i = i + 1
        end
        i = 0
        robot.turnRight()
        while(i < rights) do
            robot.forward()
            i = i + 1
        end
    else
        --travel mode
        local i = 0
        while(i < forwards) do
            robot.forward()
            i = i + 1
        end
        i = 0
        robot.turnRight()
        while(i < rights) do
            robot.forward()
            i = i + 1
        end
    end
end

local function dump()
    robot.turnLeft()
    for i=1,16 do
        robot.select(i)
        robot.drop(64)
    end
    robot.turnRight()
    robot.select(1)
    inv.equip()
    robot.drop()
    os.sleep(charge_time)
    robot.suck()
    inv.equip()
    robot.turnRight()
end
--dump robot inventory

local function excavate()
    while (mined < area) do
        path_finding(1)
        local relY = 0
        while 1 do
            robot.swingDown()
            os.sleep(1)
            if(robot.detectDown()) then
                break
            else
                robot.down()
                relY = relY + 1
            end
        end
        charge_time = math.ceil(relY / 10)
        while(relY > 0) do
            robot.up()
            relY = relY - 1
        end
        path_finding(0)
        dump()
        mined = mined + 1
    end
end

excavate()