git-lg

#!/bin/bash -e

# Git script for printing beautiful logs.

if echo "$*" | grep -Eq -- '--help\b|-h\b'; then
    echo "usage: ${0##*/} [-h|--help] [ARGS]" 1>&2
    echo "Forwards any additional ARGS to the git log command." 1>&2
    exit 1
fi

HASH='%C(red)%h%C(reset)'
DATE='%C(green)(%cr)%C(reset)'
AUTHOR='%C(bold blue)<%an>%C(reset)'
REFS='%C(yellow)%d%C(reset)'
MESSAGE='%s'

TERM_WIDTH="$(tput cols)"
MAX_HASH_WIDTH="$((TERM_WIDTH / 4))"

make_format() {
    local delim="$1"
    echo "$HASH$delim$DATE$delim$AUTHOR$delim$REFS $MESSAGE"
}

make_log() {
    local format="$1"
    shift
    git log \
        --date=relative \
        --graph \
        --pretty="tformat:$format" \
        "$@"
}

max_hash_width() {
    make_log "$HASH" "$@" | awk '{ if (length > L) { L = length } }END{ print L }'
}

git_pretty_log() {
    local columnize
    if [[ "$(max_hash_width "$@")" -le $MAX_HASH_WIDTH ]]; then
        columnize=true
    else
        columnize=false
    fi

    # 1. Replace (2 years, 5 months) with (2 years)
    # 2. Replace (2 years ago) with (2 years)
    # 3. Color merge commits specially
    # 4. Page only if we're asked to (GIT_NO_PAGER)
    # 5. Page only if needed
    if [[ $columnize == true ]]; then
        make_log "$(make_format '}')" "$@"
    else
        make_log "$(make_format ' ')" "$@"
    fi |
        sed -Ee 's/([[:digit:]]+ [[:alpha:]]+), [[:digit:]]+ months? ago/\1/' |
        sed -Ee 's/([[:digit:]]+ [[:alpha:]]+) ago/\1/' |
        sed -Ee "s/(Merge (branch|remote-tracking branch|pull request) .*$)/$(printf '\033[31m')\\1$(printf '\033[0m')/" |
        if [[ $columnize == true ]]; then
            column -ts '}'
        else
            cat
        fi |
        if [ -n "$GIT_NO_PAGER" ]; then
            cat
        else
            less --quit-if-one-screen --no-init --RAW-CONTROL-CHARS --chop-long-lines
        fi
}

git_pretty_log "$@"