-- Input abstraction: normalises keyboard (classic dual-track / modern simplified)
-- and gamepad (always dual-stick) into a pair of track values in [-1, 1].
local Input = {}

local SETTINGS_FILE = "oma-tank_settings.dat"
local STICK_DEADZONE = 0.18

local mode = "modern"
local joystick = nil

local function clamp(v)
    if v < -1 then return -1 end
    if v > 1 then return 1 end
    return v
end

local function keyPair(positive, negative)
    local v = 0
    if love.keyboard.isDown(positive) then v = v + 1 end
    if love.keyboard.isDown(negative) then v = v - 1 end
    return v
end

local function modernTracks()
    -- Up/Down drive both tracks, Left/Right split them
    local fwd = 0
    if love.keyboard.isDown("up", "w") then fwd = fwd + 1 end
    if love.keyboard.isDown("down", "s") then fwd = fwd - 1 end

    local turn = 0
    if love.keyboard.isDown("right", "d") then turn = turn + 1 end
    if love.keyboard.isDown("left", "a") then turn = turn - 1 end

    -- Reverse at 50% feel: matches the prior simplified control
    if fwd < 0 then fwd = fwd * 0.5 end

    local left = clamp(fwd + turn)
    local right = clamp(fwd - turn)
    return left, right
end

local function classicTracks()
    -- W/S = left track, I/K = right track
    local left = keyPair("w", "s")
    local right = keyPair("i", "k")
    return clamp(left), clamp(right)
end

local function applyDeadzone(v)
    if math.abs(v) < STICK_DEADZONE then return 0 end
    return v
end

local function gamepadTracks()
    if not joystick then return 0, 0 end
    -- Stick Y axis is positive down on most gamepads; flip so "forward" on the stick = +1
    local left = -applyDeadzone(joystick:getGamepadAxis("lefty"))
    local right = -applyDeadzone(joystick:getGamepadAxis("righty"))
    return clamp(left), clamp(right)
end

function Input.tracks()
    local kl, kr
    if mode == "classic" then
        kl, kr = classicTracks()
    else
        kl, kr = modernTracks()
    end
    local gl, gr = gamepadTracks()
    -- If either source is pushing a stick, prefer gamepad values for that track
    local left = (gl ~= 0) and gl or kl
    local right = (gr ~= 0) and gr or kr
    return left, right
end

function Input.setMode(newMode)
    if newMode == "classic" or newMode == "modern" then
        mode = newMode
        Input.save()
    end
end

function Input.getMode()
    return mode
end

function Input.toggleMode()
    mode = (mode == "classic") and "modern" or "classic"
    Input.save()
end

function Input.label()
    return (mode == "classic") and "CLASSIC DUAL-TRACK" or "MODERN SIMPLIFIED"
end

function Input.save()
    pcall(function()
        love.filesystem.write(SETTINGS_FILE, "mode=" .. mode .. "\n")
    end)
end

function Input.load()
    if love.filesystem.getInfo(SETTINGS_FILE) then
        local ok, content = pcall(love.filesystem.read, SETTINGS_FILE)
        if ok and content then
            local m = content:match("mode=(%w+)")
            if m == "classic" or m == "modern" then mode = m end
        end
    end
end

function Input.attachJoystick()
    local joysticks = love.joystick.getJoysticks()
    for _, js in ipairs(joysticks) do
        if js:isGamepad() then
            joystick = js
            return
        end
    end
    joystick = nil
end

function Input.joystickAdded(js)
    if js:isGamepad() and not joystick then
        joystick = js
    end
end

function Input.joystickRemoved(js)
    if joystick == js then
        joystick = nil
        Input.attachJoystick()
    end
end

return Input