Miner

local blacklist = {
    "minecraft:stone";
}

local MODE_START = 0
local MODE_VEIN = 1
local MOVE_SHAFT = 2

local SIDE_LEFT = 0
local SIDE_RIGHT = 1

local PASS_FIRST = 0
local PASS_SECOND = 1

local VEIN_LEN = 16;

local state = {
    -- x, y, z
    relativePos = {0, 0, 0};

    -- 0: forward
    -- 1: left
    -- 2: back
    -- 3: right
    orientation = 0;

    mode = MODE_START;

    vein_len = 0;
    vein_side = SIDE_LEFT;
    vein_pass = PASS_FIRST;
    shaft_len = 0;
}

local function blacklisted(detail)
    if not detail or not detail.name then return false end
    for i,v in ipairs(blacklist) do
        if v == detail.name then
            return true
        end
    end
    return false
end

local function load_state()
    local file = fs.open("state", "r")
    if not file then return end
    print("Loading previous state")
    local t_state = textutils.unserialize(file.readAll())
    if not t_state then
        print("Failed to deserialize state")
    else
        state = t_state
    end
    file.close()
end

local function save_state()
    local file = fs.open("state", "w")
    file.write(textutils.serialize(state))
    file.close()
end


local function tryOp(op, force, force_op)
    if force then
        if not force_op then
            force_op = function() end
        end
        while not op() do force_op() end
        return true
    end

    return op()
end

local function left(force)
    if tryOp(turtle.turnLeft, force) then
        state.orientation = state.orientation + 1
        if state.orientation == 4 then
            state.orientation = 0
        end
        return true
    end
    return false
end

local function right(force)
    if tryOp(turtle.turnRight, force) then
        state.orientation = state.orientation - 1
        if state.orientation == -1 then
            state.orientation = 3
        end
        return true
    end
    return false
end

local function up(force)
    if tryOp(turtle.up, force, turtle.digUp) then
        state.relativePos[1] = state.relativePos[1] + 1
        return true
    end
    return false
end

local function down(force)
    local success
    if tryOp(turtle.down, force, turtle.digDown) then
        state.relativePos[1] = state.relativePos[1] - 1
        return true
    end
    return false
end

local function dig(force)
    return tryOp(turtle.dig, force)
end

local function digUp(force)
    return tryOp(turtle.digUp, force)
end

local function digDown(force)
    return tryOp(turtle.digDown, force)
end

local function forward(force)
    local slot, amount
    if state.orientation == 0 then
        slot = 1
        amount = 1
    elseif state.orientation == 1 then
        slot = 3
        amount = 1
    elseif state.orientation == 2 then
        slot = 1
        amount = 1
    elseif state.orientation == 3 then
        slot = 3
        amount = -1
    end

    if tryOp(turtle.forward, force, turtle.dig) then
        state.relativePos[slot] = state.relativePos[slot] + amount
        return true
    end
    return false
end

local function back(force)
    local slot, amount
    if state.orientation == 0 then
        slot = 1
        amount = 1
    elseif state.orientation == 1 then
        slot = 3
        amount = 1
    elseif state.orientation == 2 then
        slot = 1
        amount = 1
    elseif state.orientation == 3 then
        slot = 3
        amount = -1
    end

    if tryOp(turtle.back, force, function() left(true) left(true) dig() left(true) left(true) end) then
        state.relativePos[slot] = state.relativePos[slot] - amount
    end
end

load_state()

while true do
    if state.mode == MODE_START then
        print("Starting miner...")
        state.mode = MODE_SHAFT
    elseif state.mode == MODE_SHAFT then
        forward(true)
        digUp()
        digDown()

        state.shaft_len = state.shaft_len + 1
        if state.shaft_len == 3 then
            state.mode = MODE_VEIN
            left(true)
            down(true)
            forward(true)
            state.shaft_len = 0
            state.vein_side = SIDE_LEFT
            state.vein_pass = PASS_FIRST
        end
    elseif state.mode == MODE_VEIN then
        dig()
        forward(true)
        -- Check top/bottom...
        if not blacklisted(table.pack(turtle.inspectUp())[2]) then
            digUp()
        end
        if not blacklisted(table.pack(turtle.inspectDown())[2]) then
            digDown()
        end

        state.vein_len = state.vein_len + 1
        if state.vein_len == VEIN_LEN then
            state.vein_len = 0
            if state.vein_pass == PASS_FIRST then
                print("Performing second vein pass")
                up(true)
                up(true)
                up(true)
                left(true)
                left(true)
                state.vein_pass = PASS_SECOND
            else
                if state.vein_side == SIDE_LEFT then
                    print("Switching to next side")
                    down(true)
                    down(true)
                    down(true)
                    --forward(true)
                    state.vein_side = SIDE_RIGHT
                else
                    print("Switching to shaft mode")
                    right(true)
                    down(true)
                    down(true)
                    right(true)
                    state.mode = MODE_SHAFT
                end
            end
        end
    end
end