-- Configuration
local refuelLevel = 20   -- Minimum fuel level before refueling
local fuelSlot = 16      -- Slot where fuel (coal) is stored
local tunnelLength = 10  -- Length of the tunnel
local startYLevel = 70   -- Starting Y level
local targetYLevel = 12  -- Target Y level (Y=12)

-- Movement tracking (stack-based approach)
local movementLog = {}  -- Stack to store movements for backtracking
local minedOres = {}  -- List to track mined ore coordinates to prevent infinite loops
local currentY = startYLevel  -- Track Y level manually

-- List of valuables (all ores) to detect in Minecraft 1.7.10
local valuables = {
    "minecraft:iron_ore",
    "minecraft:coal_ore",
    "minecraft:gold_ore",
    "minecraft:diamond_ore",
    "minecraft:redstone_ore",
    "minecraft:emerald_ore",
    "minecraft:lapis_ore",
    "minecraft:quartz_ore"
}

-- Function to refuel the turtle
function refuel()
    if turtle.getFuelLevel() < refuelLevel then
        turtle.select(fuelSlot)
        if turtle.refuel(1) then
            print("Turtle refueled.")
        else
            print("No fuel available!")
        end
    end
end

-- Function to move forward with tracking
function moveForward()
    turtle.dig()  -- Dig if there's a block in front
    turtle.forward()
    table.insert(movementLog, "forward")  -- Track movement
end

-- Function to move down with tracking, stops at Y=12
function moveDown()
    if currentY > targetYLevel then
        turtle.digDown()  -- Dig if there's a block below
        turtle.down()     -- Move down
        currentY = currentY - 1  -- Update Y level manually
        table.insert(movementLog, "down")  -- Track movement
    else
        print("Reached target Y-level: " .. targetYLevel)
    end
end

-- Function to move up with tracking
function moveUp()
    turtle.up()
    currentY = currentY + 1  -- Update Y level manually
    table.insert(movementLog, "up")  -- Track movement
end

-- Function to move back with tracking
function moveBackward()
    turtle.back()
    table.insert(movementLog, "backward")  -- Track movement
end

-- Function to move left or right with tracking
function turnAndMove(direction)
    if direction == "left" then
        turtle.turnLeft()
        moveForward()
        turtle.turnRight()
    elseif direction == "right" then
        turtle.turnRight()
        moveForward()
        turtle.turnLeft()
    end
end

-- Function to check if a block is valuable
function isValuable(blockName)
    for _, valuable in ipairs(valuables) do
        if blockName == valuable then
            return true
        end
    end
    return false
end

-- Function to track mined ore locations to prevent looping
function isAlreadyMined(x, y, z)
    local key = x .. "," .. y .. "," .. z
    return minedOres[key] ~= nil
end

function markOreMined(x, y, z)
    local key = x .. "," .. y .. "," .. z
    minedOres[key] = true
end

-- Recursive function to mine an entire vein of ore
function mineVein()
    local directions = { "forward", "up", "down", "left", "right", "back" }

    -- Recursively mine all connected ore blocks
    for _, direction in ipairs(directions) do
        local success, block
        if direction == "forward" then
            success, block = turtle.inspect()
        elseif direction == "up" then
            success, block = turtle.inspectUp()
        elseif direction == "down" then
            success, block = turtle.inspectDown()
        elseif direction == "left" then
            turtle.turnLeft()
            success, block = turtle.inspect()
            turtle.turnRight()
        elseif direction == "right" then
            turtle.turnRight()
            success, block = turtle.inspect()
            turtle.turnLeft()
        elseif direction == "back" then
            turtle.turnRight()
            turtle.turnRight()
            success, block = turtle.inspect()
            turtle.turnRight()
            turtle.turnRight()
        end

        if success and isValuable(block.name) then
            -- Mark this ore as mined
            local x, y, z = gps.locate()  -- Assumes GPS is available, or simulate coordinate tracking manually
            if not isAlreadyMined(x, y, z) then
                markOreMined(x, y, z)

                -- Move toward the ore and mine it
                if direction == "forward" then
                    moveForward()
                elseif direction == "up" then
                    moveUp()
                elseif direction == "down" then
                    moveDown()
                elseif direction == "left" then
                    turnAndMove("left")
                elseif direction == "right" then
                    turnAndMove("right")
                elseif direction == "back" then
                    moveBackward()
                end

                -- Recursively continue mining the connected vein
                mineVein()

                -- After mining the vein, return to the original position
                if direction == "forward" then
                    moveBackward()
                elseif direction == "up" then
                    moveDown()
                elseif direction == "down" then
                    moveUp()
                elseif direction == "left" then
                    turnAndMove("right")  -- Reverse left movement
                elseif direction == "right" then
                    turnAndMove("left")  -- Reverse right movement
                elseif direction == "back" then
                    moveForward()
                end
            end
        end
    end
end

-- Function to check for and mine entire ore veins around the turtle
function checkAndMineVein()
    local success, block = turtle.inspect()
    if success and isValuable(block.name) then
        print("Ore detected, mining the entire vein...")
        moveForward()
        mineVein()  -- Mine the entire vein
        moveBackward()  -- Return to tunnel
    end

    -- Also check left, right, up, and down for veins
    turtle.turnLeft()
    success, block = turtle.inspect()
    if success and isValuable(block.name) then
        print("Ore detected on the left, mining the entire vein...")
        moveForward()
        mineVein()
        moveBackward()
    end
    turtle.turnRight() -- Return to original direction

    turtle.turnRight()
    success, block = turtle.inspect()
    if success and isValuable(block.name) then
        print("Ore detected on the right, mining the entire vein...")
        moveForward()
        mineVein()
        moveBackward()
    end
    turtle.turnLeft() -- Return to original direction

    -- Check above and below
    success, block = turtle.inspectUp()
    if success and isValuable(block.name) then
        print("Ore detected above, mining the entire vein...")
        moveUp()
        mineVein()
        moveDown()
    end

    success, block = turtle.inspectDown()
    if success and isValuable(block.name) then
        print("Ore detected below, mining the entire vein...")
        moveDown()
        mineVein()
        moveUp()
    end
end

-- Function to dig a tunnel and look for entire veins of ores
function digTunnel(length)
    print("Digging tunnel...")
    for i = 1, length do
        checkAndMineVein() -- Check and mine any veins nearby before moving
        moveForward()  -- Move forward and track the movement
        turtle.digUp() -- Clear the block above
        refuel()  -- Refuel as needed
    end
end

-- Function to dig down from Y=70 to Y=12
function digDownToY()
    print("Digging down from Y=" .. startYLevel .. " to Y=" .. targetYLevel .. "...")
    while currentY > targetYLevel do
        moveDown()
        refuel()  -- Refuel as needed
    end
    print("Reached Y=12!")
end

-- Function to backtrack to the starting point
function backtrack()
    print("Backtracking...")
    while #movementLog > 0 do
        local lastMove = table.remove(movementLog)  -- Get the last movement

        -- Reverse the last movement
        if lastMove == "forward" then
            turtle.back()
        elseif lastMove == "down" then
            turtle.up()  -- Go back up
            currentY = currentY + 1  -- Track Y level correctly
        elseif lastMove == "up" then
            turtle.down()  -- Go back down
            currentY = currentY - 1  -- Track Y level correctly
        elseif lastMove == "backward" then
            turtle.forward()  -- Move forward to undo a back movement
        end
    end
    print("Returned to starting point at Y=70!")
end

-- Main Program
refuel()  -- Initial refuel

-- Step 1: Dig down from Y=70 to Y=12, and track the depth
digDownToY()

-- Step 2: Dig a 10-block tunnel and mine entire veins of ore
digTunnel(tunnelLength)

-- Step 3: Return to the starting point at Y=70
backtrack()