import jsbind

type XMLHTTPRequest* = ref object of JSObj # Define the type. JSObj should be the root class for such types.

proc newXMLHTTPRequest*(): XMLHTTPRequest {.jsimportgWithName: "function(){return (window.XMLHttpRequest)?new XMLHttpRequest():new ActiveXObject('Microsoft.XMLHTTP')}".}

proc open*(r: XMLHTTPRequest, httpMethod, url: cstring) {.jsimport.}
proc send*(r: XMLHTTPRequest) {.jsimport.}
proc send*(r: XMLHTTPRequest, body: cstring) {.jsimport.}

proc addEventListener*(r: XMLHTTPRequest, event: cstring, listener: proc()) {.jsimport.}
proc setRequestHeader*(r: XMLHTTPRequest, header, value: cstring) {.jsimport.}

proc responseText*(r: XMLHTTPRequest): jsstring {.jsimportProp.}
proc statusText*(r: XMLHTTPRequest): jsstring {.jsimportProp.}

proc `responseType=`*(r: XMLHTTPRequest, t: cstring) {.jsimportProp.}
proc response*(r: XMLHTTPRequest): JSObj {.jsimportProp.}

proc sendRequest*(meth, url, body: string, headers: openarray[(string, string)], handler: Handler) =
    let oReq = newXMLHTTPRequest()
    var reqListener: proc()
    reqListener = proc () =
        jsUnref(reqListener)
        handler(($oReq.statusText,  $oReq.responseText))
    jsRef(reqListener)
    oReq.responseType = "text"
    oReq.addEventListener("load", reqListener)
    oReq.open(meth, url)
    for h in headers:
        oReq.setRequestHeader(h[0], h[1])
    if body.isNil:
        oReq.send()
    else:
        oReq.send(body)

import jsbind.emscripten
proc foo() {.EMSCRIPTEN_KEEPALIVE.} = # now it's possible to call this function from JS
  discard EM_ASM_INT("""
  alert("hello, world!");
  """) # Use EM_ASM_* like you would do it in C