utils.ts

import is from "../validators/is";
import { validateField, validateChild } from "../validators/validate";
import type * as t from "..";

export const VISITOR_KEYS: Record<string, string[]> = {};
export const ALIAS_KEYS: Record<string, string[]> = {};
export const FLIPPED_ALIAS_KEYS: Record<string, string[]> = {};
export const NODE_FIELDS: Record<string, FieldDefinitions> = {};
export const BUILDER_KEYS: Record<string, string[]> = {};
export const DEPRECATED_KEYS: Record<string, string> = {};
export const NODE_PARENT_VALIDATIONS: Record<string, Validator> = {};

function getType(val: any) {
  if (Array.isArray(val)) {
    return "array";
  } else if (val === null) {
    return "null";
  } else {
    return typeof val;
  }
}

type NodeTypes = t.Node["type"] | t.Comment["type"] | keyof t.Aliases;

type PrimitiveTypes = ReturnType<typeof getType>;

type FieldDefinitions = {
  [x: string]: FieldOptions;
};

type DefineTypeOpts = {
  fields?: FieldDefinitions;
  visitor?: Array<string>;
  aliases?: Array<string>;
  builder?: Array<string>;
  inherits?: NodeTypes;
  deprecatedAlias?: string;
  validate?: Validator;
};

export type Validator = (
  | { type: PrimitiveTypes }
  | { each: Validator }
  | { chainOf: Validator[] }
  | { oneOf: any[] }
  | { oneOfNodeTypes: NodeTypes[] }
  | { oneOfNodeOrValueTypes: (NodeTypes | PrimitiveTypes)[] }
  | { shapeOf: { [x: string]: FieldOptions } }
  | {}
) &
  ((node: t.Node, key: string, val: any) => void);

export type FieldOptions = {
  default?: any;
  optional?: boolean;
  validate?: Validator;
};

export function validate(validate: Validator): FieldOptions {
  return { validate };
}

export function typeIs(typeName: NodeTypes | NodeTypes[]) {
  return typeof typeName === "string"
    ? assertNodeType(typeName)
    : assertNodeType(...typeName);
}

export function validateType(typeName: NodeTypes | NodeTypes[]) {
  return validate(typeIs(typeName));
}

export function validateOptional(validate: Validator): FieldOptions {
  return { validate, optional: true };
}

export function validateOptionalType(
  typeName: NodeTypes | NodeTypes[],
): FieldOptions {
  return { validate: typeIs(typeName), optional: true };
}

export function arrayOf(elementType: Validator): Validator {
  return chain(assertValueType("array"), assertEach(elementType));
}

export function arrayOfType(typeName: NodeTypes | NodeTypes[]) {
  return arrayOf(typeIs(typeName));
}

export function validateArrayOfType(typeName: NodeTypes | NodeTypes[]) {
  return validate(arrayOfType(typeName));
}

export function assertEach(callback: Validator): Validator {
  function validator(node: t.Node, key: string, val: any) {
    if (!Array.isArray(val)) return;

    for (let i = 0; i < val.length; i++) {
      const subkey = `${key}[${i}]`;
      const v = val[i];
      callback(node, subkey, v);
      if (process.env.BABEL_TYPES_8_BREAKING) validateChild(node, subkey, v);
    }
  }
  validator.each = callback;
  return validator;
}

export function assertOneOf(...values: Array<any>): Validator {
  function validate(node: any, key: string, val: any) {
    if (values.indexOf(val) < 0) {
      throw new TypeError(
        `Property ${key} expected value to be one of ${JSON.stringify(
          values,
        )} but got ${JSON.stringify(val)}`,
      );
    }
  }

  validate.oneOf = values;

  return validate;
}

export function assertNodeType(...types: NodeTypes[]): Validator {
  function validate(node: t.Node, key: string, val: any) {
    for (const type of types) {
      if (is(type, val)) {
        validateChild(node, key, val);
        return;
      }
    }

    throw new TypeError(
      `Property ${key} of ${
        node.type
      } expected node to be of a type ${JSON.stringify(
        types,
      )} but instead got ${JSON.stringify(val?.type)}`,
    );
  }

  validate.oneOfNodeTypes = types;

  return validate;
}

export function assertNodeOrValueType(
  ...types: (NodeTypes | PrimitiveTypes)[]
): Validator {
  function validate(node: t.Node, key: string, val: any) {
    for (const type of types) {
      if (getType(val) === type || is(type, val)) {
        validateChild(node, key, val);
        return;
      }
    }

    throw new TypeError(
      `Property ${key} of ${
        node.type
      } expected node to be of a type ${JSON.stringify(
        types,
      )} but instead got ${JSON.stringify(val?.type)}`,
    );
  }

  validate.oneOfNodeOrValueTypes = types;

  return validate;
}

export function assertValueType(type: PrimitiveTypes): Validator {
  function validate(node: t.Node, key: string, val: any) {
    const valid = getType(val) === type;

    if (!valid) {
      throw new TypeError(
        `Property ${key} expected type of ${type} but got ${getType(val)}`,
      );
    }
  }

  validate.type = type;

  return validate;
}

export function assertShape(shape: { [x: string]: FieldOptions }): Validator {
  function validate(node: t.Node, key: string, val: any) {
    const errors = [];
    for (const property of Object.keys(shape)) {
      try {
        validateField(node, property, val[property], shape[property]);
      } catch (error) {
        if (error instanceof TypeError) {
          errors.push(error.message);
          continue;
        }
        throw error;
      }
    }
    if (errors.length) {
      throw new TypeError(
        `Property ${key} of ${
          node.type
        } expected to have the following:\n${errors.join("\n")}`,
      );
    }
  }

  validate.shapeOf = shape;

  return validate;
}

export function assertOptionalChainStart(): Validator {
  function validate(node: t.Node) {
    let current = node;
    while (node) {
      const { type } = current;
      if (type === "OptionalCallExpression") {
        if (current.optional) return;
        current = current.callee;
        continue;
      }

      if (type === "OptionalMemberExpression") {
        if (current.optional) return;
        current = current.object;
        continue;
      }

      break;
    }

    throw new TypeError(
      `Non-optional ${node.type} must chain from an optional OptionalMemberExpression or OptionalCallExpression. Found chain from ${current?.type}`,
    );
  }

  return validate;
}

export function chain(...fns: Array<Validator>): Validator {
  function validate(...args: Parameters<Validator>) {
    for (const fn of fns) {
      fn(...args);
    }
  }
  validate.chainOf = fns;

  if (
    fns.length >= 2 &&
    "type" in fns[0] &&
    fns[0].type === "array" &&
    !("each" in fns[1])
  ) {
    throw new Error(
      `An assertValueType("array") validator can only be followed by an assertEach(...) validator.`,
    );
  }

  return validate;
}

const validTypeOpts = [
  "aliases",
  "builder",
  "deprecatedAlias",
  "fields",
  "inherits",
  "visitor",
  "validate",
];
const validFieldKeys = ["default", "optional", "validate"];

// Wraps defineType to ensure these aliases are included.
export function defineAliasedType(...aliases: string[]) {
  return (type: string, opts: DefineTypeOpts = {}) => {
    let defined = opts.aliases;
    if (!defined) {
      if (opts.inherits) defined = store[opts.inherits].aliases?.slice();
      defined ??= [];
      opts.aliases = defined;
    }
    const additional = aliases.filter(a => !defined.includes(a));
    defined.unshift(...additional);
    return defineType(type, opts);
  };
}

export default function defineType(type: string, opts: DefineTypeOpts = {}) {
  const inherits = (opts.inherits && store[opts.inherits]) || {};

  let fields = opts.fields;
  if (!fields) {
    fields = {};
    if (inherits.fields) {
      const keys = Object.getOwnPropertyNames(inherits.fields);
      for (const key of keys) {
        const field = inherits.fields[key];
        const def = field.default;
        if (
          Array.isArray(def) ? def.length > 0 : def && typeof def === "object"
        ) {
          throw new Error(
            "field defaults can only be primitives or empty arrays currently",
          );
        }
        fields[key] = {
          default: Array.isArray(def) ? [] : def,
          optional: field.optional,
          validate: field.validate,
        };
      }
    }
  }

  const visitor: Array<string> = opts.visitor || inherits.visitor || [];
  const aliases: Array<string> = opts.aliases || inherits.aliases || [];
  const builder: Array<string> =
    opts.builder || inherits.builder || opts.visitor || [];

  for (const k of Object.keys(opts)) {
    if (validTypeOpts.indexOf(k) === -1) {
      throw new Error(`Unknown type option "${k}" on ${type}`);
    }
  }

  if (opts.deprecatedAlias) {
    DEPRECATED_KEYS[opts.deprecatedAlias] = type;
  }

  // ensure all field keys are represented in `fields`
  for (const key of visitor.concat(builder)) {
    fields[key] = fields[key] || {};
  }

  for (const key of Object.keys(fields)) {
    const field = fields[key];

    if (field.default !== undefined && builder.indexOf(key) === -1) {
      field.optional = true;
    }
    if (field.default === undefined) {
      field.default = null;
    } else if (!field.validate && field.default != null) {
      field.validate = assertValueType(getType(field.default));
    }

    for (const k of Object.keys(field)) {
      if (validFieldKeys.indexOf(k) === -1) {
        throw new Error(`Unknown field key "${k}" on ${type}.${key}`);
      }
    }
  }

  VISITOR_KEYS[type] = opts.visitor = visitor;
  BUILDER_KEYS[type] = opts.builder = builder;
  NODE_FIELDS[type] = opts.fields = fields;
  ALIAS_KEYS[type] = opts.aliases = aliases;
  aliases.forEach(alias => {
    FLIPPED_ALIAS_KEYS[alias] = FLIPPED_ALIAS_KEYS[alias] || [];
    FLIPPED_ALIAS_KEYS[alias].push(type);
  });

  if (opts.validate) {
    NODE_PARENT_VALIDATIONS[type] = opts.validate;
  }

  store[type] = opts;
}

const store = {} as Record<string, DefineTypeOpts>;