--Designate inventory slots
STONE_SLOT          = 1
COBBLE_SLOT         = 2
GRAVEL_SLOT         = 3
DIRT_SLOT           = 4
SAND_SLOT           = 5
TORCH_SLOT          = 6
ENDER_CHEST_SLOT    = 7

INV_COUNT           = 7                     --total number of inventory slots
FUEL_SLOT           = 16
TOTAL_SLOTS         = 16                    --number of slots in the turtle

--Set globals
MIN_FUEL_COUNT      = 16                    --minimum number of fuel items
TORCH_SPACE         = 10                    --number of block before placing a torch

--Instantiate random shit
CURRENT_SLOT        = STONE_SLOT            --if the turtle is not facing stone
LAST_SLOT           = STONE_SLOT            --then you are doing it wrong

DISTANCE            = 0                     --tracks total spaces moved forward
TORCHES_USED        = 0
FUEL_USED           = 0                     --tracks units of fuel used, not blocks used
LAST_FUEL           = 0                     --previous FUEL_USED
ORE                 = 0                     --total amount of ore mined
TOTAL_BLOCKS        = 0                     --total amount of blocks dug
TOTAL_SHAFTS        = 4
SHAFT_WIDTH         = 2
SHAFT_LENGTH        = 5

--Hilbert variablesr
H_REPETITION        = 2                     --Hilbert depth
H_SEG_LENGTH        = 3                     --Length of Hilbert segment

-- Hilbert function
function A(depth)
   if depth < 1 then return end
   turtle.turnLeft()
   B(depth - 1)
   TunnelForward(H_SEG_LENGTH)
   turtle.turnRight()
   A(depth - 1)
   TunnelForward(H_SEG_LENGTH)
   A(depth - 1)
   turtle.turnRight()
   TunnelForward(H_SEG_LENGTH)
   B(depth - 1)
   turtle.turnLeft()
end

function B(depth)

   if depth < 1 then return end
   turtle.turnRight()
   A(depth - 1)
   TunnelForward(H_SEG_LENGTH)
   turtle.turnLeft()
   B(depth - 1)
   TunnelForward(H_SEG_LENGTH)
   B(depth - 1)
   turtle.turnLeft()
   TunnelForward(H_SEG_LENGTH)
   A(depth - 1)
   turtle.turnRight()

end

function BlockHandler( here )
    if Detect(here) then
        if IsOre(here) then MineOre(here) end
    end
end

function CheckInventory( onInit )
    print("Checking inventory...")
    local n = 0
    local invThresh = 13                        --dump inventory after this many slots are full
    local slotReorg = 14                                --number of slots to reorgainze

    for i = INV_COUNT+1, TOTAL_SLOTS - 1 do     --first consolidate fuel items into one slot
        Select(FUEL_SLOT)
        if turtle.compareTo(i) then
            turtle.select(i)
            CURRENT_SLOT = i
            turtle.transferTo(FUEL_SLOT)
        end
        Select(LAST_SLOT)
    end

    for i = 1, slotReorg do
        if turtle.getItemCount(i) > 0 then      --slot used, reorganize, checking for duplicate slots
            n = n + 1
            CheckSlotDupes(i)
        end
    end

    result = n

    if n > invThresh then                       --dump inventory into a chest after threshold level
        result = DumpInventory("forward")
    end
    print("Done")
    return result
end

function CheckSlotDupes ( index )   --check inventory slots for duplicate items, condense
    local i
    local begin
    if index < INV_COUNT+1 then begin = INV_COUNT+1
    else begin = index + 1 end
    Select(index)
    for i = begin, TOTAL_SLOTS - 1 do
        if turtle.compareTo(i) then
            turtle.select(i)
            CURRENT_SLOT = i
            turtle.transferTo(index)
        end
    end
    Select(LAST_SLOT)
end

function Compare( here )    --compare selected slot to block
    if here == "up" then return turtle.compareUp()
    elseif here == "down" then return turtle.compareDown()
    elseif here == "forward" then return turtle.compare() end return false end

function Detect ( here )    --detect if block is air/water/lava or mineable
    if here == "up" then return turtle.detectUp()
    elseif here == "down" then return turtle.detectDown()
    elseif here == "forward" then return turtle.detect() end return false end

function Drop ( thisSlot, thisMany )
    turtle.select(thisSlot)             --if thisMany == nil then everything will be dropped
    turtle.drop(thisMany)
end

function DumpInventory( here ) --drops chest and fills it
    local i, g, result
    result = -1
    print("Placing chest...")
    RemoveBlock("forward")
    Place(ENDER_CHEST_SLOT, here)
    for i = INV_COUNT+1, TOTAL_SLOTS - 1 do
        print(i)
        Drop(i, 64)
        sleep(.1)
    end
    Select(LAST_SLOT)
    FuelCheck()
    g = turtle.getItemCount(FUEL_SLOT)      --dump fuel items if we have too many
    if g > MIN_FUEL_COUNT then
        Drop(FUEL_SLOT, g - MIN_FUEL_COUNT)
        Select(LAST_SLOT)
    end
    DigAndMove("forward")
    BlockHandler("forward")
    BlockHandler("up")
    BlockHandler("down")
    turtle.turnRight()
    BlockHandler("forward")
    turtle.turnLeft()
    turtle.turnLeft()
    BlockHandler("forward")
    turtle.turnRight()
    turtle.back()
    return result
end

function Dig( here )
    TOTAL_BLOCKS = TOTAL_BLOCKS + 1  --stats
    if here == "up" then return turtle.digUp()
    elseif here == "down" then return turtle.digDown()
    elseif here == "forward" then return turtle.dig() end end

function DigAndMove ( here )
    RemoveBlock(here)
    if here == "forward" then return turtle.forward()
    elseif here == "up" then return turtle.up()
    elseif here == "down" then return turtle.down()
    end
end

function FuelCheck()                    --checks fuel level
    local GC = turtle.getItemCount
    print("Fuel: " .. turtle.getFuelLevel())
    Stats("fuel")
    if turtle.getFuelLevel() < 100 then
        Select(FUEL_SLOT)
        print("Refueling " .. (GC(FUEL_SLOT) - 1) .. " units")
        return turtle.refuel(GC(FUEL_SLOT) - 1)
    end
    Select(LAST_SLOT)
end

function InitFuel()                     --used on first run
    print("Checking fuel")
    LAST_FUEL = turtle.getFuelLevel()
    return FuelCheck() end

function IsFull ( )                     --checks to see if inventory is full
    local n, i
    for i = INV_COUNT+1, TOTAL_SLOTS-1 do
        if turtle.getItemCount(i) > 0 then
        else
            return false
        end
    end
    return true
end

function IsOre(here)                    --cycles through inventory slots and compares to a block

    local i
    local result = nil
    if Compare(here) then
        if CURRENT_SLOT > INV_COUNT then result = true
        else result = false
        end
    else
        for i = 1, TOTAL_SLOTS - 1 do
            turtle.select(i)
            CURRENT_SLOT = i
            if Compare(here) then
                if i > INV_COUNT then result = true
                    break
                else result = false
                    break
                end
            end
        end
    end
    print(result)
    if result == nil then result = true end
    return result
end

function Left( doThis, here )           --turn left, call a function, turn right
    local result
    local doIt = doThis
    turtle.turnLeft()
    result = doIt(here)
    turtle.turnRight()
    return result
end

function MineOre( here )                --remove surrounding vein
    local m = MineOre                       --declaring functions locally is supposed to be
    local a = 0                             --much faster in lua
    local RB = RemoveBlock
    local M = Move
    local R = Right
    local BH = BlockHandler
    local RH = RotateH
    local TS = Select
    local TB = turtle.back
    local P = Place
    local D = turtle.down
    local U = turtle.up

    RB(here)                        --get ore and move in
    M(here)
    if here == "forward" then               --send surrounding area to the BlockHandler
        R(BH, "forward")
        BH("up")
        Left(BH, "forward")
        BH("down")
        BH("forward")
    else
        RH(BH, "forward")
        BH(here)
    end

    if here == "forward" then               --covering up our tracks
        TB()
        P(COBBLE_SLOT, here)
    elseif here == "up" then
        D()
        P(COBBLE_SLOT, here)
    elseif here == "down" then
        U()
        P(COBBLE_SLOT, here)
    end
end

function Move ( here )
    if here == "up" then return turtle.up()
    elseif here == "forward" then return turtle.forward()
    elseif here == "down" then return turtle.down()
    end
end

function Place( thisSlot, here )                    --places block up, forward or down.  fills in with gravel below
    Select(thisSlot)
    if here == "forward" then return turtle.place()
    elseif here == "down" then
        local t = turtle.getItemCount(GRAVEL_SLOT)
        turtle.placeDown()
        Select(GRAVEL_SLOT)
        if not turtle.detectDown() then
            while i < t do
                Place("down")
                if t == 1 then return true
                else return false
                end
                t = t + 1
            end
        else turtle.placeDown()
        end
    elseif here == "up" then return turtle.placeUp()
    end
    Select(LAST_SLOT)
    return false
end

function RemoveBlock( here )            --removes block and any gravel/sand (sand/gravel from above falls down when mined)
    local failsafe = 0
    if here == "down" then Dig("down")
    else
        if Dig(here) == true then Select(GRAVEL_SLOT)
            if Compare(here) == true then failsafe = 0
                while Dig(here) and (failsafe < 16) do  --infinite loop protection
                    sleep(.5)
                    failsafe = failsafe + 1
                end
            end
            Select(LAST_SLOT)
        end
    end
end

function RotateH( doThis, here )        --rotates and calls a function
    local result
    local doIt = doThis
    turtle.turnRight()
    doIt(here)
    turtle.turnRight()
    doIt(here)
    turtle.turnRight()
    doIt(here)
    turtle.turnRight()
    doIt(here)
end


function Stats ( this, that )           --prints various stats
    FUEL_USED = FUEL_USED + LAST_FUEL - turtle.getFuelLevel()
    LAST_FUEL = turtle.getFuelLevel()
    if this == "distance" then
        DISTANCE = DISTANCE + 1
        if DISTANCE % 5 == 0 then
            print(DISTANCE .. "m tunneled.")
            print(((TOTAL_BLOCKS + ORE) / DISTANCE) .. " blocks mined per tunnel section.")
            print((FUEL_USED/(TOTAL_BLOCKS + ORE)).. " fuel per block.")return true
        end
    elseif this == "torch" then TORCHES_USED = TORCHES_USED + 1
        return true
    elseif this == "fuel" then FUEL_USED = FUEL_USED + (LAST_FUEL - turtle.getFuelLevel())
        print(FUEL_USED .. " total fuel used.")
        print((FUEL_USED / DISTANCE) .. " fuel per m.")
        print((FUEL_USED / ORE) .. " fuel per extra ore.")
        print((turtle.getFuelLevel() /(FUEL_USED/DISTANCE)) .. "m's of fuel left.")
        return true
    elseif this == "ore" then ORE = ORE + 1
        print(ORE .. " extra ore mined.")
        print((FUEL_USED / ORE) .. " per ore.") return true
    elseif this == "fuelchunks" then end return false end

function Select ( slot )
    LAST_SLOT = CURRENT_SLOT
    turtle.select(slot)
    CURRENT_SLOT = slot
end

function TorchCheck()                   --checks to see if torch needs to be placed
    local BH = BlockHandler
    if (DISTANCE % TORCH_SPACE) == 0 and turtle.getItemCount(TORCH_SLOT) > 0 then
        Stats("torch")
        RemoveBlock("forward")
        turtle.forward()
        if turtle.detect() then BH("forward")
        else Place(COBBLE_SLOT, "forward")
        end
        if turtle.detectDown() then BH("down")
        else Place(COBBLE_SLOT, "down")
        end
        turtle.back()
        Place(TORCH_SLOT, "forward")
    end
end

function TunnelForward( thisFar )       --mine a 1x2 tunnel forward a given number of units
    local i
    for i = 1, thisFar do
        if IsFull() then CheckInventory() end
        FuelCheck()
                                            --Coords         Facing
        --turtle.now                        -- 0,0,0            N
        DigAndMove("forward")               -- 0,1,0            N
            BlockHandler("down")
            if not Detect("down") then Place(COBBLE_SLOT, "down") end
        turtle.turnLeft()                   -- 0,1,0            W
            BlockHandler("forward")
            if not Detect("forward") then Place(COBBLE_SLOT, "forward") end
        DigAndMove("up")                    -- 0,1,1            W
            BlockHandler("up")
            if not Detect("up") then Place(COBBLE_SLOT, "up") end
            BlockHandler("forward")
            if not Detect("forward") then Place(COBBLE_SLOT, "forward") end
        turtle.turnRight()                  -- 0,1,1            N
        turtle.turnRight()                  -- 0,1,1            E
            BlockHandler("forward")
            if not Detect("forward") then Place(COBBLE_SLOT, "forward") end
        turtle.down()                       -- 0,1,0            E
            BlockHandler("forward")
            if not Detect("forward") then Place(COBBLE_SLOT, "forward") end
            TorchCheck()
        turtle.turnLeft()                   -- 0,1,0            N
        Stats("distance")                   --add one to distance travelled and display stats
    end
end

function main()
    InitFuel()
    TunnelForward(SHAFT_LENGTH+2)
    turtle.turnRight()
    TunnelForward((TOTAL_SHAFTS-1)*3)
    turtle.turnRight()
    TunnelForward(SHAFT_LENGTH+1)
    turtle.turnRight()
    TunnelForward((TOTAL_SHAFTS-2)*3)
    turtle.turnRight()

    for i = 1, SHAFTS / 2 do
        TunnelForward(SHAFT_LENGTH+1)
        turtle.turnRight()
        TunnelForward(SHAFT_WIDTH+1)
        turtle.turnRight()
        TunnelForward(SHAFT_LENGTH+1)
        turtle.turnLeft()
        TunnelForward(SHAFT_WIDTH+1)
        turtle.turnLeft()
    end

end

main()