var assetTable = ee.FeatureCollection('DOallGCB');
var maskEmptyPixels = function(image) {
  var withObs = image.select('num_observations_1km').gt(0)
  return image.updateMask(withObs)
}
 
var names = assetTable.map(function(feature){
  var point = ee.Geometry.Point(ee.Number.parse(feature.get('Lon')), ee.Number.parse(feature.get('Lat')));
  var time = ee.Date(feature.get('Date'));
  //var valu=feature.get('Value');
  var id=ee.Number(feature.get('ID'));

  var collection = ee.ImageCollection('MODIS/061/MYD09GA')
                      .filterBounds(point)
                      .filterDate(time.advance(-0, 'day'), time.advance(1, 'day'))
                      .map(maskEmptyPixels)
                      .map(maskClouds);

  var collection2=ee.ImageCollection('MODIS/061/MYD11A1')
                      .filterBounds(point)
                      .filterDate(time.advance(-0, 'day'), time.advance(1, 'day'))
  
  var era5Filtered = ee.ImageCollection('ECMWF/ERA5_LAND/HOURLY')
                //.filter(ee.Filter.date('2020-07-01', '2020-07-02'))
                .filter(ee.Filter.date(time.advance(-0, 'hour'), time.advance(1, 'hour')))
                .select('surface_solar_radiation_downwards_hourly');

  if (collection === null) {
    print("No images found for feature:", feature.get('ID'));
    return feature;
  }

  else{
  var imageMean = collection.median();
  var imageMean2=collection.median();
  var imageMean3=era5Filtered.median();
  var reflectance = imageMean.reduceRegion({
    reducer: ee.Reducer.mean(),
    geometry: point,
    scale: 10
  });
    var reflectance2 = imageMean2.reduceRegion({
    reducer: ee.Reducer.mean(),
    geometry: point,
    scale: 10
  });
  var reflectance3 = imageMean3.reduceRegion({
    reducer: ee.Reducer.mean(),
    geometry: point,
    scale: 10
  });
  
   feature = feature.set(reflectance);
   feature = feature.set(reflectance2);
   feature = feature.set(reflectance3);
   feature=feature.set('time',time);
   
  //return feature.get('name');
   return feature;
  }
}
)

print('Feature :', names);


// Define the properties to include in the exported table
var exportProperties = {
  'ID':'string',
  'sur_refl_b01': 'float',
  'sur_refl_b02': 'float',
  'sur_refl_b03': 'float',
  'sur_refl_b04': 'float',
  'sur_refl_b05': 'float',
  'sur_refl_b06': 'float',
  'sur_refl_b07':'float',
  'LST_Day_1km':'int16',
  'surface_solar_radiation_downwards_sum':'float',
  'Date':'string',
  'DO':'float',
  //'DateStr':'string',
  'Lon':'string',
  'Lat':'string'
};

//print(joinedFcMapped);
// Export the joined FeatureCollection to a CSV file
Export.table.toDrive({
  collection: names,
  description: 'joined_table',
  fileFormat: 'CSV',
  selectors: Object.keys(exportProperties)
});



// Define a region of interest as a point.  Change the coordinates
// to get a classification of any place where there is imagery.
var tableera5=ee.FeatureCollection("GCBDOMODISallfac");
var gsw = ee.Image('JRC/GSW1_0/GlobalSurfaceWater');
var Globallakes10km = ee.FeatureCollection('Globallake10km');

var demImage = ee.ImageCollection("projects/sat-io/open-datasets/GLO-30").mean();
//Map.addLayer(demImage);
//var viz = {min:0, max:1000, palette:['ffffff','b7f0ae','21f600','0000FF','FDFF92','FF2700','d600ff']};
var viz = {min:2, max:15, palette:['000000','FF2700','b7f0ae','21f600','0000FF']};
  
var VIS_WATER_MASK = {
  palette: ['Green','Red']
};

var maskEmptyPixels = function(image) {
  var withObs = image.select('num_observations_1km').gt(0);
  return image.updateMask(withObs);
};
//prepare  data in a fised format
function imgmaker1(image){
  var start = image.get('system:time_start');
  var lati = ee.Image.pixelLonLat().select('latitude').rename('Lati').abs();
  var imapro=image.addBands(lati).addBands(demImage,['b1']);
  var b1=imapro.select("surface_solar_radiation_downwards_sum").abs();
  var b2=imapro.select("surface_thermal_radiation_downwards_sum").abs();    
  var b3=imapro.select("surface_pressure").abs();
  var b4=imapro.select("total_precipitation_sum").abs(); 
  var b6=imapro.select("temperature_2m").abs();
  var b7=imapro.select("b1");
  var b8=imapro.select("Lati");
  var b9=imapro.select("u_component_of_wind_10m").abs(); 
  var b10=imapro.select("v_component_of_wind_10m").abs();
  var b5=(b9.pow(2).add(b10.pow(2))).pow(0.5);
  var bred=imapro.select("sur_refl_b01");
  var Nir=imapro.select("sur_refl_b02");
  var bgreen=imapro.select("sur_refl_b04");    
  var bblue=imapro.select("sur_refl_b03");
  var SWIR=imapro.select("sur_refl_b05");
  var FAI=imapro.expression(
    'NIR-RED-(SWIR-RED)*214/595', {
      'RED': imapro.select("sur_refl_b01"),
      'NIR': imapro.select("sur_refl_b02"),
      'SWIR': imapro.select("sur_refl_b05")
});
  //var FAI=Nir.subtract(bred).subtract((SWIR.subtract(bred)).Multiply)
  var Xc=bred.multiply(2.7689).add(bgreen.multiply(1.7517)).add(bblue.multiply(1.1302));
  var Yc=bred.multiply(1.000).add(bgreen.multiply(4.5906)).add(bblue.multiply(0.0601));
  var Zc=bgreen.multiply(0.0565).add(bblue.multiply(5.5943));
  var xx=Xc.divide(Xc.add(Yc).add(Zc));
  var yy=Yc.divide(Xc.add(Yc).add(Zc));
  var aangle=(yy.subtract(0.3333)).atan2(xx.subtract(0.3333)).multiply(180).divide(Math.PI);
  
  var multibands = ee.Image([b1,b2,b3,b4,b5,b6,b7,b8,FAI,aangle]).rename(['SR', 'TR', 'Pres', 'Prec', 'Wind','AT','DEM','Lati','FAI','Acolor']);
  //var multibands2=image.addBands(multibands).copyProperties(image, ['system:time_start']);
  //var namemultibands=multibands.select(['B1','B2','B3','B4','B5','B6','B7','B8','B9','B8_1','B8_2','B2_1','B8_3','B9_1','B9_2'],['B1', 'B2', 'B3', 'B4', 'B5','B6','B7','B8','B9','B10','B11','B12','B13','B14','B15']);
  //return namemultibands.set('system:time_start', start);
  //var namemultibands=multibands.copyProperties(image, ["system:time_start"]);
  return multibands;
}

var exportMonthlyData = function(year, month) {
var startDate = ee.Date.fromYMD(year, month, 1);
var endDate = startDate.advance(1, 'month');
var filteredCollection1 = ee.ImageCollection('ECMWF/ERA5_LAND/DAILY_RAW')
                      .filterDate(startDate, endDate)
                      .map(function(image) {
  var date = ee.Date(image.get('system:time_start')).format("YYYY-MM-dd");
  date = ee.Date(date);
    return image.set('date', date);
  })
  ; 

var filteredCollection2 = ee.ImageCollection('MODIS/061/MYD09GA')
                      //.filterBounds(point)
                      .filterDate(startDate, endDate)
                      .map(maskEmptyPixels)
                      .map(maskClouds).map(function(image) {
  var date = ee.Date(image.get('system:time_start')).format("YYYY-MM-dd");
  date = ee.Date(date);
    return image.set('date', date);
  }); 
  
 var filterTimeEq = ee.Filter.equals({
    leftField: 'date',
    rightField: 'date'
    });

var simpleJoin = ee.Join.inner();
// Apply the join and select all bands from both collections
var joinedCollection = simpleJoin.apply(filteredCollection1, filteredCollection2, filterTimeEq) 
    .map(function (joinedImage) {
    var image1 = ee.Image(joinedImage.get('primary'));
    var image2 = ee.Image(joinedImage.get('secondary'));
    
    // Merge all bands from both images
    var mergedImage = image1.addBands(image2);
    
    return mergedImage;
  });
  
var imageCollection = ee.ImageCollection(joinedCollection);
var DOresult=imageCollection.map(RFpredic1);
//var filteredCollection = MODISpre.filterDate(startDate, endDate);
//var gt0mask = filteredCollection.median().gt(0.0);
var ERA5refDO=DOresult.median().updateMask(water_mask);

  
var meanChinalakes = ERA5refDO.reduceRegions({
  collection: Globallakes10km,
  reducer: ee.Reducer.median().combine({
  reducer2: ee.Reducer.stdDev(),
  sharedInputs: true
  }),
  scale: 500,
  tileScale: 4,
  crs: "EPSG:4326"
}); 
//var FormatMonth=ee.Number(month).format('%02d');
 var fileName='ERA5DO2';
  // Export to CSV
    Export.table.toDrive({  
      description: year + '_'+ month,  
      //fileNamePrefix: year + '_'+ month,  
      collection: meanChinalakes,
      folder:'ERA5DO_RFR5',
      fileFormat: 'CSV',
      selectors:['Hylak_id','median']
  });  
  
};

for (var year = 2002; year <= 2023; year++) {
  for (var month = 1; month <= 12; month++) {
    exportMonthlyData(year, month);
  }
}