# Functions for connecting to Civilytics' data sources



# postgresCon <- function(myip){
#   require("RPostgreSQL")
#   require("pool")
#   drv <- dbDriver("PostgreSQL")
#   con <- dbPool(drv, dbname = "crime", host = myip,
#                 port = 5432, user="admin", password = "betterplacemakeworld")
#   return(con)
# }


#' Clean unreported data counts in UCR data
#'
#' @param x a column of data, if character, substitute and conver to numeric
#'
#' @return a numeric column of data
#' @export
countCleanr <- function(x){
  if ("character" %in% class(x)) {
    x[x == "None not reported"] <- "0"
    x[x == "Not applicable"] <- NA
    x <- as.numeric(x)
    return(x)
  } else{
    return(x)
  }
}



#' Find columns in a dataframe that have values with a "."
#'
#' @param data a dataframe
#'
#' @return the names of columns in the dataframe with one or more entries equal to "."
#' @export
findDots <- function(data){
  return(names(data)[lapply(data, countDots) > 0])

}

#' Count the number of single period entries in a vector
#'
#' @param x a character vector
#'
#' @return
#' An integer counting the number of "." occurences in a vector
#' @export
countDots <- function(x){
  len <- length(x[x == "." & !is.na(x)])
  totlen <- length(x)
  return(len)
}


#' Make names safe for inclusion in a database
#'
#' @param names a character vector of possible column or table names
#'
#' @return a vector the same length as the input vector with clean names
#' @export
dbSafeNames <- function(names) {
  names = gsub('[^a-z0-9]+','_',tolower(names))
  names = make.names(names, unique = TRUE, allow_ = TRUE)
  names = gsub('.','_',names, fixed = TRUE)
  names
}

#' Count number of missing values in a vector
#'
#' @param x a vector of values
#'
#' @return an integer equal to the number of NA entries in the vector
#' @export
#'
#' @examples
#' countNA(letters) # = 0
#' countNA(c(letters, NA)) # = 1
countNA <- function(x){
  length(x[is.na(x)])
}


#' Count the number of unique values in a vector
#'
#' @param x a vector of values
#'
#' @return an integer equal to the number of unique values in a vector
#' @export
#'
#' @examples
#' nvals(letters) # = 26
#' nvals(state.abb) # = 50
nvals <- function(x){
  length(unique(x))
}


#' Capitalize a character string after each space
#'
#' @param x a character string
#'
#' @return a vector of characters with all values after a space capitalized
#' @export
#'
#' @examples
#' my_string <- c("Happy school", "Easy school", "cool School", "big school")
#' simpleCap(my_string)
simpleCap <- function(x) {
  stopifnot("character" %in% class(x))

  # Vectorised over elements of x — each element is capitalised independently.
  # unname() strips names inherited from the input vector so the output
  # matches the original scalar behaviour (no names attribute).
  unname(vapply(x, function(word) {
    s <- strsplit(word, " ")[[1]]
    paste(toupper(substring(s, 1, 1)), substring(s, 2),
          sep = "", collapse = " ")
  }, character(1)))
}