package org.keycloak.adapters;

import org.jboss.logging.Logger;
import org.keycloak.jose.jws.JWSInput;
import org.keycloak.jose.jws.crypto.RSAProvider;
import org.keycloak.representations.adapters.action.AdminAction;
import org.keycloak.representations.adapters.action.LogoutAction;
import org.keycloak.representations.adapters.action.PushNotBeforeAction;
import org.keycloak.representations.adapters.action.SessionStats;
import org.keycloak.representations.adapters.action.SessionStatsAction;
import org.keycloak.representations.adapters.action.UserStats;
import org.keycloak.representations.adapters.action.UserStatsAction;
import org.keycloak.util.JsonSerialization;
import org.keycloak.util.StreamUtil;

import java.util.HashMap;
import java.util.Map;

/**
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @version $Revision: 1 $
 */
public class PreAuthActionsHandler {

    private static final Logger log = Logger.getLogger(PreAuthActionsHandler.class);

    protected UserSessionManagement userSessionManagement;
    protected KeycloakDeployment deployment;
    protected HttpFacade facade;

    public PreAuthActionsHandler(UserSessionManagement userSessionManagement, KeycloakDeployment deployment, HttpFacade facade) {
        this.userSessionManagement = userSessionManagement;
        this.deployment = deployment;
        this.facade = facade;
    }

    public boolean handleRequest() {
        if (!deployment.isConfigured()) return false;
        String requestUri = facade.getRequest().getURI();
        log.debugv("adminRequest {0}", requestUri);
        if (preflightCors()) {
            return true;
        }
        if (requestUri.endsWith(AdapterConstants.K_LOGOUT)) {
            handleLogout();
            return true;
        } else if (requestUri.endsWith(AdapterConstants.K_PUSH_NOT_BEFORE)) {
            handlePushNotBefore();
            return true;
        } else if (requestUri.endsWith(AdapterConstants.K_GET_SESSION_STATS)) {
            handleGetSessionStats();
            return true;
        }else if (requestUri.endsWith(AdapterConstants.K_GET_USER_STATS)) {
            handleGetUserStats();
            return true;
        }
        return false;
    }

    public boolean preflightCors() {
        log.debugv("checkCorsPreflight {0}", facade.getRequest().getURI());
        if (!facade.getRequest().getMethod().equalsIgnoreCase("OPTIONS")) {
            return false;
        }
        if (facade.getRequest().getHeader(CorsHeaders.ORIGIN) == null) {
            log.debug("checkCorsPreflight: no origin header");
            return false;
        }
        log.debug("Preflight request returning");
        facade.getResponse().setStatus(200);
        String origin = facade.getRequest().getHeader(CorsHeaders.ORIGIN);
        facade.getResponse().setHeader(CorsHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, origin);
        facade.getResponse().setHeader(CorsHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
        String requestMethods = facade.getRequest().getHeader(CorsHeaders.ACCESS_CONTROL_REQUEST_METHOD);
        if (requestMethods != null) {
            if (deployment.getCorsAllowedMethods() != null) {
                requestMethods = deployment.getCorsAllowedMethods();
            }
            facade.getResponse().setHeader(CorsHeaders.ACCESS_CONTROL_ALLOW_METHODS, requestMethods);
        }
        String allowHeaders = facade.getRequest().getHeader(CorsHeaders.ACCESS_CONTROL_REQUEST_HEADERS);
        if (allowHeaders != null) {
            if (deployment.getCorsAllowedHeaders() != null) {
                allowHeaders = deployment.getCorsAllowedHeaders();
            }
            facade.getResponse().setHeader(CorsHeaders.ACCESS_CONTROL_ALLOW_HEADERS, allowHeaders);
        }
        if (deployment.getCorsMaxAge() > -1) {
            facade.getResponse().setHeader(CorsHeaders.ACCESS_CONTROL_MAX_AGE, Integer.toString(deployment.getCorsMaxAge()));
        }
        return true;
    }

    protected void handleLogout()  {
        log.info("K_LOGOUT sent");
        try {
            JWSInput token = verifyAdminRequest();
            if (token == null) {
                return;
            }
            LogoutAction action = JsonSerialization.readValue(token.getContent(), LogoutAction.class);
            if (!validateAction(action)) return;
            String user = action.getUser();
            if (user != null) {
                log.info("logout of session for: " + user);
                userSessionManagement.logout(user);
            } else {
                log.info("logout of all sessions");
                if (action.getNotBefore() > deployment.getNotBefore()) {
                    deployment.setNotBefore(action.getNotBefore());
                }
                userSessionManagement.logoutAll();
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }



    protected void handlePushNotBefore()  {
        log.info("K_PUSH_NOT_BEFORE sent");
        try {
            JWSInput token = verifyAdminRequest();
            if (token == null) {
                return;
            }
            PushNotBeforeAction action = JsonSerialization.readValue(token.getContent(), PushNotBeforeAction.class);
            if (!validateAction(action)) return;
            deployment.setNotBefore(action.getNotBefore());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    protected JWSInput verifyAdminRequest() throws Exception {
        String token = StreamUtil.readString(facade.getRequest().getInputStream());
        if (token == null) {
            log.warn("admin request failed, no token");
            facade.getResponse().sendError(403, "no token");
            return null;
        }

        JWSInput input = new JWSInput(token);
        boolean verified = false;
        try {
            verified = RSAProvider.verify(input, deployment.getRealmKey());
        } catch (Exception ignore) {
        }
        if (!verified) {
            log.warn("admin request failed, unable to verify token");
            facade.getResponse().sendError(403, "no token");
            return null;
        }
        return input;
    }


    protected boolean validateAction(AdminAction action)  {
        if (!action.validate()) {
            log.warn("admin request failed, not validated" + action.getAction());
            facade.getResponse().sendError(400, "Not validated");
            return false;
        }
        if (action.isExpired()) {
            log.warn("admin request failed, expired token");
            facade.getResponse().sendError(400, "Expired token");
            return false;
        }
        if (!deployment.getResourceName().equals(action.getResource())) {
            log.warn("Resource name does not match");
            facade.getResponse().sendError(400, "Resource name does not match");
            return false;

        }
        return true;
    }

    protected void handleGetSessionStats()  {
        log.info("K_GET_SESSION_STATS sent");
        try {
            JWSInput token = verifyAdminRequest();
            if (token == null) return;
            SessionStatsAction action = JsonSerialization.readValue(token.getContent(), SessionStatsAction.class);
            if (!validateAction(action)) return;
            SessionStats stats = new SessionStats();
            stats.setActiveSessions(userSessionManagement.getActiveSessions());
            stats.setActiveUsers(userSessionManagement.getActiveUsers().size());
            if (action.isListUsers() && userSessionManagement.getActiveSessions() > 0) {
                Map<String, UserStats> list = new HashMap<String, UserStats>();
                for (String user : userSessionManagement.getActiveUsers()) {
                    list.put(user, getUserStats(user));
                }
                stats.setUsers(list);
            }
            facade.getResponse().setStatus(200);
            facade.getResponse().setHeader("Content-Type", "application/json");
            JsonSerialization.writeValueToStream(facade.getResponse().getOutputStream(), stats);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    protected void handleGetUserStats()  {
        log.info("K_GET_USER_STATS sent");
        try {
            JWSInput token = verifyAdminRequest();
            if (token == null) return;
            UserStatsAction action = JsonSerialization.readValue(token.getContent(), UserStatsAction.class);
            if (!validateAction(action)) return;
            String user = action.getUser();
            UserStats stats = getUserStats(user);
            facade.getResponse().setStatus(200);
            facade.getResponse().setHeader("Content-Type", "application/json");
            JsonSerialization.writeValueToStream(facade.getResponse().getOutputStream(), stats);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    protected UserStats getUserStats(String user) {
        UserStats stats = new UserStats();
        Long loginTime = userSessionManagement.getUserLoginTime(user);
        if (loginTime != null) {
            stats.setLoggedIn(true);
            stats.setWhenLoggedIn(loginTime);
        } else {
            stats.setLoggedIn(false);
        }
        return stats;
    }
}
