##SCRAPING KNMI DATA 

###
### knmi.info - information on KNMI moels scraped from webpage in early 2009
###
### download_html - utility function to read webpages
###
### read.knmi.models - function to read KNMI model data. Requires
###   field - "tas" is the field name for temperature. Only one tested so far 
###   model - use alias nomenclature from knmi.info.
###   scenario- use nomenclature from knmi.info. "20c3m" and "sresa1b" are examples. Radio "SCenario Runs" for nomenclature.
###   landtype - default is all. Can be "land" or "sea" 
###   lat - south to north. default c(-90,90)
###   long - 0 to 360. default c(0,360) 
###   version - default is anomaly. "centigrade" gets Centigrade
###   Info - requires knmi.info 
###
### get.knmi - function to read observation data. Just beginning on this. 

knmi.info=read.csv("http://www.climateaudit.org/data/models/knmi/knmi.info.csv",sep="\t",header=TRUE)

download_html =function(url) {
	download.file(url, "temp.html");
	html_handle <- file("temp.html", "rt");
	html_data <- readLines(html_handle);
	close(html_handle);
	unlink("temp.html");
	return(html_data);
  }


read.knmi.models=function(field, model,scenario,landtype="",lat=c(-90,90),
		long=c(0,360), suffix= "&standardunits=true",email=Email,version="anomaly", method="default",Info=knmi.info) {
    #construct cgi call  
	prefix=paste("http://climexp.knmi.nl/get_index.cgi?email=",email,sep="")
	suffix=paste(suffix,"&lat1=",lat[1],"&lat2=",lat[2],"&lon1=",long[1],"&lon2=",long[2],sep="")
	nruns= Info[Info$scenario==scenario&Info$alias==model,"runs"]; #2
	url= paste(prefix,"&field=",field,"_",model,"_",scenario,"&",suffix,sep="")
	if( !(landtype=="")) url=paste(url,"&masktype=",landtype,sep="");url
    #ping KNMI to retrieve data using above call
	my_info=download_html(url)
	  #my_info[grep("raw data",my_info)]
 #option for anomaly data
   #paste the location of the raw data file (anomaly)
   if (version=="anomaly") {
	rawdata_call= my_info[grep("raw data",my_info)][3]; #y
	n=nchar(rawdata_call)
	   #suffix2=paste(long[1],"-",long[2],"E_",lat[1],"-",lat[2],"N",sep="")
   	if(nruns==1) nruncall="a" else nruncall="__++a"
 	loc=paste("http://climexp.knmi.nl/",substr(rawdata_call,10,n-16) ,sep="") ; #loc
	Sys.sleep(2)
      #retrieve the data
     	test=readLines(loc);test[1:5]
      #extract the model runs in time series form from the data: ncol=1 and ncol>1 
	index=grep("ensemble",test) #   1 1817 3633 5449 7265
	K=length(index);
	if(K>0) { index=c(index,length(test)+1)
	 writeLines(substr(test,1,24),"temp.dat")
	 test=NULL
	 for (i in 1:K) {
	  working=read.table("temp.dat",skip=index[i]+1,nrow= (index[i+1]-2)-(index[i]+1) ) ; 
	  test=ts.union(test,ts(working[,2],start=c(floor(working[1,1]),round( 12* (working[1,1]%%1),0)+1),freq=12))
	  }
	dimnames(test)[[2]]=1:K
	read.knmi.models=test} else {
 	  writeLines(substr(test,1,24),"temp.dat")
	  working=read.table("temp.dat",nrow= length(test)-2) ; 
	  read.knmi.models= ts(as.matrix(working[,2]),start=c(floor(working[1,1]),round( 12* (working[1,1]%%1),0)+1),freq=12)
	   }
	if(method=="verbose") read.knmi.models=list(data=read.knmi.models,info=list(field=field,model=as.character(model),scenario=scenario,region=region,loc=loc) )
  } #end anomaly version
  if (version=="centigrade") {
	latcall=paste(long[1],"-",long[2],"E_",lat[1],"-",lat[2],"N",sep="")
	working=NULL
	for (j in 1:nruns) {
	  loc=paste("http://climexp.knmi.nl/data/i",field,"_",model,"_",scenario,"_",latcall,"_","n","_",numbertochar(j-1),".dat",sep="" )
	    #test=readLines(loc)
	  test=  read.fwf(loc,widths=c(5,10,rep(14,11) ),skip=5 )
	  working=ts.union(working, ts( c(t( test[,2:13])),start=test[1,1],freq=12) )
	}
	dimnames(working)[[2]]=1:nruns
	read.knmi.models=working
   } #end non-anomaly version  
read.knmi.models
}


numbertochar=function(x) {if(x<10) paste ("0",x,sep="") else paste(x) } 


get.knmi=function(field,long=c(0,360),lat=c(-90,90),email=Email) { 
	prefix= paste("http://climexp.knmi.nl/get_index.cgi?email=",email,sep="")
	fieldfix=paste("field",field,sep="=")
	suffix="standardunits=true"
	latfix= paste("lat1=",lat[1],"&lat2=",lat[2],"&lon1=",long[1],"&lon2=",long[2],sep="") # 0 to 360 longitude
   #logon
 	logon=download_html( paste("http://climexp.knmi.nl/start.cgi?",email,sep=""))
   #ping data
	url=paste(prefix,fieldfix,suffix,latfix,sep="&")
 	my_info=download_html(url)
	   #my_info[grep("raw data",my_info)] # my_info[grep("raw data",my_info)][3];
   	Sys.sleep(4)
    #retrieve data
	latcall= paste(long[1],"-",long[2],"E_",lat[1],"-",lat[2],"N",sep="")
	loc=paste(  paste("http://climexp.knmi.nl/data/i",field,sep=""), latcall,"na.txt",sep="_");loc
	test=read.fwf(loc,widths=c(10,14))
	test=test[!is.na(test[,1]),]
	get.knmi=ts( test[,2],start=test[1,1],freq=12)
	#if(method="verbose") get.knmi=list(data=ts( test[,2],start=test[1,1],freq=12),loc=loc)
	get.knmi
 }