#!/bin/sh

# Copyright (c) 2011, 2013, 2014, 2015 Michele Bini

# This program is free software: you can redistribute it and/or modify
# it under the terms of the version 3 of the GNU General Public License
# as published by the Free Software Foundation.

# 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/>.

set -e

usage() {
    echo "Invalid invocation.  For more info: $0 --usage"
}

println() {
    printf "%s\n" "$*"
}

warn() {
    println "$0: $*" >&2
}

die() {
    warn "$*"
    exit 1
}

if [ -z "$1" ]; then usage; exit 1; fi

xargln() {
  while IFS="" read -r line; do
    "$@" "$line" </dev/tty
  done
}

greprx="^"
gitsed_greprx() { # REGEXP - Select only files matching REGEXP
    greprx="$1"; shift; args "$@"
}

gitsed_sedopts() { # ARGS - Pass ARGS to sed
    SEDOPTS="$1"; shift; args "$@"
}

test=""
gitsed_test() { # - When combined with sed 'p' modifer, print lines that would change, without applying any actual change.
    test=1; args "$@"
}

backupext=""
gitsed_backupext() { # EXT - Backup files before changing them to fileEXT
    backupext=1
    (echo -n "$backupext"|grep -q "[^a-zA-Z0-9$.]") && die "Invalid alphanumeric characters in --backupext"
    args "$@"
}

gitsed_usage() { # - Print help
    echo Usage: git-sed OPTIONS* -- SEDEXPR FILES*
    echo
    echo Options:
    sed -n "s/^gitsed_/  --/g;T;s/() {//;s/ *# / /;p" <"$0"
}

content=""
filenames=""

gitsed_content() { # - Apply sed expression to content.
    content=1
    args "$@"
}

gitsed_filenames() { # - Apply sed expression to filenames.
    filenames=1
    args "$@"
}

gitsed_both() { # - Apply sed expression to both content and filenames
    content=1
    filenames=1
    args "$@"
}

force_unstaged=""
gitsed_force() { # - Continue even in the presence of unstable changes
    force_unstaged=1
    args "$@"
}

gitsed_help() {
    gitsed_usage "$@"
}

gitsed_debug() {
    set -x; args "$@"
}

xargln() {
  while IFS="" read -r line; do
    "$@" "$line"
  done
}

dosed() {
    fname="$1"
    if [ -n "$test" ]; then
	sed -n $SEDOPTS -- "$sedexpr" <"$fname"
    else
	sed $SEDOPTS -- "$sedexpr" "$fname"  && git update-index -- "$fname"
    fi
}

mover() {
          filename="$1"
	  newname="$(println "$filename"|sed $SEDOPTS -- "$sedexpr")"
	  if [ "$filename" = "$newname" ]; then :; else
	      mkdir -p "$(dirname "$newname")"
	      if [ -n "$test" ]; then
		  echo "Would rename $filename to $newname"
	      else
	          git mv -v -- "$filename" "$newname"
	      fi
	  fi
}

listfiles() {
  git grep --no-full-name -l -e "^" -- "$@"
  # git ls-files "$@"
}

apply() {
    if [ -n "$test" ]; then
	SEDOPTS="$SEDOPTS -n"
	backupexit=""
    fi

    sedexpr="$1"

    [ -z "$sedexpr" ] && die "You didn't specify a sed expression"

    shift

    if [ -z "$filenames" ] && [ -z "$content" ]; then
	die "You need to add a --filenames, --content or --both option."
    fi

    if [ -n "$filenames" ]; then
        listfiles "$@" | xargln mover
    fi

    if [ -z "$force_unstaged" ]; then
	git diff --quiet -- "$@" || die "There are unstaged changes.  Please stage or discard them before running git-sed."
    fi
    
    if [ -n "$test" ]; then
	true
    elif [ -n "$backupext" ]; then
	SEDOPTS="$SEDOPTS -i$backupext"
    else
	SEDOPTS="$SEDOPTS --in-place"
    fi

    if [ -n "$content" ]; then
	git grep --no-full-name -l -e "$greprx" -- "$@"|xargln dosed
    fi
}

args() {
  if [ -n "$1" ]; then
      N="$1"; shift
      case "$N" in
	  --) apply "$@" ;;
	  -E) SEDOPTS="$SEDOPTS -E"
	      args "$@"
	      ;;
	  --*) gitsed_"${N#--}" "$@" ;;
	  *) apply "$N" "$@" ;;
      esac
  fi
}

args "$@"