_G.requireInjector()

local class  = require('class')
local Config = require('config')
local Event  = require('event')
local FileUI = require('ui.fileui')
local NFT    = require('nft')
local SHA1   = require('sha1')
local Tween  = require('ui.tween')
local UI     = require('ui')
local Util   = require('util')

local colors     = _G.colors
local fs         = _G.fs
local pocket     = _G.pocket
local shell      = _ENV.shell
local term       = _G.term
local turtle     = _G.turtle

if not _ENV.multishell then
  error('multishell is required')
end

local REGISTRY_DIR = 'usr/.registry'

UI:configure('Overview', ...)

local config = {
  Recent = { },
  currentCategory = 'Apps',
}
Config.load('Overview', config)

local applications = { }

local function loadApplications()

  local requirements = {
    turtle = function() return turtle end,
    advancedTurtle = function() return turtle and term.isColor() end,
    pocket = function() return pocket end,
    advancedPocket = function() return pocket and term.isColor() end,
    advancedComputer = function() return not turtle and not pocket and term.isColor() end,
  }

  applications = Util.readTable('sys/etc/app.db')

  if fs.exists(REGISTRY_DIR) then
    local files = fs.list(REGISTRY_DIR)
    for _,file in pairs(files) do
      local app = Util.readTable(fs.combine(REGISTRY_DIR, file))
      if app and app.key then
        app.filename = fs.combine(REGISTRY_DIR, file)
        applications[app.key] = app
      end
    end
  end

  Util.each(applications, function(v, k) v.key = k end)
  applications = Util.filter(applications, function(a)
    if a.disabled then
      return false
    end

    if a.requires then
      local fn = requirements[a.requires]
      if fn and not fn() then
        return false
      end
    end

    return true -- Util.startsWidth(a.run, 'http') or shell.resolveProgram(a.run)
  end)
end

loadApplications()

local defaultIcon = NFT.parse("\03180\031711\03180\
\031800\03171\03180\
\03171\031800\03171")

local sx, sy = term.current().getSize()
local maxRecent = math.ceil(sx * sy / 62)

local function elipse(s, len)
  if #s > len then
    s = s:sub(1, len - 2) .. '..'
  end
  return s
end

local buttons = { }
local categories = { }
for _,f in pairs(applications) do
  if not categories[f.category] then
    categories[f.category] = true
    table.insert(buttons, { text = f.category })
  end
end
table.sort(buttons, function(a, b) return a.text < b.text end)
table.insert(buttons, 1, { text = 'Recent' })
table.insert(buttons, { text = '+', event = 'new' })

local function parseIcon(iconText)
  local icon

  local s, m = pcall(function()
    icon = NFT.parse(iconText)
    if icon then
      if icon.height > 3 or icon.width > 8 then
        error('Invalid size')
      end
    end
    return icon
  end)

  if s then
    return icon
  end

  return s, m
end

UI.VerticalTabBar = class(UI.TabBar)
function UI.VerticalTabBar:setParent()
  self.x = 1
  self.width = 8
  self.height = nil
  self.ey = -1
  UI.TabBar.setParent(self)
  for k,c in pairs(self.children) do
    c.x = 1
    c.y = k + 1
    c.ox, c.oy = c.x, c.y
    c.ow = 8
    c.width = 8
  end
end

local cx = 9
local cy = 1
if sx < 30 then
  UI.VerticalTabBar = UI.TabBar
  cx = 1
  cy = 2
end

local page = UI.Page {
  tabBar = UI.VerticalTabBar {
    buttons = buttons,
  },
  container = UI.Viewport {
    x = cx,
    y = cy,
  },
  notification = UI.Notification(),
  accelerators = {
    r = 'refresh',
    e = 'edit',
    f = 'files',
    s = 'shell',
    l = 'lua',
    [ 'control-n' ] = 'new',
    delete = 'delete',
  },
}

UI.Icon = class(UI.Window)
UI.Icon.defaults = {
  UIElement = 'Icon',
  width = 14,
  height = 4,
}
function UI.Icon:eventHandler(event)
  if event.type == 'mouse_click' then
    self:setFocus(self.button)
    return true
  elseif event.type == 'mouse_doubleclick' then
    self:emit({ type = self.button.event, button = self.button })
  elseif event.type == 'mouse_rightclick' then
    self:setFocus(self.button)
    self:emit({ type = 'edit', button = self.button })
  end
  return UI.Window.eventHandler(self, event)
end

function page.container:setCategory(categoryName, animate)

  -- reset the viewport window
  self.children = { }
  self.offy = 0

  local function filter(it, f)
    local ot = { }
    for _,v in pairs(it) do
      if f(v) then
        table.insert(ot, v)
      end
    end
    return ot
  end

  local filtered

  if categoryName == 'Recent' then
    filtered = { }

    for _,v in ipairs(config.Recent) do
      local app = Util.find(applications, 'key', v)
      if app then -- and fs.exists(app.run) then
        table.insert(filtered, app)
      end
    end

  else
    filtered = filter(applications, function(a)
      return a.category == categoryName -- and fs.exists(a.run)
    end)
    table.sort(filtered, function(a, b) return a.title < b.title end)
  end

  for _,program in ipairs(filtered) do

    local icon
    if program.icon then
      icon = parseIcon(program.icon)
    end
    if not icon then
      icon = defaultIcon
    end

    local title = elipse(program.title, 8)

    local width = math.max(icon.width + 2, #title + 2)
    table.insert(self.children, UI.Icon({
      width = width,
      image = UI.NftImage({
        x = math.floor((width - icon.width) / 2) + 1,
        image = icon,
        width = 5,
        height = 3,
      }),
      button = UI.Button({
        x = math.floor((width - #title - 2) / 2) + 1,
        y = 4,
        text = title,
        backgroundColor = self.backgroundColor,
        backgroundFocusColor = colors.gray,
        textColor = colors.white,
        textFocusColor = colors.white,
        width = #title + 2,
        event = 'button',
        app = program,
      }),
    }))
  end

  local gutter = 2
  if UI.term.width <= 26 then
    gutter = 1
  end
  local col, row = gutter, 2
  local count = #self.children

  local r = math.random(1, 5)
  -- reposition all children
  for k,child in ipairs(self.children) do
    if r == 1 then
      child.x = math.random(1, self.width)
      child.y = math.random(1, self.height)
    elseif r == 2 then
      child.x = self.width
      child.y = self.height
    elseif r == 3 then
      child.x = math.floor(self.width / 2)
      child.y = math.floor(self.height / 2)
    elseif r == 4 then
      child.x = self.width - col
      child.y = row
    elseif r == 5 then
      child.x = col
      child.y = row
      if k == #self.children then
        child.x = self.width
        child.y = self.height
      end
    end
    child.tween = Tween.new(6, child, { x = col, y = row }, 'linear')

    if not animate then
      child.x = col
      child.y = row
    end

    if k < count then
      col = col + child.width
      if col + self.children[k + 1].width + gutter - 2 > self.width then
        col = gutter
        row = row + 5
      end
    end
  end

  self:initChildren()
  if animate then                      -- need to fix transitions under layers
    local function transition(args)
      local i = 1
      return function(device)
        self:clear()
        for _,child in pairs(self.children) do
          child.tween:update(1)
          child.x = math.floor(child.x)
          child.y = math.floor(child.y)
          child:draw()
        end
        args.canvas:blit(device, args, args)
        i = i + 1
        return i < 7
      end
    end
    self:addTransition(transition)
  end
end

function page:refresh()
  local pos = self.container.offy
  self:focusFirst(self)
  self.container:setCategory(config.currentCategory)
  self.container:setScrollPosition(pos)
end

function page:resize()
  UI.Page.resize(self)
  self:refresh()
end

function page:eventHandler(event)

  if event.type == 'tab_select' then
    self.container:setCategory(event.button.text, true)
    self.container:draw()

    config.currentCategory = event.button.text
    Config.update('Overview', config)

  elseif event.type == 'button' then
    for k,v in ipairs(config.Recent) do
      if v == event.button.app.key then
        table.remove(config.Recent, k)
        break
      end
    end
    table.insert(config.Recent, 1, event.button.app.key)
    if #config.Recent > maxRecent then
      table.remove(config.Recent, maxRecent + 1)
    end
    Config.update('Overview', config)
    shell.switchTab(shell.openTab(event.button.app.run))

  elseif event.type == 'shell' then
    shell.switchTab(shell.openTab('sys/apps/shell'))

  elseif event.type == 'lua' then
    shell.switchTab(shell.openTab('sys/apps/Lua.lua'))

  elseif event.type == 'files' then
    shell.switchTab(shell.openTab('sys/apps/Files.lua'))

  elseif event.type == 'focus_change' then
    if event.focused.parent.UIElement == 'Icon' then
      event.focused.parent:scrollIntoView()
    end

  elseif event.type == 'refresh' then -- remove this after fixing notification
    loadApplications()
    self:refresh()
    self:draw()
    self.notification:success('Refreshed')

  elseif event.type == 'delete' then
    local focused = page:getFocused()
    if focused.app then
      focused.app.disabled = true
      local filename = focused.app.filename or fs.combine(REGISTRY_DIR, focused.app.key)
      Util.writeTable(filename, focused.app)
      loadApplications()
      page:refresh()
      page:draw()
      self.notification:success('Removed')
    end

  elseif event.type == 'new' then
    local category = 'Apps'
    if config.currentCategory ~= 'Recent' then
      category = config.currentCategory or 'Apps'
    end
    UI:setPage('editor', { category = category })

  elseif event.type == 'edit' then
    local focused = page:getFocused()
    if focused.app then
      UI:setPage('editor', focused.app)
    end

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

local formWidth = math.max(UI.term.width - 8, 26)

local editor = UI.Dialog {
  height = 11,
  width = formWidth,
  title = 'Edit Application',
  form = UI.Form {
    y = 2,
    height = 9,
    title = UI.TextEntry {
      formLabel = 'Title', formKey = 'title', limit = 11, help = 'Application title',
      required = true,
    },
    run = UI.TextEntry {
      formLabel = 'Run', formKey = 'run', limit = 100, help = 'Full path to application',
      required = true,
    },
    category = UI.TextEntry {
      formLabel = 'Category', formKey = 'category', limit = 11, help = 'Category of application',
      required = true,
    },
    loadIcon = UI.Button {
      x = 11, y = 6,
      text = 'Icon', event = 'loadIcon', help = 'Select icon'
    },
    image = UI.NftImage {
      y = 6, x = 2, height = 3, width = 8,
    },
  },
  statusBar = UI.StatusBar(),
  iconFile = '',
}

function editor:enable(app)
  if app then
    self.form:setValues(app)

    local icon
    if app.icon then
      icon = parseIcon(app.icon)
    end
    self.form.image:setImage(icon)
  end
  UI.Dialog.enable(self)
  self:focusFirst()
end

function editor.form.image:draw()
  self:clear()
  UI.NftImage.draw(self)
end

function editor:updateApplications(app)
  if not app.key then
    app.key = SHA1.sha1(app.title)
  end
  local filename = app.filename or fs.combine(REGISTRY_DIR, app.key)
  Util.writeTable(filename, app)
  loadApplications()
end

function editor:eventHandler(event)

  if event.type == 'form_cancel' or event.type == 'cancel' then
    UI:setPreviousPage()

  elseif event.type == 'focus_change' then
    self.statusBar:setStatus(event.focused.help or '')
    self.statusBar:draw()

  elseif event.type == 'loadIcon' then
    local fileui = FileUI({
      x = self.x,
      y = self.y,
      z = 2,
      width = self.width,
      height = self.height,
    })
    UI:setPage(fileui, fs.getDir(self.iconFile), function(fileName)
      if fileName then
        self.iconFile = fileName
        local s, m = pcall(function()
          local iconLines = Util.readFile(fileName)
          if not iconLines then
            error('Unable to load file')
          end
          local icon, m = parseIcon(iconLines)
          if not icon then
            error(m)
          end
          self.form.values.icon = iconLines
          self.form.image:setImage(icon)
          self.form.image:draw()
        end)
        if not s and m then
          local msg = m:gsub('.*: (.*)', '%1')
          page.notification:error(msg)
        end
      end
    end)

  elseif event.type == 'form_invalid' then
    page.notification:error(event.message)

  elseif event.type == 'form_complete' then
    local values = self.form.values
    UI:setPreviousPage()
    self:updateApplications(values)
    page:refresh()
    page:draw()
  else
    return UI.Dialog.eventHandler(self, event)
  end
  return true
end

UI:setPages({
  editor = editor,
  main = page,
})

Event.on('os_register_app', function()
  loadApplications()
  page:refresh()
  page:draw()
  page:sync()
end)

page.tabBar:selectTab(config.currentCategory or 'Apps')
page.container:setCategory(config.currentCategory or 'Apps')
UI:setPage(page)

UI:pullEvents()