#!/bin/bash

# Log output:
#
# * 51c333e    (12 days)    <Gary Bernhardt>   add vim-eunuch
#
# The time massaging regexes start with ^[^<]* because that ensures that they
# only operate before the first "<". That "<" will be the beginning of the
# author name, ensuring that we don't destroy anything in the commit message
# that looks like time.
#
# The log format uses } characters between each field, and `column` is later
# used to split on them. A } in the commit subject or any other field will
# break this.

HASH="%C(yellow)%h%Creset"
RELATIVE_TIME="%Cgreen(%ar)%Creset"
AUTHOR="%C(blue)<%an>%Creset"
REFS="%C(red)%d%Creset"
SUBJECT="%s"

FORMAT="$HASH}$RELATIVE_TIME}$AUTHOR}$REFS $SUBJECT"

ANSI_BLACK='\033[30m'
ANSI_RED='\033[31m'
ANSI_GREEN='\033[32m'
ANSI_YELLOW='\033[33m'
ANSI_BLUE='\033[34m'
ANSI_MAGENTA='\033[35m'
ANSI_CYAN='\033[36m'
ANSI_WHITE='\033[37m'
ANSI_RESET='\033[0m'

git log --graph --pretty="tformat:${FORMAT}" $* |
  # Replace (2 years ago) with (2 years)
  sed -Ee 's/(^[^<]*) ago\)/\1)/' |
  # Replace (2 years, 5 months) with (2 years)
  sed -Ee 's/(^[^<]*), [[:digit:]]+ .*months?\)/\1)/' |
  # Line columns up based on } delimiter
  column -s '}' -t |
  # Color merge commits specially
  sed -Ee "s/(Merge (branch|remote-tracking branch|pull request) .*$)/$(printf $ANSI_RED)\1$(printf $ANSI_RESET)/" |
  # Page only if we're asked to.
  if [ -n "$GIT_NO_PAGER" ]; then
    cat
  else
    # Page only if needed.
    less --quit-if-one-screen --no-init --RAW-CONTROL-CHARS --chop-long-lines
  fi