#!/bin/bash
#
# Provides short mappings for common Git commands
#
# Copyright (C) 2011, 2012, 2013, 2014, 2015 Mike Gerwitz
#
#  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/>.
# #

declare -r __git_short_path="${1:-$(pwd)/shortmaps}"


__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" 1>/dev/null \
    || complete -o default -o nospace -F"$fn" "$cmd"
}


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

  # only perform completion when within a git dir
  git rev-parse &>/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)
  "${__git_short_comp[$shortcmd]}"
}


__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 [ "$shortcmd" == --help ]; then
    __git-short_help
    return
  fi

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

  local cmd="${__git_short_maps[$shortcmd]}"
  test -n "$cmd" || return

  # pipe cmd prefix indicates a verbatim command
  if [ "${cmd:0:1}" == '|' ]; then
    eval "${cmd:1}" '"$@"'
    return
  fi

  # intentionally unquoted
  $cmd "$@"
}


__git-short_help()
{
cat <<EOH
Git Shortmaps loaded from:
  - $HOME/.git-shortmaps
  - $__git_short_path

Defined shortmaps:
$( __git-short_map_out | sed 's/^/  /' )

git-shortmaps Copyright (C) 2011, 2012, 2013, 2014 Mike Gerwitz
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions; see the GNU GPLv3+ for details at
<https://www.gnu.org/licenses/>.
EOH
}


__git-short_map_out()
{
  local shortcmd

  for shortcmd in "${!__git_short_maps[@]}"; do
    echo -e "$shortcmd\t${__git_short_maps[$shortcmd]}"
  done \
    | sort \
    | { type column &>/dev/null && column -t -s$'\t' || cat; }
}


# load shortmaps from cwd (or provided path) and home dir (if available)
__git-short_load_maps()
{
  local -r path="$1"
  cat "$path" ~/.git-shortmaps 2>/dev/null
}


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


declare shortcmd comp cmd
declare -gA __git_short_maps __git_short_comp

# register each shortmap
while read shortcmd comp cmd; do
  test -n "$shortcmd" || continue

  if [ "${cmd:0:1}" == : ]; then
    cmd="git ${cmd:1}"
  fi

  __git_short_maps["$shortcmd"]="$cmd"
  __git_short_comp["$shortcmd"]="$comp"

  __git-short_docomplete "$shortcmd" __git-short_shortmap
  __git-short_register_alias "$shortcmd"
done < <( __git-short_load_maps "$__git_short_path" )


# some distros use completion lazy-loading
type -t _completion_loader &>/dev/null \
  && _completion_loader git