function onload(saved_data)
    revealCardPositions = {
        Vector(3.5, 0.25, 0),
        Vector(-3.5, 0.25, 0)
    }

    revealCardPositionsSwap = {
        Vector(-3.5, 0.25, 0),
        Vector(3.5, 0.25, 0)
    }

    self.createButton({
        label          = 'Underworld Market\nHelper',
        click_function = "none",
        function_owner = self,
        position       = {0,-0.1,-1.6},
        height         = 0,
        width          = 0,
        font_size      = 145,
        font_color     = {1,1,1}
    })

    hiddenCards = 10
    hiddenCardLabel = '-----'

    isSetup = false
    movingCards = false

    self.addContextMenuItem('Reset helper', resetHelper)

    if saved_data != '' then
        local loaded_data = JSON.decode(saved_data)
        hiddenCards = loaded_data.saved_hiddenCards

        isSetup = true
        refreshButtons()
    end
end

function onSave()
    return JSON.encode({
        saved_hiddenCards = hiddenCards
    })
end

function onObjectEnterContainer(container, object)
    if container ~= self then return end

    if isSetup and object.tag == "Card" then
        refreshButtons()
    end

    if object.tag == "Deck" then
        if validateDeck(object) then
            takeDeckOut(object.getGUID(), self.getPosition() + Vector(0, 0.1, 0))
            refreshButtons()
            
            isSetup = true
        end
    elseif object.tag ~= "Card" then
        broadcastToAll("The 'Underworld Market Helper' is meant to be used for cards.", "White")
    end
end

function onObjectLeaveContainer(container, object)
    if container ~= self then return end
    
    if isSetup then
        refreshButtons()
    end
end

function validateDeck(deck)
    if deck.getQuantity() ~= 10 then
        print('Underworld Market Helper: Deck must include exactly 10 cards.')
        return false
    end

    local illicitCount = 0

    for _, card in ipairs(deck.getObjects()) do
        decodedGMNotes = JSON.decode(card.gm_notes)

        if decodedGMNotes ~= nil and string.find(decodedGMNotes.traits, "Illicit", 1, true) then
            illicitCount = illicitCount + 1
        end
    end

    if illicitCount ~= 10 then
        print('Underworld Market Helper: Deck must include 10 Illicit cards.')
        return false
    end

    return true
end

function refreshButtons()
    local cardsList = ''

    for i, card in ipairs(self.getObjects()) do
        local localCardName = card.name

        if i <= hiddenCards then
            localCardName = hiddenCardLabel
        end

        cardsList = cardsList .. localCardName .. '\n'
    end

    self.clearButtons()

    self.createButton({
        label          = 'Market Deck:',
        click_function = "none",
        function_owner = self,
        position       = {0,-0.1,-1.6},
        height         = 0,
        width          = 0,
        font_size      = 150,
        font_color     = {1,1,1}
    })

    self.createButton({
        label          = cardsList,
        click_function = "none",
        function_owner = self,
        position       = {0,-0.1,0.15},
        height         = 0,
        width          = 0,
        font_size      = 115,
        font_color     = {1,1,1}
    })

    self.createButton({
        click_function = 'revealFirstTwoCards',
        function_owner = self,
        label = 'Reveal',
        position = {-0.85,0,1.6},
        width = 375,
        height = 175,
        font_size = 90
    })

    self.createButton({
        click_function = 'swap',
        function_owner = self,
        label = 'Swap',
        position = {0,0,1.6},
        width = 375,
        height = 175,
        font_size = 90
    })

    self.createButton({
        click_function = 'finish',
        function_owner = self,
        label = 'Finish',
        position = {0.85,0,1.6},
        width = 375,
        height = 175,
        font_size = 90
    })
end

function takeDeckOut(guid, pos)
    local deck = self.takeObject({ guid = guid, position = pos, smooth = false })

    for i = 1, #deck.getObjects() do
        self.putObject(deck.takeObject({ position = pos + Vector(0, 0.1 * i, 0), smooth = false }))
    end

    self.shuffle()
end

function getRevealedCards()
    local revealedCards = {}

    for _, pos in ipairs(revealCardPositions) do
        local hitList = Physics.cast({
            origin       = self.positionToWorld(pos) + Vector(0, 0.25, 0),
            direction    = {0,-1,0},
            type         = 1,
            max_distance = 2
        })

        for _, hit in ipairs(hitList) do
            if hit.hit_object != self and hit.hit_object.tag == "Card" then
                table.insert(revealedCards, hit.hit_object.getGUID())
            end
        end
    end

    return revealedCards
end

function revealFirstTwoCards()
    if movingCards or #getRevealedCards() > 0 then return end

    for i, card in ipairs(self.getObjects()) do
        movingCards = true

        self.takeObject({
            index = 0,
            rotation = self.getRotation(),
            position = self.positionToWorld(revealCardPositions[i]),
            callback_function = function(obj)
                obj.resting = true
                movingCards = false
            end
        })

        hiddenCards = hiddenCards - 1

        if i == 2 or #self.getObjects() == 0 then
            break
        end
    end

    refreshButtons()
end

function swap()
    if movingCards then return end

    local revealedCards = getRevealedCards()

    if #revealedCards == 2 then
        for i, revealedCardGUID in ipairs(revealedCards) do
            local revealedCard = getObjectFromGUID(revealedCardGUID)

            revealedCard.setPositionSmooth(self.positionToWorld(revealCardPositionsSwap[i]), false, false)
        end
    end
end

function finish()
    if movingCards then return end

    local revealedCards = getRevealedCards()

    movingCards = true

    for i, revealedCardGUID in ipairs(revealedCards) do
        self.putObject(getObjectFromGUID(revealedCardGUID))
    end

    Wait.time(
        function()
            movingCards = false
        end,
    0.75)
end

function resetHelper()
    for i, card in ipairs(self.getObjects()) do
        self.takeObject({
            index = 0,
            smooth = false,
            rotation = self.getRotation(),
            position = self.positionToWorld(revealCardPositions[2])
        })
    end

    self.clearButtons()

    self.createButton({
        label          = 'Underworld Market\nHelper',
        click_function = "none",
        function_owner = self,
        position       = {0,-0.1,-1.6},
        height         = 0,
        width          = 0,
        font_size      = 145,
        font_color     = {1,1,1}
    })

    hiddenCards = 10
    isSetup = false
    movingCards = false

    self.reset()

    print('Underworld Market Helper: Helper has been reset.')
end