#!/usr/bin/env bash
#
# git log interactive viewer
#
# @params
# Globals
#   ${mydir}: current dir of the script
#   ${selected_action}: action to take on the selected commit
#   ${selected_commit}: user selected commit
#   ${confirm}: confirm status of user
# Arguments
#   -h|--help: display help message
#   -r|--revert: revert the selected commit
#   -R|--reset: reset HEAD back to the selected commit
#   -e|--edit: edit commmit (interactive rebase)
#   -c|--checkout: checkout selected commmit
#   -y|--yes: confirm action by default and skip confirmation

set -e
set -f

mydir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
source "${mydir}"/../helper/set_variable.sh
source "${mydir}"/../helper/git_query.sh
source "${mydir}"/../helper/get_confirmation.sh

function usage() {
  echo -e "Usage: dotbare flog [-h] [-r] [-R] [-e] [-c] [-y] ...

Interactive log viewer with action menu.
Action menu contains options including revert|reset|edit|checkout|exit.

Default: list all commits and prompt a menu to select action to perform.

Optional arguments:
  -h, --help\t\tshow this help message and exit.
  -r, --revert\t\trevert the selected commit and skip action menu.
  -R, --reset\t\treset HEAD back to selected commit and skip action menu.
  -e, --edit\t\tedit selected commit through interactive rebase and skip action menu.
  -c, --checkout\tcheckout selected commit and skip action menu.
  -y, --yes\t\tacknowledge all actions that will be taken and skip confirmation."
}

#######################################
# draw action menu for selected commit
# Arguments:
#   $1: selected commit hash, used to display commit message in fzf header
#   $2: selected action, if selected, skip menu, return action
# Outputs:
#   ${selected_action}: user selected action
#######################################
function draw_menu() {
  local selected_commit="$1"
  local selected_action="$2"
  local menu header message
  if [[ -n "$selected_action" ]]; then
    echo "${selected_action}"
  else
    menu="revert: revert the selected commit\n"
    menu="${menu}reset: reset HEAD to the selected commit using --mixed flag\n"
    menu="${menu}edit: edit selected commit through interactive rebase\n"
    menu="${menu}checkout: checkout the selected commit\n"
    menu="${menu}exit: quit dotbare flog"
    message=$(
      git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
      log --format=%B -n 1 "${selected_commit}"
    )
    header="commit ${selected_commit}: ${message}"
    selected_action=$(echo -e "${menu}" \
      | fzf --no-multi --header="${header}" \
      | awk -F ":" '{
          print $1
        }'
    )
    echo "${selected_action}"
  fi
}

selected_action=""
selected_commit=""
confirm=""

while [[ "$#" -gt 0 ]]; do
  case "$1" in
    -r|--revert)
      selected_action="revert"
      shift
      ;;
    -R|--reset)
      selected_action="reset"
      shift
      ;;
    -e|--edit)
      selected_action="edit"
      shift
      ;;
    -c|--checkout)
      selected_action="checkout"
      shift
      ;;
    -y|--yes)
      confirm='y'
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      echo "Invalid option: $1" >&2
      usage
      exit 1
      ;;
  esac
done

while :; do
  selected_commit=$(get_commit)
  [[ -z "${selected_commit}" ]] && exit 1
  selected_action=$(draw_menu "${selected_commit}" "${selected_action}")
  [[ -n "${selected_action}" ]] && break
done

if [[ "${selected_action}" != 'exit' ]]; then
  if [[ "${selected_action}" == "reset" ]] && [[ -z "${confirm}" ]]; then
    echo "(dryrun) reset HEAD to ${selected_commit}"
  elif [[ -z "${confirm}" ]]; then
    echo "(dryrun) ${selected_action} ${selected_commit}"
  fi
  [[ -z "${confirm}" ]] && confirm=$(get_confirmation)
  [[ "${confirm}" != 'y' ]] && exit 1
fi

case "${selected_action}" in
  revert)
    git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
    revert "${selected_commit}"
    ;;
  reset)
    git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
    reset "${selected_commit}"
    ;;
  edit)
    git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
    rebase -i "${selected_commit}"~
    ;;
  checkout)
    git --git-dir="${DOTBARE_DIR}" --work-tree="${DOTBARE_TREE}" \
    checkout "${selected_commit}"
    ;;
  exit)
    exit 0
    ;;
  *)
    exit 1
    ;;
esac