-----------------------------------------------------------------------------
-- |
-- Module      :  Distribution.Package
-- Copyright   :  Isaac Jones 2003-2004
--
-- Maintainer  :  cabal-devel@haskell.org
-- Portability :  portable
--
-- Defines a package identifier along with a parser and pretty printer for it.
-- 'PackageIdentifier's consist of a name and an exact version. It also defines
-- a 'Dependency' data type. A dependency is a package name and a version
-- range, like @\"foo >= 1.2 && < 2\"@.

{- All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * Neither the name of Isaac Jones nor the names of other
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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module Distribution.Package (
        -- * Package ids
        PackageName(..),
        PackageIdentifier(..),
        PackageId,

        -- * Package dependencies
        Dependency(..),
        thisPackageVersion,
        notThisPackageVersion,

        -- * Package classes
        Package(..), packageName, packageVersion,
        PackageFixedDeps(..),
  ) where

import Distribution.Version
         ( Version(..), VersionRange, anyVersion, thisVersion, notThisVersion )

import Distribution.Text (Text(..))
import qualified Distribution.Compat.ReadP as Parse
import Distribution.Compat.ReadP ((<++))
import qualified Text.PrettyPrint as Disp
import Text.PrettyPrint ((<>), (<+>))
import qualified Data.Char as Char ( isDigit, isAlphaNum )
import Data.List ( intersperse )

newtype PackageName = PackageName String
    deriving (Read, Show, Eq, Ord)

instance Text PackageName where
  disp (PackageName n) = Disp.text n
  parse = do
    ns <- Parse.sepBy1 component (Parse.char '-')
    return (PackageName (concat (intersperse "-" ns)))
    where
      component = do
        cs <- Parse.munch1 Char.isAlphaNum
        if all Char.isDigit cs then Parse.pfail else return cs
        -- each component must contain an alphabetic character, to avoid
        -- ambiguity in identifiers like foo-1 (the 1 is the version number).

-- | Type alias so we can use the shorter name PackageId.
type PackageId = PackageIdentifier

-- | The name and version of a package.
data PackageIdentifier
    = PackageIdentifier {
        pkgName    :: PackageName, -- ^The name of this package, eg. foo
        pkgVersion :: Version -- ^the version of this package, eg 1.2
     }
     deriving (Read, Show, Eq, Ord)

instance Text PackageIdentifier where
  disp (PackageIdentifier n v) = case v of
    Version [] _ -> disp n -- if no version, don't show version.
    _            -> disp n <> Disp.char '-' <> disp v

  parse = do
    n <- parse
    v <- (Parse.char '-' >> parse) <++ return (Version [] [])
    return (PackageIdentifier n v)

-- ------------------------------------------------------------
-- * Package dependencies
-- ------------------------------------------------------------

data Dependency = Dependency PackageName VersionRange
                  deriving (Read, Show, Eq)

instance Text Dependency where
  disp (Dependency name ver) =
    disp name <+> disp ver

  parse = do name <- parse
             Parse.skipSpaces
             ver <- parse <++ return anyVersion
             Parse.skipSpaces
             return (Dependency name ver)

thisPackageVersion :: PackageIdentifier -> Dependency
thisPackageVersion (PackageIdentifier n v) =
  Dependency n (thisVersion v)

notThisPackageVersion :: PackageIdentifier -> Dependency
notThisPackageVersion (PackageIdentifier n v) =
  Dependency n (notThisVersion v)

-- | Class of things that can be identified by a 'PackageIdentifier'
--
-- Types in this class are all notions of a package. This allows us to have
-- different types for the different phases that packages go though, from
-- simple name\/id, package description, configured or installed packages.
--
class Package pkg where
  packageId :: pkg -> PackageIdentifier

packageName    :: Package pkg => pkg -> PackageName
packageName     = pkgName    . packageId

packageVersion :: Package pkg => pkg -> Version
packageVersion  = pkgVersion . packageId

instance Package PackageIdentifier where
  packageId = id

-- | Subclass of packages that have specific versioned dependencies.
--
-- So for example a not-yet-configured package has dependencies on version
-- ranges, not specific versions. A configured or an already installed package
-- depends on exact versions. Some operations or data structures (like
--  dependency graphs) only make sense on this subclass of package types.
--
class Package pkg => PackageFixedDeps pkg where
  depends :: pkg -> [PackageIdentifier]
