#!/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