{-# LANGUAGE DeriveFunctor #-}
module Distribution.Client.TargetProblem (
    TargetProblem(..),
    TargetProblem',
) where

import Distribution.Client.Compat.Prelude
import Prelude ()

import Distribution.Client.ProjectPlanning    (AvailableTarget)
import Distribution.Client.TargetSelector     (SubComponentTarget, TargetSelector)
import Distribution.Package                   (PackageId, PackageName)
import Distribution.Simple.LocalBuildInfo     (ComponentName (..))
import Distribution.Types.UnqualComponentName (UnqualComponentName)

-- | Target problems that occur during project orchestration.
data TargetProblem a
    = TargetNotInProject                   PackageName
    | TargetAvailableInIndex               PackageName

    | TargetComponentNotProjectLocal
      PackageId ComponentName SubComponentTarget

    | TargetComponentNotBuildable
      PackageId ComponentName SubComponentTarget

    | TargetOptionalStanzaDisabledByUser
      PackageId ComponentName SubComponentTarget

    | TargetOptionalStanzaDisabledBySolver
      PackageId ComponentName SubComponentTarget

    | TargetProblemUnknownComponent
      PackageName (Either UnqualComponentName ComponentName)

    | TargetProblemNoneEnabled TargetSelector [AvailableTarget ()]
      -- ^ The 'TargetSelector' matches component (test/benchmark/...) but none are buildable

    | TargetProblemNoTargets TargetSelector
      -- ^ There are no targets at all

    -- The target matching stuff only returns packages local to the project,
    -- so these lookups should never fail, but if 'resolveTargets' is called
    -- directly then of course it can.
    | TargetProblemNoSuchPackage           PackageId
    | TargetProblemNoSuchComponent         PackageId ComponentName

      -- | A custom target problem
    | CustomTargetProblem a
  deriving (Eq, Show, Functor)

-- | Type alias for a 'TargetProblem' with no user-defined problems/errors.
--
-- Can use the utilities below for reporting/rendering problems.
type TargetProblem' = TargetProblem Void