#!/bin/bash
#set -x
#trap read debug
set -o nounset
set -o errexit


#
# Merges github PRs into local git clone of ASF project 
# ('https://github.com/apache/xxx') 
#
# Process:
# - locate/raise JIRA ticket, eg ISIS-1162
# - checkout branch from which PR was forked (usually just 'master')
# - merge PR into temporary branch using this script
# - check build
# - merge temporary branch into mainline, and commit
#
#
# Usage: github-pr.sh isis 1162 31
#
#        where 
#               - isis is the JIRA project and repo
#               - 1162 is the JIRA ticket number
#               - 31   is the gthub PR issue number
#
# uses 'jq' to parse JSON
# - on Linux: aptitude install jq
# - on Mac: brew install jq 
# - on Windows: download exe from http://stedolan.github.io/jq/download/
#

function die {
	local prefix="[$(date +%Y/%m/%d\ %H:%M:%S)]: "
	echo "${prefix} ERROR: $@" 1>&2
	exit 10
}


#
# validate script args
#
if [ $# -ne 3 ]; then
    die "usage: github-pr.sh proj nnn pp"
fi

project=$1
jira_suffix=$2
pr_number=$3
project_lower=$(echo $project | tr '[:upper:]' '[:lower:]')
project_upper=$(echo $project | tr '[:lower:]' '[:upper:]')

jira_number="$project_upper-$jira_suffix"

echo ""


#
# validate JIRA ticket
#
jira_url="https://issues.apache.org/jira/rest/api/2/search?jql=key%20in%20($jira_number)"
jira_json=$(curl -s "$jira_url")
if [ $? -ne 0 ]; then
    die "Failed to query JIRA for issue; url: $jira_url"
fi

err_message=$(echo $jira_json | jq --raw-output '.errorMessages')

if [ "$err_message" != "null" ]; then
	die "Cannot find the info about JIRA issue $jira_number" 
fi

echo ""
echo "Found JIRA ticket"


#
# validate github PR
#
github_url="https://api.github.com/repos/apache/$project_lower/pulls/$pr_number"
github_json=$(curl -s $github_url)
if [ $? -ne 0 ]; then
    die "Failed to query github for PR; url: $github_url"
fi

err_message=$(echo $github_json | jq --raw-output '.message')
if [ "x$err_message" = "xNot Found" ]; then
	die "Cannot find the info about PR $pr_number" 
fi

echo "Found github PR"

branch_name_local=$(git rev-parse --abbrev-ref HEAD)
username=$(echo $github_json | jq --raw-output '.head .user .login')
repo_full_name=$(echo $github_json | jq --raw-output '.head .repo .full_name')
repo_clone_url=$(echo $github_json | jq --raw-output '.head .repo .clone_url')
branch_name_fork=$(echo $github_json | jq --raw-output '.head .ref')

branch_name_temp="${jira_number}_pr-$pr_number"

echo "branch_name_local: $branch_name_local"
echo "username         : $username"
echo "repo_full_name   : $repo_full_name"
echo "repo_clone_url   : $repo_clone_url"
echo "branch_name_fork : $branch_name_fork"

echo ""
echo "merging into: $branch_name_temp"
echo ""


branch_exists=$(git branch --list $branch_name_temp)
if [ "x$branch_exists" != "x" ]; then
	echo "Deleting branch '$branch_name_temp'"
	git branch -D $branch_name_temp 
fi

echo "Creating the branch $branch_name_temp"
git checkout -b $branch_name_temp $branch_name_local

echo "Pulling the changes from $repo_clone_url $branch_name_fork"
git pull $repo_clone_url $branch_name_fork

echo ""
echo "Merged the PR; hit enter to build"

read 
echo "Building..."
echo

mvn clean install -o

echo
echo
echo
echo "If build successful and happy to merge, execute:"
echo
echo "git checkout $branch_name_local && git merge --no-ff $branch_name_temp && git branch -d $branch_name_temp"
echo