package main

import (
        "fmt"
        "log"
        "time"
        "math"
        "strings"
        "strconv"
        "io/ioutil"
        "net/http"
)

const api_url="https://proxy1.lpn.swisscom.ch/thingpark/lrc/rest"

func MakePost(url string) {
	req, err := http.NewRequest("POST", url, nil)
	if err != nil {
		log.Fatal("Error reading request. ", err)
	}
 
	// Set headers
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 
	// Set client timeout
	client := &http.Client{Timeout: time.Second * 10}
 
	// Send request
	resp, err := client.Do(req)
	if err != nil {
		log.Fatal("Error reading response. ", err)
	}
	defer resp.Body.Close()
 
	fmt.Println("response Status:", resp.Status)
	fmt.Println("response Headers:", resp.Header)
 
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatal("Error reading body. ", err)
	}
 
	fmt.Printf("%s\n", body)
}

func ResetNodeToZero(deveui string, w1_0 int32, w2_0 int32) {
  fmt.Printf("Called ResetNodeToZero for deveui %s\n", deveui)
  valstr := fmt.Sprintf("%08X%08X%08X%08X",uint32(w1_0),uint32(w2_0),0,0)
  s := fmt.Sprintf("%s/downlink?DevEUI=%s&FPort=1&Payload=00%s", api_url, deveui, valstr)
  MakePost(s)
  SetDownlinkCommand(deveui,"do_nothing")
}

func CalibrateScale(deveui string, downlink_command string, w1 int32, w2 int32) {
  fmt.Printf("Called CalibrateScale for deveui %s, downlink_command: %s\n", deveui, downlink_command)
  var cur_cal_settings CalSettings 
  cur_cal_settings = GetCurrentCalibrationSettings(deveui)
  var calibration_weight_gram int32
  var calibration_weight2_gram int32
  tokens := strings.Split(downlink_command," ")
  if (len(tokens) < 2) {
    // no value in gram included!
    fmt.Printf("Error: invalid downlink_command: %s, examples: \"tare_a 10000\", \"tare_b 10000\", \"tare 10000 10000\" devuid: %s\n", downlink_command, deveui)
    return
  }
  n, err := strconv.ParseInt(tokens[1], 10, 32)
  if err == nil {
    calibration_weight_gram = int32(n)
  } else {
    fmt.Printf("Error: cannot get tare weight in gram: %s, deveui: %s\n", downlink_command, deveui)
    return
  }

  if (len(tokens) > 2) {
    n, err := strconv.ParseInt(tokens[2], 10, 32)
    if err == nil {
      calibration_weight2_gram = int32(n)
    } else {
      fmt.Printf("Error: cannot get tare weight2 in gram: %s, deveui: %s\n", downlink_command, deveui)
      return
    }
  }

  if (tokens[0] == "tare_a") {
    new_w1_c := float32(w1 - cur_cal_settings.w1_0) / float32(calibration_weight_gram)
    valstr := fmt.Sprintf("%08X%08X%08X%08X",uint32(cur_cal_settings.w1_0),uint32(cur_cal_settings.w2_0),math.Float32bits(new_w1_c),math.Float32bits(cur_cal_settings.w2_c))
    s := fmt.Sprintf("%s/downlink?DevEUI=%s&FPort=1&Payload=01%s", api_url, deveui, valstr)
    MakePost(s)
    SetDownlinkCommand(deveui,"do_nothing")
  } else if (tokens[0] == "tare_b") {
    new_w2_c := float32(w2 - cur_cal_settings.w2_0) / float32(calibration_weight_gram)
    valstr := fmt.Sprintf("%08X%08X%08X%08X",uint32(cur_cal_settings.w1_0),uint32(cur_cal_settings.w2_0),math.Float32bits(cur_cal_settings.w1_c),math.Float32bits(new_w2_c))
    s := fmt.Sprintf("%s/downlink?DevEUI=%s&FPort=1&Payload=01%s", api_url, deveui, valstr)
    MakePost(s)
    SetDownlinkCommand(deveui,"do_nothing")
  } else if (tokens[0] == "tare") {
    new_w1_c := float32(w1 - cur_cal_settings.w1_0) / float32(calibration_weight_gram)
    new_w2_c := float32(w2 - cur_cal_settings.w2_0) / float32(calibration_weight2_gram)
    valstr := fmt.Sprintf("%08X%08X%08X%08X",uint32(cur_cal_settings.w1_0),uint32(cur_cal_settings.w2_0),math.Float32bits(new_w1_c),math.Float32bits(new_w2_c))
    s := fmt.Sprintf("%s/downlink?DevEUI=%s&FPort=1&Payload=01%s", api_url, deveui, valstr)
    MakePost(s)
    SetDownlinkCommand(deveui,"do_nothing")
  } else {
    fmt.Printf("Error: either use tare_a or tare_b or tare; deveui %s\n", deveui)
  }
}

func UpdateCalibrationSettingsFromNode(deveui string, w1_0 int32, w2_0 int32, w1_c float32, w2_c float32) {
  fmt.Printf("Called UpdateCalibrationSettingsFromNode for deveui %s\n", deveui)
  var cur_cal_settings CalSettings 
  var new_cal_settings CalSettings 

  cur_cal_settings = GetCurrentCalibrationSettings(deveui)

  new_cal_settings.w1_0 = w1_0
  new_cal_settings.w2_0 = w2_0
  new_cal_settings.w1_c = w1_c
  new_cal_settings.w2_c = w2_c

  if ((new_cal_settings.w1_0 != cur_cal_settings.w1_0) ||
      (new_cal_settings.w2_0 != cur_cal_settings.w2_0) ||
      (new_cal_settings.w1_c != cur_cal_settings.w1_c) ||
      (new_cal_settings.w2_c != cur_cal_settings.w2_c)) {
    SetCurrentCalibrationSettings(deveui,new_cal_settings)
    // since something has changed and is reflected in the local config, we don't do anything any more...
    SetDownlinkCommand(deveui,"do_nothing")
  } else {
    fmt.Printf("Info: no change in calibration settings for deveui %s\n", deveui)
  }
}