-- Input system
-- TODO: replace this with universal system
local Input = {
    keyboardButtons = { 'escape', 'space' },
    keyboardPressed = {},
    lastKeyboardPressed = {},
    actions = {}
}

local function mapAction( input, action, keys )
    input.actions[action] = {}
    for _, key in pairs( keys ) do
        table.insert( input.actions[action], key )
    end
end

local function loadMap( input )
    mapAction( input, 'exit', { 'escape' } )
    mapAction( input, 'nextlevel', { 'space' } )
end

local function predHolded( pressed, _ )
    return pressed
end

local function predPressed( pressed, lastPressed )
    return pressed and not lastPressed
end

local function predReleased( pressed, lastPressed )
    return not pressed and lastPressed
end

local function testAction( input, action, predicate )
    for _, key in ipairs( input.actions[action] ) do
        local pressed, lastPressed

        pressed = input.keyboardPressed
        lastPressed = input.lastKeyboardPressed

        if predicate( pressed[key], lastPressed[key] ) then
            return true
        end
    end

    return false
end

function Input.init()
    for btn in ipairs( Input.keyboardButtons ) do
        Input.keyboardPressed[Input.keyboardButtons[btn]] = false
        Input.lastKeyboardPressed[Input.keyboardButtons[btn]] = false
    end

    loadMap( Input )

    return Input
end

function Input:update()
    for k, _ in pairs( self.keyboardPressed ) do
            self.lastKeyboardPressed[k] = self.keyboardPressed[k]
    end

    for button in ipairs( self.keyboardButtons ) do
            self.keyboardPressed[self.keyboardButtons[button]] = love.keyboard.isDown( self.keyboardButtons[button] )
    end
end

function Input:actionHolded( action )
    return testAction( self, action, predHolded )
end

function Input:actionReleased( action )
    return testAction( self, action, predReleased )
end

function Input:actionPressed( action )
    return testAction( self, action, predPressed )
end

function Input:actionDiff( negative, positive )
    local negResult = testAction( self, negative, predHolded )
    local posResult = testAction( self, positive, predHolded )

    if negResult and not posResult then
        return -1
    elseif posResult and not negResult then
        return 1
    else
        return 0
    end
end

return Input.init()