Implement review interface (GET /tasks/:id/review with accept/reject)

All checks pass. The review interface implementation is complete:

1. **GET /tasks/:id/review** - Shows review interface with task details
2. **POST /tasks/:id/accept** - Marks task as Done and clears retry
cont 3. **POST /tasks/:id/reject** - Reopens task as Open with retry
context 4. Commit lookup by Task-Id using git log 5. Git diff display
in a pre/code block 6. Merge conflict detection using cherry-pick
check 7. "No commit found" message when applicable

The hlint warning about avoiding lambda was fixed by using `(<.)`
compos

Task-Id: t-1o2g8gugkr1.6

1 files changed, 284 insertions, 3 deletions

diff --git a/Omni/Jr/Web.hs b/Omni/Jr/Web.hs
index 3ab0998..107df95 100644
--- a/Omni/Jr/Web.hs
+++ b/Omni/Jr/Web.hs
@@ -8,6 +8,7 @@
 -- : dep lucid
 -- : dep servant-lucid
 -- : dep http-api-data
+-- : dep process
 module Omni.Jr.Web
   ( run,
     defaultPort,
@@ -22,7 +23,9 @@ import qualified Network.Wai.Handler.Warp as Warp
 import qualified Omni.Task.Core as TaskCore
 import Servant
 import qualified Servant.HTML.Lucid as Lucid
-import Web.FormUrlEncoded (FromForm (..), parseUnique)
+import qualified System.Exit as Exit
+import qualified System.Process as Process
+import Web.FormUrlEncoded (FromForm (..), lookupUnique, parseUnique)
 
 type PostRedirect = Verb 'POST 303 '[Lucid.HTML] (Headers '[Header "Location" Text] NoContent)
 
@@ -35,6 +38,9 @@ type API =
     :<|> "tasks" :> Get '[Lucid.HTML] TaskListPage
     :<|> "tasks" :> Capture "id" Text :> Get '[Lucid.HTML] TaskDetailPage
     :<|> "tasks" :> Capture "id" Text :> "status" :> ReqBody '[FormUrlEncoded] StatusForm :> PostRedirect
+    :<|> "tasks" :> Capture "id" Text :> "review" :> Get '[Lucid.HTML] TaskReviewPage
+    :<|> "tasks" :> Capture "id" Text :> "accept" :> PostRedirect
+    :<|> "tasks" :> Capture "id" Text :> "reject" :> ReqBody '[FormUrlEncoded] RejectForm :> PostRedirect
 
 data HomePage = HomePage TaskCore.TaskStats [TaskCore.Task] [TaskCore.Task]
 
@@ -46,6 +52,20 @@ data TaskDetailPage
   = TaskDetailFound TaskCore.Task [TaskCore.Task]
   | TaskDetailNotFound Text
 
+data TaskReviewPage
+  = ReviewPageFound TaskCore.Task ReviewInfo
+  | ReviewPageNotFound Text
+
+data ReviewInfo
+  = ReviewNoCommit
+  | ReviewMergeConflict Text [Text]
+  | ReviewReady Text Text
+
+newtype RejectForm = RejectForm (Maybe Text)
+
+instance FromForm RejectForm where
+  fromForm form = Right (RejectForm (either (const Nothing) Just (lookupUnique "notes" form)))
+
 newtype StatusForm = StatusForm TaskCore.Status
 
 instance FromForm StatusForm where
@@ -406,6 +426,14 @@ instance Lucid.ToHtml TaskDetailPage where
               Lucid.ul_ [Lucid.class_ "child-list"] <| do
                 traverse_ renderChild children
 
+        when (TaskCore.taskStatus task == TaskCore.Review) <| do
+          Lucid.div_ [Lucid.class_ "review-link-section"] <| do
+            Lucid.a_
+              [ Lucid.href_ ("/tasks/" <> TaskCore.taskId task <> "/review"),
+                Lucid.class_ "review-link-btn"
+              ]
+              "Review This Task"
+
         Lucid.div_ [Lucid.class_ "status-form"] <| do
           Lucid.h3_ "Update Status"
           Lucid.form_ [Lucid.method_ "POST", Lucid.action_ ("/tasks/" <> TaskCore.taskId task <> "/status")] <| do
@@ -490,13 +518,169 @@ detailStyles =
   \                 font-size: 14px; margin-right: 8px; } \
   \.submit-btn { padding: 8px 16px; background: #0066cc; color: white; border: none; \
   \              border-radius: 4px; font-size: 14px; cursor: pointer; } \
-  \.submit-btn:hover { background: #0052a3; }"
+  \.submit-btn:hover { background: #0052a3; } \
+  \.review-link-section { margin: 16px 0; } \
+  \.review-link-btn { display: inline-block; padding: 12px 24px; background: #8b5cf6; \
+  \                   color: white; text-decoration: none; border-radius: 6px; \
+  \                   font-size: 16px; font-weight: 500; } \
+  \.review-link-btn:hover { background: #7c3aed; }"
+
+instance Lucid.ToHtml TaskReviewPage where
+  toHtmlRaw = Lucid.toHtml
+  toHtml (ReviewPageNotFound tid) =
+    Lucid.doctypehtml_ <| do
+      Lucid.head_ <| do
+        Lucid.title_ "Task Not Found - Jr Review"
+        Lucid.meta_ [Lucid.charset_ "utf-8"]
+        Lucid.meta_
+          [ Lucid.name_ "viewport",
+            Lucid.content_ "width=device-width, initial-scale=1"
+          ]
+        Lucid.style_ reviewStyles
+      Lucid.body_ <| do
+        Lucid.h1_ "Task Not Found"
+        Lucid.p_ <| do
+          "The task "
+          Lucid.code_ (Lucid.toHtml tid)
+          " could not be found."
+        Lucid.p_ <| Lucid.a_ [Lucid.href_ "/tasks"] "<- Back to Tasks"
+  toHtml (ReviewPageFound task reviewInfo) =
+    Lucid.doctypehtml_ <| do
+      Lucid.head_ <| do
+        Lucid.title_ <| Lucid.toHtml ("Review: " <> TaskCore.taskId task <> " - Jr")
+        Lucid.meta_ [Lucid.charset_ "utf-8"]
+        Lucid.meta_
+          [ Lucid.name_ "viewport",
+            Lucid.content_ "width=device-width, initial-scale=1"
+          ]
+        Lucid.style_ reviewStyles
+      Lucid.body_ <| do
+        Lucid.p_ <| Lucid.a_ [Lucid.href_ ("/tasks/" <> TaskCore.taskId task)] "<- Back to Task"
+
+        Lucid.h1_ "Review Task"
+
+        Lucid.div_ [Lucid.class_ "task-summary"] <| do
+          Lucid.div_ [Lucid.class_ "detail-row"] <| do
+            Lucid.span_ [Lucid.class_ "detail-label"] "ID:"
+            Lucid.code_ [Lucid.class_ "detail-value"] (Lucid.toHtml (TaskCore.taskId task))
+          Lucid.div_ [Lucid.class_ "detail-row"] <| do
+            Lucid.span_ [Lucid.class_ "detail-label"] "Title:"
+            Lucid.span_ [Lucid.class_ "detail-value"] (Lucid.toHtml (TaskCore.taskTitle task))
+          Lucid.div_ [Lucid.class_ "detail-row"] <| do
+            Lucid.span_ [Lucid.class_ "detail-label"] "Status:"
+            Lucid.span_ [Lucid.class_ "detail-value"] <| statusBadge (TaskCore.taskStatus task)
+
+        case reviewInfo of
+          ReviewNoCommit -> do
+            Lucid.div_ [Lucid.class_ "no-commit-msg"] <| do
+              Lucid.h3_ "No Commit Found"
+              Lucid.p_ "No commit with this task ID was found in the git history."
+              Lucid.p_ "The worker may not have completed yet, or the commit message doesn't include the task ID."
+          ReviewMergeConflict commitSha conflictFiles -> do
+            Lucid.div_ [Lucid.class_ "conflict-warning"] <| do
+              Lucid.h3_ "Merge Conflict Detected"
+              Lucid.p_ <| do
+                "Commit "
+                Lucid.code_ (Lucid.toHtml (Text.take 8 commitSha))
+                " cannot be cleanly merged."
+              Lucid.p_ "Conflicting files:"
+              Lucid.ul_ <| traverse_ (Lucid.li_ <. Lucid.toHtml) conflictFiles
+          ReviewReady commitSha diffText -> do
+            Lucid.div_ [Lucid.class_ "diff-section"] <| do
+              Lucid.h3_ <| do
+                "Commit: "
+                Lucid.code_ (Lucid.toHtml (Text.take 8 commitSha))
+              Lucid.pre_ [Lucid.class_ "diff-block"] (Lucid.toHtml diffText)
+
+            Lucid.div_ [Lucid.class_ "review-actions"] <| do
+              Lucid.form_
+                [ Lucid.method_ "POST",
+                  Lucid.action_ ("/tasks/" <> TaskCore.taskId task <> "/accept"),
+                  Lucid.class_ "inline-form"
+                ]
+                <| do
+                  Lucid.button_ [Lucid.type_ "submit", Lucid.class_ "accept-btn"] "Accept"
+
+              Lucid.form_
+                [ Lucid.method_ "POST",
+                  Lucid.action_ ("/tasks/" <> TaskCore.taskId task <> "/reject"),
+                  Lucid.class_ "reject-form"
+                ]
+                <| do
+                  Lucid.textarea_
+                    [ Lucid.name_ "notes",
+                      Lucid.class_ "reject-notes",
+                      Lucid.placeholder_ "Rejection notes (optional)"
+                    ]
+                    ""
+                  Lucid.button_ [Lucid.type_ "submit", Lucid.class_ "reject-btn"] "Reject"
+    where
+      statusBadge :: (Monad m) => TaskCore.Status -> Lucid.HtmlT m ()
+      statusBadge status =
+        let (cls, label) = case status of
+              TaskCore.Open -> ("badge badge-open", "Open")
+              TaskCore.InProgress -> ("badge badge-inprogress", "In Progress")
+              TaskCore.Review -> ("badge badge-review", "Review")
+              TaskCore.Approved -> ("badge badge-approved", "Approved")
+              TaskCore.Done -> ("badge badge-done", "Done")
+         in Lucid.span_ [Lucid.class_ cls] label
+
+reviewStyles :: Text
+reviewStyles =
+  "* { box-sizing: border-box; } \
+  \body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; \
+  \       margin: 0; padding: 16px; background: #f5f5f5; max-width: 1000px; } \
+  \h1 { margin: 16px 0; } \
+  \h3 { margin: 16px 0 8px 0; color: #374151; } \
+  \.task-summary { background: white; border-radius: 8px; padding: 16px; \
+  \                box-shadow: 0 1px 3px rgba(0,0,0,0.1); margin-bottom: 16px; } \
+  \.detail-row { display: flex; padding: 8px 0; border-bottom: 1px solid #e5e7eb; } \
+  \.detail-row:last-child { border-bottom: none; } \
+  \.detail-label { font-weight: 600; width: 100px; color: #6b7280; } \
+  \.detail-value { flex: 1; } \
+  \.badge { display: inline-block; padding: 4px 8px; border-radius: 4px; \
+  \         font-size: 12px; font-weight: 500; } \
+  \.badge-open { background: #fef3c7; color: #92400e; } \
+  \.badge-inprogress { background: #dbeafe; color: #1e40af; } \
+  \.badge-review { background: #ede9fe; color: #6b21a8; } \
+  \.badge-approved { background: #d1fae5; color: #065f46; } \
+  \.badge-done { background: #d1fae5; color: #065f46; } \
+  \.no-commit-msg { background: #fff3cd; border: 1px solid #ffc107; border-radius: 8px; \
+  \                 padding: 16px; margin: 16px 0; } \
+  \.conflict-warning { background: #f8d7da; border: 1px solid #dc3545; border-radius: 8px; \
+  \                    padding: 16px; margin: 16px 0; } \
+  \.diff-section { background: white; border-radius: 8px; padding: 16px; \
+  \                box-shadow: 0 1px 3px rgba(0,0,0,0.1); margin: 16px 0; } \
+  \.diff-block { background: #1e1e1e; color: #d4d4d4; padding: 16px; border-radius: 4px; \
+  \              font-family: 'SF Mono', Monaco, 'Courier New', monospace; font-size: 13px; \
+  \              overflow-x: auto; white-space: pre; margin: 0; max-height: 600px; overflow-y: auto; } \
+  \.review-actions { background: white; border-radius: 8px; padding: 16px; \
+  \                  box-shadow: 0 1px 3px rgba(0,0,0,0.1); display: flex; gap: 16px; \
+  \                  align-items: flex-start; flex-wrap: wrap; } \
+  \.inline-form { display: inline-block; } \
+  \.reject-form { display: flex; gap: 8px; flex: 1; min-width: 300px; } \
+  \.reject-notes { flex: 1; padding: 8px; border: 1px solid #d1d5db; border-radius: 4px; \
+  \                font-size: 14px; resize: vertical; min-height: 38px; } \
+  \.accept-btn { padding: 10px 24px; background: #10b981; color: white; border: none; \
+  \              border-radius: 4px; font-size: 14px; font-weight: 500; cursor: pointer; } \
+  \.accept-btn:hover { background: #059669; } \
+  \.reject-btn { padding: 10px 24px; background: #ef4444; color: white; border: none; \
+  \              border-radius: 4px; font-size: 14px; font-weight: 500; cursor: pointer; } \
+  \.reject-btn:hover { background: #dc2626; }"
 
 api :: Proxy API
 api = Proxy
 
 server :: Server API
-server = homeHandler :<|> readyQueueHandler :<|> taskListHandler :<|> taskDetailHandler :<|> taskStatusHandler
+server =
+  homeHandler
+    :<|> readyQueueHandler
+    :<|> taskListHandler
+    :<|> taskDetailHandler
+    :<|> taskStatusHandler
+    :<|> taskReviewHandler
+    :<|> taskAcceptHandler
+    :<|> taskRejectHandler
   where
     homeHandler :: Servant.Handler HomePage
     homeHandler = do
@@ -528,6 +712,103 @@ server = homeHandler :<|> readyQueueHandler :<|> taskListHandler :<|> taskDetail
       liftIO <| TaskCore.updateTaskStatus tid newStatus []
       pure <| addHeader ("/tasks/" <> tid) NoContent
 
+    taskReviewHandler :: Text -> Servant.Handler TaskReviewPage
+    taskReviewHandler tid = do
+      tasks <- liftIO TaskCore.loadTasks
+      case TaskCore.findTask tid tasks of
+        Nothing -> pure (ReviewPageNotFound tid)
+        Just task -> do
+          reviewInfo <- liftIO <| getReviewInfo tid
+          pure (ReviewPageFound task reviewInfo)
+
+    taskAcceptHandler :: Text -> Servant.Handler (Headers '[Header "Location" Text] NoContent)
+    taskAcceptHandler tid = do
+      liftIO <| do
+        TaskCore.clearRetryContext tid
+        TaskCore.updateTaskStatus tid TaskCore.Done []
+      pure <| addHeader ("/tasks/" <> tid) NoContent
+
+    taskRejectHandler :: Text -> RejectForm -> Servant.Handler (Headers '[Header "Location" Text] NoContent)
+    taskRejectHandler tid (RejectForm maybeNotes) = do
+      liftIO <| do
+        maybeCommit <- findCommitForTask tid
+        let commitSha = fromMaybe "" maybeCommit
+        maybeCtx <- TaskCore.getRetryContext tid
+        let attempt = maybe 1 (\ctx -> TaskCore.retryAttempt ctx + 1) maybeCtx
+        let reason = "rejected: " <> fromMaybe "(no notes)" maybeNotes
+        TaskCore.setRetryContext
+          TaskCore.RetryContext
+            { TaskCore.retryTaskId = tid,
+              TaskCore.retryOriginalCommit = commitSha,
+              TaskCore.retryConflictFiles = [],
+              TaskCore.retryAttempt = attempt,
+              TaskCore.retryReason = reason
+            }
+        TaskCore.updateTaskStatus tid TaskCore.Open []
+      pure <| addHeader ("/tasks/" <> tid) NoContent
+
+getReviewInfo :: Text -> IO ReviewInfo
+getReviewInfo tid = do
+  maybeCommit <- findCommitForTask tid
+  case maybeCommit of
+    Nothing -> pure ReviewNoCommit
+    Just commitSha -> do
+      conflictResult <- checkMergeConflict (Text.unpack commitSha)
+      case conflictResult of
+        Just conflictFiles -> pure (ReviewMergeConflict commitSha conflictFiles)
+        Nothing -> do
+          (_, diffOut, _) <-
+            Process.readProcessWithExitCode
+              "git"
+              ["show", Text.unpack commitSha]
+              ""
+          pure (ReviewReady commitSha (Text.pack diffOut))
+
+findCommitForTask :: Text -> IO (Maybe Text)
+findCommitForTask tid = do
+  let grepArg = "--grep=" <> Text.unpack tid
+  (code, shaOut, _) <-
+    Process.readProcessWithExitCode
+      "git"
+      ["log", "--pretty=format:%H", "-n", "1", grepArg]
+      ""
+  if code /= Exit.ExitSuccess || null shaOut
+    then pure Nothing
+    else case List.lines shaOut of
+      (x : _) -> pure (Just (Text.pack x))
+      [] -> pure Nothing
+
+checkMergeConflict :: String -> IO (Maybe [Text])
+checkMergeConflict commitSha = do
+  (_, origHead, _) <- Process.readProcessWithExitCode "git" ["rev-parse", "HEAD"] ""
+
+  (cpCode, _, cpErr) <-
+    Process.readProcessWithExitCode
+      "git"
+      ["cherry-pick", "--no-commit", commitSha]
+      ""
+
+  _ <- Process.readProcessWithExitCode "git" ["cherry-pick", "--abort"] ""
+  _ <- Process.readProcessWithExitCode "git" ["reset", "--hard", List.head (List.lines origHead)] ""
+
+  case cpCode of
+    Exit.ExitSuccess -> pure Nothing
+    Exit.ExitFailure _ -> do
+      let errLines = Text.lines (Text.pack cpErr)
+          conflictLines = filter (Text.isPrefixOf "CONFLICT") errLines
+          files = mapMaybe extractConflictFile conflictLines
+      pure (Just (if null files then ["(unknown files)"] else files))
+
+extractConflictFile :: Text -> Maybe Text
+extractConflictFile line =
+  case Text.breakOn "Merge conflict in " line of
+    (_, rest)
+      | not (Text.null rest) -> Just (Text.strip (Text.drop 18 rest))
+    _ -> case Text.breakOn "in " line of
+      (_, rest)
+        | not (Text.null rest) -> Just (Text.strip (Text.drop 3 rest))
+      _ -> Nothing
+
 app :: Application
 app = serve api server