#!/bin/sh

# A sample pre-deploy hook
#
# Checks the Github status of the build, waiting for a pending build to complete for up to 720 seconds.
#
# Fails unless the combined status is "success"
#
# These environment variables are available:
# MRSK_RECORDED_AT
# MRSK_PERFORMER
# MRSK_VERSION
# MRSK_HOSTS
# MRSK_COMMAND
# MRSK_SUBCOMMAND
# MRSK_ROLE (if set)
# MRSK_DESTINATION (if set)

#!/usr/bin/env ruby

# Only check the build status for production deployments
if ENV["MRSK_COMMAND"] == "rollback" || ENV["MRSK_DESTINATION"] != "production"
  exit 0
end

require "bundler/inline"

# true = install gems so this is fast on repeat invocations
gemfile(true, quiet: true) do
  source "https://rubygems.org"

  gem "octokit"
  gem "faraday-retry"
end

MAX_ATTEMPTS = 72
ATTEMPTS_GAP = 10

def exit_with_error(message)
  $stderr.puts message
  exit 1
end

def first_status_url(combined_status, state)
  first_status = combined_status[:statuses].find { |status| status[:state] == state }
  first_status && first_status[:target_url]
end

remote_url = `git config --get remote.origin.url`.strip.delete_prefix("https://github.com/")
git_sha = `git rev-parse HEAD`.strip

repository = Octokit::Repository.from_url(remote_url)
github_client = Octokit::Client.new(access_token: ENV["GITHUB_TOKEN"])
attempts = 0

begin
  loop do
    combined_status = github_client.combined_status(remote_url, git_sha)
    state = combined_status[:state]
    first_status_url = first_status_url(combined_status, state)

    case state
    when "success"
      puts "Build passed, see #{first_status_url}"
      exit 0
    when "failure"
      exit_with_error "Build failed, see #{first_status_url}"
    when "pending"
      attempts += 1
    end

    puts "Waiting #{ATTEMPTS_GAP} more seconds for build to complete#{", see #{first_status_url}" if first_status_url}..."

    if attempts == MAX_ATTEMPTS
      exit_with_error "Build status is still pending, gave up after #{MAX_ATTEMPTS * ATTEMPTS_GAP} seconds"
    end

    sleep(ATTEMPTS_GAP)
  end
rescue Octokit::NotFound
  exit_with_error "Build status could not be found"
end