Faster Excavate (v1)

-- fast_excavate v1

if not turtle then
    print("This program requires a turtle")
    exit()
end

local tArgs = { ... }
local expect = require "cc.expect"
print(tArgs[1]);
expect(1, tonumber(tArgs[1]), "number");
expect(2, tonumber(tArgs[2]), "number", "nil");
expect(3, tonumber(tArgs[3]), "number", "nil");
local self = require "self"

local depth = 0;
local x = tonumber(tArgs[1])
local y = tonumber(tArgs[2]) or tonumber(tArgs[1])
local maxDepth = tonumber(tArgs[3]) or 1000000
local facing = false;

local function unload()
    local bookmark = self.getPosition();
    self.goToPosition(0, 0, 0, 2);
    for i=1,16 do
        self.select(i);
        self.drop(64);
    end
    self.select(1);
    self.goToPosition(bookmark);
end

local function endProgram()
    self.goToPosition(0, 0, 0, 0);
    print("Finished!");
end

local function refuel()
    self.refuel()
end

local function miningCycle()
        if not self.forward() then endProgram() end
        if self.getItemCount(15) > 0 then self.back() unload() self.forward() end
        self.digUp();
        if self.getItemCount(15) > 0 then unload() end
        self.digDown();
        if self.getItemCount(15) > 0 then unload() end
end

local function main()
    self.forced = true;
    local cont = false;

    local p = self.getPosition();
    p.y = p.y-1; -- Start only one tile below the chest
    -- Repeat while it can move down
    while self.goToPosition(p) do
        -- Make sure to grab the block dircetly under it when it moves down
        self.digDown()
        if self.getItemCount(15) > 0 then unload() end
        for width=1,x do
            if cont then
                if facing then
                    self.turnLeft()
                    miningCycle()
                    self.turnLeft()
                else
                    self.turnRight()
                        miningCycle()
                    self.turnRight()
                end
                facing = not facing
            end
            cont = true;
            for depth=2,y do
                miningCycle()
            end
        end
--      self.turnLeft()
--      self.turnLeft()
        p = self.getPosition();
        p.y = p.y-3;
        p.h = (p.h+2)%4;
--      if x%2 == 1 then facing = not facing end
--      facing = not facing
        cont = false;
    end
    endProgram()
end

main()