#!/usr/bin/env bash

#
# blackbox_whatsnew - show what has changed in the last commit for a given file
#

blackbox_home=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
source "${blackbox_home}/_blackbox_common.sh"

if [[ $# -ne 1 ]]
then
  echo "Pass only 1 file at a time"
  exit 1
fi

fail_if_not_in_repo

if [[ -z $GPG_AGENT_INFO ]]; then
  echo 'WARNING: You probably want to run gpg-agent as'
  echo 'you will be asked for your passphrase many times.'
  echo 'Example: $ eval $(gpg-agent --daemon)'
  read -r -p 'Press CTRL-C now to stop. ENTER to continue: '
fi

COLUMNS=`tput cols`
FILE=$1
GIT="git log --abbrev-commit --pretty=oneline"
CURR_COMMIT=`$GIT                  $FILE | head -1 | awk '{print $1}'`
PREV_COMMIT=`$GIT ${CURR_COMMIT}~1 $FILE | head -1 | awk '{print $1}'`
# Use colordiff if available
if which colordiff > /dev/null 2>&1
  then DIFF="colordiff"
  else DIFF="diff"
fi

cat_commit()
{
  COMMIT=$1
  git checkout $COMMIT $FILE
  echo "[$COMMIT] $FILE"
  echo "---------------------"
  "${blackbox_home}/blackbox_cat" $FILE | sed '/========== PLAINFILE/,/========== EXTRACTING/d'
}

CURR_CONTENT=`cat_commit $CURR_COMMIT`
PREV_CONTENT=`cat_commit $PREV_COMMIT`
clear

# For some unknown reason this command executes fine but return exit code 1
$DIFF -y --width $COLUMNS \
  <(echo "CURRENT"  "$CURR_CONTENT" | fold -w $(( $COLUMNS / 2 - 4 ))  ) \
  <(echo "PREVIOUS" "$PREV_CONTENT" | fold -w $(( $COLUMNS / 2 - 4 ))  )

git checkout $CURR_COMMIT $FILE
echo