#!/usr/bin/env bash

# We want to catch any unexpected failure, and exit immediately
set -e

# Download helper for svn, to be called from the download wrapper script
#
# Options:
#   -q          Be quiet.
#   -o FILE     Generate archive in FILE.
#   -u URI      Checkout from repository at URI.
#   -c REV      Use revision REV.
#   -n NAME     Use basename NAME.
#
# Environment:
#   SVN      : the svn command to call

verbose=
while getopts "${BR_BACKEND_DL_GETOPTS}" OPT; do
    case "${OPT}" in
    q)  verbose=-q;;
    o)  output="${OPTARG}";;
    u)  uri="${OPTARG}";;
    c)  rev="${OPTARG}";;
    n)  basename="${OPTARG}";;
    :)  printf "option '%s' expects a mandatory argument\n" "${OPTARG}"; exit 1;;
    \?) printf "unknown option '%s'\n" "${OPTARG}" >&2; exit 1;;
    esac
done

shift $((OPTIND-1)) # Get rid of our options

# Caller needs to single-quote its arguments to prevent them from
# being expanded a second time (in case there are spaces in them)
_svn() {
    eval ${SVN} "${@}"
}

_svn export ${verbose} "${@}" "'${uri}@${rev}'" "'${basename}'"

# Get the date of the revision, to generate reproducible archives.
# The output format is YYYY-MM-DDTHH:MM:SS.mmmuuuZ (i.e. always in the
# UTC timezone), which we can feed as-is to the --mtime option for tar.
# In case there is a redirection (e.g. http -> https), just keep the
# last line (svn outputs everything on stdout)
date="$( _svn info --show-item last-changed-date "'${uri}@${rev}'" |tail -n 1 )"

# Generate the archive, sort with the C locale so that it is reproducible.
# We do not want the .svn dir; we keep other .svn files, in case they are the
# only files in their directory.
find "${basename}" -not -type d \
       -and -not -path "./.svn/*" >"${output}.list"
LC_ALL=C sort <"${output}.list" >"${output}.list.sorted"

# Create GNU-format tarballs, since that's the format of the tarballs on
# sources.buildroot.org and used in the *.hash files
tar cf - --transform="s#^\./#${basename}/#" \
         --numeric-owner --owner=0 --group=0 --mtime="${date}" --format=gnu \
         -T "${output}.list.sorted" >"${output}.tar"
gzip -6 -n <"${output}.tar" >"${output}"

rm -f "${output}.list"
rm -f "${output}.list.sorted"