#!/bin/bash

# Specify a directory with all Git repositories
REPODIR=~/Git

# Regex or fixed name (brackets need to be escaped with a backslash)
REPOUSER="\(structix\|Janek\)"

# Specify the start date, where the statistics should be gathered
STARTDATE="01 Jan 2018"

# --------------------

# Switch into the REPODIR
pushd $REPODIR

# total commits
commitcounter=0

# total diff stats
totalfiles=0
totalinsertions=0
totaldeletions=0

# Iterate over all subdirectories
for dir in $REPODIR/*/
do
    dir=${dir%*/}
    echo ${dir##*/}

    # enter directory
    cd ${dir##*/}

    # --- RUN COMMANDS

    # show amount of commits of all users
    committemp=$(git rev-list --count --all --author=$REPOUSER --since="$STARTDATE")

    # Add to the total commit counter
    commitcounter=$((commitcounter + committemp))


    # calculate total changes between given date and HEAD
    extractdiff=$(git diff @{"$STARTDATE"} HEAD --shortstat) 2>/dev/null

    # set the separator to ,
    IFS=','
    array=( $extractdiff )
    totalfiles=$(( ${array[0]//[!0-9]} + totalfiles))
    totalinsertions=$(( ${array[1]//[!0-9]} + totalinsertions))
    totaldeletions=$(( ${array[2]//[!0-9]} + totaldeletions))


    # ------------------
    # Output the commit counter of the current iteration
    echo $committemp

    # go back
    cd ..
done

echo "Total commits since $STARTDATE: $commitcounter"
echo "Total files changed: $totalfiles"
echo "Total insertions: $totalinsertions"
echo "Total deletions: $totaldeletions"

# Switch back to the original directory state
popd