#!/bin/bash

# There are mostly three reasons the synapse database tends to get large over time:
#
#  - Stuff that no longer needs to be kept around and should be deleted
#  - Synapse is extremely cache-happy, and this takes a lot of space
#  - Table bloat & Index bloat in PostgreSQL
#
# See also:
# https://github.com/matrix-org/synapse/wiki/SQL-for-analyzing-Synapse-PostgreSQL-database-stats

# Exit on first failure
set -e

# Adjust as needed to your own setup
TOKEN="<TOKEN from matrix-client>"
export PGPASSWORD="<PG_PASSWORD>"
PGUSER="synapse_user"
PGDB="synapse"
PGHOST="localhost"
FQDN="<your.matrix-server.fqdn>"

WORKDIR=/root/matrix_cleanup
SUJET="Matrix server cleanup - $(hostname -f)";
POSTMASTER="root"
RESULTAT="KO"
LOGFILE=/var/log/matrix/cleanup.log

# Ensure dirs exist
[[ -d $(dirname ${LOGFILE}) ]] || mkdir -p $(dirname ${LOGFILE})
[[ -d ${WORKDIR} ]] || mkdir -p ${WORKDIR}

jnl() {
    echo "$(date +%c) : $1" | tee -a "${LOGFILE}"
}

two_months_ago() {
    timestamp=$(date +"%s" -d '2 months ago')
    echo "${timestamp}"
}

one_year_ago() {
    date +"%s%N" -d '1 year ago'|cut -b1-13
}

notify() {
   jnl "End of programme."
   cat $LOGFILE | mail -s "${SUJET} : ${RESULTAT}" ${POSTMASTER}
   [ "${RESULTAT}" = "OK" ] && exit 0 || exit 1
}

#####################################
#      Main
#####################################

# pre-cleanup
jnl "Remove temporary files..."
rm -f /opt/synapse-compress/*.sql
rm -f /root/matrix_cleanup/*.txt

jnl "Dumping current status on Database"

biggestTables=$(echo "SELECT nspname || '.' || relname AS \"relation\", pg_size_pretty(pg_total_relation_size(C.oid)) AS "total_size" FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace) WHERE nspname NOT IN ('pg_catalog', 'information_schema') AND C.relkind <> 'i' AND nspname !~ '^pg_toast' ORDER BY pg_total_relation_size(C.oid) DESC LIMIT 20;" | psql -h ${PGHOST} -d ${PGDB} -U ${PGUSER})

jnl "${biggestTables}"

# Removing empty rooms
jnl "Getting empty rooms..."

curl -H "HOST: ${FQDN}" -H "Authorization: Bearer $TOKEN" 'http://127.0.0.1:8008/_synapse/admin/v1/rooms?limit=300' | jq '.rooms[] | select(.joined_local_members == 0) | .room_id'|sed 's/^"//;s/"$//' > ${WORKDIR}/to_purge.txt

jnl < ${WORKDIR}/to_purge.txt

while read room_id; do 
    jnl "purging room ${room_id}..."
    #curl -w "\n" --header "Authorization: Bearer $TOKEN" -X POST -H "Content-Type: application/json" -d "{ \"room_id\": $room_id }" -H "HOST: ${FQDN}" 'http://127.0.0.1:8008/_synapse/admin/v1/purge_room'
    curl -w "\n" --header "Authorization: Bearer $TOKEN" -X DELETE -H "Content-Type: application/json" -d "{ \"purge\": true }" -H "HOST: ${FQDN}" "http://127.0.0.1:8008/_synapse/admin/v2/rooms/${room_id}"
     sleep 0.5
done < ${WORKDIR}/to_purge.txt

jnl "Deleting history of more than 2 months in large rooms"

curl -H "HOST: ${FQDN}" -H "Authorization: Bearer $TOKEN" 'http://127.0.0.1:8008/_synapse/admin/v1/rooms?limit=300' | jq '.rooms[] | select(.state_events > 100) | .room_id' | sed 's/\"//g' > ${WORKDIR}/history_to_purge.txt

if [[ -s ${WORKDIR}/history_to_purge.txt ]]; then
    dateUntil=$(two_months_ago)

    while read room_id; do 
        jnl "purging history for ${room_id}..."
        echo curl  -w "\n" --header "Authorization: Bearer $TOKEN" -X POST -H "Content-Type: application/json" -d "{ \"delete_local_events\": false, \"purge_up_to_ts\": ${dateUntil} }" -H "HOST: ${FQDN}" "http://127.0.0.1:8008/_synapse/admin/v1/purge_history/$room_id"
        curl  -w "\n" --header "Authorization: Bearer $TOKEN" -X POST -H "Content-Type: application/json" -d "{ \"delete_local_events\": false, \"purge_up_to_ts\": ${dateUntil} }" -H "HOST: ${FQDN}" "http://127.0.0.1:8008/_synapse/admin/v1/purge_history/$room_id"
        sleep 0.5
    done < ${WORKDIR}/history_to_purge.txt 
fi

    echo curl -X POST -H "HOST: ${FQDN}" -H "Authorization: Bearer $TOKEN"  "http://127.0.0.1:8008/_synapse/admin/v1/purge_media_cache?before_ts=$(one_year_ago)"
    curl -X POST -H "HOST: ${FQDN}" -H "Authorization: Bearer $TOKEN"  "http://127.0.0.1:8008/_synapse/admin/v1/purge_media_cache?before_ts=$(one_year_ago)"

jnl "Optimizing synapse cache for rooms with more than 100 000 state changes"
# Get the list of rooms with more than 99 999 state groups events

jnl "Gathering list"
psql -h "${PGHOST}" -d "${PGDB}" -U "${PGUSER}" -t -c "SELECT room_id, count(*) AS count FROM state_groups_state GROUP BY room_id HAVING count(*) > 99999 ORDER BY count DESC;" | sed -r 's/\s//g' | egrep -v '^$' |awk -F "|" '{print $1}' > ${WORKDIR}/to_compress.txt

jnl "Prepare compression files state-compressor"
cpt=1
while read room_id; do 
    # Could we remove the password / is it using .pgpass?
    echo room_id ${room_id}
    /usr/local/bin/synapse-compress-state -t -o /opt/synapse-compress/state-compressor_${cpt}.sql -p "host=${PGHOST} user=${PGUSER} password=${PGPASSWORD} dbname=${PGDB}" -r "$room_id"
    ((cpt++))
    sleep 0.5
done < ${WORKDIR}/to_compress.txt

jnl "Running the compressions..."
for file in `ls /opt/synapse-compress/state-compressor*.sql`; do 
    jnl "Compressing ${file}"
    psql -h ${PGHOST} -d ${PGDB} -U ${PGUSER} < ${file}
    sleep 0.5
done

# If needed, or to do once in a while 
# REINDEX (VERBOSE) DATABASE matrix_prod;
# VACUUM FULL VERBOSE state_groups_state;

RESULTAT="OK"
notify

exit 0