prev_screen = screen_workbench
message_idx = 1
conversation_active = false

function phoebe_say(face_sprite, words, ...)
    x,y=10,80

    --background color 
    local c = sget((face_sprite*8) % 128, flr((face_sprite*8)/128)*8)
    -- facebox
    draw_paper_with_color(x,y, 4*8+1, 4*8+1, c)
    spr(face_sprite, x+1,y+1, 4,4)
    -- textbox
    draw_paper_with_color(x+4*8+4, y, 68, 4*8+1, c) 
    color(base_text_color)
    print(wrap(words, 16), x+4*8+4+2, y+2)
end

function draw_chatbox(face_sprite, words, ...)
    x,y=10,80
    --background color 
    local c = sget((face_sprite*8) % 128, flr((face_sprite*8)/128)*8)
    -- textbox
    draw_paper_with_color(x, y, 68, 4*8+1, c)
    color(light_text_color)
    print(wrap(words, 16), x+2, y+2)
    -- facebox
    draw_paper_with_color(x+68+3, y, 4*8+1,4*8+1, 0)
    spr(face_sprite, x+69+3,y+1, 4,4)
end

function conversation_draw(screen)
    --prev_screen.draw()
    message = messages[message_idx]

    if message[1] == ph_p then
        phoebe_say(unpack(message))
    else
        draw_chatbox(unpack(message))
    end
end

function conversation_update(after)
    return function()
        conversation_active = true
        if btnp(4) or btnp(5) then
            callback = messages[message_idx][3]
            if callback ~= nil then callback() end

            if message_idx == #messages then
                if after ~= nil then
                    after()
                else
                    change_screen(prev_screen)
                end

                conversation_active = false
            else
                message_idx += 1
            end
        end
    end
end

-- base holds the screen to display under the conversation. nil if you want to simply use the existing screen.
-- convo holds a list of {headsprite, message} pairs to display as a conversation
-- after holds a callback for what to do after the screen is displayed. usually you'll call change_screen().
function screen_conversation(convo, after, base) 
    return {
        before=function()
            if base ~= nil then
                prev_screen=base
            end
            messages=convo
            message_idx=1
            conversation_active = true
        end,
        update=conversation_update(after), 
        draw=conversation_draw
    }
end