#!/usr/bin/env bash

# Display changes made to a file in all the active branches

if [[ $1 == "" ]] ; then
  echo "branches-diff <files...|folders...>"
  exit 1
fi

branches_on_origin_remote_with_last_commit_less_than_a_year_ago(){
  one_year_ago=$(date -d "-1 year" +%Y-%m-%d)
  git for-each-ref --format='%(committerdate:iso) %(refname)' --sort -committerdate | \
    awk '{if($1>"'$one_year_ago'")print $4}' | \
    grep -vE 'HEAD|master' | \
    grep origin | \
    sed 's|^.*/origin/||'
}

{
  for branch in $(branches_on_origin_remote_with_last_commit_less_than_a_year_ago) ; do
    branch_start=$(git merge-base master $branch | cut -c 1-7)
    tmp_file="/tmp/git_branch_diff_${branch_start}_${branch}"
    git --no-pager diff --color=always $branch_start $branch -- $@ > "$tmp_file"
    lines_count=$(wc -l "$tmp_file" | awk '{print $1}')
    if [[ "$lines_count" != "0" ]] ; then
      echo -e "\n\e[0;44m================\e[0m  diff $branch_start - $branch  \e[0;44m================\e[0m"
      cat "$tmp_file";
    else
      echo -e "\e[0;30m================ diff $branch_start - $branch  ================\e[0m"
    fi
  done
} | less -R