#!/bin/sh

# A hook script to verify what is about to be pushed.  Called by "git
# push" after it has checked the remote status, but before anything has been
# pushed.  If this script exits with a non-zero status nothing will be pushed.
#
# This hook is called with the following parameters:
#
# $1 -- Name of the remote to which the push is being done
# $2 -- URL to which the push is being done
#
# If pushing without using a named remote those arguments will be equal.
#
# Information about the commits which are being pushed is supplied as lines to
# the standard input in the form:
#
#   <local ref> <local sha1> <remote ref> <remote sha1>

remote="$1"
url="$2"

zero=0000000000000000000000000000000000000000

upstream_pattern="github\.com.flashprog/flashprog(\.git)?|flashprog\.org.git/flashprog(\.git)?"

# Only care about the upstream repositories
if echo "$url" | grep -q -v -E "$upstream_pattern" ; then
	exit 0
fi

while read local_ref local_sha remote_ref remote_sha ; do

	# Only allow the stable and staging branches as well as versioned stable branches (e.g., 0.0.x).
	# The matching expression's RE is always anchored to the first character (^ is undefined).
	# The outer parentheses are needed to print out the whole matched string.
	version=$(expr ${remote_ref#*refs/heads/} : '\(\([0-9]\+\.\)\{2,\}x\)$')
	if [ "$remote_ref" != "refs/heads/staging" ] && \
	   [ "$remote_ref" != "refs/heads/stable" ] && \
	   [ -z "$version" ]; then
		echo "Feature branches not allowed ($remote_ref)." >&2
		exit 1
	fi

	if [ "$local_sha" = $zero ]; then
		echo "Deletion of branches is prohibited." >&2
		exit 1
	fi

	# Check for Signed-off-by and Acked-by
	commit=$(git rev-list -n 1 --all-match --invert-grep -E \
		--grep '^Signed-off-by: .+ <.+@.+\..+>$' \
		--grep '^Acked-by: .+ <.+@.+\..+>$' \
		"$remote_sha..$local_sha")
	if [ -n "$commit" ]; then
		echo "Commit $local_sha in $local_ref is missing either \"Signed-off-by\"" \
			" or \"Acked-by\" lines, not pushing." >&2
		exit 1
	fi

	# Make _really_ sure we do not rewrite history of any head/branch
	if [ "${remote_ref#*refs/heads/}" != "$remote_ref" ]; then
		nonreachable=$(git rev-list $remote_sha ^$local_sha | head -1)
		if [ -n "$nonreachable" ]; then
			echo "Only fast-forward pushes are allowed on branches." >&2
			echo "At least $nonreachable is not included in $remote_sha while pushing to " \
			     "$remote_ref" >&2
			exit 1
		fi
	fi

	# FIXME: check commit log format (subject without full stop at the end etc).
	# FIXME: do buildbot checks if authorized?
done

exit 0