#!/bin/bash
set -e
. functions.sh

if [ -z "$1" ]; then
	COMMIT_ID="$TRAVIS_COMMIT"
	COMMIT_MESSAGE="$TRAVIS_COMMIT_MESSAGE"
	BRANCH_NAME="travis-$TRAVIS_BUILD_ID"
	GITHUB_USERNAME="nodejs-github-bot"
else
	COMMIT_ID="$1"
	COMMIT_MESSAGE="$(git show -s --format=%B "$1")"
	BRANCH_NAME="travis-$(date +%s)"
	if [[ "$(git remote get-url origin)" =~ github.com/([^/]*)/docker-node.git ]]; then
		GITHUB_USERNAME="${BASH_REMATCH[1]}"
	fi
fi

if [[ "$COMMIT_MESSAGE" =~ Merge\ pull\ request\ \#([0-9]*) ]]; then

	# This is a merge from a pull request
	PR_NUMBER="${BASH_REMATCH[1]}"
	COMMIT_MESSAGE="$(printf "%s" "$COMMIT_MESSAGE" | tail -n 1)"
fi

IMAGES_FILE="library/node"
REPO_NAME="official-images"
ORIGIN_SLUG="$GITHUB_USERNAME/$REPO_NAME"
UPSTREAM_SLUG="docker-library/$REPO_NAME"
DOCKER_SLUG="nodejs/docker-node"
gitpath="$REPO_NAME"

function updated() {
	local versions
	local images_changed

	IFS=' ' read -ra versions <<< "$(IFS=','; get_versions)"
	images_changed=$(git diff --name-only "$COMMIT_ID".."$COMMIT_ID"~1 "${versions[@]}")

	if [ -z "$images_changed" ]; then
		return 1
	else
		return 0
	fi
}

function auth_header() {
	echo "Authorization: token $GITHUB_API_TOKEN"
}

function permission_check() {
	if [ -z "$GITHUB_API_TOKEN" ]; then
		fatal "Environment variable \$GITHUB_API_TOKEN is missing or empty"
	fi

	auth="$(curl -H "$(auth_header)" \
		-s \
		"https://api.github.com")"

	if [ "$(echo "$auth" | jq .message)" = "\"Bad credentials\"" ]; then
		fatal "Authentication Failed! Invalid \$GITHUB_API_TOKEN"
	fi

	auth="$(curl -H "$(auth_header)" \
		-s \
		"https://api.github.com/repos/$ORIGIN_SLUG/collaborators/$GITHUB_USERNAME/permission")"
	if [ "$(echo "$auth" | jq .message)" != "null" ]; then
		fatal "\$GITHUB_API_TOKEN can't push to https://github.com/$ORIGIN_SLUG.git"
	fi
}

function setup_git_author() {
	GIT_AUTHOR_NAME="$(git show -s --format="%aN" "$COMMIT_ID")"
	GIT_AUTHOR_EMAIL="$(git show -s --format="%aE" "$COMMIT_ID")"
	GIT_COMMITTER_NAME="$(git show -s --format="%cN" "$COMMIT_ID")"
	GIT_COMMITTER_EMAIL="$(git show -s --format="%cN" "$COMMIT_ID")"

	export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_COMMITTER_NAME GIT_COMMITTER_EMAIL
}

function message() {
	echo "Node: $COMMIT_MESSAGE"
}

function pr_payload() {
	local escaped_message
	IFS=' ' read -ra escaped_message <<< "$COMMIT_MESSAGE"
	escaped_message="$(printf '%q ' "${escaped_message[@]}")"
	echo '{
		"title": "Node: '"$escaped_message"'",
		"body": "Commit: nodejs/docker-node@'"$COMMIT_ID"'",
		"head": "'"$GITHUB_USERNAME"':'"$BRANCH_NAME"'",
		"base": "master"
	}'
}

function comment_payload() {
	local pr_url
	pr_url="$1"
	echo '{
		"body": "Created PR to the '"$REPO_NAME"' repo ('"$pr_url"')"
	}'
}

if updated; then

	permission_check

	# Set Git User Info
	setup_git_author

	info "Cloning..."
	git clone --depth 50  "https://github.com/$UPSTREAM_SLUG.git" $gitpath 2> /dev/null

	stackbrew="$(./generate-stackbrew-library.sh)"

	cd $gitpath

	echo "$stackbrew" > "$IMAGES_FILE"
	git checkout -b "$BRANCH_NAME"
	git add "$IMAGES_FILE"
	git commit -m "$(message)"

	info "Pushing..."
	git push "https://$GITHUB_API_TOKEN:x-oauth-basic@github.com/$ORIGIN_SLUG.git" -f "$BRANCH_NAME" 2> /dev/null || fatal "Error pushing the updated stackbrew"

	cd - && rm -rf $gitpath

	info "Creating Pull request"
	pr_response_payload="$(curl -H "$(auth_header)" \
		-s \
		-X POST \
		-d "$(pr_payload)" \
		"https://api.github.com/repos/$UPSTREAM_SLUG/pulls")"

	url="$(echo "$pr_response_payload" | jq -r .html_url)"
	if [ "$url" != "null" ]; then
		info "Pull request created at $url"

		if [ ! -z "$PR_NUMBER" ]; then
			comment_endpoint="https://api.github.com/repos/$DOCKER_SLUG/issues/$PR_NUMBER/comments"
		else
			comment_endpoint="https://api.github.com/repos/$DOCKER_SLUG/commits/$COMMIT_ID/comments"
		fi

		info "Creating Commit Comment"
		commit_response_payload="$(curl -H "$(auth_header)" \
			-s \
			-X POST \
			-d "$(comment_payload "$url")" \
			"$comment_endpoint")"

		if [ "$(echo "$commit_response_payload" | jq .message)" != "null" ]; then
			fatal "Error linking the pull request ($error_message)"
		else
			comment_url="$(echo "$commit_response_payload" | jq -r .html_url)"
			info "Created comment at $comment_url"
		fi
	else
		error_message=$(echo "$pr_response_payload" | jq .message)
		fatal "Error creating pull request ($error_message)"
	fi
else
	info "No change!"
fi