Incremental.elm

module Incremental where

import Html exposing (text, div)
import Html.Attributes exposing (class, style)
import Html.Events exposing (onClick)
import Time exposing (fps)
import Signal

import String
import Array
import Debug

nodes world = Array.fromList [
        {text="All you can do is wait.",wait=3000},
        {text="And wait some more.",wait=15000 / (1+world.count)},
        {text="Done. Start over?",wait=0}
    ]

start = { time = 0, node = 0, count = 0 }

update action world =
    case action of
        Frame dt -> updateFrame dt world
        Goto node -> {world | node <- node, time <- 0, count <- world.count + 1}

updateFrame dt world =
    let time' = world.time + dt
        (Just node) = Array.get world.node (nodes world)
        next = world.node + 1
        limit = (Array.length (nodes world))-1
        node' = if time' > node.wait then min next limit else world.node
        time'' = if node' == world.node then time' else 0
    in {world | time <- time'', node <- node'}

display world =
    let (Just value) = Array.get world.node (nodes world)
        percent = if value.wait > 0 then (100 * (1 - (world.time / value.wait))) else 0
        counters = if world.count > 0 then [text <| String.concat ["You have ",toString world.count," widgets"]] else []
        clickers = [
            div (if percent > 0 then [class "button disabled"]
                 else [class ("button"), onClick actions.address (Goto 0)]
                )
                [
                text value.text,
                div [
                    class "progress",
                    style [("width",String.concat [toString percent, "%"])]
                ] []
            ]
        ]
    in  div [] <| List.concat [counters, clickers]

type Action = Frame Float | Goto Int

actions = Signal.mailbox (Goto 0)

main =
    let frames = Signal.map Frame (fps 30)
        clicks = actions.signal
        signals = Signal.mergeMany [frames, clicks]
        states = Signal.foldp update start signals
    in Signal.map display states