--list of all ores or blocks we want to mine--
local ores = {"minecraft:iron_ore",
"minecraft:diamond_ore", 
"minecraft:coal_ore",
"minecraft:gold_ore",
"minecraft:emerald_ore",
"minecraft:restone_ore"}

--stuff to throw away--
local garbage = {"minecraft:dirt",
"minecraft:cobblestone",
"minecraft:gravel",
"minecraft:sand",
"minecraft:granite",
"minecraft:andesite",
"minecraft:diorite"}

--if below this number it will use coal to refuel--
local refill = 1000

local tArgs = {...}
local tunnelLength = 0

--set tunnels length--
if tonumber(tArgs[1]) > 0 then 
     tunnelLength = tonumber(tArgs[1])
else
     tunnelLength = 50
end

local fuelLevel = turtle.getFuelLevel()
local fuelFormula = math.ceil((tunnelLength*4)+(tunnelLength*0.45)+100)

--test fuel level. If good ask if ready--
if fuelLevel < fuelFormula then
     error("[Fuel Required]: " .. fuelFormula - fuelLevel)
end

--this function checks the block and gives info--
function inspect(side)
     local worked, data = false, {}
     if not side then
          worked, data = turtle.inspect()
     elseif side == 1 then
          worked, data = turtle.inspectUp()
     elseif side == 2 then
          worked, data = turtle.inspectDown()
     end
     
     if worked then
          for i=1,#ores do
               if data.name == ores[i] then
                    return data.name
                end
          end
          return false 
     end
end

--all movement functions. Makes it look better--

function forward()
     repeat turtle.dig() until turtle.forward()
     return true
end

function back()
    if not turtle.back() then
        turtle.turnRight()
        turtle.turnRight()
        repeat turtle.dig() until turtle.forward()
        turtle.turnLeft()
        turtle.turnLeft()
    end
    return true
end

function up()
     repeat turtle.digUp() until turtle.up()
     return true
end

function down()
     repeat turtle.digDown() until turtle.down()
     return true
end
     
--this is what does all the looking for ores around the turtle. Recursive function--

function scan( nTry )

     if not nTry then
          nTry = 1
     elseif nTry > 180 then
          return
     end

--check to the right--
     turtle.turnRight()
     if inspect() then
          forward()
          scan(nTry+1)
          back()
     end
     turtle.turnLeft()

--check to the left--
     turtle.turnLeft()
     if inspect() then
         forward()
         scan(nTry+1)
         back()
     end
     turtle.turnRight()

--check in front--
     if inspect() then
          forward()
          scan(nTry+1)
          back()
     end

--check up--
     if inspect(1) then
          up()
          scan(nTry+1)
          down()
     end

--check down--
     if inspect(2) then
          down()
          scan(nTry+1)
          up()
     end
end

--cleans out and reorganizes the inventory--
function purgeInv()
     for i=1,16 do
          if turtle.getItemCount(i) > 0 then
              local data = turtle.getItemDetail(i)
              
               if turtle.getItemCount(i) < 64 then
                    for j=i+1,16 do
                      local  d = turtle.getItemDetail(j)
                         if d and d.name == data.name then
                              turtle.select(j)
                              turtle.transferTo(i)
                         end
                    end
               end
                
               for b=1,#garbage do
                    if data.name == garbage[b] then
                         turtle.select(i)
                         turtle.drop()
                         break
                    elseif data.name == "minecraft:coal" then
                         if turtle.getFuelLevel() < refill then
                              turtle.refuel()
                              break
                         end
                    end
               end
          end
     end
end

--this is the main function where all the other functions are called in order and makes it work--

function main()
     print("TUNNEL LENGTH: " .. tunnelLength)
     print("START [Y/N]")
     while true do
     
         local _,c = os.pullEvent("char")
          
          if c:lower() == "y" then
          
               --start mining--
               for t=1,tunnelLength do
                    forward()
                    scan()
                    up()
                    scan()
                    down()
                    purgeInv()
                end
               
               turtle.turnRight()
               turtle.turnRight()
               
               --return trip--
               for t=1, tunnelLength do
                    forward()
               end
               return
          else
               error("You didn't press y")
          end
     end
end



--call the main function to start it all--
main()