import $Ref from "./ref.js";
import * as url from "./util/url.js";
import type { JSONSchema4Type, JSONSchema6Type, JSONSchema7Type } from "json-schema";
import type { ParserOptions } from "./options.js";
import convertPathToPosix from "./util/convert-path-to-posix";
import type { JSONSchema } from "./types";

interface $RefsMap<S extends object = JSONSchema, O extends ParserOptions<S> = ParserOptions<S>> {
  [url: string]: $Ref<S, O>;
}
/**
 * When you call the resolve method, the value that gets passed to the callback function (or Promise) is a $Refs object. This same object is accessible via the parser.$refs property of $RefParser objects.
 *
 * This object is a map of JSON References and their resolved values. It also has several convenient helper methods that make it easy for you to navigate and manipulate the JSON References.
 *
 * See https://apidevtools.com/json-schema-ref-parser/docs/refs.html
 */
export default class $Refs<S extends object = JSONSchema, O extends ParserOptions<S> = ParserOptions<S>> {
  /**
   * This property is true if the schema contains any circular references. You may want to check this property before serializing the dereferenced schema as JSON, since JSON.stringify() does not support circular references by default.
   *
   * See https://apidevtools.com/json-schema-ref-parser/docs/refs.html#circular
   */
  public circular: boolean;

  /**
   * Returns the paths/URLs of all the files in your schema (including the main schema file).
   *
   * See https://apidevtools.com/json-schema-ref-parser/docs/refs.html#pathstypes
   *
   * @param types (optional) Optionally only return certain types of paths ("file", "http", etc.)
   */
  paths(...types: (string | string[])[]): string[] {
    const paths = getPaths(this._$refs, types.flat());
    return paths.map((path) => {
      return convertPathToPosix(path.decoded);
    });
  }

  /**
   * Returns a map of paths/URLs and their correspond values.
   *
   * See https://apidevtools.com/json-schema-ref-parser/docs/refs.html#valuestypes
   *
   * @param types (optional) Optionally only return values from certain locations ("file", "http", etc.)
   */
  values(...types: (string | string[])[]): S {
    const $refs = this._$refs;
    const paths = getPaths($refs, types.flat());
    return paths.reduce<Record<string, any>>((obj, path) => {
      obj[convertPathToPosix(path.decoded)] = $refs[path.encoded].value;
      return obj;
    }, {}) as S;
  }

  /**
   * Returns `true` if the given path exists in the schema; otherwise, returns `false`
   *
   * See https://apidevtools.com/json-schema-ref-parser/docs/refs.html#existsref
   *
   * @param $ref The JSON Reference path, optionally with a JSON Pointer in the hash
   */
  /**
   * Determines whether the given JSON reference exists.
   *
   * @param path - The path being resolved, optionally with a JSON pointer in the hash
   * @param [options]
   * @returns
   */
  exists(path: string, options: any) {
    try {
      this._resolve(path, "", options);
      return true;
    } catch {
      return false;
    }
  }

  /**
   * Resolves the given JSON reference and returns the resolved value.
   *
   * @param path - The path being resolved, with a JSON pointer in the hash
   * @param [options]
   * @returns - Returns the resolved value
   */
  get(path: string, options?: O): JSONSchema4Type | JSONSchema6Type | JSONSchema7Type {
    return this._resolve(path, "", options)!.value;
  }

  /**
   * Sets the value at the given path in the schema. If the property, or any of its parents, don't exist, they will be created.
   *
   * @param path The JSON Reference path, optionally with a JSON Pointer in the hash
   * @param value The value to assign. Can be anything (object, string, number, etc.)
   */
  set(path: string, value: JSONSchema4Type | JSONSchema6Type | JSONSchema7Type) {
    const absPath = url.resolve(this._root$Ref.path!, path);
    const withoutHash = url.stripHash(absPath);
    const $ref = this._$refs[withoutHash];

    if (!$ref) {
      throw new Error(`Error resolving $ref pointer "${path}". \n"${withoutHash}" not found.`);
    }

    $ref.set(absPath, value);
  }
  /**
   * Returns the specified {@link $Ref} object, or undefined.
   *
   * @param path - The path being resolved, optionally with a JSON pointer in the hash
   * @returns
   * @protected
   */
  _get$Ref(path: string) {
    path = url.resolve(this._root$Ref.path!, path);
    const withoutHash = url.stripHash(path);
    return this._$refs[withoutHash];
  }

  /**
   * Creates a new {@link $Ref} object and adds it to this {@link $Refs} object.
   *
   * @param path  - The file path or URL of the referenced file
   */
  _add(path: string) {
    const withoutHash = url.stripHash(path);

    const $ref = new $Ref<S, O>(this);
    $ref.path = withoutHash;

    this._$refs[withoutHash] = $ref;
    this._root$Ref = this._root$Ref || $ref;

    return $ref;
  }

  /**
   * Resolves the given JSON reference.
   *
   * @param path - The path being resolved, optionally with a JSON pointer in the hash
   * @param pathFromRoot - The path of `obj` from the schema root
   * @param [options]
   * @returns
   * @protected
   */
  _resolve(path: string, pathFromRoot: string, options?: O) {
    const absPath = url.resolve(this._root$Ref.path!, path);
    const withoutHash = url.stripHash(absPath);
    const $ref = this._$refs[withoutHash];

    if (!$ref) {
      throw new Error(`Error resolving $ref pointer "${path}". \n"${withoutHash}" not found.`);
    }

    return $ref.resolve(absPath, options, path, pathFromRoot);
  }

  /**
   * A map of paths/urls to {@link $Ref} objects
   *
   * @type {object}
   * @protected
   */
  _$refs: $RefsMap<S, O> = {};

  /**
   * The {@link $Ref} object that is the root of the JSON schema.
   *
   * @type {$Ref}
   * @protected
   */
  _root$Ref: $Ref<S, O>;

  constructor() {
    /**
     * Indicates whether the schema contains any circular references.
     *
     * @type {boolean}
     */
    this.circular = false;

    this._$refs = {};

    // @ts-ignore
    this._root$Ref = null;
  }

  /**
   * Returns the paths of all the files/URLs that are referenced by the JSON schema,
   * including the schema itself.
   *
   * @param [types] - Only return paths of the given types ("file", "http", etc.)
   * @returns
   */
  /**
   * Returns the map of JSON references and their resolved values.
   *
   * @param [types] - Only return references of the given types ("file", "http", etc.)
   * @returns
   */

  /**
   * Returns a POJO (plain old JavaScript object) for serialization as JSON.
   *
   * @returns {object}
   */
  toJSON = this.values;
}

/**
 * Returns the encoded and decoded paths keys of the given object.
 *
 * @param $refs - The object whose keys are URL-encoded paths
 * @param [types] - Only return paths of the given types ("file", "http", etc.)
 * @returns
 */
function getPaths<S extends object = JSONSchema, O extends ParserOptions<S> = ParserOptions<S>>(
  $refs: $RefsMap<S, O>,
  types: string[],
) {
  let paths = Object.keys($refs);

  // Filter the paths by type
  types = Array.isArray(types[0]) ? types[0] : Array.prototype.slice.call(types);
  if (types.length > 0 && types[0]) {
    paths = paths.filter((key) => {
      return types.includes($refs[key].pathType as string);
    });
  }

  // Decode local filesystem paths
  return paths.map((path) => {
    return {
      encoded: path,
      decoded: $refs[path].pathType === "file" ? url.toFileSystemPath(path, true) : path,
    };
  });
}
