#!/usr/bin/env bash

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

# Download helper for git, to be called from the download wrapper script
# Expected arguments:
#   $1: output file
#   $2: git repo
#   $3: git cset
#   $4: package's basename (eg. foobar-1.2.3)
# And this environment:
#   GIT      : the git command to call

output="${1}"
repo="${2}"
cset="${3}"
basename="${4}"

# Try to see if we can do a shallow clone, since it is faster
# than a full clone.
git_done=0
if [ -n "$(${GIT} ls-remote "${repo}" "${cset}" 2>&1)" ]; then
    printf "Doing shallow clone\n"
    if ${GIT} clone --depth 1 -b "${cset}" --bare "${repo}" "${basename}"; then
        git_done=1
    else
        printf "Shallow clone failed, falling back to doing a full clone\n"
    fi
fi
if [ ${git_done} -eq 0 ]; then
    printf "Doing full clone\n"
    ${GIT} clone --bare "${repo}" "${basename}"
fi

GIT_DIR="${basename}" \
${GIT} archive --prefix="${basename}/" -o "${output}.tmp" --format=tar "${cset}"

gzip <"${output}.tmp" >"${output}"