// output static file as base64 string
//   image must exist as file in /static
func imagefileAsBase64(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	c := appengine.NewContext(r)

	p := r.FormValue("p")
	if p == "" {
		p = "static/chartbg_400x960__480x1040__12x10.png"
	}

	f, err := os.Open(p)
	loghttp.E(w, r, err, false)
	defer f.Close()

	img, whichFormat, err := image.Decode(f)
	loghttp.E(w, r, err, false)
	aelog.Infof(c, "format %v - subtype %T\n", whichFormat, img)

	imgRGBA, ok := img.(*image.RGBA)
	loghttp.E(w, r, ok, true, "source image was not convertible to image.RGBA - gifs or jpeg?")

	// => header with mime prefix always prepended
	//   and its always image/PNG
	str_b64 := conv.Rgba_img_to_base64_str(imgRGBA)

	w.Header().Set("Content-Type", "text/html")
	io.WriteString(w, "<p>Image embedded in HTML as Base64:</p><img width=200px src=\"")
	io.WriteString(w, str_b64)
	io.WriteString(w, "\"> ")

}

func SaveEntry(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	contnt, ok := m["content"].(string)
	loghttp.E(w, r, ok, false, "need a key 'content' with a string")

	c := appengine.NewContext(r)

	g := GbsaveEntry{
		Content:           contnt,
		Date:              time.Now(),
		TypeShiftingField: 2,
	}
	if u := user.Current(c); u != nil {
		g.Author = u.String()
	}
	g.Comment1 = "comment"

	/* We set the same parent key on every GB entry entity
	   to ensure each GB entry is in the same entity group.

	   Queries across the single entity group will be consistent.
	   However, we should limit write rate to single entity group ~1/sec.

		NewIncompleteKey(appengine.Context, kind string , parent *Key)
			has neither a string key, nor an integer key
		 	only a "kind" (classname) and a parent
		Upon usage the datastore generates an integer key
	*/

	incomplete := ds.NewIncompleteKey(c, GbEntryKind, keyParent(c))
	concreteNewKey, err := ds.Put(c, incomplete, &g)
	loghttp.E(w, r, err, false)
	_ = concreteNewKey // we query entries via keyParent - via parent

}

func makeRequest(w http.ResponseWriter, r *http.Request, path string) CGI_Result {

	c := appengine.NewContext(r)
	client := urlfetch.Client(c)

	url_exe := spf(`http://%s%s%s&ts=%s`, dns_cam, path, credentials, urlParamTS())
	url_dis := spf(`http://%s%s&ts=%s`, dns_cam, path, urlParamTS())
	wpf(w, "<div style='font-size:10px; line-height:11px;'>requesting %v<br></div>\n", url_dis)
	resp1, err := client.Get(url_exe)
	loghttp.E(w, r, err, false)

	bcont, err := ioutil.ReadAll(resp1.Body)
	defer resp1.Body.Close()
	loghttp.E(w, r, err, false)

	cgiRes := CGI_Result{}
	xmlerr := xml.Unmarshal(bcont, &cgiRes)
	loghttp.E(w, r, xmlerr, false)

	if cgiRes.Result != "0" {
		wpf(w, "<b>RESPONSE shows bad mood:</b><br>\n")
		psXml := stringspb.IndentedDump(cgiRes)
		dis := strings.Trim(psXml, "{}")
		wpf(w, "<pre style='font-size:10px;line-height:11px;'>%v</pre>", dis)
	}

	if debug {
		scont := string(bcont)
		wpf(w, "<pre style='font-size:10px;line-height:11px;'>%v</pre>", scont)
	}

	return cgiRes

}

// m contains defaults or overwritten template contents
func templatesExtend(w http.ResponseWriter, r *http.Request, subtemplates map[string]string) *tt.Template {

	var err error = nil
	tder := cloneFromBase(w, r)

	//for k,v := range furtherDefinitions{
	//	tder, err = tder.Parse( `{{define "` + k  +`"}}`   + v + `{{end}}` )
	//	loghttp.E(w,r,err,false)
	//}

	for k, v := range subtemplates {

		if len(v) > lenLff && v[0:lenLff] == PrefixLff {
			fileName := v[lenLff:]
			fcontent, err := ioutil.ReadFile("templates/" + fileName + ".html")
			loghttp.E(w, r, err, false, "could not open static template file")
			v = string(fcontent)
		}

		tder, err = tder.Parse(`{{define "` + k + `"}}` + v + `{{end}}`)
		loghttp.E(w, r, err, false)

	}

	return tder
}

func submitUpload(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	c := appengine.NewContext(r)
	uploadURL, err := blobstore.UploadURL(c, "/blob2/processing-new-upload", nil)
	loghttp.E(w, r, err, false)

	w.Header().Set("Content-type", "text/html; charset=utf-8")
	err = upload2.Execute(w, uploadURL)
	loghttp.E(w, r, err, false)
}

func ListEntries(w http.ResponseWriter,
	r *http.Request) (gbEntries []GbEntryRetr, report string) {

	c := appengine.NewContext(r)
	/* High Replication Datastore:
	Ancestor queries are strongly consistent.
	Queries spanning MULTIPLE entity groups are EVENTUALLY consistent.
	If .Ancestor was omitted from this query, there would be slight chance
	that recent GB entry would not show up in a query.
	*/
	q := ds.NewQuery(GbEntryKind).Ancestor(keyParent(c)).Order("-Date").Limit(10)
	gbEntries = make([]GbEntryRetr, 0, 10)
	keys, err := q.GetAll(c, &gbEntries)

	if fmt.Sprintf("%T", err) == fmt.Sprintf("%T", new(ds.ErrFieldMismatch)) {
		//s := fmt.Sprintf("%v %T  vs %v %T <br>\n",err,err,ds.ErrFieldMismatch{},ds.ErrFieldMismatch{})
		loghttp.E(w, r, err, true)
		err = nil // ignore this one - it's caused by our deliberate differences between gbsaveEntry and gbEntrieRetr
	}
	loghttp.E(w, r, err, false)

	// for investigative purposes,
	// we
	var b1 bytes.Buffer
	var sw string
	var descrip []string = []string{"class", "path", "key_int_guestbk"}
	for i0, v0 := range keys {
		sKey := fmt.Sprintf("%v", v0)
		v1 := strings.Split(sKey, ",")
		sw = fmt.Sprintf("key %v", i0)
		b1.WriteString(sw)
		for i2, v2 := range v1 {
			d := descrip[i2]
			sw = fmt.Sprintf(" \t %v:  %q ", d, v2)
			b1.WriteString(sw)
		}
		b1.WriteString("\n")
	}
	report = b1.String()

	for _, gbe := range gbEntries {
		s := gbe.Comment1
		if len(s) > 0 {
			if pos := strings.Index(s, "0300"); pos > 1 {
				i1 := util.Max(pos-4, 0)
				i2 := util.Min(pos+24, len(s))
				s1 := s[i1:i2]
				s1 = strings.Replace(s1, "3", "E", -1)
				report = fmt.Sprintf("%v -%v", report, s1)
			}
		}
	}

	return
}

func templatesCompileDemo(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	w.Header().Set("Content-Type", "text/html")

	funcMap := tt.FuncMap{
		"unescape": html.UnescapeString,
		"escape":   html.EscapeString,
	}

	var t_base *tt.Template
	var err error = nil

	// creating T0 - naming it - adding func map
	t_base = tt.Must(tt.New("str_T0_outmost").Funcs(funcMap).Parse(T0))
	loghttp.E(w, r, err, false)

	// adding the definition of T1 - introducing reference to T2 - undefined yet
	t_base, err = t_base.Parse(T1) // definitions must appear at top level - but not at the start
	loghttp.E(w, r, err, false)

	// create two clones
	// now both containing T0 and T1
	tc_1, err := t_base.Clone()
	loghttp.E(w, r, err, false)
	tc_2, err := t_base.Clone()
	loghttp.E(w, r, err, false)

	// adding different T2 definitions
	s_if := "{{if .}}{{.}}{{else}}no dyn data{{end}}"
	tc_1, err = tc_1.Parse("{{define `T2`}}T2-A  <br>--" + s_if + "--  {{end}}")
	loghttp.E(w, r, err, false)
	tc_2, err = tc_2.Parse("{{define `T2`}}T2-B  <br>--" + s_if + "--  {{end}}")
	loghttp.E(w, r, err, false)

	// writing both clones to the response writer
	err = tc_1.ExecuteTemplate(w, "str_T0_outmost", nil)
	loghttp.E(w, r, err, false)

	// second clone is written with dynamic data on two levels
	dyndata := map[string]string{"key1": "dyn val 1", "key2": "dyn val 2"}
	err = tc_2.ExecuteTemplate(w, "str_T0_outmost", dyndata)
	loghttp.E(w, r, err, false)

	// Note: it is important to pass the DOT
	//		 {{template "T1" .}}
	//		 {{template "T2" .key2 }}
	//						 ^
	// otherwise "dyndata" can not be accessed by the inner templates...

	// leaving T2 undefined => error
	tc_3, err := t_base.Clone()
	loghttp.E(w, r, err, false)
	err = tc_3.ExecuteTemplate(w, "str_T0_outmost", dyndata)
	// NOT logging the error:
	// loghttp.E(w, r, err, false)

}

// a clone factory
//  as t_base is a "app scope" variable
//  it will live as long as the application runs
func cloneFromBase(w http.ResponseWriter, r *http.Request) *tt.Template {

	// use INDEX to access certain elements
	funcMap := tt.FuncMap{
		"unescape":   html.UnescapeString,
		"escape":     html.EscapeString,
		"fMult":      fMult,
		"fAdd":       fAdd,
		"fChop":      fChop,
		"fMakeRange": fMakeRange,
		"fNumCols":   fNumCols,
		"df": func(g time.Time) string {
			return g.Format("2006-01-02 (Jan 02)")
		},
	}

	if t_base == nil {
		t_base = tt.Must(tt.New("n_page_scaffold_01").Funcs(funcMap).Parse(c_page_scaffold_01))
	}

	t_derived, err := t_base.Clone()
	loghttp.E(w, r, err, false)

	return t_derived
}

func emailSend(w http.ResponseWriter, r *http.Request, m map[string]string) {

	c := appengine.NewContext(r)
	//addr := r.FormValue("email")

	if _, ok := m["subject"]; !ok {
		m["subject"] = "empty subject line"
	}

	email_thread_id := []string{"3223"}

	msg := &ae_mail.Message{
		//Sender:  "Peter Buchmann <[email protected]",
		//		Sender: "[email protected]",
		Sender: "[email protected]",
		//To:	   []string{addr},
		To: []string{"[email protected]"},

		Subject: m["subject"],
		Body:    "some_body some_body2",
		Headers: go_mail.Header{"References": email_thread_id},
	}
	err := ae_mail.Send(c, msg)
	loghttp.E(w, r, err, false, "could not send the email")

}

func imgServingExample3(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	c := appengine.NewContext(r)

	p := r.FormValue("p")
	if p == "" {
		p = "static/chartbg_400x960__480x1040__12x10.png"
	}
	if p == "" {
		p = "static/pberg1.png"
	}
	// try p=static/unmodifiable_format.jpg

	// prepare a cutout rect
	var p1, p2 image.Point
	p1.X, p1.Y = 10, 60
	p2.X, p2.Y = 400, 255
	var rec image.Rectangle = image.Rectangle{Min: p1, Max: p2}

	f, err := os.Open(p)
	loghttp.E(w, r, err, false)
	defer f.Close()

	img, whichFormat, err := image.Decode(f)
	loghttp.E(w, r, err, false, "only jpeg and png are 'activated' ")
	c.Infof("serving format %v %T\n", whichFormat, img)

	switch t := img.(type) {

	default:
		loghttp.E(w, r, false, false, "internal color formats image.YCbCr and image.RGBA are understood")

	case *image.RGBA, *image.YCbCr:
		imgXFull, ok := t.(*image.RGBA)
		loghttp.E(w, r, ok, false, "image.YCbCr can not be typed to image.RGBA - this will panic")

		imgXCutout, ok := imgXFull.SubImage(rec).(*image.RGBA)
		loghttp.E(w, r, ok, false, "cutout operation failed")

		// we serve it as JPEG
		w.Header().Set("Content-Type", "image/jpeg")
		jpeg.Encode(w, imgXCutout, &jpeg.Options{Quality: jpeg.DefaultQuality})

	}

}

func GetChartDataFromDatastore(w http.ResponseWriter, r *http.Request, key string) *CData {

	c := appengine.NewContext(r)

	key_combi := "dsu.WrapBlob__" + key

	dsObj, err := dsu.BufGet(c, key_combi)
	loghttp.E(w, r, err, false)

	serializedStruct := bytes.NewBuffer(dsObj.VByte)
	dec := gob.NewDecoder(serializedStruct)
	newCData := new(CData) // hell, it was set to nil above - causing this "unassignable value" error
	err = dec.Decode(newCData)
	loghttp.E(w, r, err, false, "VByte was ", dsObj.VByte[:10])

	return newCData
}

func call(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	// params trial: https://www.twilio.com/user/account/developer-tools/api-explorer/call-create
	// params docu:  https://www.twilio.com/docs/api/rest/making-calls
	v := url.Values{}
	v.Set("To", phoneTo)
	v.Set("From", phoneFrom)
	v.Set("Url", callbackUrl)
	v.Set("Method", "GET")
	v.Set("FallbackMethod", "GET")
	v.Set("StatusCallbackMethod", "GET")
	// v.Set("SendDigits", "32168")
	v.Set("Timeout", "4")
	v.Set("Record", "false")
	rb := *strings.NewReader(v.Encode())

	// Create Client
	// client := &http.Client{}  // local, not on appengine

	c := appengine.NewContext(r)
	// following appengine method, derived from big-query is non working:
	// config := oauth2_google.NewAppEngineConfig(c, []string{twilioURLPrefix})
	// client := &http.Client{Transport: config.NewTransport()}
	clientClassic := urlfetch.Client(c)
	//clientTwilio := twilio.NewClient(accountSid, authToken, clientClassic)  // not needed

	req, _ := http.NewRequest("POST", twilioFullURL, &rb)
	req.SetBasicAuth(accountSid, authToken)
	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")

	resp, err := clientClassic.Do(req)
	loghttp.E(w, r, err, false, "something wrong with the http client")

	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
		var data map[string]interface{}
		bodyBytes, _ := ioutil.ReadAll(resp.Body)
		err := json.Unmarshal(bodyBytes, &data)
		if err == nil {
			fmt.Println(data["sid"])
		}
		fmt.Fprintf(w, "%#v", resp)
	} else {
		loghttp.E(w, r, err, false, "twilio response not ok", resp.Status)
	}
}

func GetImageFromDatastore(w http.ResponseWriter, r *http.Request, key string) *image.RGBA {

	c := appengine.NewContext(r)

	dsObj, err := dsu.BufGet(c, "dsu.WrapBlob__"+key)
	loghttp.E(w, r, err, false)

	s := string(dsObj.VByte)

	img, whichFormat := conv.Base64_str_to_img(s)
	aelog.Infof(c, "retrieved img from base64: format %v - subtype %T\n", whichFormat, img)

	i, ok := img.(*image.RGBA)
	loghttp.E(w, r, ok, false, "saved image needs to be reconstructible into a format png of subtype *image.RGBA")

	return i
}

func SaveChartDataToDatastore(w http.ResponseWriter, r *http.Request, cd CData, key string) string {

	c := appengine.NewContext(r)

	internalType := fmt.Sprintf("%T", cd)
	//buffBytes, _	 := StringToVByte(s)  // instead of []byte(s)

	// CData to []byte
	serializedStruct := new(bytes.Buffer)
	enc := gob.NewEncoder(serializedStruct)
	err := enc.Encode(cd)
	loghttp.E(w, r, err, false)

	key_combi, err := dsu.BufPut(c,
		dsu.WrapBlob{Name: key, VByte: serializedStruct.Bytes(), S: internalType}, key)
	loghttp.E(w, r, err, false)

	return key_combi
}

func imgServingExample1(w http.ResponseWriter, r *http.Request) {

	c := appengine.NewContext(r)

	p := r.FormValue("p")
	if p == "" {
		p = "static/chartbg_400x960__480x1040__12x10.png"
	}
	if p == "" {
		p = "static/pberg1.png"
	}

	f, err := os.Open(p)
	loghttp.E(w, r, err, false)
	defer f.Close()

	mode := r.FormValue("mode")
	if mode == "" {
		mode = "direct"
	}

	if mode == "direct" {

		// file reader directly to http writer

		w.Header().Set("Content-Type", "image/png")
		c.Infof("serving directly %v \n", p)
		io.Copy(w, f)

	} else {

		// file to memory image - memory image to http writer

		img, whichFormat, err := image.Decode(f)
		loghttp.E(w, r, err, false)
		c.Infof("serving as memory image %v - format %v - type %T\n", p, whichFormat, img)

		// initially a png - we now encode it to jpg
		w.Header().Set("Content-Type", "image/jpeg")
		jpeg.Encode(w, img, &jpeg.Options{Quality: jpeg.DefaultQuality})
	}

}

func SaveImageToDatastore(w http.ResponseWriter, r *http.Request, i *image.RGBA, key string) string {

	c := appengine.NewContext(r)

	s := conv.Rgba_img_to_base64_str(i)
	internalType := fmt.Sprintf("%T", i)
	//buffBytes, _     := StringToVByte(s)  // instead of []byte(s)
	key_combi, err := dsu.BufPut(c, dsu.WrapBlob{Name: key, VByte: []byte(s), S: internalType}, key)
	loghttp.E(w, r, err, false)

	return key_combi

}

func saveURLWithAncestor(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	c := appengine.NewContext(r)

	k := ds.NewKey(c, kindUrl, "", 0, ancKey(c))

	s := util.TimeMarker()
	ls := len(s)
	lc := len("09-26 17:29:25")
	lastURL_fictitious_1 := LastURL{"with_anc " + s[ls-lc:ls-3]}
	_, err := ds.Put(c, k, &lastURL_fictitious_1)
	loghttp.E(w, r, err, false)

}

// saving some data by kind and key
//   without ancestor key
func saveURLNoAnc(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	c := appengine.NewContext(r)

	k := ds.NewKey(c, kindUrl, keyUrl, 0, nil)
	e := new(LastURL)
	err := ds.Get(c, k, e)
	if err == ds.ErrNoSuchEntity {
		c.Errorf("%v", err)
	} else {
		loghttp.E(w, r, err, false)
	}

	old := e.Value
	e.Value = r.URL.Path + r.URL.RawQuery

	_, err = ds.Put(c, k, e)
	loghttp.E(w, r, err, false)

	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
	w.Write([]byte("old=" + old + "\n"))
	w.Write([]byte("new=" + e.Value + "\n"))

}

func serveThumb(w http.ResponseWriter, r *http.Request, m map[string]interface{}) {

	c := appengine.NewContext(r)

	// c := appengine.NewContext(r)
	k := appengine.BlobKey(r.FormValue("blobkey"))

	var o image.ServingURLOptions = *new(image.ServingURLOptions)
	o.Size = 200
	o.Crop = true
	url, err := image.ServingURL(c, k, &o)

	loghttp.E(w, r, err, false)

	http.Redirect(w, r, url.String(), http.StatusFound)
}

func FuncTplBuilder(w http.ResponseWriter, r *http.Request) (f1 func(string, string, interface{}),
	f2 func(http.ResponseWriter, *http.Request)) {

	// prepare collections
	mtc := map[string]string{}      // map template content
	mtd := map[string]interface{}{} // map template data

	// template key - template content, template data
	f1 = func(tk string, tc string, td interface{}) {
		mtc[tk] = tc
		mtd[tk] = td
	}

	f2 = func(w http.ResponseWriter, r *http.Request) {

		// merge arguments with defaults
		map_result := map[string]string{}
		for k, v := range map_default {
			if _, ok := mtc[k]; ok {
				map_result[k] = mtc[k]
				delete(mtc, k)
			} else {
				map_result[k] = v
			}
			if dbg {
				w.Write([]byte(fmt.Sprintf("  %q  %q \n", map_result[k], v)))
			}
		}

		// additional templates beyond the default
		for k, v := range mtc {
			map_result[k] = v
			if dbg {
				w.Write([]byte(fmt.Sprintf("  %q  %q \n", map_result[k], v)))
			}
		}

		tpl_extended := templatesExtend(w, r, map_result)

		err := tpl_extended.ExecuteTemplate(w, "n_page_scaffold_01", mtd)
		loghttp.E(w, r, err, false)

	}

	return f1, f2
}