import { add, classname, crawl, merge, STOP_CRAWLING } from "./Tools";

function isObject(value: any): boolean {
  return value instanceof Object && !Array.isArray(value);
}

/**
 * A typescript object serializer.
 */
export class Serializer {
  namespace: { [name: string]: (...args: any) => any };
  ignored: string[] = [];

  constructor(namespace: { [name: string]: (...args: any) => any } = {}) {
    this.namespace = namespace;
  }

  /**
   * Add a class to the ignore list
   */
  addIgnoredClass(name: string) {
    this.ignored.push(name);
  }

  /**
   * Construct an object from a constructor name
   */
  constructObject(ctype: string): Object {
    if (ctype == "Object") {
      return {};
    } else {
      let cl = this.namespace[ctype];
      if (cl) {
        return Object.create(cl.prototype);
      } else {
        console.error("Can't find class", ctype);
        return {};
      }
    }
  }

  /**
   * Serialize an object to a string
   */
  serialize(obj: any): string {
    // Collect objects
    var objects: Object[] = [];
    var stats: any = {};
    crawl(obj, value => {
      if (isObject(value)) {
        var vtype = classname(value);
        if (vtype != "" && this.ignored.indexOf(vtype) < 0) {
          stats[vtype] = (stats[vtype] || 0) + 1;
          add(objects, value);
          return value;
        } else {
          return STOP_CRAWLING;
        }
      } else {
        return value;
      }
    });
    //console.log("Serialize stats", stats);

    // Serialize objects list, transforming deeper objects to links
    var fobjects = objects.map(value => <Object>{ $c: classname(value), $f: merge({}, value) });
    return JSON.stringify(fobjects, (key, value) => {
      if (key != "$f" && isObject(value) && !value.hasOwnProperty("$c") && !value.hasOwnProperty("$i")) {
        return { $i: objects.indexOf(value) };
      } else {
        return value;
      }
    });
  }

  /**
   * Unserialize a string to an object
   */
  unserialize(data: string): any {
    // Unserialize objects list
    var fobjects = JSON.parse(data);

    // Reconstruct objects
    var objects = fobjects.map((objdata: any) => merge(this.constructObject(objdata['$c']), objdata['$f']));

    // Reconnect links
    crawl(objects, value => {
      if (value instanceof Object && value.hasOwnProperty('$i')) {
        return objects[value['$i']];
      } else {
        return value;
      }
    }, true);

    // Post unserialize hooks
    crawl(objects[0], value => {
      if (value instanceof Object && typeof value.postUnserialize == "function") {
        value.postUnserialize();
      }
    });

    // First object was the root
    return objects[0];
  }
}