sub init()

  m.options = m.top.findNode("options")
  m.tvGuide = invalid

  m.itemGrid = m.top.findNode("itemGrid")
  m.backdrop = m.top.findNode("backdrop")
  m.newBackdrop = m.top.findNode("backdropTransition")
  m.emptyText = m.top.findNode("emptyText")

  m.swapAnimation = m.top.findNode("backroundSwapAnimation")
  m.swapAnimation.observeField("state", "swapDone")

  m.loadedRows = 0
  m.loadedItems = 0

  m.data = CreateObject("roSGNode", "ContentNode")

  m.itemGrid.content = m.data
  m.itemGrid.setFocus(true)

  m.itemGrid.observeField("itemFocused", "onItemFocused")
  m.itemGrid.observeField("itemSelected", "onItemSelected")
  m.newBackdrop.observeField("loadStatus", "newBGLoaded")

  'Background Image Queued for loading
  m.queuedBGUri = ""

  'Item sort - maybe load defaults from user prefs?
  m.sortField = "SortName"
  m.sortAscending = true

  m.filter = "All"

  m.loadItemsTask = createObject("roSGNode", "LoadItemsTask2")

end sub

'
'Load initial set of Data
sub loadInitialItems()

  if m.top.parentItem.backdropUrl <> invalid
    SetBackground(m.top.parentItem.backdropUrl)
  end if

  m.loadItemsTask.itemId = m.top.parentItem.Id
  m.loadItemsTask.sortField = m.sortField
  m.loadItemsTask.sortAscending = m.sortAscending
  m.loadItemsTask.filter = m.filter
  m.loadItemsTask.startIndex = 0

  if m.top.parentItem.collectionType = "movies"
    m.loadItemsTask.itemType = "Movie"
  else if m.top.parentItem.collectionType = "tvshows"
    m.loadItemsTask.itemType = "Series"
  else if m.top.parentItem.collectionType = "livetv"
    m.loadItemsTask.itemType = "LiveTV"

    'For LiveTV, we want to "Fit" the item images, not zoom
    m.top.imageDisplayMode = "scaleToFit"
    
    if get_user_setting("display.livetv.landing") = "guide" 
       showTvGuid()
    end if

  else if m.top.parentItem.collectionType = "CollectionFolder" OR m.top.parentItem.collectionType = "boxsets" or m.top.parentItem.Type = "Folder" or m.top.parentItem.Type = "Channel"
    ' Non-recursive, to not show subfolder contents
    m.loadItemsTask.recursive = false
  else if m.top.parentItem.collectionType = "Channel"
    m.top.imageDisplayMode = "scaleToFit"
  else
    print "[ItemGrid] Unknown Type: " m.top.parentItem
  end if

  m.loadItemsTask.observeField("content", "ItemDataLoaded")
  m.loadItemsTask.control = "RUN"

  SetUpOptions()

end sub

' Data to display when options button selected
sub SetUpOptions()

  options = {}
  options.filter = []

  'Movies
  if m.top.parentItem.collectionType = "movies"
    options.views = [
      { "Title": tr("Movies"), "Name": "movies" },
    ]
    options.sort = [
      { "Title": tr("TITLE"), "Name": "SortName" },
      { "Title": tr("IMDB_RATING"), "Name": "CommunityRating" },
      { "Title": tr("CRITIC_RATING"), "Name": "CriticRating" },
      { "Title": tr("DATE_ADDED"), "Name": "DateCreated" },
      { "Title": tr("DATE_PLAYED"), "Name": "DatePlayed" },
      { "Title": tr("OFFICIAL_RATING"), "Name": "OfficialRating" },
      { "Title": tr("PLAY_COUNT"), "Name": "PlayCount" },
      { "Title": tr("RELEASE_DATE"), "Name": "PremiereDate" },
      { "Title": tr("RUNTIME"), "Name": "Runtime" }
    ]
    options.filter = [
      { "Title": tr("All"), "Name": "All" },
      { "Title": tr("Favorites"), "Name": "Favorites" }
    ]
  'Boxsets
  else if m.top.parentItem.collectionType = "boxsets"
    options.views = [{ "Title": tr("Shows"), "Name": "shows" }]
    options.sort = [
      { "Title": tr("TITLE"), "Name": "SortName" },
      { "Title": tr("DATE_ADDED"), "Name": "DateCreated" },
      { "Title": tr("DATE_PLAYED"), "Name": "DatePlayed" },
      { "Title": tr("RELEASE_DATE"), "Name": "PremiereDate" },
    ]
    options.filter = [
      { "Title": tr("All"), "Name": "All" },
      { "Title": tr("Favorites"), "Name": "Favorites" }
    ]
  'TV Shows
  else if m.top.parentItem.collectionType = "tvshows"
    options.views = [{ "Title": tr("Shows"), "Name": "shows" }]
    options.sort = [
      { "Title": tr("TITLE"), "Name": "SortName" },
      { "Title": tr("IMDB_RATING"), "Name": "CommunityRating" },
      { "Title": tr("DATE_ADDED"), "Name": "DateCreated" },
      { "Title": tr("DATE_PLAYED"), "Name": "DatePlayed" },
      { "Title": tr("OFFICIAL_RATING"), "Name": "OfficialRating" },
      { "Title": tr("RELEASE_DATE"), "Name": "PremiereDate" },
    ]
    options.filter = []
  'Live TV
  else if m.top.parentItem.collectionType = "livetv"
    options.views = [
      {"Title": tr("Channels"), "Name": "livetv" },
      {"Title": tr("TV Guide"), "Name": "tvGuide", "Selected": get_user_setting("display.livetv.landing") = "guide" }
    ]
    options.sort = [
      { "Title": tr("TITLE"), "Name": "SortName" }
    ]
    options.filter = []
  else
    options.views = [
      {"Title": tr("Default"), "Name": "default" }
    ]
    options.sort = [
      { "Title": tr("TITLE"), "Name": "SortName" }
    ]
    options.filter = []
  end if

  for each o in options.sort
    if o.Name = m.sortField
      o.Selected = true
      o.Ascending = m.sortAscending
    end if
  end for

  for each o in options.filter
    if o.Name = m.filter
      o.Selected = true
    end if
  end for

  m.options.options = options

end sub


'
'Handle loaded data, and add to Grid
sub ItemDataLoaded(msg)

  itemData = msg.GetData()
  m.loadItemsTask.unobserveField("content")
  m.loadItemsTask.content = []

  if itemData = invalid
    m.Loading = false
    return
  end if

  for each item in itemData
    m.data.appendChild(item)
  end for

  'Update the stored counts
  m.loadedItems = m.itemGrid.content.getChildCount()
  m.loadedRows = m.loadedItems / m.itemGrid.numColumns
  m.Loading = false

  'If there are no items to display, show message
  if m.loadedItems = 0
    m.emptyText.text = tr("NO_ITEMS").Replace("%1", m.top.parentItem.Type)
    m.emptyText.visible = true
  end if

  m.itemGrid.setFocus(true)

end sub

'
'Set Background Image
sub SetBackground(backgroundUri as string)

  'If a new image is being loaded, or transitioned to, store URL to load next
  if m.swapAnimation.state <> "stopped" or m.newBackdrop.loadStatus = "loading"
    m.queuedBGUri = backgroundUri
    return
  end if

  m.newBackdrop.uri = backgroundUri
end sub

'
'Handle new item being focused
sub onItemFocused()

  focusedRow = CInt(m.itemGrid.itemFocused / m.itemGrid.numColumns) + 1

  itemInt = m.itemGrid.itemFocused

  ' If no selected item, set background to parent backdrop
  if itemInt = -1
    return
  end if

  ' Set Background to item backdrop
  SetBackground(m.itemGrid.content.getChild(m.itemGrid.itemFocused).backdropUrl)

  ' Load more data if focus is within last 3 rows, and there are more items to load
  if focusedRow >= m.loadedRows - 3 and m.loadeditems < m.loadItemsTask.totalRecordCount
    loadMoreData()
  end if
end sub

'
'When Image Loading Status changes
sub newBGLoaded()
  'If image load was sucessful, start the fade swap
  if m.newBackdrop.loadStatus = "ready"
    m.swapAnimation.control = "start"
  end if
end sub

'
'Swap Complete
sub swapDone()

  if m.swapAnimation.state = "stopped"

    'Set main BG node image and hide transitioning node
    m.backdrop.uri = m.newBackdrop.uri
    m.backdrop.opacity = 0.25
    m.newBackdrop.opacity = 0

    'If there is another one to load
    if m.newBackdrop.uri <> m.queuedBGUri and m.queuedBGUri <> ""
      SetBackground(m.queuedBGUri)
      m.queuedBGUri = ""
    end if
  end if
end sub

'
'Load next set of items
sub loadMoreData()

  if m.Loading = true then return

  m.Loading = true
  m.loadItemsTask.startIndex = m.loadedItems
  m.loadItemsTask.observeField("content", "ItemDataLoaded")
  m.loadItemsTask.control = "RUN"
end sub

'
'Item Selected
sub onItemSelected()
  m.top.selectedItem = m.itemGrid.content.getChild(m.itemGrid.itemSelected)
end sub


'
'Check if options updated and any reloading required
sub optionsClosed()

  if m.options.view = "tvGuide"
    showTVGuid()
    return
  else if m.tvGuide <> invalid
    ' Try to hide the TV Guide
    m.top.removeChild(m.tvGuide)
  end if

  reload = false
  if m.options.sortField <> m.sortField or m.options.sortAscending <> m.sortAscending
    m.sortField = m.options.sortField
    m.sortAscending = m.options.sortAscending
    reload = true
  end if
  if m.options.filter <> m.filter
    m.filter = m.options.filter
    reload = true
  end if
  if reload
    m.loadedRows = 0
    m.loadedItems = 0
    m.data = CreateObject("roSGNode", "ContentNode")
    m.itemGrid.content = m.data
    loadInitialItems()
  end if
  m.itemGrid.setFocus(true)
end sub

sub showTVGuid()
  m.top.signalBeacon("EPGLaunchInitiate") ' Required Roku Performance monitoring
  if m.tvGuide = invalid 
     m.tvGuide = createObject("roSGNode", "Schedule")
  endif
  m.tvGuide.observeField("watchChannel", "onChannelSelected")
  m.top.appendChild(m.tvGuide)
  m.tvGuide.lastFocus.setFocus(true)
end sub

sub onChannelSelected(msg) 
  node = msg.getRoSGNode()
  m.top.lastFocus = lastFocusedChild(node)
  if node.watchChannel <> invalid 
    ' Clone the node when it's reused/update in the TimeGrid it doesn't automatically start playing
    m.top.selectedItem = node.watchChannel.clone(false)
  end if
end sub

function onKeyEvent(key as string, press as boolean) as boolean

  if not press then return false

  if key = "options"
    if m.options.visible = true
      m.options.visible = false
      m.top.removeChild(m.options)
      optionsClosed()
    else
      m.options.visible = true
      m.top.appendChild(m.options)
      m.options.setFocus(true)
    end if
    return true
  else if key = "back"
    if m.options.visible = true
      m.options.visible = false
      optionsClosed()
      return true
    end if
  else if key = "play"
    markupGrid = m.top.getChild(2)
    itemToPlay = markupGrid.content.getChild(markupGrid.itemFocused)
    if itemToPlay <> invalid and (itemToPlay.type = "Movie" or itemToPlay.type = "Episode")
      m.top.quickPlayNode = itemToPlay
    end if
    return true
  end if
  return false
end function