local Ansi       = require('ansi')
local Event      = require('event')
local Milo       = require('milo')
local UI         = require('ui')
local Util       = require('util')

local colors     = _G.colors
local context    = Milo:getContext()
local device     = _G.device
local monitor    = context.storage:getSingleNode('activity')

--[[ Configuration Page ]]--
local template =
[[%sDisplays the amount of items entering or leaving storage.%s

Right-clicking on the activity monitor will reset the totals.

%sMilo must be restarted to activate diplay.]]

local activityWizardPage = UI.Window {
  title = 'Activity Monitor',
  index = 2,
  backgroundColor = colors.cyan,
  [1] = UI.TextArea {
    x = 2, ex = -2, y = 2, ey = -2,
    marginRight = 0,
    value = string.format(template, Ansi.yellow, Ansi.reset, Ansi.orange),
  },
}

function activityWizardPage:isValidType(node)
  local m = device[node.name]
  return m and m.type == 'monitor' and {
    name = 'Activity Monitor',
    value = 'activity',
    help = 'Display storage activity'
  }
end

function activityWizardPage:isValidFor(node)
  return node.mtype == 'activity'
end

UI:getPage('nodeWizard').wizard:add({ activity = activityWizardPage })

if not monitor then
  return
end

local page = UI.Window {
  parent = UI.Device {
    device = monitor.adapter,
    textScale = .5,
  },
  grid = UI.Grid {
    columns = {
      { heading = 'Qty',    key = 'count',       width = 6 },
      { heading = 'Change', key = 'change',      width = 6 },
      { heading = 'Rate',   key = 'rate',        width = 6 },
      { heading = 'Name',   key = 'displayName' },
    },
    sortColumn = 'displayName',
  },
}

function page.grid:getRowTextColor(row, selected)
  if row.lastCount and row.lastCount ~= row.count then
    return row.count > row.lastCount and colors.yellow or colors.lightGray
  end
  return UI.Grid:getRowTextColor(row, selected)
end

function page.grid:getDisplayValues(row)
  row = Util.shallowCopy(row)

  local ind = '+'
  if row.change < 0 then
    ind = ''
  end

  row.change = ind .. Util.toBytes(row.change)
  row.count = Util.toBytes(row.count)
  row.rate = Util.toBytes(row.rate)

  return row
end

function page:reset()
  self.lastItems = nil
  self.grid:setValues({ })
  self.grid:clear()
  self.grid:draw()
end

function page:refresh()
  local t = context.storage.cache

  if not self.lastItems then
    self.lastItems = { }
    for k,v in pairs(t) do
      self.lastItems[k] = {
        displayName = v.displayName,
        initialCount = v.count,
      }
    end
    self.timestamp = os.clock()
    self.grid:setValues({ })

  else
    for _,v in pairs(self.lastItems) do
      v.lastCount = v.count
      v.count = nil
    end

    self.elapsed = os.clock() - self.timestamp

    for k,v in pairs(t) do
      local v2 = self.lastItems[k]
      if v2 then
        v2.count = v.count
      else
        self.lastItems[k] = {
          displayName = v.displayName,
          count = v.count,
          initialCount = 0,
        }
      end
    end

    local changedItems = { }
    for k,v in pairs(self.lastItems) do
      if not v.count then
        v.count = 0
      end
      if v.count ~= v.initialCount then
        v.change  = v.count - v.initialCount
        v.rate = Util.round(60 / self.elapsed * v.change, 1)
        changedItems[k] = v
      end
    end

    self.grid:setValues(changedItems)
  end
  self.grid:draw()
end

function page:update()
  page:refresh()
  page:sync()
end

Event.on('monitor_touch', function(_, side)
  if side == monitor.adapter.side then
    page:reset()
    page:sync()
  end
end)

page:enable()
page:draw()
page:sync()

--[[ Task ]]--
local ActivityTask = {
  name = 'activity',
  priority = 30,
}

function ActivityTask:cycle()
  page:update()
end

Milo:registerTask(ActivityTask)