Add a randomDate provider

mfussenegger · mfussenegger · commit 0ef2efb41259 · 2018-12-22T13:03:47.000+01:00
diff --git a/README.md b/README.md
@@ -24,6 +24,7 @@ a field within the JSON object.
  - randomChar
  - randomInt(lower, upper)
  - randomDouble(lower, upper)
+ - randomDate
  - array(expr [, ...])
  - oneOf(arrayExpr)
  - oneOf(expr, expr [, ...])
diff --git a/package.yaml b/package.yaml
@@ -37,6 +37,7 @@ dependencies:
   - containers
   - regex-tdfa
   - optparse-applicative
+  - time
 
 library:
   source-dirs: src
diff --git a/src/Fake.hs b/src/Fake.hs
@@ -27,6 +27,7 @@ import qualified Data.Scientific            as S
 import qualified Data.Set                   as Set
 import qualified Data.Text                  as T
 import qualified Data.Text.Encoding         as T
+import           Data.Time.Calendar         (Day (..), showGregorian)
 import qualified Data.UUID                  as UUID
 import qualified Data.UUID.V1               as UUID1
 import qualified Data.Vector                as V
@@ -276,6 +277,16 @@ randomChar = charToString <$> State.state random
     charToString = String . T.pack . (: [])
 
 
+-- | Generate a random date between (inclusive) 1858-11-17 and 2132-09-01
+--
+-- >>> exec "randomDate()"
+-- String "2063-01-23"
+randomDate :: (RandomGen g, MonadState g m) => m Value
+randomDate = dayAsValue . ModifiedJulianDay <$> State.state (randomR (0, 100000))
+  where
+    dayAsValue = String . T.pack . showGregorian
+
+
 -- | Create a value getter for an expression
 --
 -- >>> exec "uuid4"
@@ -295,6 +306,7 @@ eval (FunctionCall "randomBool" []) = randomBool
 eval (FunctionCall "randomChar" []) = randomChar
 eval (FunctionCall "randomInt" [lower, upper]) = randomInt lower upper
 eval (FunctionCall "randomDouble" [lower, upper]) = randomDouble lower upper
+eval (FunctionCall "randomDate" []) = randomDate
 eval (FunctionCall "array" args) = Array . V.fromList <$> mapM eval args
 eval (FunctionCall "oneOf" [arg]) = oneOfArray arg
 eval (FunctionCall "oneOf" args) = oneOfArgs args
