local love = assert( love )
local lk = assert( love.keyboard )
local lg = assert( love.graphics )

local utf8 = assert( require 'utf8' )
local string = assert( string )

local _lt
local _lkp
local _lmm
local _lmp
local _callback


local textInput = { }
local __mt = { __index = textInput }

local font = lg.newFont( 36 )

-- There is only one active text input widget at a time. 
-- It takes exclusive control of key input.
local activeWidget 

textInput.width = 200
textInput.length = 20
textInput.x = 0
textInput.y = 0

function textInput.new( t )
  t = t or {}
  t.text = lg.newText( font, "")
  t.str = ""
  return setmetatable( t, __mt )
end

function textInput.keypressed(key, code, isRepeat)
  if activeWidget and textInput[code] then return textInput[code]() end
end

function textInput:clear()
  self.str = ""
  self.text:set( self.str )
end

function textInput:contains(x, y)
  local mx, my, Mx, My = self.x, self.y, self.x + self.width, self.y + font:getHeight()
  return (x < Mx and x > mx and y > my and y < My)
end

function textInput:draw()
  local w, h = self.text:getDimensions() 
  lg.setColor( 1, 1, 1, 0.5 )
  lg.rectangle( "fill", self.x, self.y, w, h )
  if activeWidget == self then lg.rectangle( "fill", self.x, self.y, self.width, font:getHeight(), 5 ) end
  lg.rectangle( "line", self.x - 3, self.y - 3, self.width + 6, font:getHeight() + 6, 5 )
  lg.setColor( 0, 0, 0, 1 )
  lg.draw( self.text, self.x or 0, self.y or 0)
end

function textInput:getText()
  return self.str
end

function textInput.textInput( s )
  activeWidget.str = activeWidget.str..s
  activeWidget.text:set( activeWidget.str )
end

function textInput.backspace( )
  local str = activeWidget.str
  local byteoffset = utf8.offset(str, -1)
  if byteoffset then str = string.sub(str, 1, byteoffset - 1)
  else return end
  activeWidget.str = str
  activeWidget.text:set( activeWidget.str )
end

function textInput:enterText( callback )
  _lt = love.textinput
  _lkp = love.keypressed
  _lmm = love.mousemoved
  _lmp = love.mousepressed
  _callback = assert( callback )
  love.textinput = textInput.textInput
  love.keypressed = textInput.keypressed
  self.oldStr = self.str
  activeWidget = self
end

local function disable()
  activeWidget = nil
  love.textinput = _lt
  love.keypressed = _lkp
  love.mousemoved = _lmm
  love.mousepressed = _lmp
end

function textInput.escape()
  activeWidget.str = activeWidget.oldStr or ""
  activeWidget.text:set( activeWidget.str )
  disable()
  return _callback()
end

textInput["return"] = function() --unusual decl because return is a keyword
  local str = activeWidget.str
  disable()
  return _callback( str )
end

return textInput