import {Map, MapWrapper, StringMapWrapper, ListWrapper} from 'angular2/src/core/facade/collection';
import {unimplemented} from 'angular2/src/core/facade/exceptions';
import {isPresent, isBlank, normalizeBlank, Type} from 'angular2/src/core/facade/lang';
import {Promise} from 'angular2/src/core/facade/async';

import {PathRecognizer} from './path_recognizer';
import {Url} from './url_parser';

/**
 * `RouteParams` is an immutable map of parameters for the given route
 * based on the url matcher and optional parameters for that route.
 *
 * You can inject `RouteParams` into the constructor of a component to use it.
 *
 * ## Example
 *
 * ```
 * import {bootstrap, Component, View} from 'angular2/angular2';
 * import {Router, ROUTER_DIRECTIVES, routerBindings, RouteConfig} from 'angular2/router';
 *
 * @Component({...})
 * @View({directives: [ROUTER_DIRECTIVES]})
 * @RouteConfig([
 *  {path: '/user/:id', component: UserCmp, as: 'UserCmp'},
 * ])
 * class AppCmp {}
 *
 * @Component({...})
 * @View({ template: 'user: {{id}}' })
 * class UserCmp {
 *   string: id;
 *   constructor(params: RouteParams) {
 *     this.id = params.get('id');
 *   }
 * }
 *
 * bootstrap(AppCmp, routerBindings(AppCmp));
 * ```
 */
export class RouteParams {
  constructor(public params: {[key: string]: string}) {}

  get(param: string): string { return normalizeBlank(StringMapWrapper.get(this.params, param)); }
}

/**
 * `Instruction` is a tree of {@link ComponentInstruction}s with all the information needed
 * to transition each component in the app to a given route, including all auxiliary routes.
 *
 * `Instruction`s can be created using {@link Router#generate}, and can be used to
 * perform route changes with {@link Router#navigateByInstruction}.
 *
 * ## Example
 *
 * ```
 * import {bootstrap, Component, View} from 'angular2/angular2';
 * import {Router, ROUTER_DIRECTIVES, routerBindings, RouteConfig} from 'angular2/router';
 *
 * @Component({...})
 * @View({directives: [ROUTER_DIRECTIVES]})
 * @RouteConfig([
 *  {...},
 * ])
 * class AppCmp {
 *   constructor(router: Router) {
 *     var instruction = router.generate(['/MyRoute']);
 *     router.navigateByInstruction(instruction);
 *   }
 * }
 *
 * bootstrap(AppCmp, routerBindings(AppCmp));
 * ```
 */
export class Instruction {
  constructor(public component: ComponentInstruction, public child: Instruction,
              public auxInstruction: {[key: string]: Instruction}) {}

  /**
   * Returns a new instruction that shares the state of the existing instruction, but with
   * the given child {@link Instruction} replacing the existing child.
   */
  replaceChild(child: Instruction): Instruction {
    return new Instruction(this.component, child, this.auxInstruction);
  }
}

/**
 * Represents a partially completed instruction during recognition that only has the
 * primary (non-aux) route instructions matched.
 *
 * `PrimaryInstruction` is an internal class used by `RouteRecognizer` while it's
 * figuring out where to navigate.
 */
export class PrimaryInstruction {
  constructor(public component: ComponentInstruction, public child: PrimaryInstruction,
              public auxUrls: Url[]) {}
}

export function stringifyInstruction(instruction: Instruction): string {
  var params = instruction.component.urlParams.length > 0 ?
                   ('?' + instruction.component.urlParams.join('&')) :
                   '';

  return instruction.component.urlPath + stringifyAux(instruction) +
         stringifyPrimary(instruction.child) + params;
}

function stringifyPrimary(instruction: Instruction): string {
  if (isBlank(instruction)) {
    return '';
  }
  var params = instruction.component.urlParams.length > 0 ?
                   (';' + instruction.component.urlParams.join(';')) :
                   '';
  return '/' + instruction.component.urlPath + params + stringifyAux(instruction) +
         stringifyPrimary(instruction.child);
}

function stringifyAux(instruction: Instruction): string {
  var routes = [];
  StringMapWrapper.forEach(instruction.auxInstruction, (auxInstruction, _) => {
    routes.push(stringifyPrimary(auxInstruction));
  });
  if (routes.length > 0) {
    return '(' + routes.join('//') + ')';
  }
  return '';
}


/**
 * A `ComponentInstruction` represents the route state for a single component. An `Instruction` is
 * composed of a tree of these `ComponentInstruction`s.
 *
 * `ComponentInstructions` is a public API. Instances of `ComponentInstruction` are passed
 * to route lifecycle hooks, like {@link CanActivate}.
 *
 * `ComponentInstruction`s are [https://en.wikipedia.org/wiki/Hash_consing](hash consed). You should
 * never construct one yourself with "new." Instead, rely on {@link Router/PathRecognizer} to
 * construct `ComponentInstruction`s.
 *
 * You should not modify this object. It should be treated as immutable.
 */
export abstract class ComponentInstruction {
  reuse: boolean = false;
  public urlPath: string;
  public urlParams: string[];
  public params: {[key: string]: any};

  /**
   * Returns the component type of the represented route, or `null` if this instruction
   * hasn't been resolved.
   */
  get componentType() { return unimplemented(); };

  /**
   * Returns a promise that will resolve to component type of the represented route.
   * If this instruction references an {@link AsyncRoute}, the `loader` function of that route
   * will run.
   */
  abstract resolveComponentType(): Promise<Type>;

  /**
   * Returns the specificity of the route associated with this `Instruction`.
   */
  get specificity() { return unimplemented(); };

  /**
   * Returns `true` if the component type of this instruction has no child {@link RouteConfig},
   * or `false` if it does.
   */
  get terminal() { return unimplemented(); };

  /**
   * Returns the route data of the given route that was specified in the {@link RouteDefinition},
   * or `null` if no route data was specified.
   */
  abstract routeData(): Object;
}

export class ComponentInstruction_ extends ComponentInstruction {
  constructor(urlPath: string, urlParams: string[], private _recognizer: PathRecognizer,
              params: {[key: string]: any} = null) {
    super();
    this.urlPath = urlPath;
    this.urlParams = urlParams;
    this.params = params;
  }

  get componentType() { return this._recognizer.handler.componentType; }
  resolveComponentType(): Promise<Type> { return this._recognizer.handler.resolveComponentType(); }
  get specificity() { return this._recognizer.specificity; }
  get terminal() { return this._recognizer.terminal; }
  routeData(): Object { return this._recognizer.handler.data; }
}