/**
 *  Copyright (c) 2021 GraphQL Contributors
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree. An additional grant
 *  of patent rights can be found in the PATENTS file in the same directory.
 */

import CodeMirror from 'codemirror';

import getTypeInfo from './utils/getTypeInfo';
import {
  getArgumentReference,
  getDirectiveReference,
  getEnumValueReference,
  getFieldReference,
  getTypeReference,
} from './utils/SchemaReference';
import './utils/jump-addon';
import { GraphQLSchema } from 'graphql';
import type { State } from 'graphql-language-service';

export interface GraphQLJumpOptions {
  schema?: GraphQLSchema;
  onClick?: () => void;
  state?: State;
}

/**
 * Registers GraphQL "jump" links for CodeMirror.
 *
 * When command-hovering over a token, this converts it to a link, which when
 * pressed will call the provided onClick handler.
 *
 * Options:
 *
 *   - schema: GraphQLSchema provides positionally relevant info.
 *   - onClick: A function called when a named thing is clicked.
 *
 */
CodeMirror.registerHelper(
  'jump',
  'graphql',
  (token: CodeMirror.Token, options: GraphQLJumpOptions) => {
    if (!options.schema || !options.onClick || !token.state) {
      return;
    }

    // Given a Schema and a Token, produce a "SchemaReference" which refers to
    // the particular artifact from the schema (such as a type, field, argument,
    // or directive) that token references.
    const { state } = token;
    const { kind, step } = state;
    const typeInfo = getTypeInfo(options.schema, state);

    if (
      (kind === 'Field' && step === 0 && typeInfo.fieldDef) ||
      (kind === 'AliasedField' && step === 2 && typeInfo.fieldDef)
    ) {
      return getFieldReference(typeInfo);
    }
    if (kind === 'Directive' && step === 1 && typeInfo.directiveDef) {
      return getDirectiveReference(typeInfo);
    }
    if (kind === 'Argument' && step === 0 && typeInfo.argDef) {
      return getArgumentReference(typeInfo);
    }
    if (kind === 'EnumValue' && typeInfo.enumValue) {
      return getEnumValueReference(typeInfo);
    }
    if (kind === 'NamedType' && typeInfo.type) {
      return getTypeReference(typeInfo);
    }
  },
);