#!/usr/bin/env bash

abort() {
  echo $@
  exit 1
}

url="$1"

test -z "$url" && url=`git remote get-url origin 2> /dev/null` && origin=true

# validate repo url
test -z "$url" && abort "github repo needs to be specified as an argument"

# validate user
echo "Enter your github username"
read user
[ "$user" = 'n' ] && abort "git username required"

# extract owner + project from repo url
project=${url##*/}
owner=${url%/$project}
[[ $project == *.git ]] && project=${project%.git}
if [[ $owner == git@* ]]; then
  owner=${owner##*:}
else
  owner=${owner##*/}
fi

# validate
[ -z "$project" -o -z "$owner" ] && abort "github repo needs to be specified as an argument"

# create pull request
curl -X POST -u "$user" "https://api.github.com/repos/$owner/$project/forks"
[ $? = 0 ] || abort "fork failed"

if [ "$origin" = true ]; then
    git remote rename origin upstream
    git remote add origin "https://github.com/$user/$project"
    git fetch origin
else
    # clone forked repo into current dir
    git clone "https://github.com/$user/$project" "$project"

    # add reference to origin fork so can merge in upstream changes
    cd "$project"
    git remote add upstream "https://github.com/$owner/$project"
    git fetch upstream
fi