#! /bin/sh

################################################################################
# Script for checking out and updating Haskell packages via darcs
################################################################################

set -e
scriptname=$0
package_list="package-list"
hackage_archive="http://hackage.haskell.org/packages/archive"

################################################################################
# Output an informative message if we are in verbose mode.
################################################################################

message ()
{
  if test ${verbose} = "yes"; then
    echo "== $*" >&2
  fi
}

################################################################################
# Print an error message on stderr and terminate script with an error code.
################################################################################

die ()
{
  echo "${scriptname}: $1" >&2
  exit 1
}

################################################################################
# Run an external command if we are not in dry-run mode.
################################################################################

run_command()
{
  message "Running \"$*\""
  if test ${dry_run} = "no"; then
    "$@"
  fi
}

################################################################################
# Higher order shell programming: Map a function over all packages.
################################################################################

map_packages()
{
  func="$*"
  while read url kind version; do

    # Ignore empty lines and comment lines.
    if test -z "${url}"; then
      continue
    fi

    case ${url} in
      \#*)
        continue ;;
      */*)
        package_url_prefix=`echo ${url} | sed 's,/[^/]*$,,'`
        package=`echo ${url} | sed 's,.*/,,'` ;;
      *)
        package_url_prefix=""
        package=${url} ;;
    esac

    # Sanity check
    if test -z "${kind}" -o -z "${version}"; then
      die "Missing kind/version in package list."
    fi

    ${func} "${package_url_prefix}" "${package}" "${kind}" "${version}"
  done < "${package_list}"
}

################################################################################
# Handle command line arguments.
################################################################################

extra="no"
nofib="no"
testsuite="no"
release="no"
dry_run="no"
list_packages="no"
verbose="no"

while test $# -gt 0; do
  case $1 in
    -e | --extra)         extra="yes" ;;
    -n | --nofib)         nofib="yes" ;;
    -t | --testsuite)     testsuite="yes" ;;
    -r | --release)       release="yes" ;;
    -d | --dry-run)       dry_run="yes" ;;
    -l | --list-packages) list_packages="yes" ;;
    -v | --verbose)       verbose="yes" ;;
    -*)                   die "unknown flag \"$1\"" ;;
    *)                    break ;;
  esac
  shift
done

################################################################################
# Make sure we are called in the correct place, i.e. the top level.
################################################################################

if test ! -d "_darcs" -o ! -f ${package_list}; then
  die "run \"$0\" in the top level directory of the project"
fi

message "We are at the top level of a darcs project."

################################################################################
# If requested, list package names and exit.
################################################################################

# I want anonymous shell functions! Join the petition!
echo_package()
{
  package_url_prefix=$1; package=$2; kind=$3; version=$4
  if test "${kind}" = "core" -o ${extra} = "yes"; then
    echo "${package}"
  fi
}

if test ${list_packages} = "yes"; then
  map_packages echo_package
  exit
fi

################################################################################
# Automagically determine our Haskell implementation via .spec files.
################################################################################

implementation="unknown"
for i in *.spec *.spec.in; do
  if test -f ${i}; then
    implementation=`echo ${i} | sed 's/\.spec$//' | sed 's/\.spec\.in$//'`
    break
  fi
done

if test ${implementation} = "unknown"; then
  die "can't determine Haskell implementation"
fi

message "It looks like we are at the top level of the \"${implementation}\" project."

################################################################################
# Creativity is not *always* a good thing: Figure out where the individual tools
# and packages should live.
################################################################################

case ${implementation} in
  ghc)
    tools_dir="."
    packages_dir="libraries" ;;
  hugs98)
    tools_dir="."
    packages_dir="packages" ;;
  nhc98)
    tools_dir="src"
    packages_dir="src/libraries" ;;
  *)
    die "unknon implementation \"${implementation}\"" ;;
esac

message "Tools will live in \"${tools_dir}\"."

if test -d ${packages_dir}; then
  message "Packages will live in \"${packages_dir}\"."
else
  run_command mkdir "${packages_dir}"
  message "Packages will live in \"${packages_dir}\" (created)."
fi

################################################################################
# Figure out where to get the other repositories from, based on where this repo
# itself came from.
################################################################################

defaultrepo=`cat _darcs/prefs/defaultrepo`
case ${defaultrepo} in
  http://* | *@*:*)
    repository_base=`echo ${defaultrepo} | sed 's!/[^/]*$!!'`
    lib_repository_base="${repository_base}/packages" ;;
  /*)
    repository_base=${defaultrepo}
    lib_repository_base="${defaultrepo}/libraries" ;;
  *)
    die "malformed default repository \"${defaultrepo}\"" ;;
esac

message "Repository base is \"${repository_base}\"."
message "Libaries repository base is \"${lib_repository_base}\"."

################################################################################
# Normalize darcs command name.
################################################################################

if test $# -eq 0; then
  die "missing darcs command"
fi

case $1 in
  g | ge | get)
    darcs_command="get" ;;
  w | wh | wha | what | whats | whatsn | whatsne | whatsnew)
    darcs_command="whatsnew" ;;
  *)
    darcs_command=$1 ;;
esac
shift

message "The darcs command is \"${darcs_command}\"."

################################################################################
# To avoid pulling in a decade of patches, we make partial repositories the
# default, but the user can override this, of course.
################################################################################

case $* in
  *--complete* | *--partial*)
    additional_get_option="" ;;
  *)
    message "Adding \"--partial\" to darcs commands."
    additional_get_option="--partial" ;;
esac

################################################################################
# If we are going to retrieve a release version, we need either curl or wget.
# Try to figure out which one via some ugly autoconf-like shell horror.
################################################################################

if test "${darcs_command}" = "get" -a ${release} = "yes"; then

  path_separator=":"
  test_x_works="no"

  # In a dry run, we simply make assumptions, avoiding the creation of a script.
  if test ${dry_run} = "yes"; then
    message "Note: In a dry run we assume that ':' is the path separator and 'test' does not support '-x'"
  else

    # For the tests below, we temporarily need an executable file in the current
    # directory, which returns successfully.
    test_script="darcs-all$$.sh"
    cat > ${test_script} << EOF
#! /bin/sh
exit 0
EOF
    chmod +x ${test_script}

    # The *nix vs. Windows war continues...
    ( PATH="/nonexistentsillydir;."; ${test_script} ) > /dev/null 2>&1 && path_separator=';'

    # The -x option of 'test' is not available everywhere, but it is not strictly
    # needed later, anyway.
    test -x ${test_script} > /dev/null 2>&1 && test_x_works="yes"

    rm -f ${test_script}
  fi

  # Walk through the PATH to find either curl or wget.
  downloader=""
  for prog in curl wget; do
    saved_IFS=$IFS
    IFS=$path_separator
    for dir in $PATH; do
      IFS=$saved_IFS
      test -z "${dir}" && dir="."
      if test -f "${dir}/${prog}"; then
        test ${test_x_works} = "yes" && test ! -x "${dir}/${prog}" && continue
        downloader=${prog}
        break
      fi
    done
    IFS=$saved_IFS
    test -n "${downloader}" && break
  done

  if test -z "${downloader}" -a ${dry_run} = "yes"; then
    message "Neither \"curl\" nor \"wget\" could be found in the PATH, assuming \"curl\"."
    downloader="curl"
  fi

  case "x${downloader}" in
    x)     die "Neither \"curl\" nor \"wget\" could be found in the PATH." ;;
    xcurl) download_command="curl" ;;
    xwget) download_command="wget --output-document=-" ;;
  esac
  message "We will use \"${download_command}\" to retrieve released packages."
fi

################################################################################
# Process ourselves and any tools.
################################################################################

tools=""

# We don't need to get ourselves again.
if test "${darcs_command}" != "get"; then
  tools=". ${tools}"
fi

case ${implementation} in
  ghc)
    if test "${darcs_command}" = "get"; then
      if test ${nofib} = "yes"; then tools="${tools} nofib"; fi
      if test ${testsuite} = "yes"; then tools="${tools} testsuite"; fi
    else
      if test -d "${tools_dir}/nofib"; then tools="${tools} nofib"; fi
      if test -d "${tools_dir}/testsuite"; then tools="${tools} testsuite"; fi
    fi ;;
  hugs98 | nhc98)
    tools="${tools} cpphs hsc2hs" ;;
esac

for tool in ${tools}; do
  if test "${darcs_command}" = "get"; then
    if test -d "${tools_dir}/${tool}"; then
      message "The tool \"${tool}\" already exists, skipping."
      continue
    fi
    run_command darcs "${darcs_command}" ${additional_get_option} "$@" --repodir "${tools_dir}/${tool}" "${repository_base}/${tool}"
  else
    if test ! -d "${tools_dir}/${tool}/_darcs"; then
      message "The directory \"${tools_dir}/${tool}\" is not present or not a repository, skipping."
      continue
    fi
    run_command darcs "${darcs_command}" "$@" --repodir "${tools_dir}/${tool}"
  fi
done

################################################################################
# Process packages using the package list.
################################################################################

user_darcs_options="$*"

retrieve_package()
{
  package_url_prefix=$1; package=$2; kind=$3; version=$4

  # We need to handle the "get" command differently, mostly due to the "release"
  # mode, where we use curl/wget to retrieve a specific version.
  if test "${darcs_command}" = "get"; then

    if test "${kind}" = "extra" -a ${extra} = "no"; then
      message "Package \"${package}\" is not a core package, skipping."
      continue
    fi

    if test -d "${packages_dir}/${package}"; then
      message "Package \"${package}\" already exists, skipping."
      continue
    fi

    if test ${release} = "yes"; then
      # Retrieve a numbered version from Hackage via curl/wget.
      run_command ${download_command} "${hackage_archive}/${package}/${package}-${version}.tar.gz" | \
        ( if test ${dry_run} = "yes"; then cat; else gunzip -c | ( cd ${packages_dir}; tar xf - ); fi )
      run_command mv "${packages_dir}/${package}-${version}" "${packages_dir}/${package}"
    else
      # Retrieve a bleeding edge version from the same repository as we came
      # from or from a given URL.
      if test -z "${package_url_prefix}"; then
         package_url_prefix=${lib_repository_base}
      fi
      run_command darcs "${darcs_command}" ${additional_get_option} ${user_darcs_options} --repodir "${packages_dir}/${package}" "${package_url_prefix}/${package}"
    fi

  else
    # This is not a "get" command, so proceed as usual.
    if test ! -d "${packages_dir}/${package}/_darcs"; then
      message "The directory \"${packages_dir}/${package}\" is not present or not a repository, skipping."
      continue
    fi
    message "Processing \"${packages_dir}/${package}\""
    run_command darcs "${darcs_command}" ${user_darcs_options} --repodir "${packages_dir}/${package}"
  fi
}

map_packages retrieve_package