#!/bin/bash

NEWSVNURL="file:///home/colin/svn-git/soft"
SOFTWARE=
if [ -d ".git" -a -f ".git/config" -a -f ".git/svn/.metadata" ]; then
  SOFTWARE=$(grep "fetch = " .git/config | cut -d'=' -f2- | cut -d':' -f1 | sed 's,/trunk,,' | trim)
fi

if [ -z "$SOFTWARE" ]; then
  echo "You must run this in a git-svn clone folder." >&2
  exit 1
fi

if [ -d ../$SOFTWARE.git ]; then
  echo "It seems the converted git repository already exists (../$SOFTWARE.git)"
  exit 1
fi

echo -n "Finding UUID for SVN Repository $NEWSVNURL... "
NEWSVNUUID=$(svn info $NEWSVNURL | grep "^Repository UUID:" | sed 's/Repository UUID: //')
echo $NEWSVNUUID

echo -n "Updating SVN Remote config (old value: $(git config svn-remote.svn.url))... "
git config svn-remote.svn.url $NEWSVNURL
echo "done"

echo -n "Updating Internal SVN metadata... "
sed -i "s,reposRoot = .*$,reposRoot = $NEWSVNURL,;s,uuid = .*$,uuid = $NEWSVNUUID," .git/svn/.metadata
echo "done"


echo
echo "OK now the fun stuff beings. You need to find the git commit at which you want to"
echo "start the magiea import. This will typically require some investigation but the"
echo "date will be around February 2011."
echo "I will drop you to a shell. When you are done, simply copy the SHA1 sum and exit."
echo "The commands you like want are 'git log trunk' and 'git show SHA1'"
echo
echo "Press any key to contiue."
read -n 1
bash
echo
echo "OK you're back :)"
echo "What was the SHA1?"
read resetsha1
if [ -z "$resetsha1" ]; then
  echo "You did not give any SHA1 sum. I will not reset the git repository and carry on importing"
  echo "from it's current state. You can quit this script and start again if this is incorrect."
else
  echo "I got SHA1 '$resetsha1'. I hope that's correct".
  echo
  echo "I will now reset your git trunk and master branches. Is this OK? (press ctrl+c if not)"
  read -n 1
  git update-ref -m "Rewind SVN Git to pre-Magiea import" refs/remotes/trunk $resetsha1
  git checkout master
  git reset --hard trunk
fi


echo
echo "I will now run 'svn log' on the software. You should be able to guess the right revision"
echo "to base the import on. When done, simply copy (or remember) the revision number and enter it"
echo "into this script."
echo
echo "Press any key to contiue."
read -n 1

svn log $NEWSVNURL/$SOFTWARE | less

echo
echo "OK you're back :)"
echo "What was the revision number?"
read revision
revision=$(( $revision + 0 ))
echo "I got revision '$revision'. I hope that's correct".
echo
echo "The next step is the dangerous bit. We will clear out all files in the current"
echo "working copy, run an svn export and then drop you to a shell to investigate the differences"
echo "In that shell you must git add any new files that appear and ensure you are happy with"
echo "the generate state of things."
echo
echo "Continue? (press ctrl+c if not)"
read -n 1
git reset --hard trunk
resetsha1=$(git rev-list --max-count=1 HEAD)
# The below is a "safer" verion of rm -rf * that also deletes hidden files
find . -depth -not -iwholename '.' -not -iwholename "./.git" -not -iwholename "./.git/*" -not -iwholename "./.git/.*" -delete
svn export --force --ignore-keywords --ignore-externals -r $revision $NEWSVNURL/$SOFTWARE/trunk .
echo
echo "Dropping you to a shell. Use 'git status', 'git diff' and 'git add'."
echo "DO NOT run 'git commit', I'll do that later for you."
bash

echo
echo "OK you're back :)"
echo "If everything is OK, and you're ready to continue, then hit return."
read -n 1

COMMITTXT=$(mktemp /tmp/commitmsg.XXXXXX)
cat >$COMMITTXT <<EOF
Synthesized commit during git-svn import combining previous Mandriva history with Magiea.

This commit consitsts of the following subversion commits:

EOF
svn log -r 1:$revision $NEWSVNURL/$SOFTWARE >>$COMMITTXT

COMMITDATE=$(svn log -r $revision $NEWSVNURL/$SOFTWARE | head -n2 | tail -n1| cut -d'|' -f3 | cut -d'(' -f1 | trim)
git commit --author="Mageia SVN-Git Migration <svn-git-migration@mageia.org>" --date="$COMMITDATE" --file=$COMMITTXT -a
rm -f $COMMITTXT

echo
echo "OK, looks like we're good to go :)"
echo "Press any key to continue with the subversion import process".
read -n 1

git svn gc
sha1=$(git rev-list --max-count=1 HEAD)
echo
echo -n "Updating trunk branch to include synthesised commit $sha1... "
git update-ref -m "Reset to synthesized commit representing Magiea cleaned import (SVN Git)" refs/remotes/trunk $sha1
echo "done"

echo -n "Faking git-svn metadata to allow continuation... "
printf "0000000: %08x%s\t................" $revision $sha1 | xxd -r -c24 >.git/svn/refs/remotes/trunk/.rev_map.$NEWSVNUUID
echo "done"

# Keep a small log of the sha1's etc.
if [ ! -f ../svn-import.log ]; then
  echo "software,startingcommit,startingrevision,fakecommit" >../svn-import.log
fi
echo "drakx,$resetsha1,$revision,$sha1" >>../svn-import.log

echo "Continuing svn fetch"
git svn fetch -A ../authors-transform.txt -r $(( $revision + 1 )):HEAD
git reset --hard trunk
echo
echo "done"

echo
echo "Now creating bare git repository"
git init --bare ../$SOFTWARE.git
git remote rm origin
git remote add origin ../$SOFTWARE.git
#git push --set-upstream master
git push origin master 'refs/remotes/*:refs/heads/*'

pushd ../$SOFTWARE.git
git branch -D trunk
git branch -D origin/master
git for-each-ref --format='%(refname)' refs/heads/tags | cut -d / -f 4 | \
  while read ref; do
    git tag "$ref" "refs/heads/tags/$ref"
    git branch -D "tags/$ref"
  done

git gc --aggressive
popd