require 'httparty'

module PandaPal
  class Platform
    require_relative "platform/canvas"

    def public_jwks
      require "json/jwt"

      jwk_json = Rails.cache.fetch("panda_pal/jwks/#{jwks_url}")
      jwk_json ||= begin
        response = HTTParty.get(jwks_url)
        response.success? ? response.body : nil
      end

      return nil unless jwk_json.present?

      Rails.cache.write("panda_pal/jwks/#{jwks_url}", jwk_json, expires_in: 24.hours)

      JSON::JWK::Set.new(JSON.parse(jwk_json))
    rescue
      nil
    end

    def self.from_serialized(ser)
      cls = ser[:platform_class].safe_constantize
      cls.deserialize(ser)
    end

    def self.deserialize(params)
      new(params)
    end

    def serialize
      {
        platform_class: self.class.to_s,
      }
    end

    def self.resolve_platform(params)
      resolved = resolve_raw_platform(params)
      resolved.is_a?(Class) ? resolved.new({ iss: params[:iss] }) : resolved
    end

    def self.resolve_platform_class(params)
      resolved = resolve_raw_platform(params)
      resolved.is_a?(Class) ? resolved : resolved.class
    end

    def self.resolve_raw_platform(params)
      platform = PandaPal.lti_options[:platform] || "canvas.instructure.com"

      if platform.is_a? Symbol
        platform_const = Object.send(platform, params)
        return platform_const if platform_const

      elsif platform.is_a? Proc
        platform_const = platform.call(params)
        return platform_const if platform_const

      else
        return Platform::Canvas if platform == "canvas.instructure.com"

        platform_const = platform.safe_constantize
        return platform_const if platform_const.is_a? Class
      end

      # TODO Default logic?
      return Platform::Canvas if Platform::Canvas::TRUSTED_ISSUERS.include?(params[:iss])

      raise "Unknown platform '#{platform}'"
    end

    def self.organization_api
      return PandaPal::Organization unless defined?(self::OrgExtension)
      return PandaPal::Organization if PandaPal::Organization < self::OrgExtension

      oext = self::OrgExtension

      @organization_api ||= self::OrganizationApi ||= Class.new(PandaPal::Organization) do
        include oext
      end
    end

    protected

    def self.find_org_setting(paths, org = current_organization)
      paths.each do |p|
        p = p.split('.').map(&:to_sym)
        val = org.settings.dig(*p)
        return val if val.present?
      end
      nil
    end
  end

  class Platform::Generic < Platform
    def self.from_urls(base_url, jwks: nil, auth_redirect: nil, grant: nil)
      new({
        base_url: base_url,
        jwks_url: jwks,
        auth_redirect_url: auth_redirect,
        grant_url: grant,
      })
    end

    def initialize(options)
      @options = options
    end

    def platform_uri
      options[:issuer] || options[:base_url]
    end

    def jwks_url
      URI.join(options[:base_url], options[:jwks_url] || "/api/lti/security/jwks").to_s
    end

    def authentication_redirect_url
      URI.join(options[:base_url], options[:auth_redirect_url] || "/api/lti/authorize_redirect").to_s
    end

    def grant_url
      URI.join(options[:base_url], options[:grant_url] || "/login/oauth2/token").to_s
    end

    def serialize
      super.merge(options)
    end
  end
end