pxweb_query.R

#' Create a PXWEB query
#'
#' @description
#' Creates a pxweb query object from either a list with named values,
#' a json query file or json query string. See examples below.
#'
#' @param x an object to cast as a pxweb_query object.
#'
#' @seealso \code{\link{pxweb_query_as_json}}, \code{\link{pxweb_query_as_rcode}}
#'
#' @examples
#' dims <- list(
#'   Alue = c("*"),
#'   "Asuntokunnan koko" = c("*"),
#'   Talotyyppi = c("S"),
#'   Vuosi = c("*")
#' )
#' pxq1 <- pxweb_query(dims)
#'
#' json_query <- file.path(
#'   system.file(package = "pxweb"),
#'   "extdata", "examples", "json_query_example.json"
#' )
#' pxq2 <- pxweb_query(json_query)
#'
#' @export
pxweb_query <- function(x) {
  UseMethod("pxweb_query")
}

#' @rdname pxweb_query
#' @keywords internal
#' @export
pxweb_query.character <- function(x) {
  obj <- jsonlite::fromJSON(x, simplifyDataFrame = FALSE)
  if (is.character(obj)) {
    stop("jsonlite::fromJSON() cannot parse the PXWEB (JSON) query. Please check your (JSON) query.", call. = FALSE)
  }
  class(obj) <- c("pxweb_query", "list")
  assert_pxweb_query(obj, check_response_format = FALSE)
  if (tolower(obj$response$format) == "json") {
    obj$response$format <- "json"
  } else if (tolower(obj$response$format) %in% c("json-stat", "jsonstat")) {
    obj$response$format <- "json-stat"
  } else if (tolower(obj$response$format) %in% pxweb_file_response_formats()) {

  } else {
    warning(paste0("'", obj$response$format, "' is not a valid query response format, set to 'json'."))
    obj$response$format <- "json"
  }
  assert_pxweb_query(obj)
  obj
}

pxweb_file_response_formats <- function() c("px", "sdmx")

#' @rdname pxweb_query
#' @keywords internal
#' @export
pxweb_query.json <- function(x) {
  pxweb_query(x = as.character(x))
}

#' @rdname pxweb_query
#' @keywords internal
#' @export
pxweb_query.pxweb_query <- function(x) {
  return(x)
}

#' @rdname pxweb_query
#' @keywords internal
#' @export
pxweb_query.list <- function(x) {
  checkmate::assert_named(x)
  obj <- list(
    query = list(),
    response = list(format = "json")
  )
  for (i in seq_along(x)) {
    obj$query[[i]] <- list(
      code = names(x)[i],
      selection = list(
        filter = "item",
        values = x[[i]]
      )
    )
    if (x[[i]][1] == "*") {
      obj$query[[i]]$selection$filter <- "all"
    }
  }
  class(obj) <- c("pxweb_query", "list")
  assert_pxweb_query(obj)
  obj
}

#' @rdname pxweb_query
#' @keywords internal
#' @export
pxweb_query.response <- function(x) {
  if (is.null(x$request$options$postfields)) {
    return(NULL)
  }
  pxweb_query(x = readBin(x$request$options$postfields, what = "character"))
}


#' @rdname pxweb_query
#' @keywords internal
#' @export
pxweb_query.pxweb_explorer <- function(x) {
  checkmate::assert_true(pxe_position_is_full_query(x))
  md_ch <- pxe_metadata_choices(x)
  mdo <- pxe_pxobj_at_position(x)
  mdo_vnm <- pxweb_metadata_dim(mdo)

  obj <- list()
  for (i in seq_along(mdo$variables)) {
    var_nm <- mdo$variables[[i]]$code
    if (md_ch[[var_nm]][1] == "eliminate") {
      next
    }
    obj[[var_nm]] <- mdo$variables[[i]]$values[md_ch[[var_nm]]]
  }
  pxq <- pxweb_query(obj)
  pxweb_validate_query_with_metadata(pxq, mdo)
  pxq
}

#' Assert a pxweb_query object
#'
#' @param x an object to assert conferms to the structure of an pxweb_query object.
#'
#' @keywords internal
assert_pxweb_query <- function(x, check_response_format = TRUE) {
  checkmate::assert_class(x, c("pxweb_query", "list"), .var.name = "pxweb_query")
  checkmate::assert_names(names(x), must.include = c("query", "response"), .var.name = "names(pxweb_query)")
  checkmate::assert_names(names(x$response), must.include = c("format"))
  if (check_response_format) {
    checkmate::assert_choice(x$response$format, c("json", "json-stat", pxweb_file_response_formats()))
  }


  checkmate::assert_named(x$query, "unnamed")
  for (i in seq_along(x$query)) {
    checkmate::assert_character(x$query[[i]]$code, any.missing = FALSE, min.len = 1)
    checkmate::assert_names(names(x$query[[i]]$selection), must.include = c("filter", "values"))
    checkmate::assert_character(x$query[[i]]$selection$filter, len = 1, any.missing = FALSE)
    checkmate::assert_character(x$query[[i]]$selection$values)
    checkmate::assert_named(x$query[[i]]$selection$values, type = "unnamed")
  }

  # Assert filter values
  for (i in seq_along(x$query)) {
    filter_aggr <- FALSE
    if (grepl(x = x$query[[i]]$selection$filter, "^[Vv]s:.*")) {
      filter_aggr <- TRUE
    }
    if (grepl(x = x$query[[i]]$selection$filter, "^[Aa]gg:.*")) {
      filter_aggr <- TRUE
    }
    if (!filter_aggr) {
      checkmate::assert_choice(x$query[[i]]$selection$filter, choices = c("item", "all", "top", "agg:[aggregated values]", "vs:[other value set]"))
      if (x$query[[i]]$selection$filter %in% c("all", "top")) {
        checkmate::assert_character(x$query[[i]]$selection$values, len = 1, .var.name = paste0("x$query[[", i, "]]$selection$values"))
      }
    }
  }
}



#' @export
print.pxweb_query <- function(x, ...) {
  cat("PXWEB QUERY\n")
  cat("query:\n")
  for (i in seq_along(x$query)) {
    cat(" [[", i, "]] ", x$query[[i]]$code, " (", x$query[[i]]$selection$filter, "):\n", sep = "")
    cat("   ", paste(x$query[[i]]$selection$values, collapse = ", "), "\n", sep = "")
  }
  if (x$response$format == "json-stat") {
    cat("return: json-stat\n")
  }
}



#' Validate a \code{pxweb_query} with a \code{pxweb_metadata} object
#'
#' @details
#' Validate a query with a metadata object to asses that the query can be used to
#' query the table.
#'
#' @param pxq a \code{pxweb_query} object.
#' @param pxmd a \code{pxweb_metadata} object.
#'
#' @examples
#' \dontrun{
#' url <- "https://api.scb.se/OV0104/v1/doris/sv/ssd/BE/BE0101/BE0101A/BefolkningNy"
#' json_query <- file.path(
#'   system.file(package = "pxweb"),
#'   "extdata", "examples", "json_query_example.json"
#' )
#' pxq <- pxweb_query(json_query)
#' pxweb_validate_query_with_metadata(pxq, pxweb_get(url))
#' }
#'
#' @export
pxweb_validate_query_with_metadata <- function(pxq, pxmd) {
  checkmate::assert_class(pxq, "pxweb_query")
  checkmate::assert_class(pxmd, "pxweb_metadata")

  pxweb_metadata_variables <- unlist(lapply(pxmd$variables, function(x) x$code))
  query_variables <- character(length(pxq$query))
  for (i in seq_along(pxq$query)) {
    query_variables[i] <- pxq$query[[i]]$code
    pxweb_query_variable_code <- pxq$query[[i]]$code
    checkmate::assert_choice(pxweb_query_variable_code, choices = pxweb_metadata_variables)
    if (tolower(pxq$query[[i]]$selection$filter) == "item") {
      pxweb_query_variable_values <- pxq$query[[i]]$selection$values
      meta_idx <- which(pxweb_metadata_variables %in% pxweb_query_variable_code)
      pxweb_metadata_variable_values <- pxmd$variables[[meta_idx]]$values
      if (!is.null(pxweb_metadata_variable_values)) {
        checkmate::assert_subset(pxweb_query_variable_values, choices = pxweb_metadata_variable_values, .var.name = pxq$query[[i]]$code)
      }
    }
  }
  mandatory_variables <- character(0)
  for (i in seq_along(pxmd$variables)) {
    if (!pxmd$variables[[i]]$elimination) {
      mandatory_variables <- c(mandatory_variables, pxmd$variables[[i]]$code)
    }
  }
  if (!all(mandatory_variables %in% query_variables)) {
    mandatory_variables_missing <- mandatory_variables[!mandatory_variables %in% query_variables]
    stop("Mandatory variable(s) '", paste0(mandatory_variables_missing, collapse = "', '"), "' is missing in the query.", call. = FALSE)
  }
}


#' Add and remove metadata to query
#'
#' @details
#' Add metadata values to variables with a query with filter "all".
#'
#' @param pxq a \code{pxweb_query} object.
#' @param pxmd a \code{pxweb_metadata} object.
#'
#' @keywords internal
pxweb_add_metadata_to_query <- function(pxq, pxmd) {
  checkmate::assert_class(pxq, "pxweb_query")
  checkmate::assert_class(pxmd, "pxweb_metadata")

  # Set values to filter "all"
  pxweb_metadata_variables <- unlist(lapply(pxmd$variables, function(x) x$code))
  for (i in seq_along(pxq$query)) {
    pxweb_query_variable_code <- pxq$query[[i]]$code
    checkmate::assert_choice(pxweb_query_variable_code, choices = pxweb_metadata_variables)
    if (tolower(pxq$query[[i]]$selection$filter) == "all") {
      px_pattern <- pxq$query[[i]]$selection$values
      px_pattern <- paste0("^", gsub(pattern = "\\*", replacement = "\\.\\+", px_pattern))
      meta_data_values <- pxmd$variables[[which(pxweb_metadata_variables %in% pxweb_query_variable_code)]]$values
      if (!is.null(meta_data_values)) {
        meta_data_values <- meta_data_values[grepl(x = meta_data_values, pattern = px_pattern)]
        pxq$query[[i]]$selection$values <- meta_data_values
        pxq$query[[i]]$selection$filter <- "item"
      }
    }
  }

  assert_pxweb_query(pxq)
  pxq
}

#' @rdname pxweb_add_metadata_to_query
#' @keywords internal
pxweb_remove_metadata_from_query <- function(pxq, pxmd) {
  checkmate::assert_class(pxq, "pxweb_query")
  checkmate::assert_class(pxmd, "pxweb_metadata")

  # set full queries to all *
  pxweb_metadata_variables <- unlist(lapply(pxmd$variables, function(x) x$code))
  for (i in seq_along(pxq$query)) {
    query_size <- length(pxq$query[[i]]$selection$values)
    pxweb_query_variable_code <- pxq$query[[i]]$code
    meta_data_size <- length(pxmd$variables[[which(pxweb_metadata_variables %in% pxweb_query_variable_code)]]$values)
    if (query_size >= meta_data_size & query_size > 1) {
      pxq$query[[i]]$selection$filter <- "all"
      pxq$query[[i]]$selection$values <- "*"
    }
  }
  assert_pxweb_query(pxq)
  pxq
}

#' Compue the dimension of the query
#'
#' @param pxq a \code{pxweb_query} object.
#'
#' @keywords internal
pxweb_query_dim <- function(pxq) {
  checkmate::assert_class(pxq, "pxweb_query")
  dim_res <- numeric(length(pxq$query))
  for (i in seq_along(pxq$query)) {
    names(dim_res)[i] <- pxq$query[[i]]$code
    if (tolower(pxq$query[[i]]$selection$filter) == "top") {
      dim_res[i] <- as.numeric(pxq$query[[i]]$selection$values)
    } else if (tolower(pxq$query[[i]]$selection$filter) == "all") {
      warning("Cannot compute the dimension for a variable with filter 'all', set to 1.", call. = FALSE)
      dim_res[i] <- 1
    } else {
      dim_res[i] <- length(pxq$query[[i]]$selection$values)
    }
  }
  dim_res
}


#' Get query filter
#'
#' @param pxq a \code{pxweb_query} object.
#'
#' @return query variable selection values as a named list of character vectors.
#'
#' @keywords internal
pxweb_query_values <- function(pxq) {
  checkmate::assert_class(pxq, "pxweb_query")
  res <- lapply(pxq$query, function(x) x$selection$values)
  names(res) <- unlist(lapply(pxq$query, function(x) x$code))
  res
}


#' Get query values
#'
#' @param pxq a \code{pxweb_query} object.
#'
#' @return query variable selection filters as a named character vector.
#'
#' @keywords internal
pxweb_query_filter <- function(pxq) {
  checkmate::assert_class(pxq, "pxweb_query")
  res <- unlist(lapply(pxq$query, function(x) x$selection$filter))
  names(res) <- unlist(lapply(pxq$query, function(x) x$code))
  res
}


#' Convert a \code{pxweb_query} object to a \code{json} string
#'
#' @param pxq a \code{pxweb_query} object.
#' @param ... further argument to \code{jsonlite::toJSON()}.
#'
#' @seealso \code{\link{pxweb_query}}, \code{\link{pxweb_query_as_rcode}}
#'
#' @examples
#' json_query <- file.path(
#'   system.file(package = "pxweb"),
#'   "extdata", "examples", "json_query_example.json"
#' )
#' pxq <- pxweb_query(json_query)
#' json <- pxweb_query_as_json(pxq, pretty = TRUE)
#'
#' @export
pxweb_query_as_json <- function(pxq, ...) {
  checkmate::assert_class(pxq, "pxweb_query")
  pxq$response$format <- jsonlite::unbox(pxq$response$format)
  for (i in seq_along(pxq$query)) {
    pxq$query[[i]]$code <- jsonlite::unbox(pxq$query[[i]]$code)
    pxq$query[[i]]$selection$filter <- jsonlite::unbox(pxq$query[[i]]$selection$filter)
  }
  jsonlite::toJSON(pxq, ...)
}

#' Print a \code{pxweb_query} object as R code
#'
#' @param pxq a \code{pxweb_query} object.
#'
#' @seealso \code{\link{pxweb_query_as_json}}, \code{\link{pxweb_query}}
#'
#' @export
pxweb_query_as_rcode <- function(pxq) {
  checkmate::assert_class(pxq, "pxweb_query")

  res <- character(length(pxq$query))
  for (i in seq_along(pxq$query)) {
    res[i] <- paste0("\"", pxq$query[[i]]$code, "\"=c(", paste(paste0("\"", pxq$query[[i]]$selection$values, "\""), collapse = ","), ")")
    if (i == 1) {
      res[i] <- paste0("  list(", res[i])
    } else {
      res[i] <- paste0("       ", res[i])
    }
  }
  res[length(res)] <- paste0(res[length(res)], ")")
  if (length(res) > 1) {
    res[-length(res)] <- paste0(res[-length(res)], ",")
  }
  res <- c("pxweb_query_list <- ", res)
  cat(res, sep = "\n")
  invisible(res)
}