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 os         = _G.os

--[[ Configuration Page ]]--
local template =
[[%sDisplays the amount of items entering or leaving storage.%s
Right-clicking on the activity monitor will reset the totals.]]

local wizardPage = UI.Window {
  title = 'Activity Monitor',
  index = 2,
  backgroundColor = colors.cyan,
  [1] = UI.TextArea {
    x = 2, ex = -2, y = 2, ey = 6,
    marginRight = 0,
    value = string.format(template, Ansi.yellow, Ansi.reset),
  },
  form = UI.Form {
    x = 2, ex = -2, y = 7, ey = -2,
    manualControls = true,
    [1] = UI.Chooser {
      width = 9,
      formLabel = 'Font Size', formKey = 'textScale',
      nochoice = 'Small',
      choices = {
        { name = 'Small', value = .5 },
        { name = 'Large', value = 1  },
      },
      help = 'Adjust text scaling',
    },
  },
}

function wizardPage:setNode(node)
  self.form:setValues(node)
end

function wizardPage:validate()
  return self.form:save()
end

function wizardPage:saveNode(node)
  os.queueEvent('monitor_resize', node.name)
end

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

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

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

--[[ Display ]]--
local function createPage(node)
  local monitor = UI.Device {
    device = node.adapter,
    textScale = node.textScale or .5,
  }

  function monitor:resize()
    self.textScale = node.textScale or .5
    UI.Device.resize(self)
  end

  local page = UI.Page {
    parent = monitor,
    grid = UI.Grid {
      ey = -2,
      columns = {
        { heading = 'Qty',    key = 'count',       width = 5 },
        { heading = 'Change', key = 'change',      width = 5 },
        { heading = 'Rate',   key = 'rate',        width = 6 },
        { heading = 'Name',   key = 'displayName' },
      },
      sortColumn = 'displayName',
    },
    buttons = UI.Window {
      y = -1,
      backgroundColor = colors.gray,
      prevButton = UI.Button {
        x = 1, width = 5,
        event = 'previous',
        backgroundColor = colors.lightGray,
        text = ' < '
      },
      resetButton = UI.Button {
        x = 7, ex = -7,
        event = 'reset',
        backgroundColor = colors.lightGray,
        text = 'Reset'
      },
      nextButton = UI.Button {
        x = -5, width = 5,
        event = 'next',
        backgroundColor = colors.lightGray,
        text = ' > '
      },
    },
    timestamp = os.clock(),
  }

  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:eventHandler(event)
    if event.type == 'reset' then
      self:reset()

    elseif event.type == 'next' then
      self.grid:nextPage()

    elseif event.type == 'previous' then
      self.grid:previousPage()

    else
      return UI.Page.eventHandler(self, event)
    end

    Event.onTimeout(.1, function()
      self:setFocus(self.grid)
      self:sync()
    end)
    return true
  end

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

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

    if t and 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

  UI:setPage(page)
  return page
end

local pages = { }

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

function ActivityTask:cycle()
  for node in context.storage:filterActive('activity') do
    if not pages[node.name] then
      pages[node.name] = createPage(node)
    end
    pages[node.name]:update()
  end
end

Milo:registerTask(ActivityTask)