# All files / build-tools validate-cfn.ts

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     /* eslint-disable no-console */
    /**
     * CloudFormation spec validator
     *
     * "Why not JSON Schema?", you might ask, and it's a fair question. The answer is:
     * because the error reporting from JSON schema is pretty bad, and I want the validation
     * errors reported from this check to be blindingly obvious, as non-spec-experts
     * are going to have to consume and understand them.
     *
     * I tried JSON Schema validation and its errors look like:
     *
     * ```
     * - instance.PropertyTypes["..."].Properties.Xyz does not match allOf schema <#/definitions/Typed> with 7 error[s]:
     * - instance.PropertyTypes["..."].Properties.Xyz requires property "PrimitiveType"
     * - instance.PropertyTypes["..."].Properties.Xyz requires property "Type"
     * - instance.PropertyTypes["..."].Properties.Xyz requires property "Type"
     * - instance.PropertyTypes["..."].Properties.Xyz requires property "ItemType"
     * - instance.PropertyTypes["..."].Properties.Xyz requires property "Type"
     * - instance.PropertyTypes["..."].Properties.Xyz requires property "PrimitiveItemType"
     * - instance.PropertyTypes["..."].Properties.Xyz is not exactly one from "Primitive","Complex Type","Collection of Primitives","Collection of Complex Types"
     * ```
     *
     * No bueno. In contrast, this script prints:
     *
     * ```
     * {
     *   "ResourceTypes": {
     *     "AWS::SageMaker::Device": {
     *       "Properties": {
     *         "Device": {
     *
     * !!!       must have exactly one of 'Type', 'PrimitiveType', found: {"Type":"Device","PrimitiveType":"Json"} !!!
     *
     *           "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-sagemaker-device.html#cfn-sagemaker-device-device",
     *           "UpdateType": "Mutable",
     *           "Required": false,
     *           "PrimitiveType": "Json",
     *           "Type": "Device"
     *         }
     *       }
     *     }
     *   }
     * }
     * ```
     */
    import * as fs from 'fs-extra';

    export interface CfnSpec {
      PropertyTypes: Record<string, any>;
      ResourceTypes: Record<string, any>;
      ResourceSpecificationVersion: string;
    }

    export interface ValidationError {
      readonly value: JsonValue<any>;
      readonly message: string;
    }

    export class CfnSpecValidator {
      public static validate(spec: CfnSpec) {
        const ret = new CfnSpecValidator(spec);
        ret.validateSpec();
        return ret.errors;
      }

      public readonly errors = new Array<ValidationError>();
      private readonly root: JsonValue<CfnSpec>;

      constructor(spec: CfnSpec) {
        this.root = JsonValue.of(spec);
      }

      public validateSpec() {
        this.assert(this.root.get('PropertyTypes'), isObject, (propTypes) => {
          this.validateMap(propTypes, (propType) => this.validatePropertyType(propType));
        });

        this.assert(this.root.get('ResourceTypes'), isObject, (resTypes) => {
          this.validateMap(resTypes, (propType) => this.validateResourceType(propType));
        });
      }

      /**
       * Property types are extremely weird
       *
       * Nominally, they define "records" that have a `Properties` field with the defined
       * properties.
       *
       * However, they are also commonly used as aliases for other types, meaning they have
       * the same type-indicating fields as individual property *fields* would have.
       *
       * Also also, it seems to be quite common to have them empty--have no fields at all.
       * This seems to be taken as an alias for an unstructured `Json` type. It's probably
       * just a mistake, but unfortunately a mistake that S3 is participating in, so if we
       * fail on that we won't be able to consume updates to S3's schema. Our codegen is
       * ready to deal with this and just renders it to an empty struct.
       */
      private validatePropertyType(propType: JsonValue<Record<string, any>>) {
        // If the only set of properties is "Documentation", we take this to be an alias
        // for an empty struct and allow it. I feel icky allowing this, but it seems to
        // be pragmatic for now.
        Iif (Object.keys(propType.value).join(',') === 'Documentation') {
          return;
        }

        const properties = propType.get('Properties');
        if (properties.hasValue) {
          this.assert(properties, isObject, (props) => {
            this.validateProperties(props);
          });
        } else E{
          this.validateType(propType, 'if a property type doesn\'t have "Properties", it ');
        }
      }

      private validateResourceType(resType: JsonValue<any>) {
        this.assertOptional(resType.get('Properties'), isObject, (props) => {
          this.validateProperties(props);
        });

        this.assertOptional(resType.get('Attributes'), isObject, (attrs) => {
          this.validateMap(attrs, attr => {
            this.validateType(attr);
          });
        });
      }

      private validateProperties(properties: JsonValue<Record<string, any>>) {
        this.validateMap(properties, prop => {
          this.validateType(prop);

          this.assertOptional(prop.get('UpdateType'), (x: any) => {
            Iif (!['Mutable', 'Immutable', 'Conditional'].includes(x)) {
              throw new Error(`invalid value for enum: '${x}'`);
            }
          });
        });
      }

      /**
       * Validate the type
       *
       * There must be:
       * - Either Type or PrimitiveType
       * - Only if Type is List or Map, there will be either an ItemType or a PrimitiveItemType
       * - Non-primitive Types must correspond to a property type
       */
      private validateType(typedObject: JsonValue<Record<string, any>>, errorPrefix = '') {
        const type = typedObject.get('Type');
        const primitiveType = typedObject.get('PrimitiveType');

        if (type.hasValue === primitiveType.hasValue) {
          this.report(typedObject, `${errorPrefix}must have exactly one of 'Type', 'PrimitiveType', found: ${JSON.stringify({
            Type: type.valueOrUndefined,
            PrimitiveType: primitiveType.valueOrUndefined,
          })}`);
        }

        this.assertOptional(primitiveType, isValidPrimitive);

        let isCollectionType = false;
        const itemType = typedObject.get('ItemType');
        const primitiveItemType = typedObject.get('PrimitiveItemType');

        if (type.hasValue) {
          isCollectionType = COLLECTION_TYPES.includes(type.value);
          if (isCollectionType) {
            if (itemType.hasValue === primitiveItemType.hasValue) {
              this.report(typedObject, `must have exactly one of 'ItemType', 'PrimitiveItemType', found: ${JSON.stringify({
                ItemType: itemType.valueOrUndefined,
                PrimitiveItemType: primitiveItemType.valueOrUndefined,
              })}`);
            }

            this.assertOptional(primitiveItemType, isValidPrimitive);
            if (itemType.hasValue) {
              this.assertValidPropertyTypeReference(itemType);
            }
          } else {
            this.assertValidPropertyTypeReference(type);
          }
        }

        if (!isCollectionType) {
          if (itemType.hasValue || primitiveItemType.hasValue) {
            this.report(typedObject, 'only \'List\' or \'Map\' types can have \'ItemType\', \'PrimitiveItemType\'');
          }
        }

        const dupes = typedObject.get('DuplicatesAllowed');
        Iif (dupes.hasValue && !isCollectionType) {
          this.report(dupes, 'occurs on non-collection type');
        }
      }

      private assertValidPropertyTypeReference(typeName: JsonValue<string>) {
        Iif (BUILTIN_COMPLEX_TYPES.includes(typeName.value)) {
          return;
        }

        const cfnName = typeName.path[1]; // AWS::Xyz::Resource[.Property]
        const namespace = cfnName.split('.')[0];

        const propTypeName = `${namespace}.${typeName.value}`;
        if (!this.root.get('PropertyTypes').get(propTypeName).hasValue) {
          this.report(typeName, `unknown property type name '${typeName.value}' (missing definition for '${propTypeName}')`);
        }
      }

      private assertOptional<A, B extends A>(x: JsonValue<A>, pred: (x: A) => asserts x is B, block?: (x: JsonValue<B>) => void): boolean {
        return x.hasValue ? this.assert(x, pred, block) : true;
      }

      private assert<A, B extends A>(x: JsonValue<A>, pred: (x: A) => asserts x is B, block?: (x: JsonValue<B>) => void): boolean {
        try {
          pred(x.value);
          if (block) {
            block(new JsonValue(x.value, x.path));
          }
          return true;
        } catch (e) {
          this.report(x, e.message);
          return false;
        }
      }

      private validateMap<A>(x: JsonValue<Record<string, A>>, block: (x: JsonValue<A>) => void) {
        for (const key in x.value) {
          block(x.get(key));
        }
      }

      private report(value: JsonValue<any>, message: string) {
        this.errors.push({ value, message });
      }
    }

    function isObject(x: any): asserts x is Record<string, any> {
      Iif (x == null || typeof x !== 'object' || Array.isArray(x)) {
        throw new Error(`expected object, found '${x}'`);
      }
    }

    const COLLECTION_TYPES = ['List', 'Map'];
    const BUILTIN_COMPLEX_TYPES = ['Tag'];

    function isValidPrimitive(x: any): asserts x is string {
      const primitives = ['String', 'Long', 'Integer', 'Double', 'Boolean', 'Timestamp', 'Json'];

      Iif (!primitives.includes(x)) {
        throw new Error(`must be one of ${primitives.join(', ')}, got: ${x}`);
      }
    }

    interface JsonValue<A> {
      readonly path: string[];
      readonly pathValue: any;
      readonly hasValue: boolean;
      readonly value: A;
      readonly valueOrUndefined: A | undefined;
      get<K extends keyof A>(k: K): JsonValue<A[K]>;
    }

    class JsonValue<A> implements JsonValue<A> {
      public static of<B>(x: B): JsonValue<B> {
        return new JsonValue(x, []);
      }

      public readonly hasValue: boolean = true;
      public readonly valueOrUndefined: A | undefined = this.value;
      public readonly pathValue: any = this.value;

      constructor(public readonly value: A, public readonly path: string[]) {
      }

      public get<K extends keyof A>(k: K): JsonValue<A[K]> {
        Iif (!this.value || typeof this.value !== 'object' || Array.isArray(this.value)) {
          return new ErrorValue(`expected object, found ${this.value}`, this.path, this.value);
        }
        const ret = this.value[k];
        if (ret === undefined) {
          return new ErrorValue(`missing required key '${k}'`, this.path, this.value);
        }
        return new JsonValue(ret, [...this.path, `${k}`]);
      }
    }

    class ErrorValue<A> implements JsonValue<A> {
      public readonly hasValue = false;
      public readonly valueOrUndefined: A | undefined = undefined;

      constructor(private readonly error: string, public readonly path: string[], public readonly pathValue: any) {
      }

      public get<K extends keyof A>(_k: K): JsonValue<A[K]> {
        return this as any;
      }

      public get value(): A {
        throw new Error(this.error);
      }
    }

    export function formatErrorInContext(error: ValidationError) {
      let reportValue = error.value.pathValue;
      for (let i = error.value.path.length; i > 0; i--) {
        reportValue = { [error.value.path[i - 1]]: reportValue };
      }

      const formattedLines = JSON.stringify(reportValue, undefined, 2).split('\n');

      const indent = 2 * (error.value.path.length + 1);

      // Insert the error message at line N with an appropriate indent
      formattedLines.splice(error.value.path.length + 1, 0, `\n!!!${' '.repeat(indent - 3)}${error.message} !!!\n`);

      return formattedLines.join('\n');
    }

    async function main(args: string[]) {
      const spec = await fs.readJson(args[0]);
      const errors = CfnSpecValidator.validate(spec);
      Iif (errors.length !== 0) {
        for (const error of errors) {
          console.error(formatErrorInContext(error));
        }
        process.exitCode = 1;
      }
    }

    Iif (require.main === module) {
      main(process.argv.slice(2)).catch(e => {
        process.exitCode = 1;
        // eslint-disable-next-line no-console
        console.error(e.message);
      });
    }