#!/bin/bash

# USAGE:
# migrate-postgresql-version.sh <data_directory> <old_version> <new_version>

if [ "$#" -ne 3 ]; then
    echo "USAGE: migrate-postgresql-version.sh <data_directory> <old_version> <new_version>"
    echo "Example: migrate-postgresql-version.sh pgdata 14 16"
    exit 1
fi

data_directory=$1
old_version=$2
new_version=$3

# Start a PostgreSQL 14 container
docker run --rm -d --name pg14 -v $(pwd)/$data_directory:/var/lib/postgresql/data postgres:$old_version-alpine

# Dump the db from the old container
docker exec pg14 pg_dumpall -U postgres > dump.sql

# Stop the old container
docker stop pg14

# move the data directory to a new location so we can overwrite it
mv $data_directory $data_directory.bak

# Start a PostgreSQL 16 container
docker run --rm -d --name pg16 -v $(pwd)/$data_directory:/var/lib/postgresql/data postgres:$new_version-alpine

# Load the db into the new container
docker exec -i pg16 psql -U postgres < dump.sql

# Stop the new container
docker stop pg16

# Remove the dump file
rm dump.sql

echo "Migration complete! You can delete your old data directory by running 'rm -rf $data_directory.bak'"