#!/usr/bin/env ruby

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'

  gem "erb", "~> 4.0"
  gem "json", "~> 2.0"
  gem "rack", "~> 3.0"
  gem "rackup", "~> 2.0"
  gem "securerandom", "~> 0.1"
  gem "webrick", "~> 1.0"
end

$scheme = ENV.fetch("SCHEME", "http")
$port = ENV.fetch("PORT", 8284).to_i
$host = ENV.fetch("HOST", "localhost:#{$port}")

class Project
  class << self
    def all
      @projects ||= []
    end

    def create!(attributes)
      new({ id: SecureRandom.uuid }.merge(attributes)).tap do |item|
        all << item
      end
    end
  end

  def initialize(attributes = {})
    @attributes = attributes
  end

  def to_h
    @attributes
  end
end

class API
  def call(env)
    request = Rack::Request.new(env)
    path = env['PATH_INFO']
    case env['REQUEST_METHOD']
    when 'GET'
      case path
      when '/projects.json'
        return json_ok(Project.all.map(&:to_h))
      else
        return json_not_found
      end
    when 'POST'
      case path
      when "/projects"
        if authorized?(request, :create_project)
          return json_created(Project.create!(JSON.parse(request.body.read, symbolize_names: true)))
        else
          return json_unauthorized(:create_project)
        end
      else
        return json_not_found
      end
    end
    json_not_found
  end

  private

  def authorized?(request, permission)
    # TODO:: Check the JWT for the appropriate claim
    # Connect to the Authz RPC endpoint Ability.allowed?(subject, permission, resource)
    true
  end

  def json_not_found
    http_response(code: 404)
  end

  def json_ok(body)
    http_response(code: 200, body: JSON.pretty_generate(body))
  end

  def json_created(body)
    http_response(code: 201, body: JSON.pretty_generate(body.to_h))
  end

  def json_unauthorized(permission)
    http_response(code: 401, body: JSON.pretty_generate({
      error: {
        code: 401,
        message: "`#{permission}` is required",
      }
    }))
  end

  def http_response(code:, headers: { 'Content-Type' => 'application/json' }, body: nil)
    [
      code,
      headers.merge({ 'X-Backend-Server' => 'REST' }),
      [body].compact
    ]
  end
end

if __FILE__ == $0
  app = Rack::Builder.new do
    use Rack::Reloader
    run API.new
  end.to_app

  Rackup::Server.start(app: app, Port: $port)
end