var socket = use('socket')
var c_http = use('net/http')

def CRLF = "\r\n"

def status_texts = {
  "200": "OK", "201": "Created", "204": "No Content",
  "400": "Bad Request", "401": "Unauthorized", "403": "Forbidden",
  "404": "Not Found", "405": "Method Not Allowed", "500": "Internal Server Error"
}

function serve(port) {
  var fd = socket.socket("AF_INET", "SOCK_STREAM")
  socket.setsockopt(fd, "SOL_SOCKET", "SO_REUSEADDR", true)
  socket.bind(fd, {address: "127.0.0.1", port: port})
  socket.listen(fd, 16)
  return fd
}

function parse_request(conn_fd) {
  var data = socket.recv(conn_fd, 65536)
  var raw = text(data)

  var hdr_end = search(raw, CRLF + CRLF)
  if (hdr_end == null) disrupt
  var header_text = text(raw, 0, hdr_end)
  var body_text = text(raw, hdr_end + 4)

  var lines = array(header_text, CRLF)
  var parts = array(lines[0], " ")
  var method = parts[0]
  var url = parts[1]
  var qpos = search(url, "?")
  var path = qpos != null ? text(url, 0, qpos) : url

  var headers = {}
  var i = 1
  var colon = null
  var key = null
  var val = null
  while (i < length(lines)) {
    colon = search(lines[i], ": ")
    if (colon != null) {
      key = lower(text(lines[i], 0, colon))
      val = text(lines[i], colon + 2)
      headers[key] = val
    }
    i = i + 1
  }

  var cl = headers["content-length"]
  var content_length = null
  var remaining = null
  var more = null
  if (cl != null) content_length = number(cl)
  if (content_length != null && length(body_text) < content_length) {
    remaining = content_length - length(body_text)
    more = socket.recv(conn_fd, remaining)
    body_text = body_text + text(more)
  }
  if (content_length == null || content_length == 0) body_text = null

  return {
    method: method, path: path, url: url,
    headers: headers, body: body_text, _conn: conn_fd
  }
}

function accept(server_fd) {
  var conn = socket.accept(server_fd)
  return parse_request(conn.socket)
}

function on_request(server_fd, handler) {
  var _accept = function() {
    var conn = socket.accept(server_fd)
    var req = null
    var _parse = function() {
      req = parse_request(conn.socket)
    } disruption {
      req = null
    }
    _parse()
    if (req != null) handler(req)
    socket.on_readable(server_fd, _accept)
  }
  socket.on_readable(server_fd, _accept)
}

function respond(conn, status, headers, body) {
  var st = status_texts[text(status)]
  if (st == null) st = "Unknown"
  var out = "HTTP/1.1 " + text(status) + " " + st + CRLF
  out = out + "Connection: close" + CRLF

  var body_str = ""
  var keys = null
  var i = 0
  if (body != null) {
    if (is_text(body)) body_str = body
    else body_str = text(body)
  }

  if (headers != null) {
    keys = array(headers)
    i = 0
    while (i < length(keys)) {
      out = out + keys[i] + ": " + headers[keys[i]] + CRLF
      i = i + 1
    }
  }

  out = out + "Content-Length: " + text(length(body_str)) + CRLF
  out = out + CRLF + body_str

  socket.send(conn, out)
  socket.close(conn)
}

function sse_open(conn, headers) {
  var out = "HTTP/1.1 200 OK" + CRLF
  out = out + "Content-Type: text/event-stream" + CRLF
  out = out + "Cache-Control: no-cache" + CRLF
  out = out + "Connection: keep-alive" + CRLF
  var keys = null
  var i = 0
  if (headers != null) {
    keys = array(headers)
    i = 0
    while (i < length(keys)) {
      out = out + keys[i] + ": " + headers[keys[i]] + CRLF
      i = i + 1
    }
  }
  out = out + CRLF
  socket.send(conn, out)
}

function sse_event(conn, event, data) {
  var frame = "event: " + event + "\ndata: " + data + "\n\n"
  var ok = true
  var _send = function() {
    socket.send(conn, frame)
  } disruption {
    ok = false
  }
  _send()
  return ok
}

function sse_close(conn) {
  socket.close(conn)
}

function close(fd) {
  socket.close(fd)
}

return {
  serve: serve, accept: accept, on_request: on_request,
  respond: respond,
  sse_open: sse_open, sse_event: sse_event, sse_close: sse_close,
  close: close, fetch: c_http.fetch
}