weekly statistics on a git repository

weekly_report.sh

#!/usr/bin/env bash
# Print weekly statistics on a git repository.

echo Usage: weekly_report.sh path_to_git_project iso_week_number year

gitpath=$1
week=$2
year=$3

echo Statistics for git project $1
echo Report for week $week generated on `date  --iso-8601`.

# Function weekof() takes an ISO 8601 week number and a year,
# and prints the dates of the monday and sunday corresponding
# to that week.
#
# Example:
#    $ weekof 1 2020
#    2019-12-30 2020-01-05
function weekof()
{
    local week=$1 year=$2
    local week_num_of_Jan_1 week_day_of_Jan_1
    local weeks_offset
    local first_Mon
    local date_fmt="+%Y-%m-%d"
    local monday sunday
    
    # %W produces a 0-based week number unless January 1st is a monday.
    # This is not the same definition as the ISO 8601 definition:
    # "week 01 is the week with the first Thursday of the Gregorian year in it"
    week_num_of_Jan_1=$(date -d $year-01-01 +%W)
    iso_week_num_of_Jan_1=$(date -d $year-01-01 +%V)
    week_day_of_Jan_1=$(date -d $year-01-01 +%u)

    if ((week_num_of_Jan_1)); then
        first_Mon=$year-01-01
    else
        first_Mon=$year-01-$((01 + (7 - week_day_of_Jan_1 + 1) ))
    fi
    
    if [ ${week_num_of_Jan_1} == "01" ] || [ ${iso_week_num_of_Jan_1} != "01" ]; then
        # The first monday is in ISO week 1
        weeks_offset=$((week - 1))
    else
        # The first monday is in ISO week 2
        weeks_offset=$((week - 2))           
    fi
    monday=$(date -d "$first_Mon +${weeks_offset} week" "$date_fmt")
    sunday=$(date -d "$first_Mon +${weeks_offset} week + 6 day" "$date_fmt")

    echo $monday $sunday
}

start="`weekof $week $year | awk '{print $1}'` 00:00:00"
end="`weekof $week $year | awk '{print $2}'` 23:59:59"
weekof $week $year 
echo Start date for report: $start 
echo End date for report: $end

cd $gitpath
git checkout master
git pull
git log --numstat --pretty="%H" --since="$start" --until="$end" | awk 'NF==3 {plus+=$1; minus+=$2} NF==1 {total++} END {printf("lines added: +%d\nlines deleted: -%d\ntotal commits: %d\n", plus, minus, total)}'