#installing and loading neccessary packages and setting work directory
install.packages("chron")
#setwd("....")
library(chron)
library(base)

rm(list=ls())

#creating 15 minute time points from 10/01/1990 to 08/15/2014
dates = seq.dates("10/01/1990", "08/15/2014", by = "days")
dates = as.character(as.Date(dates, format = "%m/%d/%y"))
daynum = seq(1:length(dates))
times = as.character(times(0:95/96))
Dates = rep(dates, each = length(times))
DayNum = rep(daynum, each = length(times))
Times = rep(times, length(dates))
Times = paste(substr(Times,1,5))
Timepts = paste(Dates, Times, sep="")
Timepts = as.numeric(gsub("-", "", gsub(":", "",Timepts)))

#putting timepts in a data frame
Data = data.frame(DayNum,Dates,Times,Timepts)


#reading IDA from data files
ida.old = read.table("idaold.txt", header = FALSE, sep="", colClasses = "character")
ida.new = read.table("idanew.txt", header = FALSE, sep="", na.strings = "NA", colClasses = "character")


#putting IDA timepts in same format as "Data"
#old
Ida.Old = cbind(paste(substr(ida.old[,1],1,12)), ida.old[,2])
#new
gsub1 = gsub("-", "", paste(ida.new[,1],ida.new[,2]))
gsub1 = gsub(" ", "", gsub1)
gsub1 = gsub(":", "", gsub1)
Ida.New = cbind(paste(gsub1), ida.new[,3])


#merging the two IDA data
last = Ida.Old[nrow(Ida.Old),1]
start = as.numeric(which(Ida.New[,1]==last)) + 1
Ida.New = Ida.New[start:nrow(Ida.New),]

Ida = rbind(Ida.Old, Ida.New)
IDA = cbind(as.numeric(Ida[,1]), as.numeric(Ida[,2]))

#writing a file to put readings of river flow in appropriate order
#note that it takes a while to write this file ("cfs.txt")
cfs = rep("NA", nrow(Data))
for(i in 1:nrow(Data)){
  p = which(Data[,4]==IDA[i,1])
  cfs[p] = IDA[i,2]
}
write(cfs, "cfs.txt")


#writing in a ready to use data form - "Data.txt"
cfs = read.table("cfs.txt", header = FALSE)
Data = cbind(Data,cfs)
names(Data) = c("DayNum","Dates","Times","Timepts","cfs")

write.table(Data, "Data.txt", sep="\t")