heatmaps.sh

#!/usr/bin/env bash

# Build a commit frequency histogram

ccyan="$(echo -ne '\033[0;36m')"
cnone="$(echo -ne '\033[0m')"

set -euo pipefail

ARGV=()
while [[ $# -gt 0 ]]; do
    key="$1"
    case $key in
        -n)
            LIMIT="$2"
            shift
            shift
            ;;
        -b | --base)
            REVIEW_BASE="$2"
            shift
            shift
            ;;
        -c | --char)
            CHAR="$2"
            shift
            shift
            ;;
        --width)
            WIDTH="$2"
            shift
            shift
            ;;
        -f | --filter)
            FILTER="$2"
            shift
            shift
            ;;
        -h)
            cat <<EOF
Heatmap of oft-edited files.
Usage:
  git heatmap [options] [<path>...]
Options:
  -n <top>                      Limit to top <n> files. [default: 30]
  --width <n>                   Limit histogram to <n> chars.
  -b <branch>, --base <branch>  Compare relative to <branch>. If on <branch>,
                                show heatmap for entire repo. [default: master]
  -c <char>, --char <char>      Use <char> to draw the bars. [default: █]
  -f <cmd>, --filter <cmd>      Filter output through <cmd> before creating the
                                the histogram.
  -h                            Show this message.
EOF
            exit
            ;;
        *)
            ARGV+=("$1")
            shift
            ;;
    esac
done

LIMIT=${LIMIT:-30}
REVIEW_BASE=${REVIEW_BASE:-master}
CHAR=${CHAR:-█}
WIDTH=${WIDTH:-60}
FILTER=${FILTER:-cat -}

files() {
    # https://stackoverflow.com/questions/7577052/
    git log --name-status --pretty=format: -- "${ARGV[@]+"${ARGV[@]}"}" |
        cut -f 2-
}

color_name() {
    if [ -t 1 ]; then
        sed -e "s/\(..*\/\)*\(.[^|]*\) |/\1$ccyan\2$cnone |/"
    else
        cat -
    fi
}

filter() {
    grep '.' |
        eval "$FILTER" |
        sort |
        uniq -c |
        sort -nr |
        head -n "$LIMIT"
}

histogram() {
    bars --bar "$CHAR" --width "$WIDTH"
}

if [[ "$(git branch | grep '\*')" =~ $REVIEW_BASE ]]; then
    # If on master, show heatmap for whole repo
    files | filter | histogram | color_name
else
    MERGE_BASE="$(git merge-base HEAD "$REVIEW_BASE")"
    files |
        # If on separate branch, show heatmap for files changed since master
        grep -xF -f <(git diff --name-only "$MERGE_BASE") |
        filter |
        histogram |
        color_name
fi