#! /bin/bash

set -x
set -e

# This script expects the following environment variables to be set:
#
#  - PGCOPYDB_SOURCE_PGURI
#  - PGCOPYDB_TARGET_PGURI
#  - PGCOPYDB_TABLE_JOBS
#  - PGCOPYDB_INDEX_JOBS

# make sure source and target databases are ready
pgcopydb ping

#
# Only start injecting DML traffic on the source database when pgcopydb
# follow command has been started. We know that by querying the SQLite
# catalogs database, where the prefetch/transform/catchup sub-processes
# register themselves in the process table.
#
dbf=${TMPDIR}/pgcopydb/schema/source.db

while [ ! -s ${dbf} ]
do
    sleep 1
done

sql="select pid from process where ps_type = 'prefetch'"
pidf=/tmp/prefetch.pid

while [ ! -s ${pidf} ]
do
    # sometimes we have "Error: database is locked", ignore
    sqlite3 -batch -bail -noheader ${dbf} "${sql}" > ${pidf} || echo error
    sleep 1
done

# allow replaying changes now that pgcopydb follow command is running
pgcopydb stream sentinel set apply

# allow the catchup phase to finish, ensure the following data is streamed
sleep 2

# then insert another batch of 10 rows (21..30)
psql -v a=21 -v b=30 -d ${PGCOPYDB_SOURCE_PGURI} -f /usr/src/pgcopydb/dml.sql

# also insert data that won't fit in a single Unix PIPE buffer
psql -d ${PGCOPYDB_SOURCE_PGURI} -f /usr/src/pgcopydb/dml-bufsize.sql

# add some data to update_test table
psql -d ${PGCOPYDB_SOURCE_PGURI} << EOF
begin;
insert into update_test(id, name) values
(1, 'a'),
(2, 'b');
commit;

begin;
update update_test set name = 'c' where id = 1;
commit;

begin;
update update_test set name = 'd' where id = 2;
commit;

EOF

# grab the current LSN, it's going to be our streaming end position
lsn=`psql -At -d ${PGCOPYDB_SOURCE_PGURI} -c 'select pg_current_wal_flush_lsn()'`
pgcopydb stream sentinel set endpos --current
pgcopydb stream sentinel get

#
# Becaure we're using docker-compose --abort-on-container-exit make sure
# that the other process in the pgcopydb service is done before exiting
# here.
#
sql="select '${lsn}'::pg_lsn <= replay_lsn from pgcopydb.sentinel"
sql="select exists(select 1 from pg_replication_slots where slot_name = 'pgcopydb')"

while [ `psql -At -d ${PGCOPYDB_SOURCE_PGURI} -c "${sql}"` = 't' ]
do
    sleep 1
done

#
# Still give some time to the pgcopydb service to finish its processing,
# with the cleanup and all.
#
sleep 10
