/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.juneau;
  
  import static org.apache.juneau.commons.utils.CollectionUtils.*;
  import static org.apache.juneau.commons.utils.StringUtils.*;
  import static org.apache.juneau.commons.utils.ThrowableUtils.*;
  import static org.apache.juneau.commons.utils.Utils.*;
  
  import java.util.function.Supplier;
  
  import org.apache.juneau.annotation.*;
  import org.apache.juneau.collections.*;
  import org.apache.juneau.commons.collections.*;
  import org.apache.juneau.parser.*;
  
  /**
   * Represents a URL broken into authority/context-root/servlet-path/path-info parts.
   *
   * <p>
   * A typical request against a URL takes the following form:
   * <p class='bcode'>
   * 	http://host:port/context-root/servlet-path/path-info
   * 	|   authority   |  context   |  resource  |  path  |
   * 	+--------------------------------------------------+
   * </p>
   *
   * <p>
   * This class allows you to convert URL strings to absolute (e.g. <js>"http://host:port/foo/bar"</js>) or root-relative
   * (e.g. <js>"/foo/bar"</js>) URLs.
   *
   */
  @Bean
  public class UriContext {
  
  	/**
  	 * Default URI context.
  	 *
  	 * <p>
  	 * No information about authority, servlet-root, context-root, or path-info is known.
  	 */
  	public static final UriContext DEFAULT = new UriContext();
  
  	/**
  	 * Static creator.
  	 *
  	 * @param s
  	 * 	The input string.
  	 * 	<br>Example: <js>{authority:'http://localhost:10000',contextRoot:'/myContext',servletPath:'/myServlet',pathInfo:'/foo'}</js>
  	 * @return A new {@link UriContext} object.
  	 */
  	public static UriContext of(String s) {
  		try {
  			return new UriContext(s);
  		} catch (ParseException e) {
  			throw toRex(e);
  		}
  	}
  
  	/**
  	 * Static creator.
  	 *
  	 * @param authority
  	 * 	The authority portion of URL (e.g. <js>"http://hostname:port"</js>)
  	 * @param contextRoot
  	 * 	The context root of the application (e.g. <js>"/context-root"</js>, or <js>"context-root"</js>)
  	 * @param servletPath
  	 * 	The servlet path (e.g. <js>"/servlet-path"</js>, or <js>"servlet-path"</js>)
  	 * @param pathInfo
  	 * 	The path info (e.g. <js>"/path-info"</js>, or <js>"path-info"</js>)
  	 * @return A new {@link UriContext} object.
  	 */
  	public static UriContext of(String authority, String contextRoot, String servletPath, String pathInfo) {
  		return new UriContext(authority, contextRoot, servletPath, pathInfo);
  	}
  
  	private static String getParent(String uri) {
  		var i = uri.lastIndexOf('/');
  		if (i <= 1)
  			return "/";
  		return uri.substring(0, i);
  	}
  
  	@SuppressWarnings("javadoc")
  	public final String authority, contextRoot, servletPath, pathInfo, parentPath;
 
 	// Memoized suppliers.
 	private final Supplier<String> aContextRoot, rContextRoot, aServletPath, rResource, aPathInfo, rPath;
 
 	/**
 	 * Default constructor.
 	 *
 	 * <p>
 	 * All <jk>null</jk> values.
 	 */
 	public UriContext() {
 		this(null, null, null, null);
 	}
 
 	/**
 	 * String constructor.
 	 *
 	 * <p>
 	 * Input string is a JSON object with the following format:
 	 * <js>{authority:'xxx',contextRoot:'xxx',servletPath:'xxx',pathInfo:'xxx'}</js>
 	 *
 	 * @param s
 	 * 	The input string.
 	 * 	<br>Example: <js>{authority:'http://localhost:10000',contextRoot:'/myContext',servletPath:'/myServlet',pathInfo:'/foo'}</js>
 	 * @throws ParseException
 	 * 	If input string is not a valid JSON object.
 	 */
 	public UriContext(String s) throws ParseException {
 		var m = JsonMap.ofJson(s);
 		this.authority = nullIfEmpty(trimSlashes(m.getString("authority")));
 		this.contextRoot = nullIfEmpty(trimSlashes(m.getString("contextRoot")));
 		this.servletPath = nullIfEmpty(trimSlashes(m.getString("servletPath")));
 		this.pathInfo = nullIfEmpty(trimSlashes(m.getString("pathInfo")));
 		this.parentPath = this.pathInfo == null || this.pathInfo.indexOf('/') == -1 ? null : this.pathInfo.substring(0, this.pathInfo.lastIndexOf('/'));
 		this.rContextRoot = mem(() -> findRContextRoot());
 		this.rResource = mem(() -> findRResource());
 		this.rPath = mem(() -> findRPath());
 		this.aContextRoot = mem(() -> findAContextRoot());
 		this.aServletPath = mem(() -> findAServletPath());
 		this.aPathInfo = mem(() -> findAPathInfo());
 	}
 
 	/**
 	 * Constructor.
 	 *
 	 * <p>
 	 * Leading and trailing slashes are trimmed of all parameters.
 	 *
 	 * <p>
 	 * Any parameter can be <jk>null</jk>.  Blanks and nulls are equivalent.
 	 *
 	 * @param authority
 	 * 	The authority portion of URL (e.g. <js>"http://hostname:port"</js>)
 	 * @param contextRoot
 	 * 	The context root of the application (e.g. <js>"/context-root"</js>, or <js>"context-root"</js>)
 	 * @param servletPath
 	 * 	The servlet path (e.g. <js>"/servlet-path"</js>, or <js>"servlet-path"</js>)
 	 * @param pathInfo
 	 * 	The path info (e.g. <js>"/path-info"</js>, or <js>"path-info"</js>)
 	 */
 	@Beanc
 	public UriContext(@Name("authority") String authority, @Name("contextRoot") String contextRoot, @Name("servletPath") String servletPath, @Name("pathInfo") String pathInfo) {
 		this.authority = nullIfEmpty(trimSlashes(authority));
 		this.contextRoot = nullIfEmpty(trimSlashes(contextRoot));
 		this.servletPath = nullIfEmpty(trimSlashes(servletPath));
 		this.pathInfo = nullIfEmpty(trimSlashes(pathInfo));
 		this.parentPath = this.pathInfo == null || this.pathInfo.indexOf('/') == -1 ? null : this.pathInfo.substring(0, this.pathInfo.lastIndexOf('/'));
 		this.rContextRoot = mem(() -> findRContextRoot());
 		this.rResource = mem(() -> findRResource());
 		this.rPath = mem(() -> findRPath());
 		this.aContextRoot = mem(() -> findAContextRoot());
 		this.aServletPath = mem(() -> findAServletPath());
 		this.aPathInfo = mem(() -> findAPathInfo());
 	}
 
 	private String findRContextRoot() {
 		return contextRoot == null ? "/" : ('/' + contextRoot);
 	}
 
 	private String findRResource() {
 		// @formatter:off
 		if (contextRoot == null)
 			return (
 				servletPath == null
 				? "/"
 				: ('/' + servletPath)
 			);
 		return (
 			servletPath == null
 			? ('/' + contextRoot)
 			: ('/' + contextRoot + '/' + servletPath)
 		);
 		// @formatter:on
 	}
 
 	private String findRPath() {
 		// @formatter:off
 		if (contextRoot == null) {
 			if (servletPath == null)
 				return (
 					pathInfo == null
 					? "/"
 					: ('/' + pathInfo)
 				);
 			return (
 				pathInfo == null
 				? ('/' + servletPath)
 				: ('/' + servletPath + '/' + pathInfo)
 			);
 		}
 		if (servletPath == null)
 			return (
 				pathInfo == null
 				? ('/' + contextRoot)
 				: ('/' + contextRoot + '/' + pathInfo)
 			);
 		return (
 			pathInfo == null
 			? ('/' + contextRoot + '/' + servletPath)
 			: ('/' + contextRoot + '/' + servletPath + '/' + pathInfo)
 		);
 		// @formatter:on
 	}
 
 	private String findAContextRoot() {
 		// @formatter:off
 		if (authority == null)
 			return rContextRoot.get();
 		return (
 			contextRoot == null
 			? authority
 			: (authority + '/' + contextRoot)
 		);
 		// @formatter:on
 	}
 
 	private String findAServletPath() {
 		// @formatter:off
 		if (authority == null)
 			return rResource.get();
 		if (contextRoot == null)
 			return (
 				servletPath == null
 				? authority
 				: authority + '/' + servletPath
 			);
 		return (
 			servletPath == null
 			? (authority + '/' + contextRoot)
 			: (authority + '/' + contextRoot + '/' + servletPath)
 		);
 		// @formatter:on
 	}
 
 	private String findAPathInfo() {
 		// @formatter:off
 		if (authority == null)
 			return rPath.get();
 		if (contextRoot == null) {
 			if (servletPath == null)
 				return (
 					pathInfo == null
 					? authority : (authority + '/' + pathInfo)
 				);
 			return (
 				pathInfo == null
 				? (authority + '/' + servletPath)
 				: (authority + '/' + servletPath + '/' + pathInfo)
 			);
 		}
 		if (servletPath == null)
 			return (
 				pathInfo == null
 				? authority + '/' + contextRoot
 				: (authority + '/' + contextRoot + '/' + pathInfo)
 			);
 		return (
 			pathInfo == null
 			? (authority + '/' + contextRoot + '/' + servletPath)
 			: (authority + '/' + contextRoot + '/' + servletPath + '/' + pathInfo)
 		);
 		// @formatter:on
 	}
 
 	/**
 	 * Returns the absolute URI of just the authority portion of this URI context.
 	 *
 	 * <p>
 	 * Example:  <js>"http://hostname:port"</js>
 	 *
 	 * <p>
 	 * If the authority is null/empty, returns <js>"/"</js>.
 	 *
 	 * @return
 	 * 	The absolute URI of just the authority portion of this URI context.
 	 * 	Never <jk>null</jk>.
 	 */
 	public String getAbsoluteAuthority() { return authority == null ? "/" : authority; }
 
 	/**
 	 * Returns the absolute URI of the context-root portion of this URI context.
 	 *
 	 * <p>
 	 * Example:  <js>"http://hostname:port/context-root"</js>
 	 *
 	 * @return
 	 * 	The absolute URI of the context-root portion of this URI context.
 	 * 	Never <jk>null</jk>.
 	 */
 	public String getAbsoluteContextRoot() {
 		return aContextRoot.get();
 	}
 
 	/**
 	 * Returns the absolute URI of the path portion of this URI context.
 	 *
 	 * <p>
 	 * Example:  <js>"http://hostname:port/context-root/servlet-path/path-info"</js>
 	 *
 	 * @return
 	 * 	The absolute URI of the path portion of this URI context.
 	 * 	Never <jk>null</jk>.
 	 */
 	public String getAbsolutePathInfo() {
 		return aPathInfo.get();
 	}
 
 	/**
 	 * Returns the parent of the URL returned by {@link #getAbsolutePathInfo()}.
 	 *
 	 * @return The parent of the URL returned by {@link #getAbsolutePathInfo()}.
 	 */
 	public String getAbsolutePathInfoParent() { return getParent(getAbsolutePathInfo()); }
 
 	/**
 	 * Returns the absolute URI of the resource portion of this URI context.
 	 *
 	 * <p>
 	 * Example:  <js>"http://hostname:port/context-root/servlet-path"</js>
 	 *
 	 * @return
 	 * 	The absolute URI of the resource portion of this URI context.
 	 * 	Never <jk>null</jk>.
 	 */
 	public String getAbsoluteServletPath() {
 		return aServletPath.get();
 	}
 
 	/**
 	 * Returns the parent of the URL returned by {@link #getAbsoluteServletPath()}.
 	 *
 	 * @return The parent of the URL returned by {@link #getAbsoluteServletPath()}.
 	 */
 	public String getAbsoluteServletPathParent() { return getParent(getAbsoluteServletPath()); }
 
 	/**
 	 * Returns the root-relative URI of the context portion of this URI context.
 	 *
 	 * <p>
 	 * Example:  <js>"/context-root"</js>
 	 *
 	 * @return
 	 * 	The root-relative URI of the context portion of this URI context.
 	 * 	Never <jk>null</jk>.
 	 */
 	public String getRootRelativeContextRoot() {
 		return rContextRoot.get();
 	}
 
 	/**
 	 * Returns the root-relative URI of the path portion of this URI context.
 	 *
 	 * <p>
 	 * Example:  <js>"/context-root/servlet-path/path-info"</js>
 	 *
 	 * @return
 	 * 	The root-relative URI of the path portion of this URI context.
 	 * 	Never <jk>null</jk>.
 	 */
 	public String getRootRelativePathInfo() {
 		return rPath.get();
 	}
 
 	/**
 	 * Returns the parent of the URL returned by {@link #getRootRelativePathInfo()}.
 	 *
 	 * @return The parent of the URL returned by {@link #getRootRelativePathInfo()}.
 	 */
 	public String getRootRelativePathInfoParent() { return getParent(getRootRelativePathInfo()); }
 
 	/**
 	 * Returns the root-relative URI of the resource portion of this URI context.
 	 *
 	 * <p>
 	 * Example:  <js>"/context-root/servlet-path"</js>
 	 *
 	 * @return
 	 * 	The root-relative URI of the resource portion of this URI context.
 	 * 	Never <jk>null</jk>.
 	 */
 	public String getRootRelativeServletPath() {
 		return rResource.get();
 	}
 
 	/**
 	 * Returns the parent of the URL returned by {@link #getRootRelativeServletPath()}.
 	 *
 	 * @return The parent of the URL returned by {@link #getRootRelativeServletPath()}.
 	 */
 	public String getRootRelativeServletPathParent() { return getParent(getRootRelativeServletPath()); }
 
 	protected FluentMap<String,Object> properties() {
 		// @formatter:off
 		return filteredBeanPropertyMap()
 			.a("aContextRoot", aContextRoot.get())
 			.a("aPathInfo", aPathInfo.get())
 			.a("aServletPath", aServletPath.get())
 			.a("authority", authority)
 			.a("contextRoot", contextRoot)
 			.a("parentPath", parentPath)
 			.a("pathInfo", pathInfo)
 			.a("rContextRoot", rContextRoot.get())
 			.a("rResource", rResource.get())
 			.a("servletPath", servletPath)
 			.a("rPath", rPath.get());
 		// @formatter:on
 	}
 
 	@Override /* Overridden from Object */
 	public String toString() {
 		return r(properties());
 	}
 }