#!/bin/sh

set -e

export LANG=C
export LC_ALL=C

[ -n "$TOPDIR" ] && cd "$TOPDIR"

try_git() {
  [ -e .git ] || return 1
  SOURCE_DATE_EPOCH="$(git log -1 --format=format:%ct)"
  [ -n "$SOURCE_DATE_EPOCH" ]
}

try_hg() {
  [ -d .hg ] || return 1
  SOURCE_DATE_EPOCH="$(hg log --template '{date}' -l 1 | cut -d. -f1)"
  [ -n "$SOURCE_DATE_EPOCH" ]
}

try_mtime() {
  perl -e 'print((stat $ARGV[0])[9])' "$0"
  [ -n "$SOURCE_DATE_EPOCH" ]
}

try_git || try_hg || try_mtime || SOURCE_DATE_EPOCH=""
echo "$SOURCE_DATE_EPOCH"