#!/bin/bash

set -x

deforg="$1"
defrepo="$2"
defbranch="$3"

[ -z "$defbranch" ] && defbranch="develop"

rm -r "$defrepo" || true

clone() {
    org=$1
    repo=$2
    branch=$3
    if [ -n "$branch" ]
    then
        echo "Trying to use $org/$repo#$branch"
        git clone git://github.com/$org/$repo.git $repo --branch "$branch" --depth 1 && exit 0
    fi
}

# Try the PR author's branch in case it exists on the deps as well.
# First we check if GITHUB_HEAD_REF is defined,
# Then we check if BUILDKITE_BRANCH is defined,
# if it isn't we can assume this is a Netlify build
if [ -n ${GITHUB_HEAD_REF+x} ]; then
	head=$GITHUB_HEAD_REF
elif [ -n ${BUILDKITE_BRANCH+x} ]; then
	head=$BUILDKITE_BRANCH
else
	# Netlify doesn't give us info about the fork so we have to get it from GitHub API
	apiEndpoint="https://api.github.com/repos/matrix-org/matrix-react-sdk/pulls/"
	apiEndpoint+=$REVIEW_ID
	head=$(curl $apiEndpoint | jq -r '.head.label')
fi

# If head is set, it will contain on BuilKite either:
#   * "branch" when the author's branch and target branch are in the same repo
#   * "fork:branch" when the author's branch is in their fork or if this is a Netlify build
# We can split on `:` into an array to check.
# For GitHub Actions we need to inspect GITHUB_REPOSITORY and GITHUB_ACTOR
# to determine whether the branch is from a fork or not
BRANCH_ARRAY=(${head//:/ })
if [[ "${#BRANCH_ARRAY[@]}" == "1" ]]; then
    if [[ "$GITHUB_REPOSITORY" = "$deforg/$defrepo" ]]; then
        clone $deforg $defrepo $head
    else
        clone $GITHUB_ACTOR $defrepo $head
    fi
elif [[ "${#BRANCH_ARRAY[@]}" == "2" ]]; then
    clone ${BRANCH_ARRAY[0]} $defrepo ${BRANCH_ARRAY[1]}
fi

# Try the target branch of the push or PR.
if [ -n ${GITHUB_BASE_REF+x} ]; then
    clone $deforg $defrepo $GITHUB_BASE_REF
elif [ -n ${BUILDKITE_PULL_REQUEST_BASE_BRANCH+x} ]; then
    clone $deforg $defrepo $BUILDKITE_PULL_REQUEST_BASE_BRANCH
fi

# Try HEAD which is the branch name in Netlify (not BRANCH which is pull/xxxx/head for PR builds)
clone $deforg $defrepo $HEAD
# Use the default branch as the last resort.
clone $deforg $defrepo $defbranch