#!/bin/sh
# Prepare systemd source package in current directory for testing an upstream
# commit, branch, or PR, without Debian patches. This replaces everything
# except the debian/ directory with an upstream checkout.
# NEVER run this in your actual packaging work directory! This is only meant
# for upstream CI.
#
# Author: Martin Pitt <martin.pitt@ubuntu.com>

set -eu
test -x debian/rules
if [ -z "${TEST_UPSTREAM:-}" ]; then
    echo "Not in upstream testing mode. Do *not* run this script unless you know what you are doing." >&2
    exit 1
fi
if [ -n "${UPSTREAM_PULL_REQUEST:-}" ]; then
    FETCH="git fetch -fu origin refs/pull/$UPSTREAM_PULL_REQUEST/head:pr"
    CO='git checkout pr'
    DESC="PR #$UPSTREAM_PULL_REQUEST"
elif [ -n "${UPSTREAM_HEAD:-}" ]; then
    FETCH=''
    CO="git checkout $UPSTREAM_HEAD"
    DESC="$UPSTREAM_HEAD"
else
    echo "WARNING: $0: Neither UPSTREAM_PULL_REQUEST nor UPSTREAM_HEAD set, ignoring" >&2
    exit 0
fi

DUMMY_USER_NAME="Merge dummy user"
DUMMY_USER_EMAIL="invalid@example.com"

UPSTREAM_REPO="${UPSTREAM_REPO:-https://github.com/systemd/systemd.git}"
BRANCH_NAME=$(git rev-parse --abbrev-ref HEAD)

# Use git, if in a git repo
if [ -d .git ]; then
    # make sure user.name/user.email are set, git commit wants them
    git config --get user.name || git config user.name "$DUMMY_USER_NAME"
    git config --get user.email || git config user.email "$DUMMY_USER_EMAIL"
fi

if [ -n "${KEEP_DEBIAN_PATCHES:-}" ]; then
        # set up pq branch if it does not exist
        if [ "$BRANCH_NAME" = HEAD ]; then
                echo "ERROR: $0 must be started from a branch when using KEEP_DEBIAN_PATCHES" >&2
                exit 1
        fi
        gbp pq import 2> /dev/null && gbp pq switch || true
        if ! git branch --contains "$BRANCH_NAME" | grep -q patch-queue/"$BRANCH_NAME"; then
                echo "ERROR: patch-queue/$BRANCH_NAME exists but it is not rebased, please rebase it." >&2
                exit 1
        fi
fi

# switch to native instead of quilt
echo '3.0 (native)' > debian/source/format

# drop our patches
rm -rf debian/patches

# disable tests which are not for upstream
[ -n "${KEEP_DEBIAN_TESTS:-}" ] || sed -i '/# NOUPSTREAM/ q' debian/tests/control

# create new git commit with debian/ changes
if [ -d .git -a -n "$(git status --short debian)" ]; then
    git add debian
    git commit -n -m "checkout-upstream: edit debian/ files for upstream testing"
fi

########
# Everything below this changes only code outside debian/
# besides temporary use of debian/tmp/
# and the update to debian/changelog
########

mkdir -p debian/tmp
(cd debian/tmp
 git clone "${UPSTREAM_REPO}" upstream || (rm -rf upstream; sleep 60; git clone "${UPSTREAM_REPO}" upstream)
 cd upstream
 $FETCH
 $CO
 git config user.email "$DUMMY_USER_EMAIL"
 git config user.name "$DUMMY_USER_NAME"
 if  [ -n "${UPSTREAM_PULL_REQUEST:-}" ]; then
     git rebase main
 fi
 git submodule update --init --recursive)
UPSTREAM_VER=$(cd debian/tmp/upstream; git describe | sed 's/^v//;s/-/./g')

# clean out original upstream sources
find -mindepth 1 -maxdepth 1 -name debian -o -name .git -prune -o -print0 | xargs -0n1 rm -rf

# replace with checkout
mv debian/tmp/upstream/* .
rm -rf debian/tmp

# create new git commit with upstream code
if [ -d .git -a -n "$(git status --short)" ] ; then
    git add .
    git commit -n -m "checkout-upstream: replace with upstream code at version ${UPSTREAM_VER}"
fi

# import Debian patches which apply cleanly
if [ -n "${KEEP_DEBIAN_PATCHES:-}" ]; then
    for c in $(git log "$BRANCH_NAME"..patch-queue/"$BRANCH_NAME" --format='%H' --reverse); do
        if ! git cherry-pick $c; then
            git cherry-pick --abort
            git reset --hard
            git clean -dxf
        fi
    done
fi

if [ -z "${UPSTREAM_KEEP_CHANGELOG:-}" ] ; then
    # craft changelog
    cat << EOF > debian/changelog.new
systemd (${UPSTREAM_VER}.0) UNRELEASED; urgency=low

  * Automatic build from upstream $DESC

 -- systemd test <pkg-systemd-maintainers@lists.alioth.debian.org>  $(date -R)

EOF
    cat debian/changelog >> debian/changelog.new
    mv debian/changelog.new debian/changelog

    # create new git commit with changelog entry
    if [ -d .git ] ; then
        git add debian
        git commit -n -m "checkout-upstream: update changelog to version ${UPSTREAM_VER}.0"
    fi
fi