require 'aws-sdk'

# ENV NEED:
# #  ENV['AWS_REGION']
# #  ENV['BDASH_OPT_DB_HOST']
# #  ENV['BDASH_OPT_DB_USERNAME']
# #  ENV['BDASH_OPT_DB_PASSWORD']
# #  ENV['BDASH_OPT_DB_NAME']
def get_aws_account_id
  begin
    iam = Aws::IAM::Client.new.get_user
    r = iam[:user][:arn].match('^arn:aws:iam::([0-9]{12}):.*$')[1]
  rescue Aws::IAM::Errors::AccessDenied
      result = $!
      r = result.to_s.match('^User: arn:aws:iam::([0-9]{12}):.*$')[1]
  end
  r
end

ret = "jdbc:mysql://#{ENV['BDASH_OPT_DB_HOST']}:3306/#{ENV['BDASH_OPT_DB_NAME']}?autoReconnect=true"
min_value = 100000

respect_tag_value="batch"
respect_tag_value=ENV["USAGE_TAG_VALUE"] unless ENV["USAGE_TAG_VALUE"] == nil

myzone_list = []
other_list = []

rds = Aws::RDS::Client.new(region: ENV['AWS_REGION'])
resp = rds.describe_db_instances
resp.db_instances.each do |r|
  if r.endpoint != nil and r.endpoint.address == ENV['BDASH_OPT_DB_HOST'] then
    replicas = []
    if r.engine == "aurora" then
      db_cluster_identifier = r.db_cluster_identifier
      recs = rds.describe_db_instances
      recs.db_instances.each do |rec|
        if rec.db_cluster_identifier == db_cluster_identifier then
           addr = rec.endpoint.address
           port = rec.endpoint.port
           cmd = "/usr/bin/mysql -u #{ENV['BDASH_OPT_DB_USERNAME']} -p#{ENV['BDASH_OPT_DB_PASSWORD']} -h #{addr} -P #{port} -e \"SHOW GLOBAL VARIABLES LIKE 'innodb_read_only';\"  | grep 'innodb_read_only' | awk '{print $2}'"
           result = `#{cmd}`
           result.strip!
           if result == "ON" then
             replicas << rec.db_instance_identifier
           end
        end
      end
    else
      replicas = r.read_replica_db_instance_identifiers
    end
p replicas
    unless replicas.empty?
      replicas.each do |x|
        res1 = rds.describe_db_instances({db_instance_identifier: x})
        if res1.db_instances.size >= 1 and res1.db_instances[0].endpoint != nil then
          account_id=get_aws_account_id
          rds_arn = sprintf("arn:aws:rds:%s:%d:db:%s", ENV['AWS_REGION'], account_id, x)
          response = rds.list_tags_for_resource(:resource_name => rds_arn)
          usage_tag = response[:tag_list].find { |tag| tag[:key] == 'usage' }
          if usage_tag != nil && usage_tag[:value] != respect_tag_value
            next
          else
            preferred_maintenance_window = res1.db_instances[0].preferred_maintenance_window
            wday = {"mon"=>1,"tue"=>2,"wed"=>3,"thu"=>4,"fri"=>5,"sat"=>6,"sun"=>0}
            weekday = wday[preferred_maintenance_window.split("-")[0].split(":")[0]]
            from_tm = preferred_maintenance_window.split("-")[0].split(":")[1].to_i - 1
            to_tm = preferred_maintenance_window.split("-")[1].split(":")[1].to_i
            current_wday = Time.now.wday
            current_tm = Time.now.hour
            if current_wday == weekday && from_tm <= current_tm && to_tm >= current_tm
              next
            end
            addr = res1.db_instances[0].endpoint.address
            port = res1.db_instances[0].endpoint.port
            if ENV["MY_ZONE"] == res1.db_instances[0].availability_zone
              myzone_list << {"addr"=>addr, "port"=>port}
            else
              other_list << {"addr"=>addr, "port"=>port}
            end
          end
        end
      end
    end
  end
end
check_list = []
if !myzone_list.empty?
  check_list = myzone_list
else
  if !other_list.empty?
    check_list = other_list
  end
end

check_list.each do |r|
  addr = r["addr"]
  port = r["port"]
  cmd = "/usr/bin/mysql -u #{ENV['BDASH_OPT_DB_USERNAME']} -p#{ENV['BDASH_OPT_DB_PASSWORD']} -h #{addr} -P #{port} -e \"show status like 'Threads_connected'\"  | grep Threads_connected | awk '{print $2}'"
  res = `#{cmd}`
  res.strip!
p cmd
p res
  if min_value > res.to_i and res.to_i != 0
    min_value = res.to_i
    ret = "jdbc:mysql://#{addr}:#{port}/#{ENV['BDASH_OPT_DB_NAME']}?autoReconnect=true"
  end
end

puts ret
ret