Add input validation to estimators

7 files changed, 168 insertions, 39 deletions

diff --git a/R/id.R b/R/id.R
index 5277591..c7c28d3 100644
--- a/R/id.R
+++ b/R/id.R
@@ -41,5 +41,12 @@
 #' # Obtain R0 when the serial distribution has a mean of three days.
 #' id(cases, mu = 3 / 7)
 id <- function(cases, mu) {
+  validate_cases(cases, min_length = 1, min_count = 1)
+  if (!is_real(mu) || mu <= 0) {
+    stop("The serial interval (`mu`) must be a number greater than 0.",
+      call. = FALSE
+    )
+  }
+
   exp(sum((log(cases) * mu) / seq_along(cases)) / length(cases))
 }
diff --git a/R/idea.R b/R/idea.R
index 14ba838..dad4220 100644
--- a/R/idea.R
+++ b/R/idea.R
@@ -42,6 +42,13 @@
 #' # Obtain R0 when the serial distribution has a mean of three days.
 #' idea(cases, mu = 3 / 7)
 idea <- function(cases, mu) {
+  validate_cases(cases, min_length = 2, min_count = 1)
+  if (!is_real(mu) || mu <= 0) {
+    stop("The serial interval (`mu`) must be a number greater than 0.",
+      call. = FALSE
+    )
+  }
+
   s <- seq_along(cases) / mu
 
   x1 <- sum(s)
diff --git a/R/seq_bayes.R b/R/seq_bayes.R
index d486d2b..ccc9a41 100644
--- a/R/seq_bayes.R
+++ b/R/seq_bayes.R
@@ -84,10 +84,31 @@
 #' # Note that the following always holds:
 #' estimate == sum(posterior$supp * posterior$pmf)
 seq_bayes <- function(cases, mu, kappa = 20, post = FALSE) {
+  validate_cases(cases, min_length = 2, min_count = 0)
+  if (!is_real(mu) || mu <= 0) {
+    stop("The serial interval (`mu`) must be a number greater than 0.",
+      call. = FALSE
+    )
+  }
+  if (!is_real(kappa) || kappa < 1) {
+    stop(
+      paste("The largest value of the uniform prior (`kappa`)",
+        "must be a number greater than or equal to 1."
+      ), call. = FALSE
+    )
+  }
+  if (!identical(post, TRUE) && !identical(post, FALSE)) {
+    stop("The posterior flag (`post`) must be set to `TRUE` or `FALSE`.",
+      call. = FALSE
+    )
+  }
+
   if (any(cases == 0)) {
     times <- which(cases > 0)
     if (length(times) < 2) {
-      stop("Vector of case counts must contain at least two positive integers.")
+      stop("Case counts must contain at least two positive integers.",
+        call. = FALSE
+      )
     }
     cases <- cases[times]
   } else {
diff --git a/R/util.R b/R/util.R
new file mode 100644
index 0000000..d8b0b59
--- /dev/null
+++ b/R/util.R
@@ -0,0 +1,55 @@
+#' Case Counts Validation
+#'
+#' This is an internal function called by the estimators. It validates the
+#' supplied case counts by ensuring it is a vector of integers of length at
+#' least `min_length` with entries greater than or equal to `min_count`.
+#' Execution is halted if these requirements are not satisfied.
+#'
+#' @param cases The case counts to be validated.
+#' @param min_length The minimum length of the vector of case counts.
+#' @param min_count The minimum value of the case count vector's entries.
+#'
+#' @noRd
+validate_cases <- function(cases, min_length, min_count) {
+  if (!is.vector(cases) || !is.numeric(cases) || any(floor(cases) != cases)) {
+    stop("Case counts must be a vector of integers.", call. = FALSE)
+  }
+  if (length(cases) < min_length) {
+    stop(paste("Case counts must have at least", min_length, "entries."),
+      call. = FALSE
+    )
+  }
+  if (any(cases < min_count)) {
+    stop(paste0("Case counts cannot be less than ", min_count, "."),
+      call. = FALSE
+    )
+  }
+}
+
+#' Real Number Testing
+#'
+#' This is an internal function which checks whether the given argument is a
+#' real number.
+#'
+#' @param x The argument to test for being a real number.
+#'
+#' @return `TRUE` if the argument is a real number, `FALSE` otherwise.
+#'
+#' @noRd
+is_real <- function(x) {
+  is.vector(x) && is.numeric(x) && length(x) == 1
+}
+
+#' Integer Testing
+#'
+#' This is an internal function which checks whether the given argument is an
+#' integer.
+#'
+#' @param n The argument to test for being an integer.
+#'
+#' @return `TRUE` if the argument is an integer, `FALSE` otherwise.
+#'
+#' @noRd
+is_integer <- function(n) {
+  is_real(n) && floor(n) == n
+}
diff --git a/R/wp.R b/R/wp.R
index 16b4bbb..fbb6ad7 100644
--- a/R/wp.R
+++ b/R/wp.R
@@ -111,12 +111,45 @@
 #' estimate$pmf
 wp <- function(cases, mu = NA, serial = FALSE,
                grid_length = 100, max_shape = 10, max_scale = 10) {
-  if (is.na(mu)) {
+  validate_cases(cases, min_length = 2, min_count = 1)
+  if (!identical(serial, TRUE) && !identical(serial, FALSE)) {
+    stop(
+      paste("The serial distribution flag (`serial`) must be set to",
+        "`TRUE` or `FALSE`."
+      ), call. = FALSE
+    )
+  }
+
+  if (identical(mu, NA)) {
+    if (!is_integer(grid_length) || grid_length < 1) {
+      stop("The grid length must be a positive integer.", call. = FALSE)
+    }
+    if (!is_real(max_shape) || max_shape <= 0) {
+      stop(
+        paste("The largest value of the shape parameter (`max_shape`)",
+          "must be a positive number."
+        ), call. = FALSE
+      )
+    }
+    if (!is_real(max_scale) || max_scale <= 0) {
+      stop(
+        paste("The largest value of the scale parameter (`max_scale`)",
+          "must be a positive number."
+        ), call. = FALSE
+      )
+    }
+
     search <- wp_search(cases, grid_length, max_shape, max_scale)
     r0 <- search$r0
     serial_supp <- search$supp
     serial_pmf <- search$pmf
   } else {
+    if (!is_real(mu) || mu <= 0) {
+      stop("The serial interval (`mu`) must be a positive number or `NA`.",
+        call. = FALSE
+      )
+    }
+
     max_range <- ceiling(qgamma(0.999, shape = 1, scale = mu))
     serial_supp <- seq_len(max_range)
     serial_pmf <- diff(pgamma(0:max_range, shape = 1, scale = mu))
diff --git a/inst/app/scripts/data.R b/inst/app/scripts/data.R
index c85e27b..8f8694c 100644
--- a/inst/app/scripts/data.R
+++ b/inst/app/scripts/data.R
@@ -141,9 +141,7 @@ validate_data <- function(input, output, react_values, data_source) {
         # corresponding columns in the estimates table.
         update_estimates_cols(new_rows, react_values)
 
-        showNotification("Datasets added successfully.",
-          duration = 3, id = "notify-success"
-        )
+        showNotification("Datasets added successfully.", duration = 3)
       }
     },
     error = function(e) {
@@ -195,9 +193,7 @@ load_samples <- function(input, output, react_values) {
       # corresponding columns in the estimates table.
       update_estimates_cols(new_rows, react_values)
 
-      showNotification("Datasets added successfully.",
-        duration = 3, id = "notify-success"
-      )
+      showNotification("Datasets added successfully.", duration = 3)
     }
   })
 }
diff --git a/inst/app/scripts/estimators.R b/inst/app/scripts/estimators.R
index b61f4d4..a86b1d4 100644
--- a/inst/app/scripts/estimators.R
+++ b/inst/app/scripts/estimators.R
@@ -29,8 +29,8 @@ add_estimator <- function(method, new_estimator, output, react_values) {
   # Check whether the new estimator is a duplicate, and warn if so.
   for (i in seq_len(num_estimators)) {
     if (identical(new_estimator, react_values$estimators[[i]])) {
-      showNotification("Error: This estimator has already been added.",
-        duration = 3, id = "notify-error"
+      showNotification(
+        "Error: This estimator has already been added.", duration = 3
       )
       return()
     }
@@ -39,9 +39,7 @@ add_estimator <- function(method, new_estimator, output, react_values) {
   # Add the new estimator to the list of estimators.
   react_values$estimators[[num_estimators + 1]] <- new_estimator
 
-  showNotification("Estimator added successfully.",
-    duration = 3, id = "notify-success"
-  )
+  showNotification("Estimator added successfully.", duration = 3)
 
   # Evaluate the new estimator on all existing datasets and create a new row in
   # the estimates table.
@@ -95,9 +93,9 @@ add_seq_bayes <- function(input, output, react_values) {
     kappa <- trimws(input$kappa)
     kappa <- if (kappa == "") 20 else suppressWarnings(as.numeric(kappa))
 
-    if (is.na(kappa) || kappa <= 0) {
+    if (is.na(kappa) || kappa < 1) {
       output$kappa_warn <- renderText(
-        "The maximum prior must be a positive number."
+        "The maximum prior must be a number greater than or equal to 1."
       )
     } else if (!is.null(mu)) {
       output$kappa_warn <- renderText("")
@@ -209,32 +207,44 @@ update_estimates_row <- function(estimator, react_values) {
 eval_estimator <- function(estimator, dataset) {
   cases <- as.integer(unlist(strsplit(dataset[, 3], ",")))
 
-  if (estimator$method == "id") {
-    mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
-    estimate <- round(Rnaught::id(cases, mu), 2)
-  } else if (estimator$method == "idea") {
-    mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
-    estimate <- round(Rnaught::idea(cases, mu), 2)
-  } else if (estimator$method == "seq_bayes") {
-    mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
-    estimate <- round(Rnaught::seq_bayes(cases, mu, estimator$kappa), 2)
-  } else if (estimator$method == "wp") {
-    if (is.na(estimator$mu)) {
-      estimate <- Rnaught::wp(cases, serial = TRUE,
-        grid_length = estimator$grid_length,
-        max_shape = estimator$max_shape, max_scale = estimator$max_scale
-      )
-      estimated_mu <- round(sum(estimate$supp * estimate$pmf), 2)
-      estimate <- paste0(round(estimate$r0, 2), " (SI = ", estimated_mu,
-        " ", tolower(dataset[, 2]), ")"
+  tryCatch(
+    {
+      if (estimator$method == "id") {
+        mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
+        estimate <- round(Rnaught::id(cases, mu), 2)
+      } else if (estimator$method == "idea") {
+        mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
+        estimate <- round(Rnaught::idea(cases, mu), 2)
+      } else if (estimator$method == "seq_bayes") {
+        mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
+        estimate <- round(Rnaught::seq_bayes(cases, mu, estimator$kappa), 2)
+      } else if (estimator$method == "wp") {
+        if (is.na(estimator$mu)) {
+          estimate <- Rnaught::wp(cases, serial = TRUE,
+            grid_length = estimator$grid_length,
+            max_shape = estimator$max_shape, max_scale = estimator$max_scale
+          )
+          estimated_mu <- round(sum(estimate$supp * estimate$pmf), 2)
+          estimate <- paste0(round(estimate$r0, 2), " (SI = ", estimated_mu,
+            " ", tolower(dataset[, 2]), ")"
+          )
+        } else {
+          mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
+          estimate <- round(Rnaught::wp(cases, mu), 2)
+        }
+      }
+
+      return(estimate)
+    }, error = function(e) {
+      showNotification(
+        paste0(toString(e),
+          " [Estimator: ", sub(" .*", "", estimator_name(estimator)),
+          ", Dataset: ", dataset[, 1], "]"
+        ), duration = 6
       )
-    } else {
-      mu <- convert_mu_units(dataset[, 2], estimator$mu_units, estimator$mu)
-      estimate <- round(Rnaught::wp(cases, mu), 2)
+      return("—")
     }
-  }
-
-  return(estimate)
+  )
 }
 
 # Create the name of an estimator to be added to the first column of the