local M = {}

local logger = require("libs.logger")

-- Optional external status setter (set via M.setStatusCallback)
local statusCallback = nil
function M.setStatusCallback(fn) statusCallback = fn end

-- Position tracking state for manual mode
local manualPos = { x = 0, y = 0, z = 0 }
local directions = { "north", "east", "south", "west" }
local facing = 1

-- GPS attempt
local function tryGPS()
    local x, y, z = gps.locate(2)  -- 2 second timeout
    if x and y and z then
        return { x = math.floor(x), y = math.floor(y), z = math.floor(z) }
    end
    return nil
end

-- Manual position update helpers
local function updatePositionOnMove(direction)
    if direction == "forward" then
        if directions[facing] == "north" then manualPos.z = manualPos.z - 1
        elseif directions[facing] == "south" then manualPos.z = manualPos.z + 1
        elseif directions[facing] == "east" then manualPos.x = manualPos.x + 1
        elseif directions[facing] == "west" then manualPos.x = manualPos.x - 1 end
    elseif direction == "back" then
        if directions[facing] == "north" then manualPos.z = manualPos.z + 1
        elseif directions[facing] == "south" then manualPos.z = manualPos.z - 1
        elseif directions[facing] == "east" then manualPos.x = manualPos.x - 1
        elseif directions[facing] == "west" then manualPos.x = manualPos.x + 1 end
    elseif direction == "up" then manualPos.y = manualPos.y + 1
    elseif direction == "down" then manualPos.y = manualPos.y - 1 end
end

local function updateFacingLeft()
    facing = facing - 1
    if facing < 1 then facing = 4 end
end

local function updateFacingRight()
    facing = facing + 1
    if facing > 4 then facing = 1 end
end

-- Public function to get current position (GPS or manual)
function M.getPosition()
    local gpsPos = tryGPS()
    if gpsPos then
        return gpsPos.x, gpsPos.y, gpsPos.z, true
    else
        return manualPos.x, manualPos.y, manualPos.z, false
    end
end

-- Minimum fuel required to proceed with one movement
local MIN_FUEL = 1

-- Attempt to refuel from inventory
local function refuelFromInventory(minRequired)
    minRequired = minRequired or MIN_FUEL
    local gained = 0

    for slot = 1, 16 do
        turtle.select(slot)
        if turtle.getItemCount() > 0 and turtle.refuel(0) then
            local before = turtle.getFuelLevel()
            if turtle.refuel(1) then
                local after = turtle.getFuelLevel()
                local added = after - before
                gained = gained + added
                logger.log(string.format("Refueled +%d from slot %d", added, slot))
                if after >= minRequired then break end
            else
                logger.log(string.format("Refuel failed from slot %d", slot))
            end
        end
    end

    return gained
end

-- Ensure fuel before doing anything
local function refuelIfNeeded()
    local fuel = turtle.getFuelLevel()
    if fuel == "unlimited" then return true end

    if fuel < MIN_FUEL then
        logger.log("Low fuel, attempting to refuel...")
        local added = refuelFromInventory(MIN_FUEL)
        fuel = turtle.getFuelLevel()
    end

    while fuel < MIN_FUEL do
        if statusCallback then statusCallback("out_of_fuel") end

        local x, y, z, gpsActive = M.getPosition()
        local posText = gpsActive and
            string.format("GPS (%d,%d,%d)", x, y, z) or
            string.format("Manual (%d,%d,%d)", x, y, z)
        logger.log("No fuel. Waiting for fuel... Location: " .. posText)

        sleep(5)

        local added = refuelFromInventory(MIN_FUEL)
        fuel = turtle.getFuelLevel()
    end

    return true
end

-- Retry a movement or action with fuel awareness
local function try(actionFn, times, name)
    times = times or 5
    for i = 1, times do
        if not refuelIfNeeded() then
            sleep(2)
        elseif actionFn() then
            if name then logger.log("Action succeeded: " .. name) end
            return true
        end
        if name then logger.log("Retrying: " .. name) end
        sleep(0.5)
    end
    if name then logger.log("Gave up after retries: " .. name) end
    return false
end

-- Movement wrappers that update manual position and use try()
function M.forward()
    local function action() return turtle.forward() end
    local result = try(action, 5, "forward")
    if result then updatePositionOnMove("forward") end
    return result
end

function M.back()
    local function action() return turtle.back() end
    local result = try(action, 5, "back")
    if result then updatePositionOnMove("back") end
    return result
end

function M.up()
    local function action() return turtle.up() end
    local result = try(action, 5, "up")
    if result then updatePositionOnMove("up") end
    return result
end

function M.down()
    local function action() return turtle.down() end
    local result = try(action, 5, "down")
    if result then updatePositionOnMove("down") end
    return result
end

-- Digging functions (not wrapped in try, but you can add if you want)
function M.digForward()
    while turtle.detect() do
        turtle.dig()
        sleep(0.3)
        logger.log("Dug block in front")
    end
end

function M.digUp()
    while turtle.detectUp() do
        turtle.digUp()
        sleep(0.3)
        logger.log("Dug block above")
    end
end

function M.digDown()
    while turtle.detectDown() do
        turtle.digDown()
        sleep(0.3)
        logger.log("Dug block below")
    end
end

-- Move forward clearing blocks as needed
function M.moveUntilClearForward()
    logger.log("Attempting to move forward (auto-clear)")
    while not M.forward() do
        if turtle.detect() then
            M.digForward()
        else
            sleep(0.5)
        end
    end
    logger.log("Moved forward")
end

-- Inspection
function M.inspectForward()
    local success, data = turtle.inspect()
    if success then return data else return nil end
end

function M.inspectUp()
    local success, data = turtle.inspectUp()
    if success then return data else return nil end
end

function M.inspectDown()
    local success, data = turtle.inspectDown()
    if success then return data else return nil end
end

-- Turning functions that update facing
function M.turnLeft()
    turtle.turnLeft()
    updateFacingLeft()
    logger.log("Turned left")
end

function M.turnRight()
    turtle.turnRight()
    updateFacingRight()
    logger.log("Turned right")
end

function M.turnAround()
    turtle.turnLeft()
    turtle.turnLeft()
    updateFacingLeft()
    updateFacingLeft()
    logger.log("Turned around")
end

return M