/*
 * Copyright 2010 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.jstestdriver.requesthandlers;

import static com.google.jstestdriver.requesthandlers.HttpMethod.ANY;

import com.google.common.base.Objects;

/**
 * A matcher that matches prefix, suffix and literal servlet path-specs.
 *
 * e.g. "*.mp3", "/root/*" or "/javascript/source.js"
 *
 * Modelled after UriPatternMatcher in Guice Servlets.
 *
 * @author rdionne@google.com (Robert Dionne)
 */
class RequestMatcher {

  private final HttpMethod method;
  private final String pattern;
  private final Kind kind;

  private enum Kind { PREFIX, SUFFIX, LITERAL }

  public RequestMatcher(HttpMethod method, String pattern) {
    this.method = method;
    if (pattern.startsWith("*")) {
      this.pattern = pattern.substring(1);
      this.kind = Kind.PREFIX;
    } else if (pattern.endsWith("*")) {
      this.pattern = pattern.substring(0, pattern.length() - 1);
      this.kind = Kind.SUFFIX;
    } else {
      this.pattern = pattern;
      this.kind = Kind.LITERAL;
    }
  }

  /**
   * @return true iff {@code this.method == method}
   * @param method the {@link HttpMethod} of the request
   */
  public boolean methodMatches(HttpMethod method) {
    return this.method.equals(method) || this.method.equals(ANY);
  }

  /**
   * @return true iff the uri matches the pattern
   * 
   * @param uri the URI of the request
   */
  public boolean uriMatches(String uri) {
    if (uri == null) {
      return false;
    }
    switch (kind) {
      case PREFIX:
        return uri.endsWith(pattern);
      case SUFFIX:
        return uri.startsWith(pattern);
      default:
        return uri.equals(pattern);
    }
  }

  public String getPrefix() {
    return kind == Kind.PREFIX ? "" : pattern;
  }

  @Override
  public int hashCode() {
    return Objects.hashCode(method, pattern, kind);
  }

  @Override
  public boolean equals(Object other) {
    if (this == other) {
      return true;
    }

    if (!(other instanceof RequestMatcher)) {
      return false;
    }

    RequestMatcher that = (RequestMatcher) other;

    return this.method.equals(that.method)
        && this.pattern.equals(that.pattern)
        && this.kind.equals(that.kind);
  }

  @Override
  public String toString() {
    return "RequestMatcher [kind=" + kind + ", method=" + method + ", pattern="
        + pattern + "]";
  }
}