--variables
--len = shaft length
local len = 1
--notDig = number of blocks that are not mined in the shaft
local notDig = 3
--torch = location of torches
local torch = 16 - notDig
--curDist = distance from start
local curDist = 0
--top = bool for checking if the turtle is mining the top ot bot level of the shaft
local top = false
--run init instead of the main program
runInit = false
--isAtHome = remember if you're at home
isAtHome = true


--clear the screen
function clrScr()
    term.clear()
    term.setCursorPos(1,1)
end

--argument parsing
local tArgs = {...}
if #tArgs > 2 or #tArgs == 0 then
    term.clear()
    print( "Type 'shaft help' for instructions" )
elseif #tArgs == 1 then
    if tArgs[1] == "help" then
        term.clear()
        print("Usage: shaft [length] [blocks]")
        print("Length is the length of the mining shaft.")
        print("Blocks is the number of blocks that will not be mined [range: 0-10]. By default it's 3 for stone, gravel and dirt and they need to be put in slots 16, 15 and 14")
        print("Enter for more...")
        io.read()
        term.clear()
        print("Torches are placed every 8 blocks and go 1 slot before the ores that won't be mined, by default 13.")
        print("Place chest underneath the starting position.")
        print("use 'shaft init' to make a starting room")
        print("Enter to continue.")
        io.read()
    elseif tArgs[1] == "init" then
        runInit = true
    else
        len = tonumber( tArgs[1] )
    end
elseif #tArgs == 2 then
    len = tonumber( tArgs[1] )
    notDig = tonumber ( tArgs[2] )
end

--refueling
function refuel(need, message)
    while turtle.getFuelLevel() < (need) do
        for n=1,(16-notDig) do
            local nCount = turtle.getItemCount(n)
            if nCount > 0 then
                turtle.select(n)
                refueled = turtle.refuel(1)
                while turtle.getFuelLevel() < need and refueled == true do
                    refueled = turtle.refuel(1)
                    if turtle.getFuelLevel() > need and refueled == true then
                        break
                    end
                end
            end
        end
        if turtle.getFuelLevel() < need and isAtHome == true then
            print(message)
            io.read()
            refuel(need,message)
        elseif turtle.getFuelLevel() < need and isAtHome == false then
            goHome()
            refuel(need,message)
            goBack()
        end
        clrScr()
        print("Turtle refuled. Returning to work...")
    end
end

--build the starting room
function initRoom()
    refuel(30, "Please input fuel to continue and press enter.")
    turtle.select(1)
    mineUp()
    digAndMove()
    turtle.turnLeft()
    digAndMove()
    turtle.turnLeft()
    digAndMove()
    digAndMove()
    turtle.digDown()
    turtle.down()
    turtle.turnLeft()
    turtle.turnLeft()
    digAndMove()
    digAndMove()
    turtle.turnRight()
    digAndMove()
    turtle.turnLeft()
    turtle.back()
    turtle.turnLeft()
    turtle.place()
    turtle.turnRight()
end

--check if blocks that should not be mined and torches are inserted
function validateInv()
    clrScr()
    while turtle.getItemCount(torch) < 2 do
        print("")
        print("Please put torches into slot ",torch," and press enter to continue.")
        io.read()
    end
    while not blocksPresent do
        blocksPresent = true
        for i = 17-notDig, 16 do
            if turtle.getItemCount(i) == 0 then blocksPresent = false end
        end
        if not blocksPresent then
            print("Please put at least 1 block into slots ",17-notDig,"-16 for the items you don't want to mine and press enter.")
            io.read()
        end
    end
    clrScr()
end

--torch placement
function placeTorch()
    turtle.select(torch)
    i = curDist
    while i > 0 do
        i = i-8
    end
    if turtle.getItemCount(torch) < 2 then
        clrScr()
        print("Almost out of torches! Returning home...")
        goHome()
        emptyInventory()
        while turtle.getItemCount(torch) < 2 do
            print("")
            print("Please insert torches into slot ",torch," and press enter.")
            io.read()
        end
        refuel(curDist*2 + 95, "Not enough fuel to return to job. Insert fuel and press enter.")
        clrScr()
        print("Turtle ready! Resuming work...")
        goBack()
    end
    if i == 0 then
        turtle.placeUp()
    end
end

--return home
function goHome()
    if top then
        turtle.turnLeft()
        turtle.turnLeft()
    else
        turtle.up()
    end
    for i = 1, curDist do
        turtle.forward()
    end
    turtle.down()
    isAtHome = true
end

--go back to work you lazy sucker!
function goBack()
    turtle.up()
    for i = 1, curDist do
        turtle.back()
    end
    if top then
        turtle.turnLeft()
        turtle.turnLeft()
    else
        turtle.down()
    end
    isAtHome = false
end

--check if there's a need to empty the inventory
function checkInventory()
    drop = 15-notDig
    tempCounter = 0
    for i = 1, drop do
        if turtle.getItemCount(i) > 0 then tempCounter = tempCounter + 1 end
    end
    if tempCounter == drop then
        clrScr()
        print("Inventory full, returning home.")
        goHome()
        emptyInventory()
        refuel(curDist*2+95, "Not enough fuel to return to work. Insert fuel and press enter.")
        clrScr()
        print("Turtle ready! Resuming work...")
        goBack()
    end
end

--function that moves forward and digs if there's an obstacle
function digAndMove()
  while not turtle.forward() do
    sleep(0.5)
    turtle.dig()
  end
end

--function to clean inventory
function emptyInventory()
    turtle.turnRight()
    for i = 1, 15-notDig do
        turtle.select(i)
        if turtle.getItemCount(i) > 0 then
            while not turtle.drop() do
                print("")
                print("Chest full. Please empty chest and press enter to continue.")
                io.read()
            end
        end
    end
    turtle.turnLeft()
end

--special case for mining up
function mineUp()
    while not turtle.up() do
      turtle.digUp()
      sleep(0.5)
    end
end

--check for ore below miner
function checkDown()
  ore = true
  if turtle.detectDown() then
    for i = 17-notDig, 16 do
        turtle.select(i)
        if turtle.compareDown() then
            ore = false
        end
    end
  else
    ore = false
  end
  return ore
end

--check for ore above miner
function checkUp()
  ore = true
  if turtle.detectUp() then
    for i = 17-notDig, 16 do
        turtle.select(i)
        if turtle.compareUp() then
            ore = false
        end
    end
  else
    ore = false
  end
  return ore
end

--check for ore in front miner
function checkFront()
  ore = true
  if turtle.detect() then
    for i = 17-notDig, 16 do
        turtle.select(i)
        if turtle.compare() then
            ore = false
        end
    end
  else
    ore = false
  end
  return ore
end

--check the 6 sides around the miner and mine if you find ore, then move in and repeat
function mineOre()
  if checkDown() then
    turtle.digDown()
    turtle.down()
    mineOre()
    turtle.up()
  end
  if checkUp() then
    mineUp()
    mineOre()
    turtle.down()
  end
  if checkFront() then
    digAndMove()
    mineOre()
    turtle.back()
  end
  turtle.turnRight()
  if checkFront() then
    digAndMove()
    mineOre()
    turtle.back()
  end
  turtle.turnRight()
  if checkFront() then
    digAndMove()
    mineOre()
    turtle.back()
  end
  turtle.turnRight()
  if checkFront() then
    digAndMove()
    mineOre()
    turtle.back()
  end
  turtle.turnRight()
end

--main program
function main()
    clrScr()
    print("Orders received.")
    print("Starting to mine a shaft ",len," long with ",notDig," block exceptions.")

    --validate the inventory before starting
    refuel(95, "Input fuel and press enter!")
    validateInv()

    --go up 1 as we will start mining at the top row
    isAtHome = false
    mineUp()
    mineOre()

    --start diging the top and checking it for ore and refueling if needed
    top = true
    for i = 1, len do
        checkInventory()
        refuel(curDist+95, "Out of fuel, please refil and press enter.")
        digAndMove()
        mineOre()
        curDist = curDist + 1
    end

    --move down to bottom row
    turtle.digDown()
    turtle.down()
    turtle.turnLeft()
    turtle.turnLeft()
    top = false
    mineOre()

    --now dig the bottom while, again, checking for ore and fuel but also place down torches
    for i = 1, (len-1) do
        checkInventory()
        refuel(curDist+95, "Out of fuel, please refil and press enter.")
        digAndMove()
        mineOre()
        curDist = curDist - 1
        placeTorch()

    end

    turtle.forward()
    emptyInventory()
    turtle.turnLeft()
    turtle.turnLeft()
    isAtHome = true

    clrScr()
    print("Work complete!")
end

--choose what to run
clrScr()
if runInit then
    turtle.select(1)
    while turtle.getItemCount(1) < 1 do
        print("Please insert chest into slot 1 and press enter")
        io.read()
    end
    initRoom()
    clrScr()
    print("Startup location ready!")
elseif tArgs[1] == "help" then
    print("")
else
    if len > 0 and notDig < 11 and #tArgs > 0 and #tArgs < 2 then
        main()
    elseif #tArgs > 0 and #tArgs < 2 then
        print("Shaft needs to be at least 1 long and blocks need to be less then 11 or empty.")
    end
end