package main

import (
  "fmt"
  "strings"
  "net/http"
  "io/ioutil"
)

func main() {

  url := "https://api.swep.net/graphql"
  method := "POST"

  payload := strings.NewReader(`{`+"
"+`
  "query": "query Calculate() {\r\n  calculateSinglePhase(request: {\r\n    inputs: {\r\n      calculationMethod: DESIGN,\r\n      selectedFluidSide1: {\r\n        fluidId: 53,\r\n        isGas: false,\r\n        inputValue: null\r\n      },\r\n      selectedFluidSide2: {\r\n        fluidId: 53,\r\n        isGas: false,\r\n        inputValue: null\r\n      },\r\n      coCurrent: false,\r\n      selectedHeatExchangers: [\r\n        {\r\n          heatExchangerInputType: PARENT,\r\n          id: 1\r\n        }\r\n      ],\r\n      heatLoad: {\r\n        amount: 50,\r\n        unit: KILOWATT\r\n      },\r\n      inletTemperatureSide1: {\r\n        amount: 80,\r\n        unit: DEGREE_CELSIUS\r\n      },\r\n      inletTemperatureSide2: {\r\n        amount: 20,\r\n        unit: DEGREE_CELSIUS\r\n      },\r\n      outletTemperatureSide1: {\r\n        amount: 40,\r\n        unit: DEGREE_CELSIUS\r\n      },\r\n      outletTemperatureSide2: {\r\n        amount: 50,\r\n        unit: DEGREE_CELSIUS\r\n      },\r\n      flowSide1: null,\r\n      flowSide2: null,\r\n      maxPressureDropSide1: {\r\n        amount: 20000,\r\n        unit: PASCAL\r\n      },\r\n      maxPressureDropSide2: {\r\n        amount: 20000,\r\n        unit: PASCAL\r\n      },\r\n      numberOfPasses: null,\r\n      numberOfPlates: null,\r\n      numberOfPlatesStack1: null,\r\n      numberOfPlatesStack2: null,\r\n      oversurface: null,\r\n      portSwitch: true,\r\n      autoperformance: false\r\n    }\r\n  }) {\r\n  res : calculationResult {\r\n    hesNewName : calculatedHeatExchangers  {\r\n      he :calculatedHeatExchanger {\r\n        modelName,\r\n        xpc {\r\n          class, type, size, material, subtype, execution, pressure\r\n        }\r\n      },\r\n      out:calculationOutputValues {\r\n        pressureDropSide2 {\r\n          amount\r\n        },\r\n        pressureDropSide1 {\r\n          amount\r\n        },\r\n        overSurface {\r\n          amount\r\n        },\r\n        portDiameter1 {\r\n          amount\r\n        }\r\n      }\r\n    }\r\n  }\r\n}\r\n}"`+"
"+`
}`)

  client := &http.Client {
  }
  req, err := http.NewRequest(method, url, payload)

  if err != nil {
    fmt.Println(err)
    return
  }
  req.Header.Add("x-api-key", "YOUR_API_KEY")
  req.Header.Add("Content-Type", "application/json")

  res, err := client.Do(req)
  if err != nil {
    fmt.Println(err)
    return
  }
  defer res.Body.Close()

  body, err := ioutil.ReadAll(res.Body)
  if err != nil {
    fmt.Println(err)
    return
  }
  fmt.Println(string(body))
}