diff --git a/cascading-pr-lib.sh b/cascading-pr-lib.sh
index 8febf6c..82b634a 100644
--- a/cascading-pr-lib.sh
+++ b/cascading-pr-lib.sh
@@ -12,6 +12,10 @@ DEBUG=false
 
 : ${TMPDIR:=$(mktemp -d)}
 
+: ${LOOPS:=80}
+
+: ${LOOP_DELAY:=5}
+
 function debug() {
     DEBUG=true
     set -x
@@ -72,3 +76,77 @@ function host_port() {
     echo ${host_port%%/}
 }
 
+function scheme() {
+    local url="$1"
+
+    echo "${url%%://*}"
+}
+
+function get_status() {
+    local api="$1"
+    local sha="$2"
+
+    forgejo-curl.sh api_json $api/commits/$sha/status
+}
+
+function check_status() {
+    local api="$1"
+    local sha="$2"
+    local expected_status="$3"
+    local expected_description="$3"
+
+    get_status $api $sha > $TMPDIR/status.json
+    local status="$(jq --raw-output .state < $TMPDIR/status.json)"
+    local description="$(jq --raw-output .statuses[0].description < $TMPDIR/status.json)"
+    if test "$status" = "$expected_status" && test -z "$expected_description" -o "$description" = "$expected_description"; then
+	echo OK
+    elif test "$status" = "failure" -o "$status" = "success"; then
+	echo NOK
+    else
+	echo RETRY
+    fi
+}
+
+function wait_success() {
+    wait_status success "$@"
+}
+
+function wait_failure() {
+    wait_status failure "$@"
+}
+
+function wait_running() {
+    wait_status pending "$@" "Has started running"
+}
+
+function wait_log() {
+    local sha="$1" expected_status="$2" expected_description="$3"
+    local status="$(jq --raw-output .state < $TMPDIR/status.json)"
+    local description="$(jq --raw-output .statuses[0].description < $TMPDIR/status.json)"
+    if test "$expected_description"; then
+	expected_description=" '$expected_description'"
+    fi
+    log_info "$sha status waiting '$expected_status'$expected_description, currently '$status' '$description'"
+}
+
+function wait_status() {
+    local api="$2"
+    local sha="$3"
+    local status="$1"
+    local description="$4"
+
+    for i in $(seq $LOOPS); do
+	if test $(check_status "$api" "$sha" "$status" "$description") != RETRY ; then
+	    break
+	fi
+	wait_log "$sha" "$status" "$description"
+	sleep $LOOP_DELAY
+    done
+    if test $(check_status "$api" "$sha" "$status" "$description") = "OK" ; then
+	log_info "$sha status OK"
+    else
+	get_status $url $repo $sha | jq .statuses
+	log_info "$sha status NOK"
+	return 1
+    fi
+}
diff --git a/cascading-pr.sh b/cascading-pr.sh
index 0dd00b8..349f541 100755
--- a/cascading-pr.sh
+++ b/cascading-pr.sh
@@ -48,9 +48,64 @@ function upsert_pr() {
     log_info "PR created $url"
 }
 
+function upsert_clone() {
+    local direction=$1 branch=$2 clone=$3
+
+    local fetch=true
+    if ! test -d $TMPDIR/$direction; then
+	git clone $clone -b $branch $TMPDIR/$direction
+	fetch=false
+    fi
+    (
+	cd $TMPDIR/$direction
+	if $fetch; then
+	    git fetch $direction
+	fi
+	git config user.email cascading-pr@example.com
+	git config user.name cascading-pr
+    )
+}
+
+function push() {
+    local direction=$1 branch=$2 clone=$3
+
+    (
+	cd $TMPDIR/$direction
+	if git diff; then
+	    log_info "nothing to push"
+	else
+	    git add .
+	    git commit -m 'cascading-pr update'
+	    git push --force-push origin $branch
+	    git rev-parse HEAD > ../$direction.sha
+	    log_info "pushed"
+	fi
+    )
+}
+
+function wait_destination_ci() {
+    local sha="$1"
+    local repo_api=${options[destination_url]}/api/v1/repos/${options[destination_repo]}
+    wait_success $repo_api $sha
+}
+
+function update() {
+    upsert_clone origin ${options[origin_head]} ${options[origin_clone]}
+    upsert_clone destination ${options[destination_head]} ${options[destination_clone]}
+    (
+	cd $TMPDIR/origin
+	${options[update]} $TMPDIR/destination
+    )
+    push destination ${options[destination_clone]}
+}
+
 function finalize_options() {
+    options[origin_scheme]=$(scheme ${options[origin_url]})
     options[origin_host_port]=$(host_port ${options[origin_url]})
+    options[origin_clone]=${options[origin_scheme]}://:${options[origin_token]}@${options[origin_host_port]}/${options[origin_repo]}
+    options[destination_scheme]=$(scheme ${options[destination_url]})
     options[destination_host_port]=$(host_port ${options[destination_url]})
+    options[destination_clone]=${options[destination_scheme]}://:${options[destination_token]}@${options[destination_host_port]}/${options[destination_repo]}
     options[destination_base]=${options[destination_branch]}
     : ${options[prefix]:=${options[origin_repo]}}
     options[destination_head]=${options[prefix]}-${options[origin_pr]}
@@ -61,12 +116,8 @@ function run() {
     upsert_branch
     upsert_pr
     repo_login ${options[origin_repo]}
-
-    # open a PR on destination
-    # checkout the head of the PR
-    # update the PR
-    # force-push the head
-    # wait on the status of the tip of the head
+    update
+    wait_destination_ci $(cat $TMPDIR/destination.sha)
 }
 
 function main() {