#!/bin/bash

# Usage:

#    ./otp-get-patches.sh /path/to/otp OTP_R14B02 fedora-R14B02

#

# otp-get-patches.sh - update erlang.spec and otp-00*.patch files

#

# otp-get-patches.sh updates the erlang.spec and otp-00*.patch

# files in the git index. After an otp-get-patches.sh run, you

# will need to review the staged git changes, possibly adapt the

# 'Release:' and '%changelog' parts of erlang.spec, and can then

# "git commit" everything.

#

# Caution: Leave the four special comment lines untouched in the

# spec file, as otp-get-patches.sh requires them and will only

# touch the parts of erlang.spec between the respective start/end

# comment pair:

#

# # start of autogenerated patch tag list

# # end of autogenerated patch tag list

# # start of autogenerated prep patch list

# # end of autogenerated prep patch list

#

# The following special comment lines in the git commit messages

# will be interpreted:

#

#    Fedora-Spec-Comment: This patch only applies to EL6 builds

#    Fedora-Spec-Before: %if 0%?el6}

#    Fedora-Spec-After: %endif

#

# If there is no "Fedora-Spec-Comment:" line, we will use

# "Fedora specific patch".

# Command line parsing

otp_dir="${1:?'Fatal: otp git repo dir required'}"

otp_upstream="${2:?'Fatal: git ref to upstream release required'}"

otp_fedora="${3:?'Fatal: git ref to branch with fedora patches required'}"

# Setup

set -e

# set -x

tmpdir="$(mktemp -d --tmpdir="$PWD")"

# Generate patch files

pushd "$otp_dir"

git format-patch -N --no-signature --no-stat -o "$tmpdir" "${otp_upstream}..${otp_fedora}" > "$tmpdir/patch-list.txt"

popd

test -s "$tmpdir/patch-list.txt"

# Process patch files

echo "# start of autogenerated patch tag list" > "$tmpdir/patch-list-tags.txt"

echo "# start of autogenerated prep patch list" > "$tmpdir/patch-list-prep.txt"

n=1

while read patch

do

	otppatch="$(dirname "$patch")/otp-$(basename "$patch")"

	${SED-sed} -e '1d' -e '/^-- $/,$d' "$patch" > "$otppatch"

	rm -f "$patch"

	comment="$(sed -n 's/^Fedora-Spec-Comment:\s*//p' "$otppatch")"

	if test "x$comment" = "x"; then comment="Fedora specific patch"; fi

	echo "# ${comment}" >> "$tmpdir/patch-list-tags.txt"

	echo "#   $(sed -n 's/^Subject: \[PATCH\] //p' "$otppatch")" >> "$tmpdir/patch-list-tags.txt"

	echo "Patch$n: $(basename "$otppatch")" >> "$tmpdir/patch-list-tags.txt"

	base="$(basename "$patch" ".patch" | sed 's/^00[0-9][0-9]-//')"

	backupext=".$(echo -n "$base" | tr -c -s '[:alnum:]' '_')"

	sed -n 's/^Fedora-Spec-Before:\s*//p' "$otppatch" >> "$tmpdir/patch-list-prep.txt"

	echo "%patch$n -p1 -b ${backupext}" >> "$tmpdir/patch-list-prep.txt"

	sed -n 's/^Fedora-Spec-After:\s*//p' "$otppatch" >> "$tmpdir/patch-list-prep.txt"

	n=$(($n + 1))

done < "$tmpdir/patch-list.txt"

echo "# end of autogenerated patch tag list" >> "$tmpdir/patch-list-tags.txt"

echo "# end of autogenerated prep patch list" >> "$tmpdir/patch-list-prep.txt"

# Create updated spec file

specfile="erlang.spec"

newspec1="${tmpdir}/${specfile}.new1"

newspec2="${tmpdir}/${specfile}.new2"

sed '/^# start of autogenerated patch tag list$/,$d' "$specfile" > "$newspec1"

cat "$tmpdir/patch-list-tags.txt" >> "$newspec1"

sed '1,/^# end of autogenerated patch tag list/d' "$specfile" >> "$newspec1"

sed '/^# start of autogenerated prep patch list$/,$d' "$newspec1" > "$newspec2"

cat "$tmpdir/patch-list-prep.txt" >> "$newspec2"

sed '1,/^# end of autogenerated prep patch list/d' "$newspec1" >> "$newspec2"

# Actually put all changes into git index

git rm -f otp-00*.patch

mv "$tmpdir/otp-00"*.patch .

git add otp-00*.patch

mv -f "$newspec2" "$specfile"

git add "$specfile"

rm -rf "$tmpdir"

# End of file.