sub init()
  m.top.itemComponentName = "HomeItem"
  ' how many rows are visible on the screen
  m.top.numRows = 2

  m.top.rowFocusAnimationStyle = "fixedFocusWrap"
  m.top.vertFocusAnimationStyle = "fixedFocus"

  m.top.showRowLabel = [true]
  m.top.rowLabelOffset = [0, 20]
  m.top.showRowCounter = [true]

  m.libariesToLoad = 0

  updateSize()

  m.top.setfocus(true)

  m.top.observeField("rowItemSelected", "itemSelected")

  ' Load the Libraries from API via task
  m.LoadLibrariesTask = createObject("roSGNode", "LoadItemsTask")
  m.LoadLibrariesTask.observeField("content", "onLibrariesLoaded")
  m.LoadLibrariesTask.control = "RUN"
  ' set up tesk nodes for other rows
  m.LoadContinueTask = createObject("roSGNode", "LoadItemsTask")
  m.LoadContinueTask.itemsToLoad = "continue"
  m.LoadNextUpTask = createObject("roSGNode", "LoadItemsTask")
  m.LoadNextUpTask.itemsToLoad = "nextUp"
end sub

sub updateSize()
  sideborder = 100
  m.top.translation = [111, 180]

  itemWidth = 480
  itemHeight = 330

  'Set width of Rows to cut off at edge of Safe Zone
  m.top.itemSize = [1703, itemHeight]

  ' spacing between rows
  m.top.itemSpacing = [0, 105]

  ' spacing between items in a row
  m.top.rowItemSpacing = [20, 0]

  m.top.visible = true
end sub

sub onLibrariesLoaded()
  ' save data for other functions
  m.libraryData = m.LoadLibrariesTask.content
  m.LoadLibrariesTask.unobserveField("content")
  ' create My Media, Continue Watching, and Next Up rows
  content = CreateObject("roSGNode", "ContentNode")
  mediaRow = content.CreateChild("HomeRow")
  mediaRow.title = tr("My Media")
  continueRow = content.CreateChild("HomeRow")
  continueRow.title = tr("Continue Watching")
  nextUpRow = content.CreateChild("HomeRow")
  nextUpRow.title = tr("Next Up >")
  sizeArray = [
    [464, 311], ' My Media
    [464, 311], ' Continue Watching
    [464, 311]  ' Next Up
  ]
  ' validate library data
  if (m.libraryData <> invalid and m.libraryData.count() > 0) then
    userConfig = m.top.userConfig
    ' populate My Media row
    filteredMedia = filterNodeArray(m.libraryData, "id", userConfig.MyMediaExcludes)
    for each item in filteredMedia
      mediaRow.appendChild(item)
    end for
    ' create a "Latest In" row for each library
    filteredLatest = filterNodeArray(m.libraryData, "id", userConfig.LatestItemsExcludes)
    for each lib in filteredLatest
      if lib.collectionType <> "boxsets" and lib.collectionType <> "livetv" then
        latestInRow = content.CreateChild("HomeRow")
        latestInRow.title = tr("Latest in") + " " + lib.name + " >"
        sizeArray.Push([464, 331])
      end if
    end for
  end if

  m.top.rowItemSize = sizeArray
  m.top.content = content
  
  ' Load the Continue Watching Data
  m.LoadContinueTask.observeField("content", "updateContinueItems")
  m.LoadContinueTask.control = "RUN"
end sub

function updateHomeRows()
  m.LoadContinueTask.observeField("content", "updateContinueItems")
  m.LoadContinueTask.control = "RUN"
end function

function updateContinueItems()
  m.LoadContinueTask.unobserveField("content")
  itemData = m.LoadContinueTask.content

  if itemData = invalid then return false

  homeRows = m.top.content
  continueRowIndex = getRowIndex("Continue Watching")

  if itemData.count() < 1 then
    if continueRowIndex <> invalid then
      ' remove the row
      deleteFromSizeArray(continueRowIndex)
      homeRows.removeChildIndex(continueRowIndex)
    end if
  else
    ' remake row using the new data
    row = CreateObject("roSGNode", "HomeRow")
    row.title = tr("Continue Watching")
    itemSize = [464, 331]
    for each item in itemData
      item.usePoster = row.usePoster
      item.imageWidth = row.imageWidth
      row.appendChild(item)
    end for

    if continueRowIndex = invalid then
      ' insert new row under "My Media"
      updateSizeArray(itemSize, 1)
      homeRows.insertChild(row, 1)
    else
      ' replace the old row
      homeRows.replaceChild(row, continueRowIndex)
    end if
  end if

  m.LoadNextUpTask.observeField("content", "updateNextUpItems")
  m.LoadNextUpTask.control = "RUN"
end function

function updateNextUpItems()
  m.LoadNextUpTask.unobserveField("content")
  itemData = m.LoadNextUpTask.content

  if itemData = invalid then return false

  homeRows = m.top.content
  nextUpRowIndex = getRowIndex("Next Up >")

  if itemData.count() < 1 then
    if nextUpRowIndex <> invalid then
      ' remove the row
      deleteFromSizeArray(nextUpRowIndex)
      homeRows.removeChildIndex(nextUpRowIndex)
    end if
  else
    ' remake row using the new data
    row = CreateObject("roSGNode", "HomeRow")
    row.title = tr("Next Up") + " >"
    itemSize = [464, 331]
    for each item in itemData
      item.usePoster = row.usePoster
      item.imageWidth = row.imageWidth
      row.appendChild(item)
    end for

    if nextUpRowIndex = invalid then
      ' insert new row under "Continue Watching"
      continueRowIndex = getRowIndex("Continue Watching")
      if continueRowIndex <> invalid then
        updateSizeArray(itemSize, continueRowIndex + 1)
        homeRows.insertChild(row, continueRowIndex + 1)
      else
        ' insert it under My Media
        updateSizeArray(itemSize, 1)
        homeRows.insertChild(row, 1)
      end if
    else
      ' replace the old row
      homeRows.replaceChild(row, nextUpRowIndex)
    end if
  end if

  ' create task nodes for "Latest In" rows
  userConfig = m.top.userConfig
  filteredLatest = filterNodeArray(m.libraryData, "id", userConfig.LatestItemsExcludes)
  for each lib in filteredLatest
    if lib.collectionType <> "livetv" and lib.collectionType <> "boxsets" then
      loadLatest = createObject("roSGNode", "LoadItemsTask")
      loadLatest.itemsToLoad = "latest"
      loadLatest.itemId = lib.id

      metadata = { "title" : lib.name }
      metadata.Append({ "contentType" : lib.json.CollectionType })
      loadLatest.metadata = metadata

      loadLatest.observeField("content", "updateLatestItems")
      loadLatest.control = "RUN"
      m.libariesToLoad += 1
    end if
  end for
end function

function updateLatestItems(msg)
  itemData = msg.GetData()

  data = msg.getField()
  node = msg.getRoSGNode()
  node.unobserveField("content")

  if itemData = invalid then return false

  homeRows = m.top.content
  rowIndex = getRowIndex(tr("Latest in") + " " + node.metadata.title + " >")

  if itemData.count() < 1 then
    ' remove row
    if rowIndex <> invalid then
      deleteFromSizeArray(rowIndex)
      homeRows.removeChildIndex(rowIndex)
    end if
  else
    ' remake row using new data
    row = CreateObject("roSGNode", "HomeRow")
    row.title = tr("Latest in") + " " + node.metadata.title + " >"
    row.usePoster = true
    ' Handle specific types with different item widths
    if node.metadata.contentType = "movies" then
      row.imageWidth = 180
      itemSize = [188, 331]
    else if node.metadata.contentType = "music" then
      row.imageWidth = 261
      itemSize = [261, 331]
    else
      row.imageWidth = 464
      itemSize = [464, 331]
    end if

    for each item in itemData
      item.usePoster = row.usePoster
      item.imageWidth = row.imageWidth
      row.appendChild(item)
    end for

    if rowIndex = invalid then
      ' append new row
      updateSizeArray(itemSize)
      homeRows.appendChild(row)
    else
      ' replace the old row
      updateSizeArray(itemSize, rowIndex, "replace")
      homeRows.replaceChild(row, rowIndex)
    end if
  end if

  m.libariesToLoad -= 1
  if m.libariesToLoad = 0 and m.global.app_loaded = false then
    m.top.signalBeacon("AppLaunchComplete") ' Roku Performance monitoring
    m.global.app_loaded = true
  end if
end function

function getRowIndex(rowTitle as string)
  rowIndex = invalid
  for i = 1 to m.top.content.getChildCount() - 1
    ' skip row 0 since it's always "My Media"
    tmpRow = m.top.content.getChild(i)
    if tmpRow.title = rowTitle then
      rowIndex = i
      exit for
    end if
  end for
  return rowIndex
end function

sub updateSizeArray(rowItemSize, rowIndex = invalid, action = "insert")
  sizeArray = m.top.rowItemSize
  ' append by default
  if rowIndex = invalid then
    rowIndex = sizeArray.count()
  end if

  newSizeArray = []
  for i = 0 to sizeArray.count()
    if rowIndex = i then
      if action = "replace" then
        newSizeArray.Push(rowItemSize)
      else if action = "insert" then
        newSizeArray.Push(rowItemSize)
        if sizeArray[i] <> invalid then
          newSizeArray.Push(sizeArray[i])
        end if
      end if
    else if sizeArray[i] <> invalid then
      newSizeArray.Push(sizeArray[i])
    end if
  end for
  m.top.rowItemSize = newSizeArray
end sub

sub deleteFromSizeArray(rowIndex)
  updateSizeArray([0, 0], rowIndex, "delete")
end sub

function itemSelected()
  m.top.selectedItem = m.top.content.getChild(m.top.rowItemSelected[0]).getChild(m.top.rowItemSelected[1])
end function

function onKeyEvent(key as string, press as boolean) as boolean
  return false
end function

function filterNodeArray(nodeArray as object, nodeKey as string, excludeArray as object) as object
  if excludeArray.IsEmpty() then return nodeArray

  newNodeArray = []
  for each node in nodeArray
    excludeThisNode = false
    for each exclude in excludeArray
      if node[nodeKey] = exclude then
        excludeThisNode = true
      end if
    end for
    if excludeThisNode = false then
      newNodeArray.Push(node)
    end if
  end for
  return newNodeArray
end function