More concise recommended list

Problem: it's easy with the current "show four most recent" to run into
situations where- for example- only GHC 7.8 has had a successful build in
the past few days, and therefore it's the only snapshot that appears.
This gives a more consistent and useful listing of recommended
snapshots.

Styling of this is up for debate.

Handler/Home.hs

@@ -2,7 +2,7 @@
 module Handler.Home where
 
 import Data.Slug
-import Database.Esqueleto as E
+import Database.Esqueleto as E hiding (isNothing)
 import Import hiding ((=.),on,(||.),(==.))
 
 -- This is a handler function for the G request method on the HomeR
@@ -14,20 +14,6 @@ import Import hiding ((=.),on,(||.),(==.))
 -- inclined, or create a single monolithic file.
 getHomeR :: Handler Html
 getHomeR = do
-    fpHandle <- mkSlug "fpcomplete"
-    stackages <- runDB $ select $ from $ \(stackage `InnerJoin` user) -> do
-        on (stackage ^. StackageUser ==. user ^. UserId)
-        orderBy [desc $ stackage ^. StackageUploaded]
-        where_ (like (user ^. UserDisplay) (val "%@fpcomplete.com") ||.
-                  user ^. UserHandle ==. val fpHandle)
-        limit 4
-        return
-            ( stackage ^. StackageIdent
-            , stackage ^. StackageTitle
-            , stackage ^. StackageUploaded
-            , user ^. UserDisplay
-            , user ^. UserHandle
-            )
     windowsLatest <- linkFor "unstable-ghc78hp-inclusive"
     restLatest    <- linkFor "unstable-ghc78-inclusive"
     defaultLayout $ do
@@ -48,3 +34,20 @@ getHomeR = do
                   runDB .
                   select .
                   from
+
+      addSnapshot title short = do
+          mex <- handlerToWidget $ linkFor $ name "exclusive"
+          min' <- handlerToWidget $ linkFor $ name "inclusive"
+          when (isJust mex || isJust min')
+              [whamlet|
+                  <dt>#{asHtml title}
+                  <dd>
+                      $maybe ex <- mex
+                        <a href=@{StackageHomeR ex}>exclusive
+                      $if isJust mex && isJust min'
+                        \ | #
+                      $maybe in <- min'
+                        <a href=@{StackageHomeR in}>inclusive
+              |]
+        where
+          name suffix = concat ["unstable-", short, "-", suffix]

templates/homepage.hamlet

@@ -3,11 +3,10 @@
         Stackage is an infrastructure to create stable builds
         of complete package sets. Think “stable Hackage”.
     <h2 .recommended-snapshots>Recommended Snapshots
-    <ul .snapshots>
-        $forall (E.Value ident, E.Value title, E.Value _uploaded, E.Value _display, E.Value _handle) <- stackages
-            <li>
-                <a href=@{StackageHomeR ident}>
-                    #{title}
+    <dl .snapshots>
+        ^{addSnapshot "GHC 7.8" "ghc78"}
+        ^{addSnapshot "GHC 7.8 + Haskell Platform" "ghc78hp"}
+        ^{addSnapshot "GHC 7.6" "ghc76"}
     <p>
         <a href="https://github.com/fpco/stackage/wiki/Stackage-Server-FAQ#whats-the-difference-between-inclusive-and-exclusive-snapshots">What's the difference between inclusive and exclusive snapshots?</a>
     <h2 .getting-started>