# SPDX-License-Identifier: Apache-2.0
#
#  The OpenSearch Contributors require contributions made to
#  this file be licensed under the Apache-2.0 license or a
#  compatible open source license.
#
#  Modifications Copyright OpenSearch Contributors. See
#  GitHub history for details.

ECS_VERSIONS = {
    v1: 'v1.9.0'
}

ECS_LOGSTASH_INDEX_PATTERNS = %w(
  ecs-logstash-*
)

task :'vendor-ecs-schemata' do
  download_ecs_schema(:v1, 1)
  download_ecs_schema(:v1, 2)
  download_ecs_schema(:v1, 7)
end
task :vendor => :'vendor-ecs-schemata'

def download_ecs_schema(ecs_major_version, opensearch_major_version)
  $stderr.puts("Vendoring ECS #{ecs_major_version} template")
  require 'net/http'
  require 'json'
  Net::HTTP.start('raw.githubusercontent.com', :use_ssl => true) do |http|
    ecs_release_tag = ECS_VERSIONS.fetch(ecs_major_version)
    response = http.get("/elastic/ecs/#{ecs_release_tag}/generated/elasticsearch/7/template.json")
    fail "#{response.code} #{response.message}" unless (200...300).cover?(response.code.to_i)
    template_directory = File.expand_path("../lib/logstash/outputs/opensearch/templates/ecs-#{ecs_major_version}", __FILE__)
    Dir.mkdir(template_directory) unless File.exists?(template_directory)
    template_file = File.join(template_directory, "/#{opensearch_major_version}x.json")
    template = replace_index_patterns(response.body, ECS_LOGSTASH_INDEX_PATTERNS)
    File.open(template_file, "w") do |handle|
        handle.write(JSON.pretty_generate(template))
    end
    index_template_file = File.join(template_directory, "/#{opensearch_major_version}x_index.json")
    template = transform_to_index_template(template)
    File.open(index_template_file, "w") do |handle|
        handle.write(JSON.pretty_generate(template))
    end
  end
end

def replace_index_patterns(template_json, replacement_index_patterns)
  template_obj = JSON.load(template_json)
  template_obj.update('index_patterns' => replacement_index_patterns)
  template_obj
end

def transform_to_index_template(template)
  if !template.key?("template")

    # `order` is replaced with `priority`
    template.delete("order")
    template["priority"] = 10   

    # index_templates have `settings` and `mappings` under `template`
    template["template"] = {
      "settings" => template.delete("settings"),
      "mappings" => template.delete("mappings")
    }
  end
  template
end