import {
  RegExp,
  RegExpWrapper,
  RegExpMatcherWrapper,
  StringWrapper,
  isPresent,
  isBlank,
  BaseException
} from 'angular2/src/facade/lang';
import {Promise, PromiseWrapper} from 'angular2/src/facade/async';
import {
  Map,
  MapWrapper,
  StringMap,
  StringMapWrapper,
  List,
  ListWrapper
} from 'angular2/src/facade/collection';
import {IMPLEMENTS} from 'angular2/src/facade/lang';

import {escapeRegex} from './url';
import {RouteHandler} from './route_handler';

// TODO(jeffbcross): implement as interface when ts2dart adds support:
// https://github.com/angular/ts2dart/issues/173
export class Segment {
  name: string;
  regex: string;
  generate(params: TouchMap): string { return ''; }
}

class TouchMap {
  map: StringMap<string, string> = StringMapWrapper.create();
  keys: StringMap<string, boolean> = StringMapWrapper.create();

  constructor(map: StringMap<string, any>) {
    if (isPresent(map)) {
      StringMapWrapper.forEach(map, (value, key) => {
        this.map[key] = isPresent(value) ? value.toString() : null;
        this.keys[key] = true;
      });
    }
  }

  get(key: string): string {
    StringMapWrapper.delete(this.keys, key);
    return this.map[key];
  }

  getUnused(): StringMap<string, any> {
    var unused: StringMap<string, any> = StringMapWrapper.create();
    var keys = StringMapWrapper.keys(this.keys);
    ListWrapper.forEach(keys, (key) => { unused[key] = StringMapWrapper.get(this.map, key); });
    return unused;
  }
}

function normalizeString(obj: any): string {
  if (isBlank(obj)) {
    return null;
  } else {
    return obj.toString();
  }
}

function parseAndAssignMatrixParams(keyValueMap, matrixString) {
  if (matrixString[0] == ';') {
    matrixString = matrixString.substring(1);
  }

  matrixString.split(';').forEach((entry) => {
    var tuple = entry.split('=');
    var key = tuple[0];
    var value = tuple.length > 1 ? tuple[1] : true;
    keyValueMap[key] = value;
  });
}

class ContinuationSegment extends Segment {}

class StaticSegment extends Segment {
  regex: string;
  name: string = '';

  constructor(public string: string) {
    super();
    this.regex = escapeRegex(string);

    // we add this property so that the route matcher still sees
    // this segment as a valid path even if do not use the matrix
    // parameters
    this.regex += '(;[^\/]+)?';
  }

  generate(params: TouchMap): string { return this.string; }
}

@IMPLEMENTS(Segment)
class DynamicSegment {
  regex: string = "([^/]+)";

  constructor(public name: string) {}

  generate(params: TouchMap): string {
    if (!StringMapWrapper.contains(params.map, this.name)) {
      throw new BaseException(
          `Route generator for '${this.name}' was not included in parameters passed.`);
    }
    return normalizeString(params.get(this.name));
  }
}


class StarSegment {
  regex: string = "(.+)";

  constructor(public name: string) {}

  generate(params: TouchMap): string { return normalizeString(params.get(this.name)); }
}


var paramMatcher = /^:([^\/]+)$/g;
var wildcardMatcher = /^\*([^\/]+)$/g;

function parsePathString(route: string): StringMap<string, any> {
  // normalize route as not starting with a "/". Recognition will
  // also normalize.
  if (StringWrapper.startsWith(route, "/")) {
    route = StringWrapper.substring(route, 1);
  }

  var segments = splitBySlash(route);
  var results = [];
  var specificity = 0;

  // The "specificity" of a path is used to determine which route is used when multiple routes match
  // a URL.
  // Static segments (like "/foo") are the most specific, followed by dynamic segments (like
  // "/:id"). Star segments
  // add no specificity. Segments at the start of the path are more specific than proceeding ones.
  // The code below uses place values to combine the different types of segments into a single
  // integer that we can
  // sort later. Each static segment is worth hundreds of points of specificity (10000, 9900, ...,
  // 200), and each
  // dynamic segment is worth single points of specificity (100, 99, ... 2).
  if (segments.length > 98) {
    throw new BaseException(`'${route}' has more than the maximum supported number of segments.`);
  }

  var limit = segments.length - 1;
  for (var i = 0; i <= limit; i++) {
    var segment = segments[i], match;

    if (isPresent(match = RegExpWrapper.firstMatch(paramMatcher, segment))) {
      results.push(new DynamicSegment(match[1]));
      specificity += (100 - i);
    } else if (isPresent(match = RegExpWrapper.firstMatch(wildcardMatcher, segment))) {
      results.push(new StarSegment(match[1]));
    } else if (segment == '...') {
      if (i < limit) {
        // TODO (matsko): setup a proper error here `
        throw new BaseException(`Unexpected "..." before the end of the path for "${route}".`);
      }
      results.push(new ContinuationSegment());
    } else if (segment.length > 0) {
      results.push(new StaticSegment(segment));
      specificity += 100 * (100 - i);
    }
  }
  var result = StringMapWrapper.create();
  StringMapWrapper.set(result, 'segments', results);
  StringMapWrapper.set(result, 'specificity', specificity);
  return result;
}

function splitBySlash(url: string): List<string> {
  return url.split('/');
}

var RESERVED_CHARS = RegExpWrapper.create('//|\\(|\\)|;|\\?|=');
function assertPath(path: string) {
  if (StringWrapper.contains(path, '#')) {
    throw new BaseException(
        `Path "${path}" should not include "#". Use "HashLocationStrategy" instead.`);
  }
  var illegalCharacter = RegExpWrapper.firstMatch(RESERVED_CHARS, path);
  if (isPresent(illegalCharacter)) {
    throw new BaseException(
        `Path "${path}" contains "${illegalCharacter[0]}" which is not allowed in a route config.`);
  }
}

// represents something like '/foo/:bar'
export class PathRecognizer {
  segments: List<Segment>;
  regex: RegExp;
  specificity: number;
  terminal: boolean = true;

  constructor(public path: string, public handler: RouteHandler) {
    assertPath(path);
    var parsed = parsePathString(path);
    var specificity = parsed['specificity'];
    var segments = parsed['segments'];
    var regexString = '^';

    ListWrapper.forEach(segments, (segment) => {
      if (segment instanceof ContinuationSegment) {
        this.terminal = false;
      } else {
        regexString += '/' + segment.regex;
      }
    });

    if (this.terminal) {
      regexString += '$';
    }

    this.regex = RegExpWrapper.create(regexString);
    this.segments = segments;
    this.specificity = specificity;
  }

  parseParams(url: string): StringMap<string, string> {
    // the last segment is always the star one since it's terminal
    var segmentsLimit = this.segments.length - 1;
    var containsStarSegment =
        segmentsLimit >= 0 && this.segments[segmentsLimit] instanceof StarSegment;

    var matrixString;
    if (!containsStarSegment) {
      var matches =
          RegExpWrapper.firstMatch(RegExpWrapper.create('^(.*\/[^\/]+?)(;[^\/]+)?\/?$'), url);
      if (isPresent(matches)) {
        url = matches[1];
        matrixString = matches[2];
      }

      url = StringWrapper.replaceAll(url, /(;[^\/]+)(?=(\/|\Z))/g, '');
    }

    var params = StringMapWrapper.create();
    var urlPart = url;

    for (var i = 0; i <= segmentsLimit; i++) {
      var segment = this.segments[i];
      if (segment instanceof ContinuationSegment) {
        continue;
      }

      var match = RegExpWrapper.firstMatch(RegExpWrapper.create('/' + segment.regex), urlPart);
      urlPart = StringWrapper.substring(urlPart, match[0].length);
      if (segment.name.length > 0) {
        params[segment.name] = match[1];
      }
    }

    if (isPresent(matrixString) && matrixString.length > 0 && matrixString[0] == ';') {
      parseAndAssignMatrixParams(params, matrixString);
    }

    return params;
  }

  generate(params: StringMap<string, any>): string {
    var paramTokens = new TouchMap(params);
    var applyLeadingSlash = false;

    var url = '';
    for (var i = 0; i < this.segments.length; i++) {
      let segment = this.segments[i];
      let s = segment.generate(paramTokens);
      applyLeadingSlash = applyLeadingSlash || (segment instanceof ContinuationSegment);

      if (s.length > 0) {
        url += (i > 0 ? '/' : '') + s;
      }
    }

    var unusedParams = paramTokens.getUnused();
    StringMapWrapper.forEach(unusedParams, (value, key) => {
      url += ';' + key;
      if (isPresent(value)) {
        url += '=' + value;
      }
    });

    if (applyLeadingSlash) {
      url += '/';
    }

    return url;
  }

  resolveComponentType(): Promise<any> { return this.handler.resolveComponentType(); }
}