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package org.apache.juneau.rest;

import static org.apache.juneau.internal.StringUtils.*;

import java.lang.reflect.*;
import java.util.*;

import javax.servlet.http.*;

import org.apache.juneau.*;
import org.apache.juneau.httppart.*;
import org.apache.juneau.oapi.*;
import org.apache.juneau.parser.*;
import org.apache.juneau.http.exception.*;

/**
 * Contains information about the matched path on the HTTP request.
 *
 * <p>
 * Provides access to the matched path variables and path match remainder.
 *
 * <ul class='seealso'>
 * 	<li class='link'>{@doc juneau-rest-server.RestMethod.RequestPathMatch}
 * </ul>
 */
public class RequestPath extends TreeMap<String,String> {
	private static final long serialVersionUID = 1L;

	/**
	 * Request attribute name for passing path variables from parent to child.
	 */
	static final String REST_PATHVARS_ATTR = "juneau.pathVars";

	private final RestRequest req;
	private HttpPartParser parser;

	RequestPath(RestRequest req) {
		super(String.CASE_INSENSITIVE_ORDER);
		this.req = req;
		@SuppressWarnings("unchecked")
		Map<String,String> parentVars = (Map<String,String>)req.getAttribute(REST_PATHVARS_ATTR);
		if (parentVars != null)
			for (Map.Entry<String,String> e : parentVars.entrySet())
				put(e.getKey(), e.getValue());
	}

	RequestPath parser(HttpPartParser parser) {
		this.parser = parser;
		return this;
	}

	RequestPath remainder(String remainder) {
		put("/**", remainder);
		put("/*", urlDecode(remainder));
		return this;
	}

	/**
	 * Sets a request query parameter value.
	 *
	 * @param name The parameter name.
	 * @param value The parameter value.
	 */
	public void put(String name, Object value) {
		super.put(name, value.toString());
	}

	/**
	 * Returns the specified path parameter converted to a String.
	 *
	 * @param name The path variable name.
	 * @return The parameter value.
	 * @throws BadRequest Thrown if input could not be parsed.
	 * @throws InternalServerError Thrown if any other exception occurs.
	 */
	public String getString(String name) throws BadRequest, InternalServerError {
		return getInner(parser, null, name, null, req.getBeanSession().string());
	}

	/**
	 * Returns the specified path parameter converted to an integer.
	 *
	 * @param name The path variable name.
	 * @return The parameter value.
	 * @throws BadRequest Thrown if input could not be parsed.
	 * @throws InternalServerError Thrown if any other exception occurs.
	 */
	public int getInt(String name) throws BadRequest, InternalServerError {
		return getInner(parser, null, name, null, getClassMeta(int.class));
	}

	/**
	 * Returns the specified path parameter converted to a boolean.
	 *
	 * @param name The path variable name.
	 * @return The parameter value.
	 * @throws BadRequest Thrown if input could not be parsed.
	 * @throws InternalServerError Thrown if any other exception occurs.
	 */
	public boolean getBoolean(String name) throws BadRequest, InternalServerError {
		return getInner(null, null, name, null, getClassMeta(boolean.class));
	}

	/**
	 * Returns the specified path parameter value converted to a POJO using the {@link HttpPartParser} registered with the resource.
	 *
	 * <h5 class='section'>Examples:</h5>
	 * <p class='bcode w800'>
	 * 	<jc>// Parse into an integer.</jc>
	 * 	<jk>int</jk> myparam = path.get(<js>"myparam"</js>, <jk>int</jk>.<jk>class</jk>);
	 *
	 * 	<jc>// Parse into an int array.</jc>
	 * 	<jk>int</jk>[] myparam = path.get(<js>"myparam"</js>, <jk>int</jk>[].<jk>class</jk>);

	 * 	<jc>// Parse into a bean.</jc>
	 * 	MyBean myparam = path.get(<js>"myparam"</js>, MyBean.<jk>class</jk>);
	 *
	 * 	<jc>// Parse into a linked-list of objects.</jc>
	 * 	List myparam = path.get(<js>"myparam"</js>, LinkedList.<jk>class</jk>);
	 *
	 * 	<jc>// Parse into a map of object keys/values.</jc>
	 * 	Map myparam = path.get(<js>"myparam"</js>, TreeMap.<jk>class</jk>);
	 * </p>
	 *
	 * <ul class='seealso'>
	 * 	<li class='jf'>{@link RestContext#REST_partParser}
	 * </ul>
	 *
	 * @param name The attribute name.
	 * @param type The class type to convert the attribute value to.
	 * @param <T> The class type to convert the attribute value to.
	 * @return The attribute value converted to the specified class type.
	 * @throws BadRequest Thrown if input could not be parsed.
	 * @throws InternalServerError Thrown if any other exception occurs.
	 */
	public <T> T get(String name, Class<T> type) throws BadRequest, InternalServerError {
		return getInner(null, null, name, null, this.<T>getClassMeta(type));
	}

	/**
	 * Same as {@link #get(String, Class)} but allows you to override the part parser.
	 *
	 * @param parser
	 * 	The parser to use for parsing the string value.
	 * 	<br>If <jk>null</jk>, uses the part parser defined on the resource/method.
	 * @param schema
	 * 	The schema object that defines the format of the input.
	 * 	<br>If <jk>null</jk>, defaults to the schema defined on the parser.
	 * 	<br>If that's also <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
	 * 	<br>Only used if parser is schema-aware (e.g. {@link OpenApiParser}).
	 * @param name The attribute name.
	 * @param type The class type to convert the attribute value to.
	 * @param <T> The class type to convert the attribute value to.
	 * @return The attribute value converted to the specified class type.
	 * @throws BadRequest Thrown if input could not be parsed or fails schema validation.
	 * @throws InternalServerError Thrown if any other exception occurs.
	 */
	public <T> T get(HttpPartParser parser, HttpPartSchema schema, String name, Class<T> type) throws BadRequest, InternalServerError {
		return getInner(parser, schema, name, null, this.<T>getClassMeta(type));
	}

	/**
	 * Returns the specified query parameter value converted to a POJO using the {@link HttpPartParser} registered with the resource.
	 *
	 * <p>
	 * Similar to {@link #get(String,Class)} but allows for complex collections of POJOs to be created.
	 *
	 * <p>
	 * Use this method if you want to parse into a parameterized <c>Map</c>/<c>Collection</c> object.
	 *
	 * <h5 class='section'>Examples:</h5>
	 * <p class='bcode w800'>
	 * 	<jc>// Parse into a linked-list of strings.</jc>
	 * 	List&lt;String&gt; myparam = req.getPathParameter(<js>"myparam"</js>, LinkedList.<jk>class</jk>, String.<jk>class</jk>);
	 *
	 * 	<jc>// Parse into a linked-list of linked-lists of strings.</jc>
	 * 	List&lt;List&lt;String&gt;&gt; myparam = req.getPathParameter(<js>"myparam"</js>, LinkedList.<jk>class</jk>, LinkedList.<jk>class</jk>, String.<jk>class</jk>);
	 *
	 * 	<jc>// Parse into a map of string keys/values.</jc>
	 * 	Map&lt;String,String&gt; myparam = req.getPathParameter(<js>"myparam"</js>, TreeMap.<jk>class</jk>, String.<jk>class</jk>, String.<jk>class</jk>);
	 *
	 * 	<jc>// Parse into a map containing string keys and values of lists containing beans.</jc>
	 * 	Map&lt;String,List&lt;MyBean&gt;&gt; myparam = req.getPathParameter(<js>"myparam"</js>, TreeMap.<jk>class</jk>, String.<jk>class</jk>, List.<jk>class</jk>, MyBean.<jk>class</jk>);
	 * </p>
	 *
	 * <ul class='notes'>
	 * 	<li>
	 * 		<c>Collections</c> must be followed by zero or one parameter representing the value type.
	 * 	<li>
	 * 		<c>Maps</c> must be followed by zero or two parameters representing the key and value types.
	 * </ul>
	 *
	 * <ul class='seealso'>
	 * 	<li class='jf'>{@link RestContext#REST_partParser}
	 * </ul>
	 *
	 * @param name The attribute name.
	 * @param type
	 * 	The type of object to create.
	 * 	<br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
	 * @param args
	 * 	The type arguments of the class if it's a collection or map.
	 * 	<br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
	 * 	<br>Ignored if the main type is not a map or collection.
	 * @param <T> The class type to convert the attribute value to.
	 * @return The attribute value converted to the specified class type.
	 * @throws BadRequest Thrown if input could not be parsed.
	 * @throws InternalServerError Thrown if any other exception occurs.
	 */
	public <T> T get(String name, Type type, Type...args) throws BadRequest, InternalServerError {
		return getInner(null, null, name, null, this.<T>getClassMeta(type, args));
	}

	/**
	 * Same as {@link #get(String, Type, Type...)} but allows you to override the part parser.
	 *
	 * @param parser
	 * 	The parser to use for parsing the string value.
	 * 	<br>If <jk>null</jk>, uses the part parser defined on the resource/method.
	 * @param schema
	 * 	The schema object that defines the format of the input.
	 * 	<br>If <jk>null</jk>, defaults to the schema defined on the parser.
	 * 	<br>If that's also <jk>null</jk>, defaults to {@link HttpPartSchema#DEFAULT}.
	 * 	<br>Only used if parser is schema-aware (e.g. {@link OpenApiParser}).
	 * @param name The attribute name.
	 * @param type
	 * 	The type of object to create.
	 * 	<br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
	 * @param args
	 * 	The type arguments of the class if it's a collection or map.
	 * 	<br>Can be any of the following: {@link ClassMeta}, {@link Class}, {@link ParameterizedType}, {@link GenericArrayType}
	 * 	<br>Ignored if the main type is not a map or collection.
	 * @param <T> The class type to convert the attribute value to.
	 * @return The attribute value converted to the specified class type.
	 * @throws BadRequest Thrown if input could not be parsed or fails schema validation.
	 * @throws InternalServerError Thrown if any other exception occurs.
	 */
	public <T> T get(HttpPartParser parser, HttpPartSchema schema, String name, Type type, Type...args) throws BadRequest, InternalServerError {
		return getInner(parser, schema, name, null, this.<T>getClassMeta(type, args));
	}

	/* Workhorse method */
	private <T> T getInner(HttpPartParser parser, HttpPartSchema schema, String name, T def, ClassMeta<T> cm) throws BadRequest, InternalServerError {
		try {
			if (cm.isMapOrBean() && isOneOf(name, "*", "")) {
				ObjectMap m = new ObjectMap();
				for (Map.Entry<String,String> e : this.entrySet()) {
					String k = e.getKey();
					HttpPartSchema pschema = schema == null ? null : schema.getProperty(k);
					ClassMeta<?> cm2 = cm.getValueType();
					m.put(k, getInner(parser, pschema, k, null, cm2));
				}
				return req.getBeanSession().convertToType(m, cm);
			}
			T t = parse(parser, schema, get(name), cm);
			return (t == null ? def : t);
		} catch (SchemaValidationException e) {
			throw new BadRequest(e, "Validation failed on path parameter ''{0}''. ", name);
		} catch (ParseException e) {
			throw new BadRequest(e, "Could not parse path parameter ''{0}''.", name) ;
		} catch (Exception e) {
			throw new InternalServerError(e, "Could not parse path parameter ''{0}''.", name) ;
		}
	}

	/* Workhorse method */
	private <T> T parse(HttpPartParser parser, HttpPartSchema schema, String val, ClassMeta<T> cm) throws SchemaValidationException, ParseException {
		if (parser == null)
			parser = this.parser;
		return parser.createPartSession(req.getParserSessionArgs()).parse(HttpPartType.PATH, schema, val, cm);
	}

	/**
	 * Returns the decoded remainder of the URL following any path pattern matches.
	 *
	 * <p>
	 * The behavior of path remainder is shown below given the path pattern "/foo/*":
	 * <table class='styled'>
	 * 	<tr>
	 * 		<th>URL</th>
	 * 		<th>Path Remainder</th>
	 * 	</tr>
	 * 	<tr>
	 * 		<td><c>/foo</c></td>
	 * 		<td><jk>null</jk></td>
	 * 	</tr>
	 * 	<tr>
	 * 		<td><c>/foo/</c></td>
	 * 		<td><js>""</js></td>
	 * 	</tr>
	 * 	<tr>
	 * 		<td><c>/foo//</c></td>
	 * 		<td><js>"/"</js></td>
	 * 	</tr>
	 * 	<tr>
	 * 		<td><c>/foo///</c></td>
	 * 		<td><js>"//"</js></td>
	 * 	</tr>
	 * 	<tr>
	 * 		<td><c>/foo/a/b</c></td>
	 * 		<td><js>"a/b"</js></td>
	 * 	</tr>
	 * 	<tr>
	 * 		<td><c>/foo//a/b/</c></td>
	 * 		<td><js>"/a/b/"</js></td>
	 * 	</tr>
	 * 	<tr>
	 * 		<td><c>/foo/a%2Fb</c></td>
	 * 		<td><js>"a/b"</js></td>
	 * 	</tr>
	 * </table>
	 *
	 * <h5 class='section'>Example:</h5>
	 * <p class='bcode w800'>
	 * 	<jc>// REST method</jc>
	 * 	<ja>@RestMethod</ja>(name=<jsf>GET</jsf>,path=<js>"/foo/{bar}/*"</js>)
	 * 	<jk>public</jk> String doGetById(RequestPathMatch path, <jk>int</jk> bar) {
	 * 		<jk>return</jk> path.getRemainder();
	 * 	}
	 * </p>
	 *
	 * <p>
	 * The remainder can also be retrieved by calling <code>get(<js>"/*"</js>)</code>.
	 *
	 * @return The path remainder string.
	 */
	public String getRemainder() {
		return get("/*");
	}

	/**
	 * Same as {@link #getRemainder()} but doesn't decode characters.
	 *
	 * <p>
	 * The undecoded remainder can also be retrieved by calling <code>get(<js>"/**"</js>)</code>.
	 *
	 * @return The un-decoded path remainder.
	 */
	public String getRemainderUndecoded() {
		return get("/**");
	}

	//-----------------------------------------------------------------------------------------------------------------
	// Helper methods
	//-----------------------------------------------------------------------------------------------------------------

	private <T> ClassMeta<T> getClassMeta(Type type, Type...args) {
		return req.getBeanSession().getClassMeta(type, args);
	}

	private <T> ClassMeta<T> getClassMeta(Class<T> type) {
		return req.getBeanSession().getClassMeta(type);
	}

	//------------------------------------------------------------------------------------------------------------------
	// Static utility methods.
	//------------------------------------------------------------------------------------------------------------------

	/**
	 * Utility method that adds path variables to the specified request.
	 */
	@SuppressWarnings("unchecked")
	static HttpServletRequest addPathVars(HttpServletRequest req, Map<String,String> vars) {
		if (vars != null && ! vars.isEmpty()) {
			Map<String,String> m = (Map<String,String>)req.getAttribute(REST_PATHVARS_ATTR);
			if (m == null) {
				m = new TreeMap<>();
				req.setAttribute(REST_PATHVARS_ATTR, m);
			}
			m.putAll(vars);
		}
		return req;
	}
}