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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 ratpack.path;

import ratpack.path.internal.DefaultPathBinderBuilder;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public abstract class PathBinders {

  private static final Pattern PLACEHOLDER = Pattern.compile("((?:^|/):(\\w+)\\??:([^/])+)|((?:^|/)::([^/])+)|((?:^|/):(\\w+)\\??)");

  private PathBinders() {

  }

  public static PathBinder parse(String path, boolean exact) {
    PathBinderBuilder pathBinderBuilder = new DefaultPathBinderBuilder();

    Matcher matchResult = PLACEHOLDER.matcher(path);

    int lastIndex = 0;

    if (matchResult.find()) {
      do {
        int thisIndex = matchResult.start();
        if (thisIndex != lastIndex) {
          pathBinderBuilder.literal(path.substring(lastIndex, thisIndex));
        }
        lastIndex = matchResult.end();
        String component = matchResult.group(0);
        boolean found = false;
        for (TokenType type : TokenType.values()) {
          if (type.match(component, pathBinderBuilder)) {
            found = true;
            break;
          }
        }
        if (!found) {
          throw new IllegalArgumentException(String.format("Cannot match path %s (%s)", path, component));
        }
      } while (matchResult.find());
      if (lastIndex < path.length()) {
        pathBinderBuilder.literal(path.substring(lastIndex));
      }
    } else {
      pathBinderBuilder.literal(path);
    }
    return pathBinderBuilder.build(exact);
  }

  public static PathBinderBuilder builder() {
    return new DefaultPathBinderBuilder();
  }

  private enum TokenType implements TokenProcessor {
    OPTIONAL_TOKEN_WITH_PATTERN("/?:(\\w*)\\?:(.+)") {
      public void process(Matcher matcher, PathBinderBuilder builder) {
        builder.optionalTokenWithPattern(matcher.group(1), matcher.group(2));
      }
    },
    LITERAL_WITH_PATTERN("/?::(.+)") {
      public void process(Matcher matcher, PathBinderBuilder builder) {
        builder.literalPattern(matcher.group(1));
      }
    },
    TOKEN_WITH_PATTERN("/?:(\\w*):(.+)") {
      public void process(Matcher matcher, PathBinderBuilder builder) {
        builder.tokenWithPattern(matcher.group(1), matcher.group(2));
      }
    },
    TOKEN("/?:(\\w*)") {
      public void process(Matcher matcher, PathBinderBuilder builder) {
        builder.token(matcher.group(1));
      }
    },
    OPTIONAL_TOKEN("/?:(\\w*)\\?") {
      public void process(Matcher matcher, PathBinderBuilder builder) {
        builder.optionalToken(matcher.group(1));
      }
    };

    boolean match(String component, PathBinderBuilder builder) {
      Matcher matcher = pattern.matcher(component);
      if (matcher.matches()) {
        process(matcher, builder);
        return true;
      }
      return false;
    }

    private Pattern pattern;

    TokenType(String pattern) {
      this.pattern = Pattern.compile(pattern);
    }
  }

  private interface TokenProcessor {
    void process(Matcher matcher, PathBinderBuilder builder);
  }
}