#!/bin/bash

set -e

top=$(pwd)

if [ "$#" -ne 3 ]; then
    echo "USAGE: $0 repo patchdir ref"
    printf "\t exports patches from 'repo' to 'patchdir' based on 'ref'\n"
    exit 1
fi

# parameters
kernel_submodule=$1
kernel_patchdir=$2
base_ref=$3

cd "${kernel_submodule}"
echo "clearing old exported patchqueue"
rm -f "${top}/${kernel_patchdir}"/*.patch
echo "exporting patchqueue using 'git format-patch [...] ${base_ref}.."
git format-patch \
    --quiet \
    --no-numbered \
    --no-cover-letter \
    --zero-commit \
    --no-signature \
    --diff-algorithm=myers \
    --output-dir \
    "${top}/${kernel_patchdir}" \
    "${base_ref}.."

git checkout "${base_ref}"

cd "${top}"