#!/usr/bin/env bash

# A simple script for opening merge conflicts in the editor.

# Use the following Mercurial settings to enable it.

#

# [ui]

# merge = editmerge

#

# [merge-tools]

# editmerge.args=$output

# editmerge.check=changed

# editmerge.premerge=keep

FILE=$1

getlines() {

  grep -n "<<<<<<" $FILE | cut -f1 -d:

}

# editor preference loosely based on https://mercurial-scm.org/wiki/editor

# hg showconfig is at the bottom though, since it's slow to run (0.15 seconds)

ED=$HGEDITOR

if [ "$ED" = "" ] ; then

  ED=$VISUAL

fi

if [ "$ED" = "" ] ; then

  ED=$EDITOR

fi

if [ "$ED" = "" ] ; then

  ED=$(hg showconfig ui.editor)

fi

if [ "$ED" = "" ] ; then

  echo "merge failed - unable to find editor"

  exit 1

fi

if [ "$ED" = "emacs" ] || [ "$ED" = "nano" ] || [ "$ED" = "vim" ] ; then

  FIRSTLINE=$(getlines | head -n 1)

  PREVIOUSLINE=""

  # open the editor to the first conflict until there are no more

  # or the user stops editing the file

  while [ ! "$FIRSTLINE" = "" ] && [ ! "$FIRSTLINE" = "$PREVIOUSLINE" ] ; do

    $ED +$FIRSTLINE $FILE

    PREVIOUSLINE=$FIRSTLINE

    FIRSTLINE=$(getlines | head -n 1)

  done

else

  $ED $FILE

fi

# get the line numbers of the remaining conflicts

CONFLICTS=$(getlines | sed ':a;N;$!ba;s/\n/, /g')

if [ ! "$CONFLICTS" = "" ] ; then

  echo "merge failed - resolve the conflicts (line $CONFLICTS) then use 'hg resolve --mark'"

  exit 1

fi

exit 0