local socket = require'socket'
local tools = require'websocket.tools'
local frame = require'websocket.frame'
local handshake = require'websocket.handshake'
local tconcat = table.concat
local tinsert = table.insert
local ev
local loop

local clients = {}
clients[true] = {}

local client = function(sock,protocol)
  assert(sock)
  sock:setoption('tcp-nodelay',true)
  local fd = sock:getfd()
  local message_io
  local close_timer
  local async_send = require'websocket.ev_common'.async_send(sock,loop)
  local self = {}
  self.state = 'OPEN'
  self.sock = sock
  local user_on_error
  local on_error = function(s,err)
    if clients[protocol] ~= nil and clients[protocol][self] ~= nil then
      clients[protocol][self] = nil
    end
    if user_on_error then
      user_on_error(self,err)
    else
      print('Websocket server error',err)
    end
  end
  local user_on_close
  local on_close = function(was_clean,code,reason)
    if clients[protocol] ~= nil and clients[protocol][self] ~= nil then
      clients[protocol][self] = nil
    end
    if close_timer then
      close_timer:stop(loop)
      close_timer = nil
    end
    message_io:stop(loop)
    self.state = 'CLOSED'
    if user_on_close then
      user_on_close(self,was_clean,code,reason or '')
    end
    sock:shutdown()
    sock:close()
  end
  
  local handle_sock_err = function(err)
    if err == 'closed' then
      if self.state ~= 'CLOSED' then
        on_close(false,1006,'')
      end
    else
      on_error(err)
    end
  end
  local user_on_message = function() end
  local TEXT = frame.TEXT
  local BINARY = frame.BINARY
  local on_message = function(message,opcode)
    if opcode == TEXT or opcode == BINARY then
      user_on_message(self,message,opcode)
    elseif opcode == frame.CLOSE then
      if self.state ~= 'CLOSING' then
        self.state = 'CLOSING'
        local code,reason = frame.decode_close(message)
        local encoded = frame.encode_close(code)
        encoded = frame.encode(encoded,frame.CLOSE)
        async_send(encoded,
          function()
            on_close(true,code or 1006,reason)
          end,handle_sock_err)
      else
        on_close(true,1006,'')
      end
    end
  end
  
  self.send = function(_,message,opcode)
    local encoded = frame.encode(message,opcode or frame.TEXT)
    return async_send(encoded)
  end
  
  self.on_close = function(_,on_close_arg)
    user_on_close = on_close_arg
  end
  
  self.on_error = function(_,on_error_arg)
    user_on_error = on_error_arg
  end
  
  self.on_message = function(_,on_message_arg)
    user_on_message = on_message_arg
  end
  
  self.broadcast = function(_,...)
    for client in pairs(clients[protocol]) do
      if client.state == 'OPEN' then
        client:send(...)
      end
    end
  end
  
  self.close = function(_,code,reason,timeout)
    if clients[protocol] ~= nil and clients[protocol][self] ~= nil then
      clients[protocol][self] = nil
    end
    if not message_io then
      self:start()
    end
    if self.state == 'OPEN' then
      self.state = 'CLOSING'
      assert(message_io)
      timeout = timeout or 3
      local encoded = frame.encode_close(code or 1000,reason or '')
      encoded = frame.encode(encoded,frame.CLOSE)
      async_send(encoded)
      close_timer = ev.Timer.new(function()
          close_timer = nil
          on_close(false,1006,'timeout')
        end,timeout)
      close_timer:start(loop)
    end
  end
  
  self.start = function()
    message_io = require'websocket.ev_common'.message_io(
      sock,loop,
      on_message,
    handle_sock_err)
  end
  
  
  return self
end

local listen = function(opts)
  assert(opts and (opts.protocols or opts.default))
  ev = require'ev'
  loop = opts.loop or ev.Loop.default
  local user_on_error
  local on_error = function(s,err)
    if user_on_error then
      user_on_error(s,err)
    else
      print(err)
    end
  end
  local protocols = {}
  if opts.protocols then
    for protocol in pairs(opts.protocols) do
      clients[protocol] = {}
      tinsert(protocols,protocol)
    end
  end
  local self = {}
  self.on_error = function(self,on_error)
    user_on_error = on_error
  end
  local listener,err = socket.bind(opts.interface or '*',opts.port or 80)
  if not listener then
    error(err)
  end
  listener:settimeout(0)
  
  self.sock = function()
    return listener
  end
  
  local listen_io = ev.IO.new(
    function()
      local client_sock = listener:accept()
      client_sock:settimeout(0)
      assert(client_sock)
      local request = {}
      local last
      ev.IO.new(
        function(loop,read_io)
          repeat
            local line,err,part = client_sock:receive('*l')
            if line then
              if last then
                line = last..line
                last = nil
              end
              request[#request+1] = line
            elseif err ~= 'timeout' then
              on_error(self,'Websocket Handshake failed due to socket err:'..err)
              read_io:stop(loop)
              return
            else
              last = part
              return
            end
          until line == ''
          read_io:stop(loop)
          local upgrade_request = tconcat(request,'\r\n')
          local response,protocol = handshake.accept_upgrade(upgrade_request,protocols)
          if not response then
            print('Handshake failed, Request:')
            print(upgrade_request)
            client_sock:close()
            return
          end
          local index
          ev.IO.new(
            function(loop,write_io)
              local len = #response
              local sent,err = client_sock:send(response,index)
              if not sent then
                write_io:stop(loop)
                print('Websocket client closed while handshake',err)
              elseif sent == len then
                write_io:stop(loop)
                local protocol_handler
                local new_client
                local protocol_index
                if protocol and opts.protocols[protocol] then
                  protocol_index = protocol
                  protocol_handler = opts.protocols[protocol]
                elseif opts.default then
                  -- true is the 'magic' index for the default handler
                  protocol_index = true
                  protocol_handler = opts.default
                else
                  client_sock:close()
                  if on_error then
                    on_error('bad protocol')
                  end
                  return
                end
                new_client = client(client_sock,protocol_index)
                clients[protocol_index][new_client] = true
                protocol_handler(new_client)
                new_client:start(loop)
              else
                assert(sent < len)
                index = sent
              end
            end,client_sock:getfd(),ev.WRITE):start(loop)
        end,client_sock:getfd(),ev.READ):start(loop)
    end,listener:getfd(),ev.READ)
  self.close = function(keep_clients)
    listen_io:stop(loop)
    listener:close()
    listener = nil
    if not keep_clients then
      for protocol,clients in pairs(clients) do
        for client in pairs(clients) do
          client:close()
        end
      end
    end
  end
  listen_io:start(loop)
  return self
end

return {
  listen = listen
}