1 files changed, 134 insertions, 0 deletions
diff --git a/src/Store/Query.hs b/src/Store/Query.hs
new file mode 100644
index 0000000..b63b176
--- /dev/null
+++ b/src/Store/Query.hs
@@ -0,0 +1,134 @@
+module Store.Query
+  ( module Store.Query.Type,
+    query,
+  )
+where
+
+import Control.Exception (throw)
+import Data.Aeson qualified as J
+import Data.Aeson.Key qualified as JK
+import Data.Aeson.KeyMap qualified as JM
+import Data.List (foldl', isSuffixOf)
+import Data.List.NonEmpty qualified as N
+import Data.Maybe (fromMaybe)
+import Data.Vector qualified as V
+import Store.Exception (DecodeException (DecodeException))
+import Store.Query.Parser ()
+import Store.Query.Printer ()
+import Store.Query.Record
+import Store.Query.Type
+import Store.Store qualified as S
+import System.FilePath ((</>))
+
+query :: Query -> IO [J.Value]
+query (Select fs c js es w) = do
+  c' <-
+    mapM (fmap (fromValue c) . decodeFile . (c </>)) =<< ls c
+  js' <-
+    mapM
+      ( \(JoinClause t c w) ->
+          fmap (\j' -> JoinClause t (map (fromValue c) j') w) . mapM (decodeFile . (c </>))
+            =<< ls c
+      )
+      js
+  es' <-
+    mapM
+      ( \(EmbedClause c w) ->
+          fmap (\e' -> EmbedClause (fromValue c e') w) . mapM (decodeFile . (c </>))
+            =<< ls c
+      )
+      es
+  pure $ map (Store.Query.select fs) $ where_ w $ embeds es' $ joins js' c'
+  where
+    ls c =
+      filter (not . (isSuffixOf "/"))
+        <$> S.withStore "." "HEAD" do
+          S.listDirectory c
+
+embeds ::
+  EmbedClauses (Record [J.Value]) ->
+  [Records J.Value] ->
+  [Records J.Value]
+embeds = flip (foldl' embed)
+
+embed ::
+  [Records J.Value] ->
+  EmbedClause (Record [J.Value]) ->
+  [Records J.Value]
+embed vss (EmbedClause (Record c es) w) =
+  map
+    ( \vs ->
+        vs
+          ++ [ fromValue
+                 c
+                 ( J.Object
+                     ( JM.singleton
+                         (JK.fromString c)
+                         ( J.Array
+                             ( V.fromList
+                                 [ e
+                                   | e <- es,
+                                     satisfies w (vs ++ [Record c e])
+                                 ]
+                             )
+                         )
+                     )
+                 )
+             ]
+    )
+    vss
+
+joins ::
+  JoinClauses (Records J.Value) ->
+  [Record J.Value] ->
+  [Records J.Value]
+joins js (map (: []) -> vss) = foldl' join vss js
+
+join ::
+  [Records J.Value] ->
+  JoinClause (Records J.Value) ->
+  [Records J.Value]
+join vss (JoinClause JoinLeft js w) =
+  concatMap
+    ( \vs -> case filter (satisfies w) $ map (\j -> vs ++ [j]) js of
+        [] -> [vs]
+        vs' -> vs'
+    )
+    vss
+join vss (JoinClause JoinRight js w) =
+  concatMap
+    ( \j -> case filter (satisfies w) $ map (\vs -> vs ++ [j]) vss of
+        [] -> [[j]]
+        vs' -> vs'
+    )
+    js
+join vss (JoinClause JoinFull js w) =
+  concatMap
+    ( \vs -> case filter (satisfies w) $ map (\j -> vs ++ [j]) js of
+        [] -> [vs]
+        vs' -> vs'
+    )
+    vss
+    ++ concatMap
+      ( \j -> case filter (satisfies w) $ map (\vs -> vs ++ [j]) vss of
+          [] -> [[j]]
+          _ -> []
+      )
+      js
+
+select :: FieldSelector -> Records J.Value -> J.Value
+select All vs = disjointUnions (map toValue vs)
+select (Only fs) vs = Store.Query.Record.select (N.toList fs) vs
+
+where_ :: Maybe WhereClause -> [Records J.Value] -> [Records J.Value]
+where_ w = filter (satisfies w)
+
+satisfies :: Maybe WhereClause -> Records J.Value -> Bool
+satisfies Nothing _ = True
+satisfies (Just (And ws)) vs = all (\w -> satisfies (Just w) vs) ws
+satisfies (Just (Or ws)) vs = any (\w -> satisfies (Just w) vs) ws
+satisfies (Just (Where (Eq f g))) vs = lookups f vs == lookups g vs
+
+decodeFile :: J.FromJSON a => Collection -> IO a
+decodeFile fp = S.withStore "." "HEAD" do
+  fromMaybe (throw DecodeException) . J.decode <$> S.readFile fp