(function engine() {
// Hidden vars (os, actorsym, init, core_path) come from env
var ACTORDATA = actorsym
var SYSYM = '__SYSTEM__'

var _cell = {}

var dylib_ext

switch(os.platform()) {
  case 'Windows': dylib_ext = '.dll'; break;
  case 'macOS': dylib_ext = '.dylib'; break;
  case 'Linux': dylib_ext = '.so'; break;
} 

var MOD_EXT = '.cm'
var ACTOR_EXT = '.ce'  

var load_internal = os.load_internal
function use_embed(name) {
  return load_internal("js_" + name + "_use")
}

function logical(val1) {
  if (val1 == 0 || val1 == false || val1 == "false" || val1 == null)
    return false;
  if (val1 == 1 || val1 == true || val1 == "true")
    return true;
  return null;
}

function some(arr, pred) {
  return find(arr, pred) != null
}

function every(arr, pred) {
  return find(arr, x => not(pred(x))) == null
}

function starts_with(str, prefix) {
  return search(str, prefix) == 0
}

function ends_with(str, suffix) {
  return search(str, suffix, -length(suffix)) != null
}

var js = use_embed('js')
var fd = use_embed('fd')

// Get the shop path from HOME environment
var home = os.getenv('HOME') || os.getenv('USERPROFILE')
if (!home) {
  throw Error('Could not determine home directory')
}
var shop_path = home + '/.cell'
var packages_path = shop_path + '/packages'
var core_path = packages_path + '/core'

if (!fd.is_dir(core_path)) {
  throw Error('Cell shop not found at ' + shop_path + '. Run "cell install" to set up.')
}

var use_cache = {}
use_cache['core/os'] = os

// Load a core module from the file system
function use_core(path) {
  var cache_key = 'core/' + path
  if (use_cache[cache_key])
    return use_cache[cache_key];

  var sym = use_embed(replace(path, '/', '_'))

  // Core scripts are in packages/core/
  var file_path = core_path + '/' + path + MOD_EXT

  if (fd.is_file(file_path)) {
    var script_blob = fd.slurp(file_path)
    var script = text(script_blob)
    var mod = `(function setup_module(use){${script}})`
    var fn = js.eval('core:' + path, mod)
    var result = call(fn,sym, [use_core])
    use_cache[cache_key] = result;
    return result;
  }

  use_cache[cache_key] = sym;
  return sym;
}

var blob = use_core('blob')

function actor() {

}

var actor_mod = use_core('actor')
var wota = use_core('wota')
var nota = use_core('nota')

function is_actor(value) {
  return is_object(value) && value[ACTORDATA]
}

var ENETSERVICE = 0.1
var REPLYTIMEOUT = 60 // seconds before replies are ignored

function caller_data(depth = 0)
{
  var file = "nofile"
  var line = 0
  
  var caller = array(Error().stack, "\n")[1+depth]
  if (caller) {
    var md = extract(caller, /\((.*)\:/)
    var m = md ? md[1] : "SCRIPT"
    if (m) file = m
    md = extract(caller, /\:(\d*)\)/)
    m = md ? md[1] : 0
    if (m) line = m
  }
  
  return {file,line}
}

function console_rec(line, file, msg) {
  return `[${text(_cell.id, 0, 5)}] [${file}:${line}]: ${msg}\n`
  // time: [${time.text("mb d yyyy h:nn:ss")}]
}

function log(name, args) {
  var caller = caller_data(1)
  var msg = args[0]

  switch(name) {
    case 'console':
      os.print(console_rec(caller.line, caller.file, msg))
      break
    case 'error':
      msg = msg ?? Error()
      if (is_proto(msg, Error))
        msg = msg.name + ": " + msg.message + "\n" + msg.stack
      os.print(console_rec(caller.line, caller.file, msg))
      break
    case 'system':
      msg = "[SYSTEM] " + msg
      os.print(console_rec(caller.line, caller.file, msg))
      break
    default:
      log.console(`unknown log type: ${name}`)
      break
  }
}

function disrupt(err)
{
  if (is_function(err.toString)) {
  os.print(err.toString())
  os.print("\n")
  os.print(err.stack)
  }

  if (overling) {
    if (err) {
      // with an err, this is a forceful disrupt
      var reason = (is_proto(err, Error)) ? err.stack : err
      report_to_overling({type:'disrupt', reason})
    } else
      report_to_overling({type:'stop'})
  }

  if (underlings) {
    var unders = array(underlings)
    arrfor(unders, function(id, index) {
      log.console(`calling on ${id} to disrupt too`)
      $_.stop(create_actor({id}))
    })
  }

  if (err) {
    if (err.message)
      log.console(err.message)
    if (err.stack)
      log.console(err.stack)
  }

  actor_mod.disrupt()
}



actor_mod.on_exception(disrupt)

_cell.args = init ?? {}
_cell.id = "newguy"

function create_actor(desc = {id:guid()}) {
  var actor = {}
  actor[ACTORDATA] = desc
  return actor
}

var $_ = {}
$_.self = create_actor()

os.use_cache = use_cache
os.global_shop_path = shop_path
os.$_ = $_

var shop = use_core('internal/shop')

var json = use_core('json')
var time = use_core('time')

var pronto = use_core('pronto')
var fallback = pronto.fallback
var parallel = pronto.parallel
var race = pronto.race
var sequence = pronto.sequence

// Create runtime environment for modules
var runtime_env = {
  logical: logical,
  some: some,
  every: every,
  starts_with: starts_with,
  ends_with: ends_with,
  actor: actor,
  is_actor: is_actor,
  log: log,
  send: send,
  fallback: fallback,
  parallel: parallel,
  race: race,
  sequence: sequence
}

// Pass to os for shop to access
os.runtime_env = runtime_env

$_.time_limit = function(requestor, seconds)
{
  if (!pronto.is_requestor(requestor))
    throw Error('time_limit: first argument must be a requestor');
  if (!is_number(seconds) || seconds <= 0)
    throw Error('time_limit: seconds must be a positive number');
    
  return function time_limit_requestor(callback, value) {
    pronto.check_callback(callback, 'time_limit')
    var finished = false
    var requestor_cancel = null
    var timer_cancel = null

    function cancel(reason) {
      if (finished) return
      finished = true
      if (timer_cancel) {
        timer_cancel()
        timer_cancel = null
      }
      if (requestor_cancel) {
        try { pronto.requestor_cancel(reason) } catch (_) {}
        requestor_cancel = null
      }
    }

    timer_cancel = $_.delay(function() {
      if (finished) return
      def reason = make_reason(factory, 'Timeout.', seconds)
      if (requestor_cancel) {
        try { requestor_cancel(reason) } catch (_) {}
        requestor_cancel = null
      }
      finished = true
      callback(null, reason)
    }, seconds)

        try {
      requestor_cancel = requestor(function(val, reason) {
        if (finished) return
        finished = true
        if (timer_cancel) {
          timer_cancel()
          timer_cancel = null
        }
        callback(val, reason)
      }, value)
    } catch (ex) {
      cancel(ex)
      callback(null, ex)
    }

    return function(reason) {
      if (requestor_cancel) {
        try { requestor_cancel(reason) } catch (_) {}
        requestor_cancel = null
      }
    }
  }
}

var config = {
  ar_timer: 60,
  actor_memory:0,
  net_service:0.1,
  reply_timeout:60,
  main: true
}

_cell.config = config

ENETSERVICE = config.net_service
REPLYTIMEOUT = config.reply_timeout



/*
  When handling a message, the message appears like this:
  {
    type: type of message
      - contact: used for contact messages
      - stop: used to issue stop command
      - etc
    reply: ID this message will respond to (callback saved on the actor)
    replycc: the actor that is waiting for the reply
    target: ID of the actor that's supposed to receive the message. Only added to non direct sends (out of portals)
    return: reply ID so the replycc actor can know what callback to send the message to
    
    data: the actual content of the message
  }

  actors look like
  {
    id: the GUID of this actor
    address: the IP this actor can be found at
    port: the port of the IP the actor can be found at
  }
*/

function guid(bits = 256)
{
  var guid = blob(bits, os.random)
  stone(guid)
  return text(guid,'h')
}

var HEADER = {}

// takes a function input value that will eventually be called with the current time in number form.
$_.clock = function(fn) {
  actor_mod.clock(_ => {
    fn(time.number())
    send_messages()
  })
}

var underlings = {} // this is more like "all actors that are notified when we die"
var overling = null
var root = null

var receive_fn = null
var greeters = {} // Router functions for when messages are received for a specific actor

function peer_connection(peer) {
  return {
    latency: peer.rtt,
    bandwidth: {
      incoming: peer.incoming_bandwidth,
      outgoing: peer.outgoing_bandwidth
    },
    activity: {
      last_sent: peer.last_send_time,
      last_received: peer.last_receive_time
    },
    mtu: peer.mtu,
    data: {
      incoming_total: peer.incoming_data_total,
      outgoing_total: peer.outgoing_data_total,
      reliable_in_transit: peer.reliable_data_in_transit
    },
    latency_variance: peer.rtt_variance,
    packet_loss: peer.packet_loss,
    state: peer.state
  }
}

// takes a callback function, an actor object, and a configuration record for getting information about the status of a connection to the actor. The configuration record is used to request the sort of information that needs to be communicated. This can include latency, bandwidth, activity, congestion, cost, partitions. The callback is given a record containing the requested information.
$_.connection = function(callback, actor, config) {
  var peer = peers[actor[ACTORDATA].id]
  if (peer) {
    callback(peer_connection(peer))
    return
  }
  if (actor_mod.mailbox_exist(actor[ACTORDATA].id)) {
    callback({type:"local"})
    return
  }
  
  callback()
}

var peers = {}
var id_address = {}
var peer_queue = {}
var portal = null
var portal_fn = null

// takes a function input value that will eventually be called with the current time in number form.
$_.portal = function(fn, port) {
  if (portal) throw Error(`Already started a portal listening on ${portal.port}`)
  if (!port) throw Error("Requires a valid port.")
  log.system(`starting a portal on port ${port}`)
  portal = enet.create_host({address: "any", port})
  portal_fn = fn
}

function handle_host(e) {
  switch (e.type) {
    case "connect":
      log.system(`connected a new peer: ${e.peer.address}:${e.peer.port}`)
      peers[`${e.peer.address}:${e.peer.port}`] = e.peer
      var queue = peer_queue.get(e.peer)
      if (queue) {
        arrfor(queue, (msg, index) => e.peer.send(nota.encode(msg)))
        log.system(`sent ${msg} out of queue`)
        peer_queue.delete(e.peer)
      }
      break
    case "disconnect":
      peer_queue.delete(e.peer)
      arrfor(array(peers), function(id, index) {
        if (peers[id] == e.peer) delete peers[id]
      })
      log.system('portal got disconnect from ' + e.peer.address + ":" + e.peer.port)
      break
    case "receive":
      var data = nota.decode(e.data)
      if (data.replycc && !data.replycc.address) {
        data.replycc[ACTORDATA].address = e.peer.address
        data.replycc[ACTORDATA].port = e.peer.port
      }
      function populate_actor_addresses(obj) {
        if (!is_object(obj)) return
        if (obj[ACTORDATA] && !obj[ACTORDATA].address) {
          obj[ACTORDATA].address = e.peer.address
          obj[ACTORDATA].port = e.peer.port
        }
        arrfor(array(obj), function(key, index) {
          if (key in obj)
            populate_actor_addresses(obj[key])
        })
      }
      if (data.data) populate_actor_addresses(data.data)
      turn(data)
      break
  }
}

// takes a callback function, an actor object, and a configuration record for getting information about the status of a connection to the actor. The configuration record is used to request the sort of information that needs to be communicated. This can include latency, bandwidth, activity, congestion, cost, partitions. The callback is given a record containing the requested information.
$_.contact = function(callback, record) {
  send(create_actor(record), record, callback)
}

// registers a function that will receive all messages...
$_.receiver = function receiver(fn) {
  receive_fn = fn
}

$_.start = function start(cb, program) {
    if (!program) return

    var id = guid()
    var startup = { 
      id, 
      overling: $_.self, 
      root, 
      program,
    }
    greeters[id] = cb
    push(message_queue, { startup })
}

// stops an underling or self.
$_.stop = function stop(actor) {
  if (!actor) {
    need_stop = true
    return
  }
  if (!is_actor(actor))
    throw Error('Can only call stop on an actor.')
  if (is_null(underlings[actor[ACTORDATA].id]))
    throw Error('Can only call stop on an underling or self.')

  sys_msg(actor, {kind:"stop"})
}

// schedules the removal of an actor after a specified amount of time.
$_.unneeded = function unneeded(fn, seconds) {
  actor_mod.unneeded(fn, seconds)
}

// schedules the invocation of a function after a specified amount of time.
$_.delay = function delay(fn, seconds = 0) {
  function delay_turn() {
    fn()
    send_messages()
  }
  var id = actor_mod.delay(delay_turn, seconds)
  return function() { actor_mod.removetimer(id) }
}

var enet = use_core('enet')

// causes this actor to stop when another actor stops.
var couplings = {}
$_.couple = function couple(actor) {
  if (actor == $_.self) return // can't couple to self
  couplings[actor[ACTORDATA].id] = true
  sys_msg(actor, {kind:'couple', from: $_.self})
  log.system(`coupled to ${actor}`)
}

function actor_prep(actor, send) {
  push(message_queue, {actor,send});
}

// Send a message immediately without queuing
function actor_send_immediate(actor, send) {
  try {
    actor_send(actor, send);
  } catch (err) {
    log.error("Failed to send immediate message:", err);
  }
}

function actor_send(actor, message) {
  if (actor[HEADER] && !actor[HEADER].replycc) // attempting to respond to a message but sender is not expecting; silently drop
    return

  if (!is_actor(actor) && !is_actor(actor.replycc)) throw Error(`Must send to an actor object. Attempted send to ${actor}`)
  
  if (!is_object(message)) throw Error('Must send an object record.')

  // message to self
  if (actor[ACTORDATA].id == _cell.id) {
    if (receive_fn) receive_fn(message.data)
    return
  }
  
  // message to actor in same flock
  if (actor[ACTORDATA].id && actor_mod.mailbox_exist(actor[ACTORDATA].id)) {
    var wota_blob = wota.encode(message)
//    log.console(`sending wota blob of ${length(wota_blob)/8} bytes`)
    actor_mod.mailbox_push(actor[ACTORDATA].id, wota_blob)
    return
  }
  
  if (actor[ACTORDATA].address) {
    if (actor[ACTORDATA].id)
      message.target = actor[ACTORDATA].id
    else
      message.type = "contact"
      
    var peer = peers[actor[ACTORDATA].address + ":" + actor[ACTORDATA].port]
    if (!peer) {
      if (!portal) {
        log.system(`creating a contactor ...`)
        portal = enet.create_host({address:"any"})
        log.system(`allowing contact to port ${portal.port}`)
      }
      log.system(`no peer! connecting to ${actor[ACTORDATA].address}:${actor[ACTORDATA].port}`)
      peer = portal.connect(actor[ACTORDATA].address, actor[ACTORDATA].port)
      peer_queue.set(peer, [message])
    } else {
      peer.send(nota.encode(message))
    }
    return
  }
  log.system(`Unable to send message to actor ${actor[ACTORDATA]}`)
}

// Holds all messages queued during the current turn.
var message_queue = []

var need_stop = false

 function send_messages() {
   // if we've been flagged to stop, bail out before doing anything
   if (need_stop) {
     disrupt()
     message_queue = []
     return
   }

   arrfor(message_queue, function(msg, index) {
     if (msg.startup) {
       // now is the time to actually spin up the actor
       actor_mod.createactor(msg.startup)
     } else {
       actor_send(msg.actor, msg.send)
     }
   })

   message_queue = []
 }

var replies = {}

function send(actor, message, reply) {
  if (!is_object(actor))
    throw Error(`Must send to an actor object. Provided: ${actor}`);

  if (!is_object(message))
    throw Error('Message must be an object')
  var send_msg = {type:"user", data: message}

  if (actor[HEADER] && actor[HEADER].replycc) {
    var header = actor[HEADER]
    if (!header.replycc || !is_actor(header.replycc))
      throw Error(`Supplied actor had a return, but it's not a valid actor! ${actor[HEADER]}`)

    actor = header.replycc
    send_msg.return = header.reply
  }

  if (reply) {
    var id = guid()
    replies[id] = reply
    $_.delay(_ => {
      if (replies[id]) {
        replies[id](null, "timeout")
        delete replies[id]
      }
    }, REPLYTIMEOUT)
    send_msg.reply = id
    send_msg.replycc = $_.self
  }

  // Instead of sending immediately, queue it
  actor_prep(actor, send_msg);
}

stone(send)

if (!_cell.args.id) _cell.id = guid()
else _cell.id = _cell.args.id

$_.self[ACTORDATA].id = _cell.id

// Actor's timeslice for processing a single message
function turn(msg)
{
  var mes = wota.decode(msg)
  handle_message(mes)
  send_messages()
}

//log.console(`FIXME: need to get main from config, not just set to true`)
actor_mod.register_actor(_cell.id, turn, true, config.ar_timer)

if (config.actor_memory)
  js.mem_limit(config.actor_memory)
  
if (config.stack_max)
  js.max_stacksize(config.system.stack_max);

overling = _cell.args.overling
$_.overling = overling

root = _cell.args.root
root ??= $_.self

if (overling) {
  $_.couple(overling) // auto couple to overling

  report_to_overling({type:'greet', actor: $_.self})
}

// sys messages are always dispatched immediately
function sys_msg(actor, msg)
{
  actor_send(actor, {[SYSYM]:msg})
}

// messages sent to here get put into the cb provided to start
function report_to_overling(msg)
{
  if (!overling) return
  sys_msg(overling, {kind:'underling', message:msg, from: $_.self})
}

// Determine the program to run from command line
var program = _cell.args.program

if (!program) {
  log.error('No program specified. Usage: cell <program.ce> [args...]')
  os.exit(1)
}

function handle_actor_disconnect(id) {
  var greeter = greeters[id]
  if (greeter) {
    greeter({type: "stopped", id})
    delete greeters[id]
  }
  log.system(`actor ${id} disconnected`)
  if (!is_null(couplings[id])) disrupt("coupled actor died") // couplings now disrupts instead of stop
}

function handle_sysym(msg)
{
  var from
  switch(msg.kind) {
    case 'stop':
      disrupt("got stop message")
      break
    case 'underling':
      from = msg.from
      var greeter = greeters[from[ACTORDATA].id]
      if (greeter) greeter(msg.message)
      if (msg.message.type == 'disrupt')
        delete underlings[from[ACTORDATA].id]
      break
    case 'contact':
      if (portal_fn) {
        var letter2 = msg.data
        letter2[HEADER] = msg
        delete msg.data
        portal_fn(letter2)
      } else throw Error('Got a contact message, but no portal is established.')
      break
    case 'couple': // from must be notified when we die
      from = msg.from
      underlings[from[ACTORDATA].id] = true
      log.system(`actor ${from} is coupled to me`)
      break
  }
}

function handle_message(msg) {
  if (msg[SYSYM]) {
    handle_sysym(msg[SYSYM], msg.from)
    return
  }

  switch (msg.type) {
    case "user":
      var letter = msg.data // what the sender really sent
      _ObjectDefineProperty(letter, HEADER, {
        value: msg, enumerable: false
      })
      _ObjectDefineProperty(letter, ACTORDATA, { // this is so is_actor == true
        value: { reply: msg.reply }, enumerable: false
      })
      
      if (msg.return) {
        var fn = replies[msg.return]
        if (fn) fn(letter)
        delete replies[msg.return]
        return
      }
      
      if (receive_fn) receive_fn(letter)
      return
    case "stopped":
      handle_actor_disconnect(msg.id)
      break
  }
};

function enet_check()
{
  if (portal) portal.service(handle_host)
  
  $_.delay(enet_check, ENETSERVICE);
}

// enet_check();

// Finally, run the program
actor_mod.setname(_cell.args.program)

var prog = _cell.args.program

var package = use_core('package')

var locator = shop.resolve_locator(_cell.args.program + ".ce", null)

if (!locator) {
  var pkg = package.find_package_dir(_cell.args.program + ".ce")
  locator = shop.resolve_locator(_cell.args.program + ".ce", pkg)
}

if (!locator)
  throw Error(`Main program ${_cell.args.program} could not be found`)

$_.clock(_ => {
  // Get capabilities for the main program
  var file_info = shop.file_info ? shop.file_info(locator.path) : null
  var inject = shop.script_inject_for ? shop.script_inject_for(file_info) : []

  // Build env object for injection
  var env = {}
  for (var i = 0; i < length(inject); i++) {
    var key = inject[i]
    if (key && key[0] == '$') key = text(key, 1)
    if (key == 'fd') env[key] = fd
    else env[key] = $_[key]
  }

  // Create use function bound to the program's package
  var pkg = file_info ? file_info.package : null
  var use_fn = function(path) { return shop.use(path, pkg) }

  // Call with signature: setup_module(args, use, env)
  // The script wrapper binds $delay, $start, etc. from env
  var val = call(locator.symbol, null, [_cell.args.arg, use_fn, env])

  if (val)
    throw Error('Program must not return anything');
})

})()