path: root/Omni/Jr/Web.hs

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE NoImplicitPrelude #-}

-- : dep warp
-- : dep servant-server
-- : dep lucid
-- : dep servant-lucid
-- : dep http-api-data
-- : dep process
-- : dep clay
module Omni.Jr.Web
  ( run,
    defaultPort,
  )
where

import Alpha
import qualified Data.List as List
import qualified Data.Text as Text
import qualified Data.Text.Lazy as LazyText
import qualified Data.Text.Lazy.Encoding as LazyText
import qualified Lucid
import qualified Network.Wai.Handler.Warp as Warp
import qualified Omni.Jr.Web.Style as Style
import qualified Omni.Task.Core as TaskCore
import Servant
import qualified Servant.HTML.Lucid as Lucid
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)

defaultPort :: Warp.Port
defaultPort = 8080

data TaskFilters = TaskFilters
  { filterStatus :: Maybe TaskCore.Status,
    filterPriority :: Maybe TaskCore.Priority,
    filterNamespace :: Maybe Text
  }
  deriving (Show, Eq)

type API =
  Get '[Lucid.HTML] HomePage
    :<|> "style.css" :> Get '[CSS] LazyText.Text
    :<|> "ready" :> Get '[Lucid.HTML] ReadyQueuePage
    :<|> "tasks"
      :> QueryParam "status" TaskCore.Status
      :> QueryParam "priority" TaskCore.Priority
      :> QueryParam "namespace" Text
      :> 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 CSS

instance Accept CSS where
  contentType _ = "text/css"

instance MimeRender CSS LazyText.Text where
  mimeRender _ = LazyText.encodeUtf8

data HomePage = HomePage TaskCore.TaskStats [TaskCore.Task] [TaskCore.Task]

newtype ReadyQueuePage = ReadyQueuePage [TaskCore.Task]

data TaskListPage = TaskListPage [TaskCore.Task] TaskFilters

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
  fromForm form = do
    statusText <- parseUnique "status" form
    case readMaybe (Text.unpack statusText) of
      Just s -> Right (StatusForm s)
      Nothing -> Left "Invalid status"

pageHead :: (Monad m) => Text -> Lucid.HtmlT m ()
pageHead title =
  Lucid.head_ <| do
    Lucid.title_ (Lucid.toHtml title)
    Lucid.meta_ [Lucid.charset_ "utf-8"]
    Lucid.meta_
      [ Lucid.name_ "viewport",
        Lucid.content_ "width=device-width, initial-scale=1"
      ]
    Lucid.link_ [Lucid.rel_ "stylesheet", Lucid.href_ "/style.css"]

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

renderTaskCard :: (Monad m) => TaskCore.Task -> Lucid.HtmlT m ()
renderTaskCard t =
  Lucid.div_ [Lucid.class_ "task-card"] <| do
    Lucid.div_ [Lucid.class_ "task-header"] <| do
      Lucid.a_
        [ Lucid.class_ "task-id",
          Lucid.href_ ("/tasks/" <> TaskCore.taskId t)
        ]
        (Lucid.toHtml (TaskCore.taskId t))
      statusBadge (TaskCore.taskStatus t)
      Lucid.span_ [Lucid.class_ "priority"] (Lucid.toHtml (tshow (TaskCore.taskPriority t)))
    Lucid.p_ [Lucid.class_ "task-title"] (Lucid.toHtml (TaskCore.taskTitle t))

instance Lucid.ToHtml HomePage where
  toHtmlRaw = Lucid.toHtml
  toHtml (HomePage stats readyTasks recentTasks) =
    Lucid.doctypehtml_ <| do
      pageHead "Jr Dashboard"
      Lucid.body_ <| do
        Lucid.div_ [Lucid.class_ "container"] <| do
          Lucid.h1_ "Jr Dashboard"

          Lucid.div_ [Lucid.class_ "actions"] <| do
            Lucid.a_ [Lucid.href_ "/tasks", Lucid.class_ "action-btn"] "View All Tasks"
            Lucid.a_ [Lucid.href_ "/ready", Lucid.class_ "action-btn action-btn-primary"] "View Ready Queue"

          Lucid.h2_ "Task Status"
          Lucid.div_ [Lucid.class_ "stats-grid"] <| do
            statCard "Open" (TaskCore.openTasks stats) "badge-open"
            statCard "In Progress" (TaskCore.inProgressTasks stats) "badge-inprogress"
            statCard "Review" (TaskCore.reviewTasks stats) "badge-review"
            statCard "Approved" (TaskCore.approvedTasks stats) "badge-approved"
            statCard "Done" (TaskCore.doneTasks stats) "badge-done"

          Lucid.h2_ <| do
            "Ready Queue "
            Lucid.a_ [Lucid.href_ "/ready", Lucid.class_ "ready-link"]
              <| Lucid.toHtml ("(" <> tshow (length readyTasks) <> " tasks)")
          if null readyTasks
            then Lucid.p_ [Lucid.class_ "empty-msg"] "No tasks ready for work."
            else
              Lucid.div_ [Lucid.class_ "task-list"]
                <| traverse_ renderTaskCard (take 5 readyTasks)

          Lucid.h2_ "Recent Activity"
          if null recentTasks
            then Lucid.p_ [Lucid.class_ "empty-msg"] "No recent tasks."
            else
              Lucid.div_ [Lucid.class_ "task-list"]
                <| traverse_ renderTaskCard recentTasks
    where
      statCard :: (Monad m) => Text -> Int -> Text -> Lucid.HtmlT m ()
      statCard label count badgeClass =
        Lucid.div_ [Lucid.class_ ("stat-card " <> badgeClass)] <| do
          Lucid.div_ [Lucid.class_ "stat-count"] (Lucid.toHtml (tshow count))
          Lucid.div_ [Lucid.class_ "stat-label"] (Lucid.toHtml label)

instance Lucid.ToHtml ReadyQueuePage where
  toHtmlRaw = Lucid.toHtml
  toHtml (ReadyQueuePage tasks) =
    Lucid.doctypehtml_ <| do
      pageHead "Ready Queue - Jr"
      Lucid.body_ <| do
        Lucid.div_ [Lucid.class_ "container"] <| do
          Lucid.p_ [Lucid.class_ "back-link"] <| Lucid.a_ [Lucid.href_ "/"] "← Back to Dashboard"
          Lucid.h1_ <| Lucid.toHtml ("Ready Queue (" <> tshow (length tasks) <> " tasks)")
          if null tasks
            then Lucid.p_ [Lucid.class_ "empty-msg"] "No tasks are ready for work."
            else Lucid.div_ [Lucid.class_ "task-list"] <| traverse_ renderTaskCard tasks

instance Lucid.ToHtml TaskListPage where
  toHtmlRaw = Lucid.toHtml
  toHtml (TaskListPage tasks filters) =
    Lucid.doctypehtml_ <| do
      pageHead "Tasks - Jr"
      Lucid.body_ <| do
        Lucid.div_ [Lucid.class_ "container"] <| do
          Lucid.p_ [Lucid.class_ "back-link"] <| Lucid.a_ [Lucid.href_ "/"] "← Back to Dashboard"
          Lucid.h1_ <| Lucid.toHtml ("Tasks (" <> tshow (length tasks) <> ")")

          Lucid.div_ [Lucid.class_ "filter-form"] <| do
            Lucid.form_ [Lucid.method_ "GET", Lucid.action_ "/tasks"] <| do
              Lucid.div_ [Lucid.class_ "filter-row"] <| do
                Lucid.div_ [Lucid.class_ "filter-group"] <| do
                  Lucid.label_ [Lucid.for_ "status"] "Status:"
                  Lucid.select_ [Lucid.name_ "status", Lucid.id_ "status", Lucid.class_ "filter-select"] <| do
                    Lucid.option_ ([Lucid.value_ ""] <> maybeSelected Nothing (filterStatus filters)) "All"
                    statusFilterOption TaskCore.Open (filterStatus filters)
                    statusFilterOption TaskCore.InProgress (filterStatus filters)
                    statusFilterOption TaskCore.Review (filterStatus filters)
                    statusFilterOption TaskCore.Approved (filterStatus filters)
                    statusFilterOption TaskCore.Done (filterStatus filters)

                Lucid.div_ [Lucid.class_ "filter-group"] <| do
                  Lucid.label_ [Lucid.for_ "priority"] "Priority:"
                  Lucid.select_ [Lucid.name_ "priority", Lucid.id_ "priority", Lucid.class_ "filter-select"] <| do
                    Lucid.option_ ([Lucid.value_ ""] <> maybeSelected Nothing (filterPriority filters)) "All"
                    priorityFilterOption TaskCore.P0 (filterPriority filters)
                    priorityFilterOption TaskCore.P1 (filterPriority filters)
                    priorityFilterOption TaskCore.P2 (filterPriority filters)
                    priorityFilterOption TaskCore.P3 (filterPriority filters)
                    priorityFilterOption TaskCore.P4 (filterPriority filters)

                Lucid.div_ [Lucid.class_ "filter-group"] <| do
                  Lucid.label_ [Lucid.for_ "namespace"] "Namespace:"
                  Lucid.input_
                    [ Lucid.type_ "text",
                      Lucid.name_ "namespace",
                      Lucid.id_ "namespace",
                      Lucid.class_ "filter-input",
                      Lucid.placeholder_ "e.g. Omni/Jr",
                      Lucid.value_ (fromMaybe "" (filterNamespace filters))
                    ]

                Lucid.button_ [Lucid.type_ "submit", Lucid.class_ "filter-btn"] "Filter"
                Lucid.a_ [Lucid.href_ "/tasks", Lucid.class_ "clear-btn"] "Clear"

          if null tasks
            then Lucid.p_ [Lucid.class_ "empty-msg"] "No tasks match the current filters."
            else Lucid.div_ [Lucid.class_ "task-list"] <| traverse_ renderTaskCard tasks
    where
      maybeSelected :: (Eq a) => Maybe a -> Maybe a -> [Lucid.Attribute]
      maybeSelected opt current = [Lucid.selected_ "selected" | opt == current]

      statusFilterOption :: (Monad m) => TaskCore.Status -> Maybe TaskCore.Status -> Lucid.HtmlT m ()
      statusFilterOption s current =
        let attrs = [Lucid.value_ (tshow s)] <> [Lucid.selected_ "selected" | Just s == current]
         in Lucid.option_ attrs (Lucid.toHtml (tshow s))

      priorityFilterOption :: (Monad m) => TaskCore.Priority -> Maybe TaskCore.Priority -> Lucid.HtmlT m ()
      priorityFilterOption p current =
        let attrs = [Lucid.value_ (tshow p)] <> [Lucid.selected_ "selected" | Just p == current]
         in Lucid.option_ attrs (Lucid.toHtml (tshow p))

instance Lucid.ToHtml TaskDetailPage where
  toHtmlRaw = Lucid.toHtml
  toHtml (TaskDetailNotFound tid) =
    Lucid.doctypehtml_ <| do
      pageHead "Task Not Found - Jr"
      Lucid.body_ <| do
        Lucid.div_ [Lucid.class_ "container"] <| do
          Lucid.h1_ "Task Not Found"
          Lucid.p_ <| do
            "The task "
            Lucid.code_ (Lucid.toHtml tid)
            " could not be found."
          Lucid.p_ [Lucid.class_ "back-link"] <| Lucid.a_ [Lucid.href_ "/tasks"] "← Back to Tasks"
  toHtml (TaskDetailFound task allTasks) =
    Lucid.doctypehtml_ <| do
      pageHead (TaskCore.taskId task <> " - Jr")
      Lucid.body_ <| do
        Lucid.div_ [Lucid.class_ "container"] <| do
          Lucid.p_ [Lucid.class_ "back-link"] <| Lucid.a_ [Lucid.href_ "/tasks"] "← Back to Tasks"

          Lucid.h1_ <| Lucid.toHtml (TaskCore.taskTitle task)

          Lucid.div_ [Lucid.class_ "task-detail"] <| 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"] "Type:"
              Lucid.span_ [Lucid.class_ "detail-value"] (Lucid.toHtml (tshow (TaskCore.taskType 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)

            Lucid.div_ [Lucid.class_ "detail-row"] <| do
              Lucid.span_ [Lucid.class_ "detail-label"] "Priority:"
              Lucid.span_ [Lucid.class_ "detail-value"] <| do
                Lucid.toHtml (tshow (TaskCore.taskPriority task))
                Lucid.span_ [Lucid.class_ "priority-desc"] (Lucid.toHtml (priorityDesc (TaskCore.taskPriority task)))

            case TaskCore.taskNamespace task of
              Nothing -> pure ()
              Just ns ->
                Lucid.div_ [Lucid.class_ "detail-row"] <| do
                  Lucid.span_ [Lucid.class_ "detail-label"] "Namespace:"
                  Lucid.span_ [Lucid.class_ "detail-value"] (Lucid.toHtml ns)

            case TaskCore.taskParent task of
              Nothing -> pure ()
              Just pid ->
                Lucid.div_ [Lucid.class_ "detail-row"] <| do
                  Lucid.span_ [Lucid.class_ "detail-label"] "Parent:"
                  Lucid.a_ [Lucid.href_ ("/tasks/" <> pid), Lucid.class_ "detail-value task-link"] (Lucid.toHtml pid)

            Lucid.div_ [Lucid.class_ "detail-row"] <| do
              Lucid.span_ [Lucid.class_ "detail-label"] "Created:"
              Lucid.span_ [Lucid.class_ "detail-value"] (Lucid.toHtml (tshow (TaskCore.taskCreatedAt task)))

            Lucid.div_ [Lucid.class_ "detail-row"] <| do
              Lucid.span_ [Lucid.class_ "detail-label"] "Updated:"
              Lucid.span_ [Lucid.class_ "detail-value"] (Lucid.toHtml (tshow (TaskCore.taskUpdatedAt task)))

            let deps = TaskCore.taskDependencies task
            unless (null deps) <| do
              Lucid.div_ [Lucid.class_ "detail-section"] <| do
                Lucid.h3_ "Dependencies"
                Lucid.ul_ [Lucid.class_ "dep-list"] <| do
                  traverse_ renderDependency deps

            case TaskCore.taskDescription task of
              Nothing -> pure ()
              Just desc ->
                Lucid.div_ [Lucid.class_ "detail-section"] <| do
                  Lucid.h3_ "Description"
                  Lucid.pre_ [Lucid.class_ "description"] (Lucid.toHtml desc)

            let children = filter (maybe False (TaskCore.matchesId (TaskCore.taskId task)) <. TaskCore.taskParent) allTasks
            unless (null children) <| do
              Lucid.div_ [Lucid.class_ "detail-section"] <| do
                Lucid.h3_ "Child Tasks"
                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
              Lucid.select_ [Lucid.name_ "status", Lucid.class_ "status-select"] <| do
                statusOption TaskCore.Open (TaskCore.taskStatus task)
                statusOption TaskCore.InProgress (TaskCore.taskStatus task)
                statusOption TaskCore.Review (TaskCore.taskStatus task)
                statusOption TaskCore.Approved (TaskCore.taskStatus task)
                statusOption TaskCore.Done (TaskCore.taskStatus task)
              Lucid.button_ [Lucid.type_ "submit", Lucid.class_ "submit-btn"] "Submit"
    where
      priorityDesc :: TaskCore.Priority -> Text
      priorityDesc p = case p of
        TaskCore.P0 -> " (Critical)"
        TaskCore.P1 -> " (High)"
        TaskCore.P2 -> " (Medium)"
        TaskCore.P3 -> " (Low)"
        TaskCore.P4 -> " (Backlog)"

      statusOption :: (Monad m) => TaskCore.Status -> TaskCore.Status -> Lucid.HtmlT m ()
      statusOption opt current =
        let attrs = [Lucid.value_ (tshow opt)] <> [Lucid.selected_ "selected" | opt == current]
         in Lucid.option_ attrs (Lucid.toHtml (tshow opt))

      renderDependency :: (Monad m) => TaskCore.Dependency -> Lucid.HtmlT m ()
      renderDependency dep =
        Lucid.li_ <| do
          Lucid.a_ [Lucid.href_ ("/tasks/" <> TaskCore.depId dep), Lucid.class_ "task-link"] (Lucid.toHtml (TaskCore.depId dep))
          Lucid.span_ [Lucid.class_ "dep-type"] <| Lucid.toHtml (" [" <> tshow (TaskCore.depType dep) <> "]")

      renderChild :: (Monad m) => TaskCore.Task -> Lucid.HtmlT m ()
      renderChild child =
        Lucid.li_ <| do
          Lucid.a_ [Lucid.href_ ("/tasks/" <> TaskCore.taskId child), Lucid.class_ "task-link"] (Lucid.toHtml (TaskCore.taskId child))
          Lucid.span_ [Lucid.class_ "child-title"] <| Lucid.toHtml (" - " <> TaskCore.taskTitle child)
          Lucid.span_ [Lucid.class_ "child-status"] <| Lucid.toHtml (" [" <> tshow (TaskCore.taskStatus child) <> "]")

instance Lucid.ToHtml TaskReviewPage where
  toHtmlRaw = Lucid.toHtml
  toHtml (ReviewPageNotFound tid) =
    Lucid.doctypehtml_ <| do
      pageHead "Task Not Found - Jr Review"
      Lucid.body_ <| do
        Lucid.div_ [Lucid.class_ "container"] <| do
          Lucid.h1_ "Task Not Found"
          Lucid.p_ <| do
            "The task "
            Lucid.code_ (Lucid.toHtml tid)
            " could not be found."
          Lucid.p_ [Lucid.class_ "back-link"] <| Lucid.a_ [Lucid.href_ "/tasks"] "← Back to Tasks"
  toHtml (ReviewPageFound task reviewInfo) =
    Lucid.doctypehtml_ <| do
      pageHead ("Review: " <> TaskCore.taskId task <> " - Jr")
      Lucid.body_ <| do
        Lucid.div_ [Lucid.class_ "container"] <| do
          Lucid.p_ [Lucid.class_ "back-link"] <| 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 ->
              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 ->
              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"

api :: Proxy API
api = Proxy

server :: Server API
server =
  homeHandler
    :<|> styleHandler
    :<|> readyQueueHandler
    :<|> taskListHandler
    :<|> taskDetailHandler
    :<|> taskStatusHandler
    :<|> taskReviewHandler
    :<|> taskAcceptHandler
    :<|> taskRejectHandler
  where
    styleHandler :: Servant.Handler LazyText.Text
    styleHandler = pure Style.css

    homeHandler :: Servant.Handler HomePage
    homeHandler = do
      stats <- liftIO <| TaskCore.getTaskStats Nothing
      readyTasks <- liftIO TaskCore.getReadyTasks
      allTasks <- liftIO TaskCore.loadTasks
      let recentTasks = take 5 <| List.sortBy (flip compare `on` TaskCore.taskUpdatedAt) allTasks
      pure (HomePage stats readyTasks recentTasks)

    readyQueueHandler :: Servant.Handler ReadyQueuePage
    readyQueueHandler = do
      readyTasks <- liftIO TaskCore.getReadyTasks
      let sortedTasks = List.sortBy (compare `on` TaskCore.taskPriority) readyTasks
      pure (ReadyQueuePage sortedTasks)

    taskListHandler :: Maybe TaskCore.Status -> Maybe TaskCore.Priority -> Maybe Text -> Servant.Handler TaskListPage
    taskListHandler maybeStatus maybePriority maybeNamespace = do
      allTasks <- liftIO TaskCore.loadTasks
      let filters = TaskFilters maybeStatus maybePriority (emptyToNothing maybeNamespace)
          filteredTasks = applyFilters filters allTasks
      pure (TaskListPage filteredTasks filters)

    emptyToNothing :: Maybe Text -> Maybe Text
    emptyToNothing (Just t) | Text.null (Text.strip t) = Nothing
    emptyToNothing x = x

    applyFilters :: TaskFilters -> [TaskCore.Task] -> [TaskCore.Task]
    applyFilters filters = filter matchesAllFilters
      where
        matchesAllFilters task =
          matchesStatus task
            && matchesPriority task
            && matchesNamespace task

        matchesStatus task = case filterStatus filters of
          Nothing -> True
          Just s -> TaskCore.taskStatus task == s

        matchesPriority task = case filterPriority filters of
          Nothing -> True
          Just p -> TaskCore.taskPriority task == p

        matchesNamespace task = case filterNamespace filters of
          Nothing -> True
          Just ns -> case TaskCore.taskNamespace task of
            Nothing -> False
            Just taskNs -> ns `Text.isPrefixOf` taskNs

    taskDetailHandler :: Text -> Servant.Handler TaskDetailPage
    taskDetailHandler tid = do
      tasks <- liftIO TaskCore.loadTasks
      case TaskCore.findTask tid tasks of
        Nothing -> pure (TaskDetailNotFound tid)
        Just task -> pure (TaskDetailFound task tasks)

    taskStatusHandler :: Text -> StatusForm -> Servant.Handler (Headers '[Header "Location" Text] NoContent)
    taskStatusHandler tid (StatusForm newStatus) = do
      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

run :: Warp.Port -> IO ()
run port = do
  putText <| "Starting Jr web server on port " <> tshow port
  Warp.run port app