git-init

#!/bin/bash

# SPDX-FileCopyrightText: 2021 - 2024 sudorook <daemon@nullcodon.com>
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.

set -euo pipefail

ROOT="$(dirname "${0}")"

source "${ROOT}"/globals

! check_command bc git timedatectl && exit 3

#
# Global functions.
#

make_random_alias() {
  local range
  local string

  range="$(date -d "1970-01-01 UTC ${RAND_RANGE}" "+%s")"
  string='! NEW_DATE="$('"${TZ:+TZ=${TZ@Q} }"'date -d "1970-01-01 UTC $(echo $(date +%s) - '"${range}"' + $(shuf -i '"0-${range}"' -n 1) | bc -l) seconds" "+%c")"'
  string="${string}"' && export GIT_AUTHOR_DATE="${NEW_DATE}" && export GIT_COMMITTER_DATE="${NEW_DATE}" &&'
  echo "${string}"
}

make_workday_alias() {
  local start_s
  local end_s
  local scale
  local string

  start_s="$(date -d "1970-01-01 UTC ${START}" '+%s')"
  end_s="$(date -d "1970-01-01 UTC ${END}" '+%s')"
  scale="$(echo "(${end_s} - ${start_s}) / 86400" | bc -l)"
  string='! NEW_DATE="$('"${TZ:+TZ=${TZ@Q} }"'date -d "00:00 $(echo '"${start_s}"' + '"${scale}"' \* "$(date -d "1970-01-01 UTC $(date +%T)" +%s)" | bc -l) seconds" "+%c")"'
  string="${string}"' && export GIT_AUTHOR_DATE="${NEW_DATE}" && export GIT_COMMITTER_DATE="${NEW_DATE}" &&'
  echo "${string}"
}

set_aliases() {
  case "${SCHEDULE}" in
    workday)
      if [[ -v START ]] && [[ -v END ]]; then
        alias="$(make_workday_alias)"
      else
        exit 3
      fi
      ;;
    random)
      if [[ -v RAND_RANGE ]]; then
        alias="$(make_random_alias)"
      else
        exit 3
      fi
      ;;
    none)
      return
      ;;
    *)
      return
      ;;
  esac

  git config --${MODE} alias.alt-commit "${alias} git commit"
  git config --${MODE} alias.alt-revert "${alias} git revert"
}

print_usage() {
  show_header "Usage:"
  show_listitem "\
  -n  --name          author name
  -e  --email         author email
  -s  --schedule      schedule (workday, random, or none)
  -r  --range         workday schedule range (e.g. 9AM-5PM)
  -o  --roffset       random schedule offset (e.g. '3 days', '1 week')
  -t  --timezone      time zone (e.g. 'America/Toronto')
  -g  --global        flag to write settings globally
  -h  --help          print (this) help message"
}

#
# Main
#

OPTIONS=n:e:s:r:o:t:hg
LONGOPTIONS=name:,email:,schedule:,range:,roffset:,timezone:,help,global
PARSED=$(getopt -o "${OPTIONS}" --long "${LONGOPTIONS}" -n "${0}" -- "${@}")
eval set -- "${PARSED}"

MODE=local

while [ ${#} -ge 1 ]; do
  case ${1} in
    -n | --name)
      NAME="${2}"
      shift 2
      ;;
    -e | --email)
      EMAIL="${2}"
      shift 2
      ;;
    -s | --schedule)
      SCHEDULE="${2}"
      shift 2
      ;;
    -r | --range)
      START="$(echo "${2}" | cut -d"-" -f1)"
      END="$(echo "${2}" | cut -d"-" -f2)"
      shift 2
      ;;
    -o | --roffset)
      RAND_RANGE="${2}"
      shift 2
      ;;
    -t | --timezone)
      TZ="${2}"
      shift 2
      ;;
    -g | --global)
      MODE=global
      shift
      ;;
    -h | --help)
      print_usage
      exit
      ;;
    --)
      shift
      break
      ;;
    *)
      print_usage
      show_error "ERROR: invalid flag."
      exit 3
      ;;
  esac
done

if [[ -v TZ ]] && [ "${TZ}" = default ]; then
  TZ="$(timedatectl show -p Timezone --value)"
fi

if [[ "${MODE}" = local ]]; then
  if git rev-parse 2> /dev/null; then
    show_warning "WARNING: Git repo already exists."
  else
    show_info "Initializing Git repo."
    git init
  fi
fi

${NAME:+git config --"${MODE}" user.name "${NAME}"}
${EMAIL:+git config --"${MODE}" user.email "${EMAIL}"}
${SCHEDULE:+set_aliases}