1 files changed, 72 insertions, 0 deletions
diff --git a/app/History/Issues.hs b/app/History/Issues.hs
new file mode 100644
index 0000000..08ad772
--- /dev/null
+++ b/app/History/Issues.hs
@@ -0,0 +1,72 @@
+module History.Issues
+  ( Issues (..),
+  )
+where
+
+import Data.Binary (Binary)
+import Data.Function (on)
+import Data.Map qualified as M
+import Data.Proxy (Proxy)
+import Data.Text qualified as T
+import GHC.Generics (Generic)
+import Git qualified
+import History.Plan (Id, Planable, Proto, assume, propagate, protoOf)
+import History.Scramble (Scramble (..), getIssuesOfFile)
+import Issue qualified as I
+
+data Issues = Issues
+  { commitHash :: Git.CommitHash,
+    issues :: M.Map T.Text I.Issue
+  }
+  deriving (Show, Generic, Binary)
+
+instance Planable Issues where
+  type Id Issues = Git.CommitHash
+  type Proto Issues = Scramble
+  protoOf :: Proxy Issues -> Git.CommitHash -> IO Scramble
+  protoOf _ commitHash = do
+    filesChanged <- Git.getChangedFilesOf commitHash
+    issues <- concat <$> mapM (getIssuesOfFile commitHash) filesChanged
+    pure $
+      Scramble
+        { issues =
+            M.unions
+              [ M.singleton issue.id issue | issue <- issues
+              ],
+          ..
+        }
+
+  assume :: Scramble -> Issues
+  assume (Scramble {..}) = Issues {..}
+
+  propagate :: [Id Issues] -> Issues -> Scramble -> Issues
+  propagate _ topIssues bottomScramble =
+    Issues
+      { commitHash = topIssues.commitHash,
+        issues =
+          M.mergeWithKey
+            ( \_ topIssue bottomIssue ->
+                Just $
+                  topIssue
+                    { I.provenance =
+                        I.Provenance
+                          { first = bottomIssue.provenance.first,
+                            last =
+                              if ((/=) `on` (.rawTextHash)) topIssue bottomIssue
+                                then topIssue.provenance.last
+                                else bottomIssue.provenance.last
+                          }
+                    }
+            )
+            ( \topIssues -> topIssues
+            )
+            ( \bottomIssues ->
+                M.map
+                  ( \bottomIssue ->
+                      bottomIssue {I.closed = True}
+                  )
+                  bottomIssues
+            )
+            topIssues.issues
+            bottomScramble.issues
+      }