#! /bin/sh

# Copyright (c) 2019, 2020, 2022, 2026 Stefan Kreutz <mail@skreutz.com>
#
# Permission to use, copy, modify, and distribute this software for any purpose
# with or without fee is hereby granted, provided that the above copyright
# notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
# OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.

set -o nounset

# Remove the temporary directory before exiting.
trap 'quit' INT
quit() {
  code="${1:-0}"
  [ -z "$postgres_pid" ] || kill -TERM "$postgres_pid"
  wait
  rm -rf "${tmpdir-}" || {
    ( >&2 printf "temp-postgres: failed to remove temporary directory: %s\\n" "${tmpdir}" )
    [ "${code}" -ne 0 ] || code=1
  }
  exit "${code}"
}

dbname="$( id -un )"
username="$( id -un )"

while [ $# -gt 0 ] ; do
  case "$1" in
    -h|--help)
      echo "Usage: temp-postgres [-h|--help] [-d|--dbname <dbname>] [-u|--username <username>] [--] [<command>]"
      exit
      ;;
    -d|--dbname)
      dbname="$2"
      shift 2
      ;;
    -u|--username)
      username="$2"
      shift 2
      ;;
    --)
      shift
      break
      ;;
    -*)
      ( >&2 echo "undefined option: $1" )
      exit 2
      ;;
    *)
      break
      ;;
  esac
done

# Create a temporary directory
tmpdir="$( mktemp -d )" || {
  ( >&2 printf "temp-postgres: failed to create temporary directory\\n" )
  quit 1
}

# Initialize the directory
initdb --pgdata="${tmpdir}" --username="${username}" || {
  ( >&2 printf "temp-postgres: failed to initialize database\\n" )
  quit 1
}

# Serve the directory
( postgres -k "${tmpdir}" -D "${tmpdir}" </dev/null ) &
postgres_pid=$!

# Test the connection
sleep 1
pg_isready --host="${tmpdir}" --dbname="nope" --username="${username}" --timeout=10 || {
  ( >&2 printf "temp-postgres: failed to connect to server\\n" )
  quit 1
}

# Create the database
createdb --host="${tmpdir}" --username="${username}" --no-password "${dbname}" || {
  ( >&2 printf "temp-postgres: failed to create database\\n" )
  quit 1
}

printf '
Connect with the following command:

\tpsql --host "%s" --dbname "%s" --username "%s"

' "$tmpdir" "$dbname" "$username"

if [ $# -eq 0 ] ; then
  wait
else
  export PGHOST="$tmpdir"
  export PGDATABASE="$dbname"
  export PGUSER="$username"
  export DATABASE_URI="postgresql:${dbname}?host=${tmpdir}&user=${username}"
  export DATABASE_URL="$DATABASE_URI"

  "$@" || {
    code=$?
    ( >&2 echo "temp-postgres: command exited ${code}" )
    quit "$code"
  }
  quit
fi