#!/bin/sh
#
# This file is part of the flashrom project.
#
# Copyright (C) 2005 coresystems GmbH <stepan@coresystems.de>
# Copyright (C) 2009,2010 Carl-Daniel Hailfinger
# Copyright (C) 2010 Chromium OS Authors
# Copyright (C) 2013 Stefan Tauner
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
#

EXIT_SUCCESS=0
EXIT_FAILURE=1

# Make sure we don't get translated output
export LC_ALL=C
# nor local times or dates
export TZ=UTC0

# Helper functions
# First argument is the path to inspect (usually optional; w/o it the whole repository will be considered)
svn_has_local_changes() {
	svn status "$1" | egrep '^ *[ADMR] *' >/dev/null
}

git_has_local_changes() {
	git update-index -q --refresh >/dev/null
	! git diff-index --quiet HEAD -- "$1"
}

git_last_commit() {
	git log --pretty=format:"%h" -1 -- "$1"
}

svn_is_file_tracked() {
	svn info "$1" >/dev/null 2>&1
}

git_is_file_tracked() {
	git ls-files --error-unmatch -- "$1" >/dev/null 2>&1
}

is_file_tracked() {
	svn_is_file_tracked "$1" || git_is_file_tracked "$1"
}

# Tries to find a remote source for the changes committed locally.
# This includes the URL of the remote repository including the last commit and a suitable branch name.
# Takes one optional argument: the path to inspect
git_url() {
	last_commit=$(git_last_commit "$1")
	# get all remote branches containing the last commit (excluding origin/HEAD and git-svn branches/tags)
	branches=$(git branch -r --contains $last_commit | sed '/\//!d;/.*->.*/d;s/[\t ]*//')
	if [ -z "$branches" ] ; then
		echo "No remote branch contains a suitable commit">&2
		return
	fi

	# find "nearest" branch
	local mindiff=9000
	local target=
	for branch in $branches ; do
		curdiff=$(git rev-list --count $last_commit..$branch)
		if [ $curdiff -ge $mindiff ] ; then
			continue
		fi
		mindiff=$curdiff
		target=$branch
	done

	echo "$(git ls-remote --exit-code --get-url ${target%/*}) ${target#*/}"
}

# Returns a string indicating where others can get the current source code (excluding uncommitted changes)
# Takes one optional argument: the path to inspect
scm_url() {
	local url=

	# for a primitive VCS like subversion finding the URL is easy: there is only one upstream host
	if svn_is_file_tracked "$1" ; then
		url="$(svn info "$1" 2>/dev/null |
		       grep URL: |
		       sed 's/.*URL:[[:blank:]]*//;s/:\/\/.*@/:\/\//' |
		       grep ^.)"
	elif git_is_file_tracked "$1" ; then
		url="$(git_url "$1")"
	else
		return ${EXIT_FAILURE}
	fi

	echo "${url}"
}

# Retrieve timestamp since last modification. If the sources are pristine,
# then the timestamp will match that of the SCM's most recent modification
# date.
timestamp() {
	local t

	if svn_is_file_tracked "$2" ; then
		if svn_has_local_changes "$2"; then
			t=$(date -u "$1")
		else
			# No local changes, get date of the last log record.
			local last_commit_date="$(svn info "$2" | \
						  grep '^Last Changed Date:' | \
						  awk '{print $4" "$5" "$6}')"
			t=$(date -d "${last_commit_date}" -u "$1")
		fi
	elif git_is_file_tracked "$2" ; then
		# are there local changes?
		if git_has_local_changes "$2" ; then
			t=$(date -u "${1}")
		else
			# No local changes, get date of the last commit
			t=$(date -d "$(git log --pretty=format:"%cD" -1 -- "$2")" -u "$1")
		fi
	else
		t=$(date -u "$1")
	fi

	echo "${t}"
}

# Retrieve local SCM revision info. This is useful if we're working in a different SCM than upstream and/or
# have local changes.
local_revision() {
	local r=

	if svn_is_file_tracked "$1" ; then
		r=$(svn_has_local_changes "$1" && echo "dirty")
	elif git_is_file_tracked "$1" ; then
		r=$(git_last_commit "$1")

		local svn_base=$(git log --grep git-svn-id -1 --format='%h')
		if [ "$svn_base" != "" ] ; then
			local diff_to_svn=$(git rev-list --count ${svn_base}..${r})
			if [ "$diff_to_svn" -gt 0 ] ; then
				r="$r-$diff_to_svn"
			fi
		fi

		if git_has_local_changes "$1" ; then
			r="$r-dirty"
		fi
	else
		return ${EXIT_FAILURE}
	fi

	echo "${r}"
}

# Get the upstream flashrom revision stored in SVN metadata.
upstream_revision() {
	local r=

	if svn_is_file_tracked "$1" ; then
		r=$(svn info "$1" 2>/dev/null | \
		    grep "Last Changed Rev:" | \
		    sed -e "s/^Last Changed Rev: *//" -e "s/\([0-9]*\).*/r\1/" | \
		    grep "r[0-9]")
	elif git_is_file_tracked "$1" ; then
		# If this is a "native" git-svn clone we could use git svn log:
		# git svn log --oneline -1 | sed 's/^r//;s/[[:blank:]].*//' or even git svn find-rev
		# but it is easier to just grep for the git-svn-id unconditionally
		r=$(git log --grep git-svn-id -1 -- "$1" | \
		    grep git-svn-id | \
		    sed 's/.*@/r/;s/[[:blank:]].*//')
	fi

	if [ -z "$r" ]; then
		r="unknown" # default to unknown
	fi
	echo "${r}"
}

show_help() {
	echo "Usage:
	${0} <command> [path]

Commands
    -h or --help
        this message
    -l or --local
        local revision information including an indicator for uncommitted changes
    -u or --upstream
        upstream revision
    -U or --url
        URL associated with the latest commit
    -d or --date
        date of most recent modification
    -t or --timestamp
        timestamp of most recent modification
"
	return
}

check_action() {
	if [ -n "$action" ]; then
		echo "Error: Multiple actions given.">&2
		exit ${EXIT_FAILURE}
	fi
}

main() {
	local query_path=
	local action=

	# The is the main loop
	while [ $# -gt 0 ];
	do
		case ${1} in
		-h|--help)
			action=show_help;
			shift;;
		-l|--local)
			check_action $1
			action=local_revision
			shift;;
		-u|--upstream)
			check_action $1
			action=upstream_revision
			shift;;
		-U|--url)
			check_action $1
			action=scm_url
			shift;;
		-d|--date)
			check_action $1
			action="timestamp +%Y-%m-%d" # refrain from suffixing 'Z' to indicate it's UTC
			shift;;
		-t|--timestamp)
			check_action $1
			action="timestamp +%Y-%m-%dT%H:%M:%SZ" # There is only one valid time format! ISO 8601
			shift;;
		-*)
			show_help;
			echo "Error: Invalid option: ${1}"
			exit ${EXIT_FAILURE};;
		*)
			if [ -z "$query_path" ] ; then
				if [ ! -e "$1" ] ; then
					echo "Error: Path \"${1}\" does not exist.">&2
					exit ${EXIT_FAILURE}
				fi
				query_path=$1
			else
				echo "Warning: Ignoring over-abundant paramter: \"${1}\"">&2
			fi
			shift;;
		esac;
	done

	# default to current directory (usually equals the whole repository)
	if [ -z "$query_path" ] ; then
		query_path=.
	fi
	if ! is_file_tracked "$query_path" ; then
		echo "Warning: Path \"${query_path}\" is not under version control.">&2
	fi
	if [ -z "$action" ] ; then
		show_help
		echo "Error: No actions specified"
		exit ${EXIT_FAILURE}
	fi

	$action "$query_path"
}

main $@