-- Default label
if not os.getComputerLabel() then
  local id = os.getComputerID()
  if turtle then
    os.setComputerLabel('turtle_' .. id)
  elseif pocket then
    os.setComputerLabel('pocket_' .. id)
  else
    os.setComputerLabel('computer_' .. id)
  end
end

multishell.term = term.current()

local defaultEnv = Util.shallowCopy(getfenv(1))

require = requireInjector(getfenv(1))
local Config = require('config')

-- Begin multishell
local parentTerm = term.current()
local w,h = parentTerm.getSize()
local tabs = {}
local currentTab
local _tabId = 0
local overviewTab
local runningTab
local tabsDirty = false

local config = {
  standard = {
    focusTextColor = colors.lightGray,
    focusBackgroundColor = colors.gray,
    textColor  = colors.black,
    backgroundColor = colors.lightGray,
    tabBarTextColor = colors.black,
    tabBarBackgroundColor = colors.lightGray,
  },
  color = {
    focusTextColor = colors.white,
    focusBackgroundColor = colors.brown,
    textColor  = colors.gray,
    backgroundColor = colors.brown,
    tabBarTextColor = colors.lightGray,
    tabBarBackgroundColor = colors.brown,
  },
--  path = '.:/apps:' .. shell.path():sub(3),
  path = '/apps:' .. shell.path(),
}

Config.load('multishell', config)

shell.setPath(config.path)

if config.aliases then
  for k in pairs(shell.aliases()) do
    shell.clearAlias(k)
  end
  for k,v in pairs(config.aliases) do
    shell.setAlias(k, v)
  end
end

local _colors = config.standard
if parentTerm.isColor() then
  _colors = config.color
end

local function redrawMenu()
  if not tabsDirty then
    os.queueEvent('multishell', 'draw')
    tabsDirty = true
  end
end

-- Draw menu
local function draw()
  tabsDirty = false

  parentTerm.setBackgroundColor( _colors.tabBarBackgroundColor )
  if currentTab and currentTab.isOverview then
     parentTerm.setTextColor( _colors.focusTextColor )
  else
    parentTerm.setTextColor( _colors.tabBarTextColor )
  end
  parentTerm.setCursorPos( 1, 1 )
  parentTerm.clearLine()
  parentTerm.write('+')

  local tabX = 2
  local function compareTab(a, b)
    return a.tabId < b.tabId
  end
  for _,tab in Util.spairs(tabs, compareTab) do

    if tab.hidden and tab ~= currentTab or tab.isOverview then
      tab.sx = nil
      tab.ex = nil
    else
      tab.sx = tabX + 1
      tab.ex = tabX + #tab.title
      tabX = tabX + #tab.title + 1
    end
  end
  for _,tab in Util.spairs(tabs) do
    if tab.sx then
      if tab == currentTab then
        parentTerm.setTextColor(_colors.focusTextColor)
        parentTerm.setBackgroundColor(_colors.focusBackgroundColor)
      else
        parentTerm.setTextColor(_colors.textColor)
        parentTerm.setBackgroundColor(_colors.backgroundColor)
      end
      parentTerm.setCursorPos(tab.sx, 1)
      parentTerm.write(tab.title)
    end
  end
  if currentTab and not currentTab.isOverview then
    parentTerm.setTextColor(_colors.textColor)
    parentTerm.setBackgroundColor(_colors.backgroundColor)
    parentTerm.setCursorPos( w, 1 )
    parentTerm.write('*')
  end

  if currentTab then
    currentTab.window.restoreCursor()
  end
end

local function selectTab( tab )
  if not tab then
    for _,ftab in pairs(tabs) do
      if not ftab.hidden then
        tab = ftab
        break
      end
    end
  end

  if not tab then
    tab = overviewTab
  end

  if currentTab and currentTab ~= tab then
    currentTab.window.setVisible(false)
    if tab and not currentTab.hidden then
      tab.previousTabId = currentTab.tabId
    end
  end

  if tab then
    currentTab = tab
    tab.window.setVisible(true)
  end
end

local function resumeTab(tab, event, eventData)
  if not tab or coroutine.status(tab.co) == 'dead' then
    return
  end

  if not tab.filter or tab.filter == event or event == "terminate" then
    eventData = eventData or { }
    term.redirect(tab.terminal)
    local previousTab = runningTab
    runningTab = tab
    local ok, result = coroutine.resume(tab.co, event, unpack(eventData))
    tab.terminal = term.current()
    if ok then
      tab.filter = result
    else
      printError(result)
    end

    runningTab = previousTab

    return ok, result
  end
end

local function nextTabId()
  _tabId = _tabId + 1
  return _tabId
end

local function launchProcess(tab)

  tab.tabId = nextTabId()
  tab.timestamp = os.clock()
  tab.window = window.create(parentTerm, 1, 2, w, h - 1, false)
  tab.terminal = tab.window
  tab.env = Util.shallowCopy(tab.env or defaultEnv)

  tab.co = coroutine.create(function()

    local result, err

    if tab.fn then
      result, err = Util.runFunction(tab.env, tab.fn, table.unpack(tab.args or { } ))
    elseif tab.path then
      result, err = os.run(tab.env, tab.path, table.unpack(tab.args or { } ))
    else
      err = 'multishell: invalid tab'
    end

    if not result and err ~= 'Terminated' then
      if err then
        printError(tostring(err))
      end
      printError('Press enter to exit')
      tab.isDead = true
      while true do
        local e, code = os.pullEventRaw('key')
        if e == 'terminate' or e == 'key' and code == keys.enter then
          if tab.isOverview then
            os.queueEvent('multishell', 'terminate')
          end
          break
        end
      end
    end
    tabs[tab.tabId] = nil
    if tab == currentTab then
      local previousTab
      if tab.previousTabId then
        previousTab = tabs[tab.previousTabId]
      end
      selectTab(previousTab)
    end
    redrawMenu()
  end)

  tabs[tab.tabId] = tab

  resumeTab(tab)

  return tab
end

local function resizeWindows()
  local windowY = 2
  local windowHeight = h-1

  local keys = Util.keys(tabs)
  for _,key in pairs(keys) do
    local tab = tabs[key]
    local x,y = tab.window.getCursorPos()
    if y > windowHeight then
      tab.window.scroll( y - windowHeight )
      tab.window.setCursorPos( x, windowHeight )
    end
    tab.window.reposition( 1, windowY, w, windowHeight )
  end

  -- Pass term_resize to all processes
  local keys = Util.keys(tabs)
  for _,key in pairs(keys) do
    resumeTab(tabs[key], "term_resize")
  end
end

local control
local hotkeys = { }

local function processKeyEvent(event, code)
  if event == 'key_up' then
    if code == keys.leftCtrl or code == keys.rightCtrl then
      control = false
    end
  elseif event == 'char' then
    control = false
  elseif event == 'key' then
    if code == keys.leftCtrl or code == keys.rightCtrl then
      control = true
    elseif control then
      local hotkey = hotkeys[code]
      control = false
      if hotkey then
        hotkey()
      end
    end
  end
end

function multishell.addHotkey(code, fn)
  hotkeys[code] = fn
end

function multishell.removeHotkey(code)
  hotkeys[code] = nil
end

function multishell.getFocus()
  return currentTab.tabId
end

function multishell.setFocus(tabId)
  local tab = tabs[tabId]
  if tab then
    selectTab(tab)
    redrawMenu()
    return true
  end
  return false
end

function multishell.getTitle(tabId)
  local tab = tabs[tabId]
  if tab then
    return tab.title
  end
end

function multishell.setTitle(tabId, sTitle)
  local tab = tabs[tabId]
  if tab then
    tab.title = sTitle or ''
    redrawMenu()
  end
end

function multishell.getCurrent()
  if runningTab then
    return runningTab.tabId
  end
end

function multishell.getTab(tabId)
  return tabs[tabId]
end

function multishell.terminate(tabId)
  local tab = tabs[tabId]
  if tab and not tab.isOverview then
    if coroutine.status(tab.co) ~= 'dead' then
      --os.queueEvent('multishell', 'terminate', tab)
      resumeTab(tab, "terminate")
    else
      tabs[tabId] = nil
      if tab == currentTab then
        local previousTab
        if tab.previousTabId then
          previousTab = tabs[tab.previousTabId]
        end
        selectTab(previousTab)
      end
      redrawMenu()
    end
  end
end

function multishell.getTabs()
  return tabs
end

function multishell.launch( tProgramEnv, sProgramPath, ... )
  -- backwards compatibility
  return multishell.openTab({
    env = tProgramEnv,
    path = sProgramPath,
    args = { ... },
  })
end

function multishell.openTab(tab)

  if not tab.title and tab.path then
    tab.title = fs.getName(tab.path)
  end

  tab.title = tab.title or 'untitled'

  local previousTerm = term.current()
  launchProcess(tab)
  term.redirect(previousTerm)

  if tab.hidden then
    if coroutine.status(tab.co) == 'dead' or tab.isDead then
      tab.hidden = false
    end
  elseif tab.focused then
    multishell.setFocus(tab.tabId)
  else
    redrawMenu()
  end
  return tab.tabId
end

function multishell.hideTab(tabId)
  local tab = tabs[tabId]
  if tab then
    tab.hidden = true
    redrawMenu()
  end
end

function multishell.unhideTab(tabId)
  local tab = tabs[tabId]
  if tab then
    tab.hidden = false
    redrawMenu()
  end
end

function multishell.getCount()
  local count
  for _,tab in pairs(tabs) do
    count = count + 1
  end
  return count
end

-- control-o - overview
multishell.addHotkey(24, function()
  multishell.setFocus(overviewTab.tabId)
end)

-- control-backspace
multishell.addHotkey(14, function()
  local tabId = multishell.getFocus()
  local tab = tabs[tabId]
  if not tab.isOverview then
    os.queueEvent('multishell', 'terminateTab', tabId)
    tab = Util.shallowCopy(tab)
    tab.isDead = false
    tab.focused = true
    multishell.openTab(tab)
  end
end)

-- control-tab - next tab
multishell.addHotkey(15, function()
  local function compareTab(a, b)
    return a.tabId < b.tabId
  end
  local visibleTabs = { }
  for _,tab in Util.spairs(tabs, compareTab) do
    if not tab.hidden then
      table.insert(visibleTabs, tab)
    end
  end
  for k,tab in ipairs(visibleTabs) do
    if tab.tabId == currentTab.tabId then
      if k < #visibleTabs then
        multishell.setFocus(visibleTabs[k + 1].tabId)
        return
      end
    end
  end
  if #visibleTabs > 0 then
    multishell.setFocus(visibleTabs[1].tabId)
  end
end)

local function startup()
  local hasError

  local function runDir(directory, open)
    if not fs.exists(directory) then
      return
    end

    local files = fs.list(directory)
    table.sort(files)

    for _,file in ipairs(files) do
      print('Autorunning: ' .. file)

      local result, err = open(directory .. '/' .. file)
      if not result then
        printError(err)
        hasError = true
      end
    end
  end

  runDir('/sys/extensions', shell.run)

  local overviewId = multishell.openTab({
    path = '/apps/Overview.lua',
    focused = true,
    hidden = true,
    isOverview = true,
  })
  overviewTab = tabs[overviewId]

  runDir('/sys/services', shell.openHiddenTab)
  runDir('/autorun', shell.run)

  if hasError then
    error('An autorun program has errored')
  end
end

-- Begin
parentTerm.clear()

multishell.openTab({
  focused = true,
  fn = startup,
  env = defaultEnv,
  title = 'Autorun',
})

if not overviewTab or coroutine.status(overviewTab.co) == 'dead' then
  --error('Overview aborted')
end

if not currentTab then
  multishell.setFocus(overviewTab.tabId)
end

draw()

while true do

  -- Get the event
  local tEventData = { os.pullEventRaw() }
  local sEvent = table.remove(tEventData, 1)

  if sEvent == "term_resize" then
    -- Resize event
    w,h = parentTerm.getSize()
    resizeWindows()
    redrawMenu()

  elseif sEvent == 'multishell' then
    local action = tEventData[1]

    if action == 'terminate' then
      break
    elseif action == 'terminateTab' then
      multishell.terminate(tEventData[2])
    elseif action == 'draw' then
      draw()
    end

  elseif sEvent == "char" or
         sEvent == "key" or
         sEvent == "paste" or
         sEvent == "terminate" then

    processKeyEvent(sEvent, tEventData[1])

    -- Keyboard event - Passthrough to current process
    resumeTab(currentTab, sEvent, tEventData)
  
  elseif sEvent == "mouse_click" then
    local button, x, y = tEventData[1], tEventData[2], tEventData[3]
    if y == 1 and os.locked then
      -- ignore
    elseif y == 1 then
      -- Switch process
      local w, h = parentTerm.getSize()
      if x == 1 then
        multishell.setFocus(overviewTab.tabId)
      elseif x == w then
        if currentTab then
          multishell.terminate(currentTab.tabId)
        end
      else
        for _,tab in pairs(tabs) do
          if not tab.hidden and tab.sx then
            if x >= tab.sx and x <= tab.ex then
              multishell.setFocus(tab.tabId)
              break
            end
          end
        end
      end
    elseif currentTab then
      -- Passthrough to current process
      resumeTab(currentTab, sEvent, { button, x, y-1 })
    end

  elseif sEvent == "mouse_drag" or sEvent == "mouse_scroll" then
    -- Other mouse event
    local p1, x, y = tEventData[1], tEventData[2], tEventData[3]
    if currentTab and (y ~= 1) then
      if currentTab.terminal.scrollUp then
        if p1 == -1 then
          currentTab.terminal.scrollUp()
        else
          currentTab.terminal.scrollDown()
        end
      else
        -- Passthrough to current process
        resumeTab(currentTab, sEvent, { p1, x, y-1 })
      end
    end

  else
    -- Other event
    -- Passthrough to all processes
    local keys = Util.keys(tabs)
    for _,key in pairs(keys) do
      resumeTab(tabs[key], sEvent, tEventData)
    end
  end
end