{-# LANGUAGE DeriveDataTypeable, FlexibleInstances, OverloadedStrings, ScopedTypeVariables, TupleSections #-}
module Debian.Debianize.Atoms
    ( Atoms
    -- * Modes of operation
    , verbosity
    , dryRun
    , validate
    , debAction
    , flags
    , warning
    -- * Cabal info
    , compilerVersion
    , packageDescription
    , buildDir
    , dataDir
    , compiler
    , extraLibMap
    , execMap
    , cabalFlagAssignments
    -- * Global debian info
    , versionSplits
    , epochMap
    -- * High level information about the debianization
    , description
    , executable
    , serverInfo
    , website
    , backups
    , apacheSite
    , missingDependencies
    , utilsPackageName
    , sourcePackageName
    , revision
    , debVersion
    , maintainer
    , packageInfo
    , omitLTDeps
    , noProfilingLibrary
    , noDocumentationLibrary
    , copyright
    , sourceArchitecture
    , binaryArchitectures
    , sourcePriority
    , binaryPriorities
    , sourceSection
    , binarySections
    , buildDeps
    , buildDepsIndep
    , depends
    , conflicts
    , extraDevDeps
    -- * Debianization files and file fragments
    , rulesHead
    , rulesFragments
    , postInst
    , postRm
    , preInst
    , preRm
    , compat
    , sourceFormat
    , watch
    , changelog
    , comments
    , control
    , standards
    , logrotateStanza
    , link
    , install
    , installTo
    , installData
    , file
    , installCabalExec
    , installCabalExecTo
    , installDir
    , installInit
    , intermediateFiles
    ) where

import Data.Generics (Data, Typeable)
import Data.Lens.Lazy (Lens, lens, getL, modL)
import Data.Map as Map (Map, fold, foldWithKey, insertWith, empty, insert)
import Data.Maybe (fromMaybe)
import Data.Monoid (Monoid(..))
import Data.Set as Set (Set, maxView, empty, union, singleton, fold, insert)
import Data.Text (Text)
import Data.Version (Version, showVersion)
import Debian.Changes (ChangeLog)
import Debian.Debianize.ControlFile (SourceDebDescription(standardsVersion), newSourceDebDescription)
import Debian.Debianize.Types (PackageInfo(..), Site(..), Server(..), InstallFile(..), VersionSplits(..), DebAction(..))
import Debian.Orphans ()
import Debian.Policy (PackageArchitectures, SourceFormat, PackagePriority, Section, StandardsVersion)
import Debian.Relation (SrcPkgName, BinPkgName, Relation(..))
import Debian.Version (DebianVersion)
import Distribution.License (License)
import Distribution.Package (PackageName(PackageName), PackageIdentifier(..))
import Distribution.PackageDescription as Cabal (PackageDescription(package), FlagName, PackageDescription)
import Distribution.Simple.Compiler (Compiler)
import Prelude hiding (init, unlines, log)
import System.FilePath ((</>))
import Text.ParserCombinators.Parsec.Rfc2822 (NameAddr)

-- All the internals of this module is a steaming pile of poo, except
-- for the stuff that is exported.

data DebAtomKey
    = Source
    | Binary BinPkgName
    deriving (Eq, Ord, Data, Typeable, Show)

-- | The smallest pieces of debhelper information.  Some of these are
-- converted directly into files in the debian directory, others
-- become fragments of those files, and others are first converted
-- into different DebAtom values as new information becomes available.
data DebAtom
    = NoDocumentationLibrary
    -- ^ Do not produce a libghc-foo-doc package.
    | NoProfilingLibrary
    -- ^ Do not produce a libghc-foo-prof package.
    | CompilerVersion Version
      -- ^ Specify the version number of the GHC compiler in the build
      -- environment.  The default is to assume that version is the same
      -- as the one in the environment where cabal-debian is running.
      -- This is used to look up hard coded lists of packages bundled
      -- with the compiler and their version numbers.  (This could
      -- certainly be done in a more beautiful way.)
    | DHPackageDescription PackageDescription
    -- ^ The cabal package description record
    | DHCompiler Compiler
    -- ^ The Compiler value returned with the Cabal
    -- PackageDescription, then used to determine what libraries
    -- (i.e. dependencies) are provided by the compiler.
    | BuildDir FilePath
    -- ^ The build directory used by cabal, typically dist/build when
    -- building manually or dist-ghc/build when building using GHC and
    -- haskell-devscripts.  This value is used to locate files
    -- produced by cabal so we can move them into the deb.  Note that
    -- the --builddir option of runhaskell Setup appends the "/build"
    -- to the value it receives, so, yes, try not to get confused.
    | DataDir FilePath
    -- ^ the pathname of the package's data directory, generally the
    -- value of the dataDirectory field in the PackageDescription.
    | DebSourceFormat SourceFormat                -- ^ Write debian/source/format
    | DebWatch Text                               -- ^ Write debian/watch
    | DHIntermediate FilePath Text                -- ^ Put this text into a file with the given name in the debianization.
    | DebRulesHead Text				  -- ^ The header of the debian/rules file.  The remainder is assembled
                                                  -- from DebRulesFragment values in the atom list.
    | DebRulesFragment Text                       -- ^ A Fragment of debian/rules
    | Warning Text                                -- ^ A warning to be reported later
    | UtilsPackageName BinPkgName                 -- ^ Name to give the package for left-over data files and executables
    | DebChangeLog ChangeLog			  -- ^ The changelog, first entry contains the source package name and version
    | DebLogComments [[Text]]			  -- ^ Each element is a comment to be added to the changelog, where the
                                                  -- element's text elements are the lines of the comment.
    | SourcePackageName SrcPkgName                -- ^ Name to give to debian source package.  If not supplied name is constructed
                                                  -- from the cabal package name.
    | DHMaintainer NameAddr			  -- ^ Value for the maintainer field in the control file.  Note that
                                                  -- the cabal maintainer field can have multiple addresses, but debian
                                                  -- only one.  If this is not explicitly set, it is obtained from the
                                                  -- cabal file, and if it is not there then from the environment.  As a
                                                  -- last resort, there is a hard coded string in here somewhere.
    | DHCabalFlagAssignments (Set (FlagName, Bool)) -- ^ Flags to pass to Cabal function finalizePackageDescription, this
                                                  -- can be used to control the flags in the cabal file.
    | DHFlags Flags                               -- ^ Information regarding mode of operation - verbosity, dry-run, usage, etc
    | DebRevision String			  -- ^ Specify the revision string to use when converting the cabal
                                                  -- version to debian.

    | OmitLTDeps				  -- ^ If present, don't generate the << dependency when we see a cabal
                                                  -- equals dependency.  (The implementation of this was somehow lost.)
    | DebVersion DebianVersion			  -- ^ Specify the exact debian version of the resulting package,
                                                  -- including epoch.  One use case is to work around the the
                                                  -- "buildN" versions that are often uploaded to the debian and
                                                  -- ubuntu repositories.  Say the latest cabal version of
                                                  -- transformers is 0.3.0.0, but the debian repository contains
                                                  -- version 0.3.0.0-1build3, we need to specify
                                                  -- debVersion="0.3.0.0-1build3" or the version we produce will
                                                  -- look older than the one already available upstream.
    | DebVersionSplits [VersionSplits]		  -- ^ Instances where the debian package name is different (for
                                                  -- some range of version numbers) from the default constructed
                                                  -- by mkPkgName.
    | BuildDep BinPkgName			  -- ^ Add a build dependency (FIXME: should be a Rel, or an OrRelation, not a BinPkgName)
    | BuildDepIndep BinPkgName			  -- ^ Add an arch independent build dependency
    | MissingDependency BinPkgName		  -- ^ Lets cabal-debian know that a package it might expect to exist
                                                  -- actually does not, so omit all uses in resulting debianization.
    | ExtraLibMapping String BinPkgName		  -- ^ Map a cabal Extra-Library name to a debian binary package name,
                                                  -- e.g. @ExtraLibMapping extraLibMap "cryptopp" "libcrypto-dev"@ adds a
                                                  -- build dependency on @libcrypto-dev@ to any package that has @cryptopp@
                                                  -- in its cabal Extra-Library list.
    | ExecMapping String BinPkgName		  -- ^ Map a cabal Build-Tool name to a debian binary package name,
                                                  -- e.g. @ExecMapping "trhsx" "haskell-hsx-utils"@ adds a build
                                                  -- dependency on @haskell-hsx-utils@ to any package that has @trhsx@ in its
                                                  -- cabal build-tool list.
    | EpochMapping PackageName Int		  -- ^ Specify epoch numbers for the debian package generated from a
                                                  -- cabal package.  Example: @EpochMapping (PackageName "HTTP") 1@.
    | DebPackageInfo PackageInfo		  -- ^ Supply some info about a cabal package.
    | DebCompat Int				  -- ^ The debhelper compatibility level, from debian/compat.
    | DebCopyright (Either License Text)	  -- ^ Copyright information, either as a Cabal License value or
                                                  -- the full text.
    | DebControl SourceDebDescription		  -- ^ The parsed contents of the control file

    -- From here down are atoms to be associated with a Debian binary
    -- package.  This could be done with more type safety, separate
    -- maps for the Source atoms and the Binary atoms.
    | DHApacheSite String FilePath Text           -- ^ Have Apache configure a site using PACKAGE, DOMAIN, LOGDIR, and APACHECONFIGFILE
    | DHLogrotateStanza Text		          -- ^ Add a stanza of a logrotate file to the binary package
    | DHLink FilePath FilePath          	  -- ^ Create a symbolic link in the binary package
    | DHPostInst Text			 	  -- ^ Script to run after install, should contain #DEBHELPER# line before exit 0
    | DHPostRm Text                     	  -- ^ Script to run after remove, should contain #DEBHELPER# line before exit 0
    | DHPreInst Text                    	  -- ^ Script to run before install, should contain #DEBHELPER# line before exit 0
    | DHPreRm Text                      	  -- ^ Script to run before remove, should contain #DEBHELPER# line before exit 0
    | DHArch PackageArchitectures       	  -- ^ Set the Architecture field of source or binary
    | DHPriority PackagePriority	       	  -- ^ Set the Priority field of source or binary
    | DHSection Section			       	  -- ^ Set the Section field of source or binary
    | DHDescription Text		       	  -- ^ Set the description of source or binary
    | DHInstall FilePath FilePath       	  -- ^ Install a build file into the binary package
    | DHInstallTo FilePath FilePath     	  -- ^ Install a build file into the binary package at an exact location
    | DHInstallData FilePath FilePath   	  -- ^ DHInstallTo somewhere relative to DataDir (see above)
    | DHFile FilePath Text              	  -- ^ Create a file with the given text at the given path
    | DHInstallCabalExec String FilePath	  -- ^ Install a cabal executable into the binary package
    | DHInstallCabalExecTo String FilePath	  -- ^ Install a cabal executable into the binary package at an exact location
    | DHInstallDir FilePath             	  -- ^ Create a directory in the binary package
    | DHInstallInit Text                	  -- ^ Add an init.d file to the binary package
    | DHExecutable InstallFile                    -- ^ Create a binary package to hold a cabal executable
    | DHServer Server                             -- ^ Like DHExecutable, but configure the executable as a server process
    | DHWebsite Site                              -- ^ Like DHServer, but configure the server as a web server
    | DHBackups String                            -- ^ Configure the executable to do incremental backups
    | Depends Relation				  -- ^ Says that the debian package should have this relation in Depends
    | Conflicts Relation			  -- ^ Says that the debian package should have this relation in Conflicts
    | DevDepends BinPkgName			  -- ^ Limited version of Depends, put a dependency on the dev library package.  The only
                                                  -- reason to use this is because we don't yet know the name of the dev library package.
    deriving (Eq, Ord, Show, Typeable)

-- | This record supplies information about the task we want done -
-- debianization, validataion, help message, etc.
data Flags = Flags
    {
    -------------------------
    -- Modes of Operation ---
    -------------------------
      verbosity_ :: Int
    -- ^ Run with progress messages at the given level of verboseness.
    , dryRun_ :: Bool
    -- ^ Don't write any files or create any directories, just explain
    -- what would have been done.
    , validate_ :: Bool
    -- ^ Fail if the debianization already present doesn't match the
    -- one we are going to generate closely enough that it is safe to
    -- debianize during the run of dpkg-buildpackage, when Setup
    -- configure is run.  Specifically, the version number in the top
    -- changelog entry must match, and the sets of package names in
    -- the control file must match.
    , debAction_ :: DebAction
    -- ^ What to do - Usage, Debianize or Substvar
    } deriving (Eq, Ord, Show)

-- | Bits and pieces of information about the mapping from cabal package
-- names and versions to debian package names and versions.  In essence,
-- an 'Atoms' value represents a package's debianization.  The lenses in
-- this module are used to get and set the values hidden in this Atoms
-- value.  Many of the values should be left alone to be set when the
-- debianization is finalized.
newtype Atoms = Atoms (Map DebAtomKey (Set DebAtom)) deriving (Eq, Show)

instance Monoid Atoms where
    -- We need mempty to actually be an empty map because we test for
    -- this in the expandAtoms recursion.
    mempty = Atoms mempty -- defaultAtoms
    mappend a b = foldAtoms insertAtom a b

-- Lenses to access values in the Atoms type.  This is an old
-- design which I plan to make private and turn into something
-- nicer, so these will remain ugly and repetitive for now.

-- | Set how much progress messages get generated.
verbosity :: Lens Atoms Int
verbosity = lens (\ a -> verbosity_ (getL flags a)) (\ b a -> modL flags (\ x -> x {verbosity_ = b}) a)

-- | Don't write anything, just output a description of what would have happened
dryRun :: Lens Atoms Bool
dryRun = lens (\ a -> dryRun_ (getL flags a)) (\ b a -> modL flags (\ x -> x {dryRun_ = b}) a)

-- | Make sure the version number and package names of the generated debianization match the
validate :: Lens Atoms Bool
validate = lens (\ a -> validate_ (getL flags a)) (\ b a -> modL flags (\ x -> x {validate_ = b}) a)

-- | Debianize, SubstVars, or Usage.  I'm no longer sure what SubstVars does, but someone
-- may still be using it.
debAction :: Lens Atoms DebAction
debAction = lens (\ a -> debAction_ (getL flags a)) (\ b a -> modL flags (\ x -> x {debAction_ = b}) a)

-- | Obsolete record containing verbosity, dryRun, validate, and debAction.
flags :: Lens Atoms Flags
flags = lens g s
    where
      g atoms = fromMaybe defaultFlags $ foldAtoms from Nothing atoms
          where
            from Source (DHFlags x') (Just x) | x /= x' = error $ "Conflicting control values:" ++ show (x, x')
            from Source (DHFlags x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const ((singleton . (Source,) . DHFlags) x)) atoms
          where
            f Source (DHFlags y) = Just y
            f _ _ = Nothing

-- | Unused
warning :: Lens Atoms (Set Text)
warning = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (Warning t) x = Set.insert t x
            from _ _ x = x
      s x atoms = Set.fold (\ text atoms' -> insertAtom Source (Warning text) atoms') (deleteAtoms p atoms) x
          where
            p Source (Warning _) = True
            p _ _ = False


-- | Set the compiler version, this is used when loading the cabal file to
compilerVersion :: Lens Atoms (Maybe Version)
compilerVersion = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (CompilerVersion x') (Just x) | x /= x' = error $ "Conflicting compat values:" ++ show (x, x')
            from Source (CompilerVersion x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . CompilerVersion) x)) atoms
          where
            f Source (CompilerVersion y) = Just y
            f _ _ = Nothing

-- | The information loaded from the cabal file.
packageDescription :: Lens Atoms (Maybe PackageDescription)
packageDescription = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DHPackageDescription x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DHPackageDescription x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DHPackageDescription) x)) atoms
          where
            f Source (DHPackageDescription y) = Just y
            f _ _ = Nothing

-- | The build directory.  This can be set by an argument to the @Setup@ script.
-- When @Setup@ is run manually it is just @dist@, when it is run by
-- @dpkg-buildpackage@ the compiler name is appended, so it is typically
-- @dist-ghc@.  Cabal-debian needs the correct value of buildDir to find
-- the build results.
buildDir :: Lens Atoms (Maybe FilePath)
buildDir = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (BuildDir x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (BuildDir x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . BuildDir) x)) atoms
          where
            f Source (BuildDir y) = Just y
            f _ _ = Nothing

-- | The data directory for the package, generated from the packageDescription
dataDir :: Lens Atoms (Maybe FilePath)
dataDir = lens g s
    where
      g atoms =
          fmap (\ p -> let PackageName pkgname = pkgName. package $ p in
                       "usr/share" </> (pkgname ++ "-" ++ (showVersion . pkgVersion . package $ p))) (getL packageDescription atoms)
      s _ _ = error "setL dataDir"


-- | The Compiler value returned when the cabal file was loaded.
compiler :: Lens Atoms (Maybe Compiler)
compiler = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DHCompiler x') (Just x) | x /= x' = error $ "Conflicting compat values:" ++ show (x, x')
            from Source (DHCompiler x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DHCompiler) x)) atoms
          where
            f Source (DHCompiler y) = Just y
            f _ _ = Nothing

-- | Map from cabal Extra-Lib names to debian binary package names.
extraLibMap :: Lens Atoms (Map String (Set BinPkgName))
extraLibMap = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from Source (ExtraLibMapping cabal debian) x = Map.insertWith union cabal (singleton debian) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ cabal debian atoms' -> Set.fold (\ debian' atoms'' -> insertAtom Source (ExtraLibMapping cabal debian') atoms'') atoms' debian) (deleteAtoms p atoms) x
          where
            p Source (ExtraLibMapping _ _) = True
            p _ _ = False

-- | Map from cabal Build-Tool names to debian binary package names.
execMap :: Lens Atoms (Map String BinPkgName)
execMap = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from Source (ExecMapping cabal debian) x = Map.insertWith (error "Conflict in execMap") cabal debian x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ cabal debian atoms' -> insertAtom Source (ExecMapping cabal debian) atoms') (deleteAtoms p atoms) x
          where
            p Source (ExecMapping _ _) = True
            p _ _ = False

-- | Cabal flag assignments to use when loading the cabal file.
cabalFlagAssignments :: Lens Atoms (Set (FlagName, Bool))
cabalFlagAssignments = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (DHCabalFlagAssignments pairs) x = union pairs x
            from _ _ x = x
      s x atoms = insertAtom Source (DHCabalFlagAssignments x) (deleteAtoms p atoms)
          where
            p Source (DHCabalFlagAssignments _) = True
            p _ _ = False

-- | Map from cabal version number ranges to debian package names.  This is a
-- result of the fact that only one version of a debian package can be
-- installed at a given time, while multiple versions of a cabal packages can.
versionSplits :: Lens Atoms [VersionSplits]
versionSplits = lens g s
    where
      g atoms = foldAtoms from [] atoms
          where
            from Source (DebVersionSplits xs') xs = xs ++ xs'
            from _ _ xs = xs
      s x atoms = insertAtom Source (DebVersionSplits x) (deleteAtoms p atoms)
          where
            p Source (DebVersionSplits _) = True
            p _ _ = False

-- | Map of Debian epoch numbers assigned to cabal packages.
epochMap :: Lens Atoms (Map PackageName Int)
epochMap = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from Source (EpochMapping name epoch) x = Map.insertWith (error "Conflicting Epochs") name epoch x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ name epoch atoms' -> insertAtom Source (EpochMapping name epoch) atoms') (deleteAtoms p atoms) x
          where
            p Source (EpochMapping _ _) = True
            p _ _ = False

-- | Map of binary deb descriptions.
description :: Lens Atoms (Map BinPkgName Text)
description = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHDescription d) x = Map.insertWith (error "description") b d x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b y atoms'-> insertAtom (Binary b) (DHDescription y) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHDescription _) = True
            p _ _ = False

-- | Create a package to hold a cabal executable
executable :: Lens Atoms (Map BinPkgName InstallFile)
executable = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHExecutable f) x = Map.insertWith (error "executable") b f x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b y atoms'-> insertAtom (Binary b) (DHExecutable y) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHExecutable _) = True
            p _ _ = False

-- | Create a package for an operating service using the given executable
serverInfo :: Lens Atoms (Map BinPkgName Server)
serverInfo = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHServer s) x = Map.insertWith (error "server") b s x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b y atoms'-> insertAtom (Binary b) (DHServer y) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHServer _) = True
            p _ _ = False

-- | Create a package for a website using the given executable as the server
website :: Lens Atoms (Map BinPkgName Site)
website = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHWebsite s) x = Map.insertWith (error "website") b s x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b y atoms'-> insertAtom (Binary b) (DHWebsite y) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHWebsite _) = True
            p _ _ = False

-- | Generate a backups package using the given cabal executable
backups :: Lens Atoms (Map BinPkgName String)
backups = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHBackups s) x = Map.insertWith (error "backups") b s x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b y atoms'-> insertAtom (Binary b) (DHBackups y) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHBackups _) = True
            p _ _ = False

-- | Create an apache configuration file with the given
-- (domain, logdir, filetext).  This is called when expanding
-- the result of the website lens above.
apacheSite :: Lens Atoms (Map BinPkgName (String, FilePath, Text))
apacheSite = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHApacheSite dom log text) x = Map.insertWith (error "backups") b (dom, log, text) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b (dom, log, text) atoms' -> insertAtom (Binary b) (DHApacheSite dom log text) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHApacheSite _ _ _) = True
            p _ _ = False

-- * Lower level hints about the debianization


-- | List if packages that should be omitted from any
-- dependency list - e.g. a profiling package missing due
-- to use of noProfilingPackage lens elsewhere.
missingDependencies :: Lens Atoms (Set BinPkgName)
missingDependencies = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (MissingDependency b) x = Set.insert b x
            from _ _ x = x
      s x atoms = Set.fold (\ b atoms' -> insertAtom Source (MissingDependency b) atoms') (deleteAtoms p atoms) x
          where
            p Source (MissingDependency _) = True
            p _ _ = False

-- | Override the package name used to hold left over data files and executables
utilsPackageName :: Lens Atoms (Maybe BinPkgName)
utilsPackageName = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (UtilsPackageName x') (Just x) | x /= x' = error $ "Conflicting compat values:" ++ show (x, x')
            from Source (UtilsPackageName x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . UtilsPackageName) x)) atoms
          where
            f Source (UtilsPackageName y) = Just y
            f _ _ = Nothing

-- | Override the debian source package name constructed from the cabal name
sourcePackageName :: Lens Atoms (Maybe SrcPkgName)
sourcePackageName = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (SourcePackageName x') (Just x) | x /= x' = error $ "Conflicting compat values:" ++ show (x, x')
            from Source (SourcePackageName x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . SourcePackageName) x)) atoms
          where
            f Source (SourcePackageName y) = Just y
            f _ _ = Nothing

-- | Revision string used in constructing the debian verison number from the cabal version
revision :: Lens Atoms (Maybe String)
revision = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebRevision x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DebRevision x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebRevision) x)) atoms
          where
            f Source (DebRevision y) = Just y
            f _ _ = Nothing

-- | Exact debian version number, overrides the version generated from the cabal version
debVersion :: Lens Atoms (Maybe DebianVersion)
debVersion = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebVersion x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DebVersion x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebVersion) x)) atoms
          where
            f Source (DebVersion y) = Just y
            f _ _ = Nothing

-- | Maintainer field.  Overrides any value found in the cabal file, or
-- in the DEBIANMAINTAINER environment variable.
maintainer :: Lens Atoms (Maybe NameAddr)
maintainer = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DHMaintainer x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DHMaintainer x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DHMaintainer) x)) atoms
          where
            f Source (DHMaintainer y) = Just y
            f _ _ = Nothing

-- | No longer sure what the purpose of this lens is.
packageInfo :: Lens Atoms (Map PackageName PackageInfo)
packageInfo = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from Source (DebPackageInfo i) x = Map.insert (cabalName i) i x
            from _ _ x = x
      s x atoms =
          Map.fold (\ i atoms' -> insertAtom Source (DebPackageInfo i) atoms') (deleteAtoms p atoms) x
          where
            p Source (DebPackageInfo _) = True
            p _ _ = False

-- | Set this to filter any less-than dependencies out of the generated debian
-- dependencies.  (Not sure if this is implemented.)
omitLTDeps :: Lens Atoms Bool
omitLTDeps = lens g s
    where
      g atoms = foldAtoms from False atoms
          where
            from Source OmitLTDeps _ = True
            from _ _ x = x
      s x atoms = (if x then insertAtom Source OmitLTDeps else id) (deleteAtoms p atoms)
          where
            p Source OmitLTDeps = True
            p _ _ = False

-- | Set this to omit the prof library deb.
noProfilingLibrary :: Lens Atoms Bool
noProfilingLibrary = lens g s
    where
      g atoms = foldAtoms from False atoms
          where
            from Source NoProfilingLibrary _ = True
            from _ _ x = x
      s x atoms = (if x then insertAtom Source NoProfilingLibrary else id) (deleteAtoms p atoms)
          where
            p Source NoProfilingLibrary = True
            p _ _ = False

-- | Set this to omit the doc library deb.
noDocumentationLibrary :: Lens Atoms Bool
noDocumentationLibrary = lens g s
    where
      g atoms = foldAtoms from False atoms
          where
            from Source NoDocumentationLibrary _ = True
            from _ _ x = x
      s x atoms = (if x then insertAtom Source NoDocumentationLibrary else id) (deleteAtoms p atoms)
          where
            p Source NoDocumentationLibrary = True
            p _ _ = False

-- | The copyright information
copyright :: Lens Atoms (Maybe (Either License Text))
copyright = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebCopyright x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DebCopyright x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebCopyright) x)) atoms
          where
            f Source (DebCopyright y) = Just y
            f _ _ = Nothing

-- | The source package architecture - @Any@, @All@, or some list of specific architectures.
sourceArchitecture :: Lens Atoms (Maybe PackageArchitectures)
sourceArchitecture = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DHArch x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DHArch x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DHArch) x)) atoms
          where
            f Source (DHArch y) = Just y
            f _ _ = Nothing

-- | Map of the binary package architectures
binaryArchitectures :: Lens Atoms (Map BinPkgName PackageArchitectures)
binaryArchitectures = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHArch x) m = Map.insert b x m
            from _ _ m = m
      s x atoms = Map.foldWithKey (\ b a atoms' -> insertAtom (Binary b) (DHArch a) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHArch _) = True
            p _ _ = False

-- | The source package priority
sourcePriority :: Lens Atoms (Maybe PackagePriority)
sourcePriority = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DHPriority x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DHPriority x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DHPriority) x)) atoms
          where
            f Source (DHPriority y) = Just y
            f _ _ = Nothing

-- | Map of the binary package priorities
binaryPriorities :: Lens Atoms (Map BinPkgName PackagePriority)
binaryPriorities = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHPriority p) x = Map.insertWith (error "priorities") b p x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b p atoms'-> insertAtom (Binary b) (DHPriority p) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHPriority _) = True
            p _ _ = False

-- | The source package's section assignment
sourceSection :: Lens Atoms (Maybe Section)
sourceSection = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DHSection x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DHSection x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DHSection) x)) atoms
          where
            f Source (DHSection y) = Just y
            f _ _ = Nothing

-- | Map of the binary deb section assignments
binarySections :: Lens Atoms (Map BinPkgName Section)
binarySections = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHSection p) x = Map.insertWith (error "sections") b p x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b p atoms'-> insertAtom (Binary b) (DHSection p) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHSection _) = True
            p _ _ = False

-- * Debian dependency info

-- | Build dependencies
buildDeps :: Lens Atoms (Set BinPkgName)
buildDeps = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (BuildDep d) x = Set.insert d x
            from _ _ x = x
      s x atoms = Set.fold (\ d atoms' -> insertAtom Source (BuildDep d) atoms') (deleteAtoms p atoms) x
          where
            p Source (BuildDep _) = True
            p _ _ = False

-- | Architecture independent
buildDepsIndep :: Lens Atoms (Set BinPkgName)
buildDepsIndep = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (BuildDepIndep d) x = Set.insert d x
            from _ _ x = x
      s x atoms = Set.fold (\ d atoms' -> insertAtom Source (BuildDepIndep d) atoms') (deleteAtoms p atoms) x
          where
            p Source (BuildDepIndep _) = True
            p _ _ = False

-- | Map of extra install dependencies for the package's binary debs.
-- This should be [[Relation]] for full generality, or Set (Set Relation)
depends :: Lens Atoms (Map BinPkgName (Set Relation))
depends = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (Depends rel) x = Map.insertWith union b (singleton rel) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b rels atoms' -> Set.fold (\ rel atoms'' -> insertAtom (Binary b) (Depends rel) atoms'') atoms' rels) (deleteAtoms p atoms) x
          where
            p (Binary _) (Depends _) = True
            p _ _ = False

-- | Map of extra install conflicts for the package's binary debs.
-- We should support all the other dependency fields - provides, replaces, etc.
conflicts :: Lens Atoms (Map BinPkgName (Set Relation))
conflicts = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (Conflicts rel) x = Map.insertWith union b (singleton rel) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b rels atoms' -> Set.fold (\ rel atoms'' -> insertAtom (Binary b) (Conflicts rel) atoms'') atoms' rels) (deleteAtoms p atoms) x
          where
            p (Binary _) (Conflicts _) = True
            p _ _ = False

-- | Extra install dependencies for the devel library.  Redundant
-- with depends, but kept for backwards compatibility.  Also, I
-- think maybe this is or was needed because it can be set before
-- the exact name of the library package is known.
extraDevDeps :: Lens Atoms (Set BinPkgName)
extraDevDeps = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (DevDepends b) x = Set.insert b x
            from _ _ x = x
      s x atoms = Set.fold (\ d atoms' -> insertAtom Source (DevDepends d) atoms') (deleteAtoms p atoms) x
          where
            p Source (DevDepends _) = True
            p _ _ = False

-- | The beginning of the rules file
rulesHead :: Lens Atoms (Maybe Text)
rulesHead = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebRulesHead x') (Just x) | x /= x' = error $ "Conflicting rulesHead values:" ++ show (x, x')
            from Source (DebRulesHead x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebRulesHead) x)) atoms
          where
            f Source (DebRulesHead y) = Just y
            f _ _ = Nothing

-- | Additional fragments of the rules file
rulesFragments :: Lens Atoms (Set Text)
rulesFragments = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (DebRulesFragment t) x = Set.insert t x
            from _ _ x = x
      s x atoms = Set.fold (\ text atoms' -> insertAtom Source (DebRulesFragment text) atoms') (deleteAtoms p atoms) x
          where
            p Source (DebRulesFragment _) = True
            p _ _ = False

-- | Map of @debian/postinst@ scripts
postInst :: Lens Atoms (Map BinPkgName Text)
postInst = lens g s
    where
      g atoms = foldAtoms from mempty atoms
          where
            from :: DebAtomKey -> DebAtom -> Map BinPkgName Text -> Map BinPkgName Text
            from (Binary b) (DHPostInst t) x = Map.insertWith (error "Conflicting postInsts") b t x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b t atoms' -> insertAtom (Binary b) (DHPostInst t) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHPostInst _) = True
            p _ _ = False

-- | Map of @debian/postrm@ scripts
postRm :: Lens Atoms (Map BinPkgName Text)
postRm = lens g s
    where
      g atoms = foldAtoms from mempty atoms
          where
            from :: DebAtomKey -> DebAtom -> Map BinPkgName Text -> Map BinPkgName Text
            from (Binary b) (DHPostRm t) m = Map.insertWith (error "Conflicting postRms") b t m
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b t atoms' -> insertAtom (Binary b) (DHPostRm t) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHPostRm _) = True
            p _ _ = False

-- | Map of @debian/preinst@ scripts
preInst :: Lens Atoms (Map BinPkgName Text)
preInst = lens g s
    where
      g atoms = foldAtoms from mempty atoms
          where
            from :: DebAtomKey -> DebAtom -> Map BinPkgName Text -> Map BinPkgName Text
            from (Binary b) (DHPreInst t) m = Map.insertWith (error "Conflicting preInsts") b t m
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b t atoms' -> insertAtom (Binary b) (DHPreInst t) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHPreInst _) = True
            p _ _ = False

-- | Map of @debian/prerm@ scripts
preRm :: Lens Atoms (Map BinPkgName Text)
preRm = lens g s
    where
      g atoms = foldAtoms from mempty atoms
          where
            from :: DebAtomKey -> DebAtom -> Map BinPkgName Text -> Map BinPkgName Text
            from (Binary b) (DHPreRm t) m = Map.insertWith (error "Conflicting preRms") b t m
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b t atoms' -> insertAtom (Binary b) (DHPreRm t) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHPreRm _) = True
            p _ _ = False

-- | The @debian/compat@ file, contains the minimum compatible version of the @debhelper@ package
compat :: Lens Atoms (Maybe Int)
compat = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebCompat x') (Just x) | x /= x' = error $ "Conflicting compat values:" ++ show (x, x')
            from Source (DebCompat x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebCompat) x)) atoms
          where
            f Source (DebCompat y) = Just y
            f _ _ = Nothing

-- | The @debian/source/format@ file.
sourceFormat :: Lens Atoms (Maybe SourceFormat)
sourceFormat = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebSourceFormat x') (Just x) | x /= x' = error $ "Conflicting compat values:" ++ show (x, x')
            from Source (DebSourceFormat x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebSourceFormat) x)) atoms
          where
            f Source (DebSourceFormat y) = Just y
            f _ _ = Nothing

-- | the @debian/watch@ file
watch :: Lens Atoms (Maybe Text)
watch = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebWatch x') (Just x) | x /= x' = error $ "Conflicting watch values:" ++ show (x, x')
            from Source (DebWatch x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebWatch) x)) atoms
          where
            f Source (DebWatch y) = Just y
            f _ _ = Nothing

-- | the @debian/changelog@ file
changelog :: Lens Atoms (Maybe ChangeLog)
changelog = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebChangeLog x') (Just x) | x /= x' = error $ "Conflicting compat values:" ++ show (x, x')
            from Source (DebChangeLog x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebChangeLog) x)) atoms
          where
            f Source (DebChangeLog y) = Just y
            f _ _ = Nothing

-- | Comment entries for the latest changelog entry (DebLogComments [[Text]])
comments :: Lens Atoms (Maybe [[Text]])
comments = lens g s
    where
      g atoms = foldAtoms from Nothing atoms
          where
            from Source (DebLogComments xss') (Just xss) | xss == xss' = error $ "Conflicting log comments: " ++ show (xss, xss')
            from Source (DebLogComments xss) _ = Just xss
            from _ _ x = x
      s x atoms = modifyAtoms' f (const (maybe Set.empty (singleton . (Source,) . DebLogComments) x)) atoms
          where
            f Source (DebLogComments y) = Just y
            f _ _ = Nothing

-- | The @debian/control@ file.
control :: Lens Atoms SourceDebDescription
control = lens g s
    where
      g atoms = fromMaybe newSourceDebDescription $ foldAtoms from Nothing atoms
          where
            from Source (DebControl x') (Just x) | x /= x' = error $ "Conflicting control values:" ++ show (x, x')
            from Source (DebControl x) _ = Just x
            from _ _ x = x
      s x atoms = modifyAtoms' f (const ((singleton . (Source,) . DebControl) x)) atoms
          where
            f Source (DebControl y) = Just y
            f _ _ = Nothing

-- | The @Standards-Version@ field of the @debian/control@ file
standards :: Lens Atoms (Maybe StandardsVersion)
standards = lens (\ a -> standardsVersion (getL control a)) (\ b a -> modL control (\ x -> x {standardsVersion = b}) a)
logrotateStanza :: Lens Atoms (Map BinPkgName (Set Text))
logrotateStanza = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHLogrotateStanza r) x = Map.insertWith Set.union b (singleton r) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b ts atoms'-> Set.fold (\ t atoms'' -> insertAtom (Binary b) (DHLogrotateStanza t) atoms'') atoms' ts) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHLogrotateStanza _) = True
            p _ _ = False
link :: Lens Atoms (Map BinPkgName (Set (FilePath, FilePath)))
link = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHLink loc txt) x = Map.insertWith Set.union b (singleton (loc, txt)) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b pairs atoms'-> Set.fold (\ (loc, txt) atoms'' -> insertAtom (Binary b) (DHLink loc txt) atoms'') atoms' pairs) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHLink _ _) = True
            p _ _ = False

-- | Install files into directories
install :: Lens Atoms (Map BinPkgName (Set (FilePath, FilePath)))
install = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHInstall src dst) x = Map.insertWith Set.union b (singleton (src, dst)) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b pairs atoms'-> Set.fold (\ (src, dst) atoms'' -> insertAtom (Binary b) (DHInstall src dst) atoms'') atoms' pairs) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHInstall _ _) = True
            p _ _ = False

-- | Rename and install files
installTo :: Lens Atoms (Map BinPkgName (Set (FilePath, FilePath)))
installTo = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHInstallTo src dst) x = Map.insertWith Set.union b (singleton (src, dst)) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b pairs atoms'-> Set.fold (\ (src, dst) atoms'' -> insertAtom (Binary b) (DHInstallTo src dst) atoms'') atoms' pairs) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHInstallTo _ _) = True
            p _ _ = False

-- | Install files into the package data directory
installData :: Lens Atoms (Map BinPkgName (Set (FilePath, FilePath)))
installData = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHInstallData src dst) x = Map.insertWith Set.union b (singleton (src, dst)) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b pairs atoms'-> Set.fold (\ (src, dst) atoms'' -> insertAtom (Binary b) (DHInstallData src dst) atoms'') atoms' pairs) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHInstallData _ _) = True
            p _ _ = False

-- | Create a file in the deb with the given text
file :: Lens Atoms (Map BinPkgName (Set (FilePath, Text)))
file = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHFile path text) x = Map.insertWith Set.union b (singleton (path, text)) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b pairs atoms'-> Set.fold (\ (path, text) atoms'' -> insertAtom (Binary b) (DHFile path text) atoms'') atoms' pairs) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHFile _ _) = True
            p _ _ = False

-- | Install a cabal executable
installCabalExec :: Lens Atoms (Map BinPkgName (Set (String, FilePath)))
installCabalExec = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHInstallCabalExec name dst) x = Map.insertWith Set.union b (singleton (name, dst)) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b pairs atoms'-> Set.fold (\ (name, dst) atoms'' -> insertAtom (Binary b) (DHInstallCabalExec name dst) atoms'') atoms' pairs) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHInstallCabalExec _ _) = True
            p _ _ = False

-- | Rename and install a cabal executable
installCabalExecTo :: Lens Atoms (Map BinPkgName (Set (String, FilePath)))
installCabalExecTo = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHInstallCabalExecTo name dst) x = Map.insertWith Set.union b (singleton (name, dst)) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b pairs atoms'-> Set.fold (\ (name, dst) atoms'' -> insertAtom (Binary b) (DHInstallCabalExecTo name dst) atoms'') atoms' pairs) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHInstallCabalExecTo _ _) = True
            p _ _ = False

-- | Create directories in the package
installDir :: Lens Atoms (Map BinPkgName (Set FilePath))
installDir = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHInstallDir path) x = Map.insertWith Set.union b (singleton path) x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b paths atoms'-> Set.fold (\ path atoms'' -> insertAtom (Binary b) (DHInstallDir path) atoms'') atoms' paths) (deleteAtoms p atoms) x
          where
            p (Binary _) (DHInstallDir _) = True
            p _ _ = False

-- | Create an /etc/init.d file in the package
installInit :: Lens Atoms (Map BinPkgName Text)
installInit = lens g s
    where
      g atoms = foldAtoms from Map.empty atoms
          where
            from (Binary b) (DHInstallInit text) x = Map.insertWith (error "installInit") b text x
            from _ _ x = x
      s x atoms = Map.foldWithKey (\ b text atoms'-> insertAtom (Binary b) (DHInstallInit text) atoms') (deleteAtoms p atoms) x
          where
            p (Binary _) (DHInstallInit _) = True
            p _ _ = False

-- | Create a file in the debianization.  This is used to implement the file lens above.
intermediateFiles :: Lens Atoms (Set (FilePath, Text))
intermediateFiles = lens g s
    where
      g atoms = foldAtoms from Set.empty atoms
          where
            from Source (DHIntermediate path text) x = Set.insert (path, text) x
            from _ _ x = x
      s x atoms =  Set.fold (\ (path, text) atoms' -> insertAtom Source (DHIntermediate path text) atoms') (deleteAtoms p atoms) x
          where
            p Source (DHIntermediate _ _) = True
            p _ _ = False

defaultFlags :: Flags
defaultFlags =
    Flags {
      verbosity_ = 1
    , debAction_ = Usage
    , dryRun_ = False
    , validate_ = False
    }

insertAtom :: DebAtomKey -> DebAtom -> Atoms -> Atoms
insertAtom mbin atom (Atoms x) = Atoms (insertWith union mbin (singleton atom) x)

insertAtoms :: Set (DebAtomKey, DebAtom) -> Atoms -> Atoms
insertAtoms s atoms =
    case maxView s of
      Nothing -> atoms
      Just ((k, a), s') -> insertAtoms s' (insertAtom k a atoms)

foldAtoms :: (DebAtomKey -> DebAtom -> r -> r) -> r -> Atoms -> r
foldAtoms f r0 (Atoms xs) = Map.foldWithKey (\ k s r -> Set.fold (f k) r s) r0 xs

-- | Split atoms out of an Atoms by predicate.
partitionAtoms :: (DebAtomKey -> DebAtom -> Bool) -> Atoms -> (Set (DebAtomKey, DebAtom), Atoms)
partitionAtoms f deb =
    foldAtoms g (mempty, Atoms mempty) deb
    where
      g k atom (atoms, deb') =
          case f k atom of
            True -> (Set.insert (k, atom) atoms, deb')
            False -> (atoms, insertAtom k atom deb')

deleteAtoms :: (DebAtomKey -> DebAtom -> Bool) -> Atoms -> Atoms
deleteAtoms p atoms = snd (partitionAtoms p atoms)

-- | Split atoms out of a Atoms by predicate.
partitionAtoms' :: (Ord a) => (DebAtomKey -> DebAtom -> Maybe a) -> Atoms -> (Set a, Atoms)
partitionAtoms' f deb =
    foldAtoms g (mempty, Atoms mempty) deb
    where
      g k atom (xs, deb') =
          case f k atom of
            Just x -> (Set.insert x xs, deb')
            Nothing -> (xs, insertAtom k atom deb')

-- | Like modifyAtoms, but...
modifyAtoms' :: (Ord a) =>
               (DebAtomKey -> DebAtom -> Maybe a)
            -> (Set a -> Set (DebAtomKey, DebAtom))
            -> Atoms
            -> Atoms
modifyAtoms' f g atoms =
    insertAtoms (g s) atoms'
    where
      (s, atoms') = partitionAtoms' f atoms