/* (c) 2017 Open Source Geospatial Foundation - all rights reserved
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.rest;

import freemarker.template.SimpleHash;
import org.geoserver.rest.wrapper.RestWrapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

import java.util.*;

/**
 * The IndexController lists the paths available for the Spring MVC ReuestMappingHandler
 * Specifically, it auto-generates an index page containing all non-templated paths relative to the router root.
 *
 */
@RestController
@RequestMapping(path = RestBaseController.ROOT_PATH, produces = {
        MediaType.APPLICATION_JSON_VALUE,
        MediaType.APPLICATION_XML_VALUE,
        MediaType.TEXT_HTML_VALUE})
public class IndexController extends RestBaseController {

    @Autowired
    private RequestMappingHandlerMapping requestMappingHandlerMapping;

    @GetMapping(value = {"", "index"}, produces = {MediaType.TEXT_HTML_VALUE})
    public RestWrapper get() {

        SimpleHash model = new SimpleHash();
        model.put("links", getLinks());
        model.put("page", RequestInfo.get());

        return wrapObject(model, SimpleHash.class);
    }

    private Set<String> getLinks() {
        final int rootSize = RestBaseController.ROOT_PATH.length()+1;
        //Ensure sorted, unique keys
        Set<String> s = new TreeSet<>();

        Map<RequestMappingInfo, HandlerMethod> handlerMethods =
                this.requestMappingHandlerMapping.getHandlerMethods();

        for(Map.Entry<RequestMappingInfo, HandlerMethod> item : handlerMethods.entrySet()) {
            RequestMappingInfo mapping = item.getKey();

            //Only list "get" endpoints
            if (mapping.getMethodsCondition().getMethods().contains(RequestMethod.GET)) {
                for (String pattern : mapping.getPatternsCondition().getPatterns()) {
                    if (!pattern.contains("{") && (pattern.length() > rootSize)) {
                        //trim root path
                        String path = pattern.substring(rootSize);
                        if (path.endsWith("/**")) {
                            path = path.substring(0, path.length()-3);
                        }
                        s.add(path);
                    }
                }
            }
        }
        return s;
    }

    @Override
    public String getTemplateName(Object o) {
        return "index";
    }
}