#!/bin/bash

usage() {
	cat << EOF
This script imports a git repo (accessible from https://\$origin/\$user/\$repo) and all its history as subdirectory of a destination (available locally at \$dest)
It is designed for non-production, archival processes and may destroy everything you've ever loved because you looked at it funny. You have been warned.
The structure of the destination will end up something like this:
~/src
- \$dest
  - origins
    - \$origin
      - \$user
        - \$repo
Required Arguments:
	-u|--user: The user that owns the repo to be imported
	-r|--repo: The name of the repository to be imported
	-d|--dest: The local name of the destination repository (assumed to be under ~/src)
	-o|--origin: The git server that is the origin of the repo to be imported
EOF
}
if [  $# -le 6 ]; then 
    usage
    exit 1
fi 

while [[ "$#" -gt 0 ]]; do
    case $1 in
        -u|--user) user="$2"; shift ;;
        -r|--repo) repo="$2"; shift ;;
    	-d|--dest) dest="$2"; shift ;;
	    -o|--origin) origin="$2"; shift ;;
    	*) echo "Unknown parameter passed: $1"; usage; exit 1 ;;
    esac
    shift
done

tmp="/tmp/_${dest}_tmp"

echo "Importing $origin/$user/$repo into $dest"

rm -rf ~/src/$repo
cd ~/src
git clone https://$origin/$user/$repo
cd $repo
git filter-branch \
	--tree-filter "mkdir -p $tmp/origin; git ls-files | cpio -pdumB $tmp/origin; git ls-files | xargs  -d '\n' rm -r; find . -type d -empty -delete; mkdir -p origins/$origin/$user; mv $tmp/origin origins/$origin/$user/$repo/"\
	--tag-name-filter cat --prune-empty -- --all
if [ $? -eq 0 ]; then
	## WAIT PATIENTLY
	cd ../$dest
	git remote add $repo ../$repo
	git fetch $repo --tags
	git merge --allow-unrelated-histories $repo/master #Youre on your own if you want a different / multiple branch(es)...
	git remote remove $repo
else
	echo failed for $user/$repo
fi