%  Copyright (C) 2002-2003 David Roundy
%  This program is free software; you can redistribute it and/or modify
%  it under the terms of the GNU General Public License as published by
%  the Free Software Foundation; either version 2, or (at your option)
%  any later version.
%  This program is distributed in the hope that it will be useful,
%  but WITHOUT ANY WARRANTY; without even the implied warranty of
%  GNU General Public License for more details.
%  You should have received a copy of the GNU General Public License
%  along with this program; see the file COPYING.  If not, write to
%  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
%  Boston, MA 02110-1301, USA.

{-# OPTIONS_GHC -cpp -fglasgow-exts #-}

#include "gadts.h"

module Darcs.Repository.Prefs ( add_to_preflist, get_preflist, set_preflist,
                   defaultrepo, set_defaultrepo,
                   get_prefval, set_prefval, change_prefval,
                   boring_file_filter, darcsdir_filter,
                   FileType(..), filetype_function,
                 ) where

import System.IO.Error ( isDoesNotExistError )
import Control.Monad ( unless, when, mplus )
import Text.Regex ( Regex, mkRegex, matchRegex, )
import Data.Char ( toUpper )
import Data.Maybe ( isNothing, isJust, catMaybes )
import Data.List ( nub, isPrefixOf )
import System.Directory ( getAppUserDataDirectory, doesDirectoryExist )
import System.Environment( getEnv )
import System.FilePath ( (</>) )

import Darcs.Flags ( DarcsFlag( NoCache, NoSetDefault, DryRun, Ephemeral, RemoteRepo ) )
import Darcs.RepoPath ( AbsolutePath, ioAbsolute, toFilePath, getCurrentDirectory )
import Darcs.Utils ( catchall, stripCr )
import Darcs.IO ( ReadableDirectory(..), WriteableDirectory(..) )
import Darcs.Patch.FileName ( fp2fn )
import Darcs.External ( gzFetchFilePS, Cachable( Cachable ) )
import qualified Data.ByteString.Char8 as BC ( unpack )
import qualified Data.ByteString       as B  ( empty )
import Darcs.Global ( darcsdir )
import Darcs.Repository.Cache ( Cache(..), CacheType(..), CacheLoc(..),
                                WritableOrNot(..) )
import Darcs.URL ( is_file )


The \verb!_darcs! directory contains a \verb!prefs!  directory.  This
directory exists simply to hold user configuration settings specific to
this repository.  The contents of this directory are intended to be
modifiable by the user, although in some cases a mistake in such a
modification may cause darcs to behave strangely.


write_default_prefs :: IO ()
write_default_prefs = do set_preflist "boring" default_boring
                         set_preflist "binaries" default_binaries
                         set_preflist "motd" []

The \verb!_darcs/prefs/repos! file contains a list of repositories you have
pulled from or pushed to, and is used for autocompletion of pull and push
commands in bash.  Feel free to delete any lines from this list that might
get in there, or to delete the file as a whole.

The \verb!_darcs/prefs/author! file contains the email address (or name) to
be used as the author when patches are recorded in this repository,
e.g.\ \verb!David Roundy <droundy@abridgegame.org>!.  This
file overrides the contents of the environment variables
\verb!$DARCS_EMAIL! and \verb!$EMAIL!.

The \verb!_darcs/prefs/boring! file may contain a list of regular
expressions describing files, such as object files, that you do not expect
to add to your project.  As an example, the boring file that I use with
my darcs repository is:
A newly created repository has a longer boring file that
includes many common source control, backup, temporary, and compiled files.

You may want to have the boring file under version
control.  To do this you can use darcs setpref to set the value
``boringfile'' to the name of your desired boring file
(e.g.\ \verb-darcs setpref boringfile .boring-, where \verb-.boring-
is the repository path of a file
that has been
darcs added to your repository).  The boringfile preference overrides
\verb!_darcs/prefs/boring!, so be sure to copy that file to the boringfile.

You can also set up a ``boring'' regexps
file in your home directory, named \verb!~/.darcs/boring!, which will be
used with all of your darcs repositories.

Any file not already managed by darcs and whose repository path (such
as \verb!manual/index.html!) matches any of
the boring regular expressions is considered boring.  The boring file is
used to filter the files provided to darcs add, to allow you to use a
simple \verb-darcs add newdir newdir/*-
without accidentally adding a bunch of
object files.  It is also used when the \verb!--look-for-adds! flag is
given to whatsnew or record.
Note that once a file has been added to darcs, it is not considered
boring, even if it matches the boring file filter.

{-# NOINLINE default_boring #-}
default_boring :: [String]
default_boring = ["# Boring file regexps:",
                  "### compiler and interpreter intermediate files",
                  "# haskell (ghc) interfaces",
                  "\\.hi$", "\\.hi-boot$", "\\.o-boot$",
                  "# object files",
                  "# profiling haskell",
                  "\\.p_hi$", "\\.p_o$",
                  "# haskell program coverage resp. profiling info",
                  "\\.tix$", "\\.prof$",
                  "# fortran module files",
                  "# linux kernel",
                  "# *.ko files aren't boring by default because they might",
                  "# be Korean translations rather than kernel modules",
                  "# \\.ko$",
                  "# python, emacs, java byte code",
                  "\\.py[co]$", "\\.elc$","\\.class$",
                  "# objects and libraries; lo and la are libtool things",
                  "# compiled zsh configuration files",
                  "# Common LISP output files for CLISP and CMUCL",
                  "### build and packaging systems",
                  "# cabal intermediates",
                  "# standard cabal build dir, might not be boring for everybody",
                  "# ^dist(/|$)",
                  "# autotools",
                  "(^|/)autom4te\\.cache($|/)", "(^|/)config\\.(log|status)$",
                  "# microsoft web expression, visual studio metadata directories",
                  "# gentoo tools",
                  "# generated dependencies",
                  "### version control systems",
                  "# cvs",
                  "# cvs, emacs locks",
                  "# rcs",
                  "(^|/)RCS($|/)", ",v$",
                  "# subversion",
                  "# mercurial",
                  "# git",
                  "# bzr",
                  "# sccs",
                  "# darcs",
                  "(^|/)"++darcsdir++"($|/)", "(^|/)\\.darcsrepo($|/)",
                  "# gnu arch",
                  "# bitkeeper",
                  "### miscellaneous",
                  "# backup files",
                  "# patch originals and rejects",
                  "\\.orig$", "\\.rej$",
                  "# X server",
                  "# image spam",
                  "\\#", "(^|/)Thumbs\\.db$",
                  "# vi, emacs tags",
                  "# core dumps",
                  "# partial broken files (KIO copy operations)",
                  "# waf files, see http://code.google.com/p/waf/",
                  "# mac os finder",
                  "(^|/)\\.DS_Store$" ]

darcsdir_filter :: [FilePath] -> [FilePath]
darcsdir_filter = filter (not.is_darcsdir)
is_darcsdir :: FilePath -> Bool
is_darcsdir ('.':'/':f) = is_darcsdir f
is_darcsdir "." = True
is_darcsdir "" = True
is_darcsdir ".." = True
is_darcsdir "../" = True
is_darcsdir fp = darcsdir `isPrefixOf` fp

global_prefs_dir :: IO (Maybe FilePath)
global_prefs_dir = do
  dir <- (</> ".darcs") `fmap` getEnv "DARCS_TESTING_HOME"
  exists <- doesDirectoryExist dir
  if exists then return $ Just dir
            else userDir
 `catch` \_ -> userDir -- no such environment variable
 where userDir = (getAppUserDataDirectory "darcs" >>= return.Just)
                   `catchall` (return Nothing)

get_global :: String -> IO [String]
get_global f = do
  dir <- global_prefs_dir
  case dir of
    (Just d) -> get_preffile $ d </> f
    Nothing -> return []

global_cache_dir :: IO (Maybe FilePath)
global_cache_dir = slash_cache `fmap` global_prefs_dir
  where slash_cache = fmap (</> "cache")

boring_file_filter :: IO ([FilePath] -> [FilePath])
boring_file_filter = do
    borefile <- def_prefval "boringfile" (darcsdir ++ "/prefs/boring")
    bores <- get_lines borefile `catchall` return []
    gbs <- get_global "boring"
    return $ actual_boring_file_filter $ map mkRegex (bores++gbs)

noncomments :: [String] -> [String]
noncomments ss = filter is_ok ss
                 where is_ok "" = False
                       is_ok ('#':_) = False
                       is_ok _ = True

get_lines :: ReadableDirectory m => FilePath -> m [String]
get_lines f = (notconflicts . noncomments . map stripCr . lines)
              `fmap` mReadBinFile (fp2fn f)
    where notconflicts = filter nc
          startswith [] _ = True
          startswith (x:xs) (y:ys) | x == y = startswith xs ys
          startswith _ _ = False
          nc l | startswith "v v v v v v v" l = False
          nc l | startswith "*************" l = False
          nc l | startswith "^ ^ ^ ^ ^ ^ ^" l = False
          nc _ = True

actual_boring_file_filter :: [Regex] -> [FilePath] -> [FilePath]
actual_boring_file_filter regexps fs =
    filter (abf (not.is_darcsdir) regexps . normalize) fs
    abf fi (r:rs) = abf (\f -> fi f && isNothing (matchRegex r f)) rs
    abf fi [] = fi

normalize :: FilePath -> FilePath
normalize ('.':'/':f) = normalize f
normalize f = normalize_helper $ reverse f
              normalize_helper ('/':rf) = normalize_helper rf
              normalize_helper rf = reverse rf

The \verb!_darcs/prefs/binaries! file may contain a list of regular
expressions describing files that should be treated as binary files rather
than text files. Darcs automatically treats files containing
\verb!^Z\! or \verb!'\0'! within the first 4096 bytes as being binary files.
You probably will want to have the binaries file under
version control.  To do this you can use darcs setpref to set the value
``binariesfile'' to the name of your desired binaries file
(e.g.\ \verb'darcs setpref binariesfile ./.binaries', where
\verb'.binaries' is a file that has been
darcs added to your repository).  As with the boring file, you can also set
up a \verb!~/.darcs/binaries! file if you like.

data FileType = BinaryFile | TextFile
                deriving (Eq)

{-# NOINLINE default_binaries #-}
default_binaries :: [String]
default_binaries =
    "# Binary file regexps:" :
    ext_regexes ["png","gz","pdf","jpg","jpeg","gif","tif",
                 "elc", "pyc"]
    where ext_regexes exts = concat $ map ext_regex exts
          ext_regex e = ["\\."++e++"$", "\\."++map toUpper e++"$"]

filetype_function :: IO (FilePath -> FileType)
filetype_function = do
    binsfile <- def_prefval "binariesfile" (darcsdir ++ "/prefs/binaries")
    bins <- get_lines binsfile `catch`
             (\e-> if isDoesNotExistError e then return [] else ioError e)
    gbs <- get_global "binaries"
    regexes <- return (map (\r -> mkRegex r) (bins ++ gbs))
    let isbin f = or $ map (\r -> isJust $ matchRegex r f) regexes
        ftf f = if isbin $ normalize f then BinaryFile else TextFile
        return ftf

-- this avoids a circular dependency with Repository
prefsDirectory :: ReadableDirectory m => m String
prefsDirectory =
    do darcs <- mDoesDirectoryExist $ fp2fn darcsdir
       if darcs
          then return $ darcsdir ++ "/prefs/"
          else fail $ "Directory " ++ darcsdir ++ "/ does not exist!"

withPrefsDirectory :: ReadableDirectory m => (String -> m ()) -> m ()
withPrefsDirectory j = do prefs <- prefsDirectory `mplus` return "x"
                          when (prefs /= "x") $ j prefs

add_to_preflist :: WriteableDirectory m => String -> String -> m ()
add_to_preflist p s = withPrefsDirectory $ \prefs -> do
  hasprefs <- mDoesDirectoryExist $ fp2fn prefs
  unless hasprefs $ mCreateDirectory $ fp2fn prefs
  pl <- get_preflist p
  mWriteBinFile (fp2fn $ prefs ++ p) $ unlines $ add_to_list s pl

get_preflist :: ReadableDirectory m => String -> m [String]
get_preflist p = do prefs <- prefsDirectory `mplus` return "x"
                    if (prefs /= "x") then get_preffile $ prefs ++ p
                                      else return []

get_preffile :: ReadableDirectory m => FilePath -> m [String]
get_preffile f = do
  hasprefs <- mDoesFileExist (fp2fn f)
  if hasprefs
    then get_lines f
    else return []

set_preflist :: WriteableDirectory m => String -> [String] -> m ()
set_preflist p ls = withPrefsDirectory $ \prefs -> do
  haspref <- mDoesDirectoryExist $ fp2fn prefs
  if haspref
     then mWriteBinFile (fp2fn $ prefs ++ p) (unlines ls)
     else return ()

add_to_list :: Eq a => a -> [a] -> [a]
add_to_list s [] = [s]
add_to_list s (s':ss) = if s == s' then (s:ss) else s': add_to_list s ss

def_prefval :: String -> String -> IO String
def_prefval p d = do
  pv <- get_prefval p
  case pv of Nothing -> return d
             Just v -> return v

get_prefval :: ReadableDirectory m => String -> m (Maybe String)
get_prefval p =
    do pl <- get_preflist "prefs"
       case map snd $ filter ((==p).fst) $ map (break (==' ')) pl of
           [val] -> case words val of
               [] -> return Nothing
               _ -> return $ Just $ tail val
           _ -> return Nothing

set_prefval :: WriteableDirectory m => String -> String -> m ()
set_prefval p v = do pl <- get_preflist "prefs"
                     set_preflist "prefs" $
                       filter ((/=p).fst.(break (==' '))) pl ++ [p++" "++v]

change_prefval :: WriteableDirectory m => String -> String -> String -> m ()
change_prefval p f t =
    do pl <- get_preflist "prefs"
       ov <- get_prefval p
       newval <- case ov of
                 Nothing -> return t
                 Just old -> if old == f then return t else return old
       set_preflist "prefs" $
                    filter ((/=p).fst.(break(==' '))) pl ++ [p++" "++newval]

defaultrepo :: [DarcsFlag] -> AbsolutePath -> [String] -> IO [String]
defaultrepo opts _ [] =
  do let fixR r | not (is_file r) = return r
                | otherwise = do absr <- ioAbsolute r
                                 return $ toFilePath absr
     case [r | RemoteRepo r <- opts] of
       [] -> do defrepo <- get_preflist "defaultrepo"
                case defrepo of
                  [r] -> (:[]) `fmap` fixR r
                  _ -> return []
       rs -> mapM fixR rs
defaultrepo _ _ r = return r

set_defaultrepo :: String -> [DarcsFlag] -> IO ()
set_defaultrepo r opts = do doit <- if (NoSetDefault `notElem` opts && DryRun `notElem` opts && r_is_not_tmp)
                                    then return True
                                    else do olddef <-
                                                get_preflist "defaultrepo"
                                            return (olddef == [])
                            when doit
                                (set_preflist "defaultrepo" [r])
                            add_to_preflist "repos" r
                         `catchall` return () -- we don't care if this fails!
  r_is_not_tmp = not $ r `elem` [x | RemoteRepo x <- opts]

The \verb!_darcs/prefs/email! file is used to provide the e-mail address for your
repository that others will use when they \verb!darcs send! a patch back to you.
The contents of the file should simply be an e-mail address.

The \verb!_darcs/prefs/sources! file is used to indicate alternative
locations from which to download patches when using a ``hashed''
repository.  This file contains lines such as:
This would indicate that darcs should first look in
\verb!/home/droundy/.darcs/cache! for patches that might be missing, and if
the patch isn't there, it should save a copy there for future use.  In that
case, darcs will look in \verb!/home/otheruser/.darcs/cache! to see if that
user might have downloaded a copy, but won't try to save a copy there, of
course.  Finally, it will look in \verb!http://darcs.net!.  Note that the
\verb!sources! file can also exist in \verb!~/.darcs/!.  Also note that the
sources mentioned in your \verb!sources! file will be tried \emph{before}
the repository you are pulling from.  This can be useful in avoiding
downloading patches multiple times when you pull from a remote repository
to more than one local repository.

We strongly advise that you enable a global cache directory, which will
allow darcs to avoid re-downloading patches (for example, when doing a
second darcs get of the same repository), and also allows darcs to use hard
links to reduce disk usage.  To do this, simply
mkdir -p $HOME/.darcs/cache
echo cache:$HOME/.darcs/cache > $HOME/.darcs/sources
Note that the cache directory should reside on the same filesystem as your
repositories, so you may need to vary this.  You can also use multiple
cache directories on different filesystems, if you have several filesystems
on which you use darcs.

getCaches :: [DarcsFlag] -> String -> IO Cache
getCaches opts repodir =
    do here <- parsehs `fmap` get_preffile (darcsdir ++ "/prefs/sources")
       there <- (parsehs . lines . BC.unpack) `fmap`
                (gzFetchFilePS (repodir ++ "/" ++ darcsdir ++ "/prefs/sources") Cachable
                 `catchall` return B.empty)
       globalcachedir <- global_cache_dir
       let globalcache = case (nocache,globalcachedir) of
                           (True,_) -> []
                           (_,Just d) -> [Cache Directory Writable d]
                           _ -> []
       globalsources <- parsehs `fmap` get_global "sources"
       thisdir <- getCurrentDirectory
       let thisrepo = if Ephemeral `elem` opts
                      then [Cache Repo NotWritable $ toFilePath thisdir]
                      else [Cache Repo Writable $ toFilePath thisdir]
       return $ Ca $ nub $ thisrepo ++ globalcache ++ globalsources ++
                  here ++ [Cache Repo NotWritable repodir] ++ there
            parsehs = catMaybes . map readln . noncomments
            readln l | take 5 l == "repo:" = Just (Cache Repo NotWritable (drop 5 l))
                     | take 9 l == "thisrepo:" = Just (Cache Repo Writable (drop 9 l))
                     | nocache = Nothing
                     | take 6 l == "cache:" = Just (Cache Directory Writable (drop 6 l))
                     | take 9 l == "readonly:" = Just (Cache Directory NotWritable (drop 9 l))
                     | otherwise = Nothing
            nocache = NoCache `elem` opts