class Arvados::V1::SchemaController < ApplicationController
  skip_before_filter :find_object_by_uuid
  skip_before_filter :require_auth_scope_all

  def show
    classes = Rails.cache.fetch 'arvados_v1_schema' do
      Rails.application.eager_load!
      classes = {}
      ActiveRecord::Base.descendants.reject(&:abstract_class?).each do |k|
        classes[k] = k.columns.collect do |col|
          if k.serialized_attributes.has_key? col.name
            { name: col.name,
              type: k.serialized_attributes[col.name].object_class.to_s }
          else
            { name: col.name,
              type: col.type }
          end
        end
      end
      classes
    end
    render json: classes
  end

  def discovery_rest_description
    discovery = Rails.cache.fetch 'arvados_v1_rest_discovery' do
      Rails.application.eager_load!
      discovery = {
        kind: "discovery#restDescription",
        discoveryVersion: "v1",
        id: "arvados:v1",
        name: "arvados",
        version: "v1",
        revision: "20131114",
        generatedAt: Time.now.iso8601,
        title: "Arvados API",
        description: "The API to interact with Arvados.",
        documentationLink: "https://redmine.clinicalfuture.com/projects/arvados/",
        protocol: "rest",
        baseUrl: root_url + "/arvados/v1/",
        basePath: "/arvados/v1/",
        rootUrl: root_url,
        servicePath: "arvados/v1/",
        batchPath: "batch",
        parameters: {
          alt: {
            type: "string",
            description: "Data format for the response.",
            default: "json",
            enum: [
                   "json"
                  ],
            enumDescriptions: [
                               "Responses with Content-Type of application/json"
                              ],
            location: "query"
          },
          fields: {
            type: "string",
            description: "Selector specifying which fields to include in a partial response.",
            location: "query"
          },
          key: {
            type: "string",
            description: "API key. Your API key identifies your project and provides you with API access, quota, and reports. Required unless you provide an OAuth 2.0 token.",
            location: "query"
          },
          oauth_token: {
            type: "string",
            description: "OAuth 2.0 token for the current user.",
            location: "query"
          }
        },
        auth: {
          oauth2: {
            scopes: {
              "https://api.clinicalfuture.com/auth/arvados" => {
                description: "View and manage objects"
              },
              "https://api.clinicalfuture.com/auth/arvados.readonly" => {
                description: "View objects"
              }
            }
          }
        },
        schemas: {},
        resources: {}
      }
      
      ActiveRecord::Base.descendants.reject(&:abstract_class?).each do |k|
        begin
          ctl_class = "Arvados::V1::#{k.to_s.pluralize}Controller".constantize
        rescue
          # No controller -> no discovery.
          next
        end
        object_properties = {}
        k.columns.
          select { |col| col.name != 'id' }.
          collect do |col|
          if k.serialized_attributes.has_key? col.name
            object_properties[col.name] = {
              type: k.serialized_attributes[col.name].object_class.to_s
            }
          else
            object_properties[col.name] = {
              type: col.type
            }
          end
        end
        discovery[:schemas][k.to_s + 'List'] = {
          id: k.to_s + 'List',
          description: k.to_s + ' list',
          type: "object",
          properties: {
            kind: {
              type: "string",
              description: "Object type. Always arvados##{k.to_s.camelcase(:lower)}List.",
              default: "arvados##{k.to_s.camelcase(:lower)}List"
            },
            etag: {
              type: "string",
              description: "List version."
            },
            items: {
              type: "array",
              description: "The list of #{k.to_s.pluralize}.",
              items: {
                "$ref" => k.to_s
              }
            },
            next_link: {
              type: "string",
              description: "A link to the next page of #{k.to_s.pluralize}."
            },
            next_page_token: {
              type: "string",
              description: "The page token for the next page of #{k.to_s.pluralize}."
            },
            selfLink: {
              type: "string",
              description: "A link back to this list."
            }
          }
        }
        discovery[:schemas][k.to_s] = {
          id: k.to_s,
          description: k.to_s,
          type: "object",
          properties: {
            uuid: {
              type: "string",
              description: "Object ID."
            },
            etag: {
              type: "string",
              description: "Object version."
            }
          }.merge(object_properties)
        }
        discovery[:resources][k.to_s.underscore.pluralize] = {
          methods: {
            get: {
              id: "arvados.#{k.to_s.underscore.pluralize}.get",
              path: "#{k.to_s.underscore.pluralize}/{uuid}",
              httpMethod: "GET",
              description: "Gets a #{k.to_s}'s metadata by UUID.",
              parameters: {
                uuid: {
                  type: "string",
                  description: "The UUID of the #{k.to_s} in question.",
                  required: true,
                  location: "path"
                }
              },
              parameterOrder: [
                               "uuid"
                              ],
              response: {
                "$ref" => k.to_s
              },
              scopes: [
                       "https://api.clinicalfuture.com/auth/arvados",
                       "https://api.clinicalfuture.com/auth/arvados.readonly"
                      ]
            },
            list: {
              id: "arvados.#{k.to_s.underscore.pluralize}.list",
              path: k.to_s.underscore.pluralize,
              httpMethod: "GET",
              description: "List #{k.to_s.underscore.pluralize}.",
              parameters: {
                limit: {
                  type: "integer",
                  description: "Maximum number of #{k.to_s.underscore.pluralize} to return.",
                  default: "100",
                  format: "int32",
                  minimum: "0",
                  location: "query"
                },
                pageToken: {
                  type: "string",
                  description: "Page token.",
                  location: "query"
                },
                q: {
                  type: "string",
                  description: "Query string for searching #{k.to_s.underscore.pluralize}.",
                  location: "query"
                },
                where: {
                  type: "object",
                  description: "Conditions for filtering #{k.to_s.underscore.pluralize}.",
                  location: "query"
                },
                order: {
                  type: "string",
                  description: "Order in which to return matching #{k.to_s.underscore.pluralize}.",
                  location: "query"
                }
              },
              response: {
                "$ref" => "#{k.to_s}List"
              },
              scopes: [
                       "https://api.clinicalfuture.com/auth/arvados",
                       "https://api.clinicalfuture.com/auth/arvados.readonly"
                      ]
            },
            create: {
              id: "arvados.#{k.to_s.underscore.pluralize}.create",
              path: "#{k.to_s.underscore.pluralize}",
              httpMethod: "POST",
              description: "Create a new #{k.to_s}.",
              parameters: {
                k.to_s.underscore => {
                  type: "object",
                  required: false,
                  location: "query",
                  properties: object_properties
                }
              },
              request: {
                required: false,
                properties: {
                  k.to_s => {
                    "$ref" => k.to_s
                  }
                }
              },
              response: {
                "$ref" => k.to_s
              },
              scopes: [
                       "https://api.clinicalfuture.com/auth/arvados"
                      ]
            },
            update: {
              id: "arvados.#{k.to_s.underscore.pluralize}.update",
              path: "#{k.to_s.underscore.pluralize}/{uuid}",
              httpMethod: "PUT",
              description: "Update attributes of an existing #{k.to_s}.",
              parameters: {
                uuid: {
                  type: "string",
                  description: "The UUID of the #{k.to_s} in question.",
                  required: true,
                  location: "path"
                },
                k.to_s.underscore => {
                  type: "object",
                  required: false,
                  location: "query",
                  properties: object_properties
                }
              },
              request: {
                required: false,
                properties: {
                  k.to_s => {
                    "$ref" => k.to_s
                  }
                }
              },
              response: {
                "$ref" => k.to_s
              },
              scopes: [
                       "https://api.clinicalfuture.com/auth/arvados"
                      ]
            },
            delete: {
              id: "arvados.#{k.to_s.underscore.pluralize}.delete",
              path: "#{k.to_s.underscore.pluralize}/{uuid}",
              httpMethod: "DELETE",
              description: "Delete an existing #{k.to_s}.",
              parameters: {
                uuid: {
                  type: "string",
                  description: "The UUID of the #{k.to_s} in question.",
                  required: true,
                  location: "path"
                }
              },
              response: {
                "$ref" => k.to_s
              },
              scopes: [
                       "https://api.clinicalfuture.com/auth/arvados"
                      ]
            }
          }
        }
        # Check for Rails routes that don't match the usual actions
        # listed above
        d_methods = discovery[:resources][k.to_s.underscore.pluralize][:methods]
        Rails.application.routes.routes.each do |route|
          action = route.defaults[:action]
          httpMethod = ['GET', 'POST', 'PUT', 'DELETE'].map { |method|
            method if route.verb.match(method)
          }.compact.first
          if httpMethod and
              route.defaults[:controller] == 'arvados/v1/' + k.to_s.underscore.pluralize and
              !d_methods[action.to_sym] and
              ctl_class.action_methods.include? action
            method = {
              id: "arvados.#{k.to_s.underscore.pluralize}.#{action}",
              path: route.path.spec.to_s.sub('/arvados/v1/','').sub('(.:format)','').sub(/:(uu)?id/,'{uuid}'),
              httpMethod: httpMethod,
              description: "#{route.defaults[:action]} #{k.to_s.underscore.pluralize}",
              parameters: {},
              response: {
                "$ref" => (action == 'index' ? "#{k.to_s}List" : k.to_s)
              },
              scopes: [
                       "https://api.clinicalfuture.com/auth/arvados"
                      ]
            }
            route.segment_keys.each do |key|
              if key != :format
                key = :uuid if key == :id
                method[:parameters][key] = {
                  type: "string",
                  description: "",
                  required: true,
                  location: "path"
                }
              end
            end
            if ctl_class.respond_to? "_#{action}_requires_parameters".to_sym
              ctl_class.send("_#{action}_requires_parameters".to_sym).each do |k, v|
                if v.is_a? Hash
                  method[:parameters][k] = v
                else
                  method[:parameters][k] = {}
                end
                method[:parameters][k][:type] ||= 'string'
                method[:parameters][k][:description] ||= ''
                method[:parameters][k][:location] = (route.segment_keys.include?(k) ? 'path' : 'query')
                if method[:parameters][k][:required].nil?
                  method[:parameters][k][:required] = v != false
                end
              end
            end
            d_methods[route.defaults[:action].to_sym] = method
          end
        end
      end
      discovery
    end
    render json: discovery
  end
end