import {BaseException, ComponentFactory, ComponentResolver} from '@angular/core';

import {DEFAULT_OUTLET_NAME} from './constants';
import {reflector} from './core_private';
import {ListWrapper, StringMapWrapper} from './facade/collection';
import {Type, isBlank, isPresent, stringify} from './facade/lang';
import {PromiseWrapper} from './facade/promise';
import {RouteMetadata, RoutesMetadata} from './metadata/metadata';
import {RouteSegment, RouteTree, Tree, TreeNode, UrlSegment, UrlTree, equalUrlSegments, rootNode} from './segments';

export function recognize(
    componentResolver: ComponentResolver, rootComponent: Type, url: UrlTree,
    existingTree: RouteTree): Promise<RouteTree> {
  let matched = new _MatchResult(rootComponent, [url.root], {}, rootNode(url).children, []);
  return _constructSegment(componentResolver, matched, rootNode(existingTree))
      .then(roots => new RouteTree(roots[0]));
}

function _recognize(
    componentResolver: ComponentResolver, parentComponent: Type, url: TreeNode<UrlSegment>,
    existingSegments: TreeNode<RouteSegment>[]): Promise<TreeNode<RouteSegment>[]> {
  let metadata = _readMetadata(parentComponent);  // should read from the factory instead
  if (isBlank(metadata)) {
    throw new BaseException(
        `Component '${stringify(parentComponent)}' does not have route configuration`);
  }

  let match: any /** TODO #9100 */;
  try {
    match = _match(metadata, url);
  } catch (e) {
    return PromiseWrapper.reject(e, null);
  }

  let segmentsWithRightOutlet = existingSegments.filter(r => r.value.outlet == match.outlet);
  let segmentWithRightOutlet =
      segmentsWithRightOutlet.length > 0 ? segmentsWithRightOutlet[0] : null;

  let main = _constructSegment(componentResolver, match, segmentWithRightOutlet);
  let aux = _recognizeMany(componentResolver, parentComponent, match.aux, existingSegments)
                .then(_checkOutletNameUniqueness);
  return PromiseWrapper.all([main, aux]).then(ListWrapper.flatten);
}

function _recognizeMany(
    componentResolver: ComponentResolver, parentComponent: Type, urls: TreeNode<UrlSegment>[],
    existingSegments: TreeNode<RouteSegment>[]): Promise<TreeNode<RouteSegment>[]> {
  let recognized =
      urls.map(u => _recognize(componentResolver, parentComponent, u, existingSegments));
  return PromiseWrapper.all(recognized).then(ListWrapper.flatten);
}

function _constructSegment(
    componentResolver: ComponentResolver, matched: _MatchResult,
    existingSegment: TreeNode<RouteSegment>): Promise<TreeNode<RouteSegment>[]> {
  return componentResolver.resolveComponent(matched.component).then(factory => {
    let segment = _createOrReuseSegment(matched, factory, existingSegment);
    let existingChildren = isPresent(existingSegment) ? existingSegment.children : [];

    if (matched.leftOverUrl.length > 0) {
      return _recognizeMany(
                 componentResolver, factory.componentType, matched.leftOverUrl, existingChildren)
          .then(children => [new TreeNode<RouteSegment>(segment, children)]);
    } else {
      return _recognizeLeftOvers(componentResolver, factory.componentType, existingChildren)
          .then(children => [new TreeNode<RouteSegment>(segment, children)]);
    }
  });
}

function _createOrReuseSegment(
    matched: _MatchResult, factory: ComponentFactory<any>,
    segmentNode: TreeNode<RouteSegment>): RouteSegment {
  let segment = isPresent(segmentNode) ? segmentNode.value : null;

  if (isPresent(segment) && equalUrlSegments(segment.urlSegments, matched.consumedUrlSegments) &&
      StringMapWrapper.equals(segment.parameters, matched.parameters) &&
      segment.outlet == matched.outlet && factory.componentType == segment.type) {
    return segment;
  } else {
    return new RouteSegment(
        matched.consumedUrlSegments, matched.parameters, matched.outlet, factory.componentType,
        factory);
  }
}

function _recognizeLeftOvers(
    componentResolver: ComponentResolver, parentComponent: Type,
    existingSegments: TreeNode<RouteSegment>[]): Promise<TreeNode<RouteSegment>[]> {
  return componentResolver.resolveComponent(parentComponent).then(factory => {
    let metadata = _readMetadata(factory.componentType);
    if (isBlank(metadata)) {
      return [];
    }

    let r = (<any[]>metadata.routes).filter(r => r.path == '' || r.path == '/');
    if (r.length === 0) {
      return PromiseWrapper.resolve([]);
    } else {
      let segmentsWithMatchingOutlet =
          existingSegments.filter(r => r.value.outlet == DEFAULT_OUTLET_NAME);
      let segmentWithMatchingOutlet =
          segmentsWithMatchingOutlet.length > 0 ? segmentsWithMatchingOutlet[0] : null;
      let existingChildren =
          isPresent(segmentWithMatchingOutlet) ? segmentWithMatchingOutlet.children : [];

      return _recognizeLeftOvers(componentResolver, r[0].component, existingChildren)
          .then(children => {
            return componentResolver.resolveComponent(r[0].component).then(factory => {
              let segment = _createOrReuseSegment(
                  new _MatchResult(r[0].component, [], {}, [], []), factory,
                  segmentWithMatchingOutlet);
              return [new TreeNode<RouteSegment>(segment, children)];
            });
          });
    }
  });
}

function _match(metadata: RoutesMetadata, url: TreeNode<UrlSegment>): _MatchResult {
  for (let r of metadata.routes) {
    let matchingResult = _matchWithParts(r, url);
    if (isPresent(matchingResult)) {
      return matchingResult;
    }
  }
  let availableRoutes = metadata.routes.map(r => `'${r.path}'`).join(', ');
  throw new BaseException(
      `Cannot match any routes. Current segment: '${url.value}'. Available routes: [${availableRoutes}].`);
}

function _matchWithParts(route: RouteMetadata, url: TreeNode<UrlSegment>): _MatchResult {
  let path = route.path.startsWith('/') ? route.path.substring(1) : route.path;

  if (path == '*') {
    return new _MatchResult(route.component, [], null, [], []);
  }

  let parts = path.split('/');
  let positionalParams = {};
  let consumedUrlSegments: any[] /** TODO #9100 */ = [];

  let lastParent: TreeNode<UrlSegment> = null;
  let lastSegment: TreeNode<UrlSegment> = null;

  let current = url;
  for (let i = 0; i < parts.length; ++i) {
    if (isBlank(current)) return null;

    let p = parts[i];
    let isLastSegment = i === parts.length - 1;
    let isLastParent = i === parts.length - 2;
    let isPosParam = p.startsWith(':');

    if (!isPosParam && p != current.value.segment) return null;
    if (isLastSegment) {
      lastSegment = current;
    }
    if (isLastParent) {
      lastParent = current;
    }

    if (isPosParam) {
      (positionalParams as any /** TODO #9100 */)[p.substring(1)] = current.value.segment;
    }

    consumedUrlSegments.push(current.value);

    current = ListWrapper.first(current.children);
  }

  let p = lastSegment.value.parameters;
  let parameters = <{[key: string]: string}>StringMapWrapper.merge(p, positionalParams);
  let axuUrlSubtrees = isPresent(lastParent) ? lastParent.children.slice(1) : [];

  return new _MatchResult(
      route.component, consumedUrlSegments, parameters, lastSegment.children, axuUrlSubtrees);
}

function _checkOutletNameUniqueness(nodes: TreeNode<RouteSegment>[]): TreeNode<RouteSegment>[] {
  let names = {};
  nodes.forEach(n => {
    let segmentWithSameOutletName = (names as any /** TODO #9100 */)[n.value.outlet];
    if (isPresent(segmentWithSameOutletName)) {
      let p = segmentWithSameOutletName.stringifiedUrlSegments;
      let c = n.value.stringifiedUrlSegments;
      throw new BaseException(`Two segments cannot have the same outlet name: '${p}' and '${c}'.`);
    }
    (names as any /** TODO #9100 */)[n.value.outlet] = n.value;
  });
  return nodes;
}

class _MatchResult {
  constructor(
      public component: Type|string, public consumedUrlSegments: UrlSegment[],
      public parameters: {[key: string]: string}, public leftOverUrl: TreeNode<UrlSegment>[],
      public aux: TreeNode<UrlSegment>[]) {}

  get outlet(): string {
    return this.consumedUrlSegments.length === 0 || isBlank(this.consumedUrlSegments[0].outlet) ?
        DEFAULT_OUTLET_NAME :
        this.consumedUrlSegments[0].outlet;
  }
}

function _readMetadata(componentType: Type) {
  let metadata = reflector.annotations(componentType).filter(f => f instanceof RoutesMetadata);
  return ListWrapper.first(metadata);
}