#!/bin/bash
#
# Provides short mappings for common Git commands
#
#  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 <http://www.gnu.org/licenses/>.
# #


__git-short_cmdok()
{
  local -r cmd="$1"
  test "${cmd:0:1}" != -
}


__git-short_docomplete()
{
  local -r cmd="$1" fn="$2"

  # ignore problem commands
  __git-short_cmdok "$cmd" || return

  complete -o bashdefault -o default -o nospace -F"$fn" "$cmd" 2>/dev/null \
    || complete -o default -o nospace -F"$fn" "$cmd"
}


__git-short_shortmap()
{
  # only perform completion when within a git dir
  __gitdir >/dev/null || return

  # populate variables used by various git completion functions
  local cur words cword prev
  _get_comp_words_by_ref -n =: cur words cword prev

  # execute the associated completion function (column two of the shortmaps
  # file)
  $( awk "/^$1 / { print \$2 }" <<< "$__git_short_maps" )
}


__git-short_register_alias()
{
  local -r cmd="$1"

  # ignore invalid aliases (for which we define functions to handle them
  # instead)
  __git-short_cmdok "$cmd" || return

  alias $cmd="__git-short_shortalias '$cmd'"
}


__git-short_shortalias()
{
  local -r shortcmd="$1"
  shift

  # if we're not within a git dir, fall back to an actual command of this
  # name
  __gitdir >/dev/null || {
    command "$shortcmd" "$@"
    return
  }

  local cmd="$(
    grep "^$shortcmd " <<< "$__git_short_maps" \
      | cut -d' ' -f3-
  )"

  if [ -z "$cmd" ]; then
    return
  elif grep -q '^|' <<< "$cmd"; then
    eval "$( sed 's/^|//' <<< "$cmd" ) $@"
    return
  fi

  # intentionally unquoted
  $cmd "$@"
}


# functions that cannot be aliased
- () { __git-short_shortalias - "$@"; }
-- () { __git-short_shortalias -- "$@"; }

# load shortmaps from cwd (or provided path) and home dir (if available)
__git_short_maps=$(
  sed 's/^\([^ ]\+ [^ ]\+\) :/\1 git /' \
    "${1:-./shortmaps}" ~/.git-shortmaps \
    2>/dev/null
)

oldifs="$IFS"

# register each shortmap
IFS=$'\n'
for line in $__git_short_maps; do
  IFS=$' '
  set -- $line

  [ -z "$1" ] && continue

  __git-short_docomplete "$1" __git-short_shortmap
  __git-short_register_alias "$1"
done

IFS="$oldifs"