#! /bin/sh
# Copyright (C) 2015 The Qt Company Ltd.
# Contact: http://www.qt.io/licensing/
#
# You may use this file under the terms of the 3-clause BSD license.
# See the file LICENSE from this package for details.
#

force=false
remove=false
while test $# != 0; do
    case $1 in
        -f) force=true;;
        -r) remove=true;;
        -*) echo "Unrecognized option $1." >&2; exit 1;;
        *) break;;
    esac
    shift
done

if test -z "$2"; then
    cat >&2 <<EOF
Usage: $0 [-f] [-r] <user> <sha-1>...

git-note-review adds Reviewed-by: lines to the log messages of the
named commits. Commits can be specified as either as a single sha1 or
as a sha1_excl..sha1_incl range (see git rev-list).
If any <whatever>-by: tag with the specified <user> is found to be
already present in a given commit, the commit is skipped.
If -f is specified, the check whether the commits were already pushed
is omitted. This only makes sense if you are planning to make a forced
push.
If -r is specified, the named user's reviews are removed from the commits.
EOF
    exit 1
fi

GIT_DIR=$(git rev-parse --git-dir 2>/dev/null)
if [ -z "$GIT_DIR" ]; then
    echo >&2 "Not a git repository."
    exit 1
fi
cd "$GIT_DIR/.."

REF=$(git symbolic-ref HEAD 2>/dev/null)
if [ -z "$REF" ]; then
    echo >&2 "Not on a branch."
    exit 1
fi

if test -n "`git diff HEAD`" ; then
    echo "You have uncommited changes. Please commit or stash them first." >&2
    exit 1
fi

who=$1
shift
SHA1s=
firstSHA1=
fail=false
for j in "$@"; do
    if test -z "${j##*..*}"; then
        if ! jj=`git rev-list $j 2> /dev/null`; then
            echo "Cannot parse commit range $j." >&2
            fail=true
            continue
        fi
        j=$jj
    fi
    for ii in $j; do
        if ! i=`git rev-parse --short $ii 2> /dev/null`; then
            echo "Cannot parse commit id $ii." >&2
            fail=true
            continue
        fi
        if test -n "`git rev-list -1 $i ^HEAD`"; then
            echo "Commit $i is not on current branch. Did you rebase it meanwhile?" >&2
            fail=true
            continue
        fi
        git log -1 --pretty=%b $i | egrep -q -i "^[-[:alpha:]]+-by: *$who\$" && hit=true || hit=false
        if $hit && ! $remove; then
            echo "Commit $i already noted as reviewed by $who."
        elif ! $hit && $remove; then
            echo "Commit $i not noted as reviewed by $who."
        else
            if test -z "$firstSHA1"; then
                firstSHA1=`git rev-parse $i`
                SHA1s=$i
            else
                firstSHA1=`git merge-base $firstSHA1 $i`
                SHA1s="$SHA1s|$i"
            fi
        fi
    done
done
if $fail; then
    echo "Exiting due to fatal errors." >&2
    exit 1
fi
if test -z "$SHA1s"; then
    echo "No commits to change." >&2
    exit 0
fi

# This would be pretty much bullet-proof, but also a lot slower.
#if test -z "$(git rev-list -1 $firstSHA1 --not $(git for-each-ref --format='%(objectname)' refs/remotes/))"; then
#    echo "$firstSHA1 has already been pushed - cannot edit it." >&2
#    exit 1
#fi
# This should be Good Enough (TM), and it is rather fast.
if ! $force && test -n "$(git rev-list -1 $firstSHA1^..@{upstream})"; then
    echo "Commit `git rev-parse --short $firstSHA1` has already been pushed - cannot edit it." >&2
    exit 1
fi

if ! $remove; then
    script='s/^\\(Reviewed-by:\\) *\\(pending\\|tbd\\|TBD\\)\$/\\1 '"$who"'/;t nx
\${
/^[-[:alpha:]]\+:/!a\\

a\\
Reviewed-by: '"$who"'
}
b
:nx;n;b nx'
else
    script='/^[-[:alpha:]]\\+-by: *'"$who"'\$/d'
fi

git filter-branch --force --original refs/note-review-backup --msg-filter '
    if echo $GIT_COMMIT | egrep -q "^('"$SHA1s"')"; then
        sed "'"$script"'"
    else
        cat
    fi
' $firstSHA1^..$REF || exit 1
rm -rf $GIT_DIR/refs/note-review-backup # we have the reflog, so what