#!/bin/bash

# ================================================================
# This script creates a file like "miller-6.0.0.tar.gz".
#
# * The developer should run this script to create that .tar.gz file
#
# * Then attach it as an asset to a release created at
#   https://github.com/johnkerl/miller/releases.
#
# * Then the 'Source' link in ./miller.spec should already be correct.
#
# * Normally this script wouldn't be run directly; rather, from the Makefile's
#   'make release_tarball' which will first run 'make build' and 'make check'.
#
# Please also see
# https://miller.readthedocs.io/en/latest/build/#creating-a-new-release-for-developers
#
# Note that GitHub makes a 'Source code (tar.gz)' which could be used in place
# of the tarball which this script creates. However, this script makes some
# effort to remove directories which are not necessary for the install, which
# reduces tarball size.
#
# Testing:
# * Run this script
# * Move the miller-i.j.k.tar.gz file off somewhere else, like /tmp
# * cd to the directory where you put the tarbll
# * tar zxf miller-i.j.k.tar.gz
# * cd miller-i.j.k
# * ./configure --prefix /usr/local
# * make build check
# * make build check install # if you prefer
# ================================================================

set -euo pipefail

# Make sure ./mlr exists so we can ask it for its version string.
if [ ! -x "./mlr" ]; then
  echo "$0: ./mlr is not executable. Please check 'make build' first." 1>&2
  exit 1
fi

# Find the Miller version string, such as "6.0.0".
VERSION=$(./mlr --bare-version)
if [ "$VERSION" == "" ] ; then
  echo "$0: could not obtain output from './mlr --bare-version'." 1>&2
  exit 1
fi

# Try to find a version of tar which supports the --transform flag.
# Linux tar does; MacOS default tar does not, but 'brew install gnu-tar' will
# install gtar which does.
tar=/usr/bin/tar
if [ -x /usr/local/bin/gtar ]; then
  tar=/usr/local/bin/gtar
fi
if [ ! -x "$tar" ]; then
  echo "$0: "$tar" is not executable. Please edit this script with the path." 1>&2
  echo "to a version of tar which supports the --transform flag." 1>&2
  exit 1
fi

# Make sure the current directory is writeable, so we can (perhaps) create a
# more informative error message than tar would.
if [ ! -w . ]; then
  echo "$0: the current directory is not writeable; cannot create tarball." 1>&2
  exit 1
fi
TGZ_NAME=miller-${VERSION}.tar.gz

# Create the release tarball.
echo "Writing $TGZ_NAME ..."
$tar \
  --transform 's,^./,miller-'$VERSION'/,'  \
  --exclude data \
  --exclude docs \
  --exclude experiments \
  --exclude todo.txt \
  --exclude perf \
  --exclude python \
  --exclude vim \
  -czf $TGZ_NAME \
  ./LICENSE.txt \
  ./README.md \
  ./README-RPM.md \
  ./configure \
  ./Makefile \
  ./create-release-tarball \
  ./go.mod \
  ./go.sum \
  ./cmd \
  ./internal \
  ./regression_test.go \
  ./man \
  ./test \
  ./tools

echo "Wrote   $TGZ_NAME"