Sentinel-2 with cloudy parts replaced by Sentinel-1

// VERSION=3
// SAR data substitution for clouded Sentinel-2 images V1.0.0
// Twitter: Pierre Markuse (@pierre_markuse)
// CC BY 4.0 International - https://creativecommons.org/licenses/by/4.0/

function setup() {
  return {
    input: [
      {
        datasource: "S2L1C",
        bands: ["B02", "B03", "B04", "CLM", "CLP"],
        units: ["REFLECTANCE", "REFLECTANCE", "REFLECTANCE", "DN", "DN"],
        mosaicking: "ORBIT"
      },
      {
        datasource: "S1GRD",
        bands: ["VV", "VH"],
        mosaicking: "ORBIT"
      },
    ],
    output: [
      { id: "default", bands: 3, sampleType: SampleType.AUTO }
    ]
  }
}

function evaluatePixel(samples) {
  var S2L1C = samples.S2L1C[0];
  var S1 = samples.S1GRD[0];
  let WAT = 25; // Water Threshold for SAR
  let CLP = S2L1C.CLP / 2.55; // Cloud Propability
  let CLPT = 70; // Cloud Propabilty Threshold in percent

  if ((CLP > CLPT && S1.VV / S1.VH <= WAT)) {
    return {
      default: [S1.VV * 3.0, S1.VV * 1.1 + S1.VH * 8.75, S1.VH * 1.75]
    }
  }

  if ((CLP > CLPT && S1.VV / S1.VH > WAT)) {
    return {
      default: [S1.VV * 1, S1.VV * 8, 0.5 + S1.VV * 3 + S1.VH * 2000]
    }
  }


  let val = [3 * S2L1C.B04, 3 * S2L1C.B03, 3 * S2L1C.B02];
  return {
    default: val
  }
}