#!/usr/bin/env bash

## Retrieve older version of the source, to be compared
## in performance against the current version.

DIRECTORY_CONTAINING_THIS_SCRIPT=$( cd $(dirname $0) ; pwd -P )
REPOSITORY_ROOT="$DIRECTORY_CONTAINING_THIS_SCRIPT/.."


SOURCE_FILENAME="flyd"
SOURCE_FILENAME_WITH_EXTENSION="$SOURCE_FILENAME.js"

OLD_VERSION_FILENAME="$SOURCE_FILENAME-old"
OLD_VERSION_FILENAME_WITH_EXTENSION="$OLD_VERSION_FILENAME.js"


# The first passed argument is the number of commits (in the
# current branch) you want to 'undo' in order to get
# to the desired old version.
# It defaults to 1.
if [ "$1" -eq "$1" ] 2>/dev/null  &&  [ "$1" -gt "0" ] 2>/dev/null
then
    how_many_commits_back="$1"
else
    how_many_commits_back="1"
fi


# Leave a copy of the old version's source
# in the root of the repository

cd "$REPOSITORY_ROOT"

git checkout HEAD~$how_many_commits_back -- $SOURCE_FILENAME_WITH_EXTENSION

cp $SOURCE_FILENAME_WITH_EXTENSION $OLD_VERSION_FILENAME_WITH_EXTENSION

git checkout HEAD -- $SOURCE_FILENAME_WITH_EXTENSION



## Run the benchmarks
cd "$DIRECTORY_CONTAINING_THIS_SCRIPT"

node perf.js



## Remove the old version of the source
cd "$REPOSITORY_ROOT"

rm $OLD_VERSION_FILENAME_WITH_EXTENSION