package org.keycloak.services.resources.account;

import com.fasterxml.jackson.annotation.JsonIgnore;
import org.jboss.resteasy.annotations.cache.NoCache;
import org.keycloak.authentication.Authenticator;
import org.keycloak.authentication.AuthenticatorFactory;
import org.keycloak.common.util.reflections.Types;
import org.keycloak.credential.CredentialMetadata;
import org.keycloak.credential.CredentialModel;
import org.keycloak.credential.CredentialProvider;
import org.keycloak.credential.CredentialProviderFactory;
import org.keycloak.credential.CredentialTypeMetadata;
import org.keycloak.credential.CredentialTypeMetadataContext;
import org.keycloak.models.AccountRoles;
import org.keycloak.models.AuthenticationExecutionModel;
import org.keycloak.models.AuthenticationFlowModel;
import org.keycloak.models.KeycloakSession;
import org.keycloak.models.RealmModel;
import org.keycloak.models.UserModel;
import org.keycloak.models.utils.ModelToRepresentation;
import org.keycloak.representations.account.CredentialMetadataRepresentation;
import org.keycloak.representations.idm.CredentialRepresentation;
import org.keycloak.services.ErrorResponse;
import org.keycloak.services.ErrorResponseException;
import org.keycloak.services.managers.Auth;
import org.keycloak.services.messages.Messages;
import org.keycloak.util.JsonSerialization;
import org.keycloak.utils.MediaType;

import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.NotFoundException;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Response;
import java.io.IOException;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import static org.keycloak.models.AuthenticationExecutionModel.Requirement.DISABLED;
import static org.keycloak.utils.CredentialHelper.createUserStorageCredentialRepresentation;

public class AccountCredentialResource {

    public static final String TYPE = "type";
    public static final String USER_CREDENTIALS = "user-credentials";


    private final KeycloakSession session;
    private final UserModel user;
    private final RealmModel realm;
    private Auth auth;

    public AccountCredentialResource(KeycloakSession session, UserModel user, Auth auth) {
        this.session = session;
        this.user = user;
        this.auth = auth;
        realm = session.getContext().getRealm();
    }


    public static class CredentialContainer {
        // ** category, displayName and helptext attributes can be ordinary UI text or a key into
        //    a localized message bundle.  Typically, it will be a key, but
        //    the UI will work just fine if you don't care about localization
        //    and you want to just send UI text.
        //
        //    Also, the ${} shown in Apicurio is not needed.
        private String type;
        private String category; // **
        private String displayName;
        private String helptext;  // **
        private String iconCssClass;
        private String createAction;
        private String updateAction;
        private boolean removeable;
        private List<CredentialMetadataRepresentation> userCredentialMetadatas;
        private CredentialTypeMetadata metadata;

        public CredentialContainer() {
        }

        public CredentialContainer(CredentialTypeMetadata metadata, List<CredentialMetadataRepresentation> userCredentialMetadatas) {
            this.metadata = metadata;
            this.type = metadata.getType();
            this.category = metadata.getCategory().toString();
            this.displayName = metadata.getDisplayName();
            this.helptext = metadata.getHelpText();
            this.iconCssClass = metadata.getIconCssClass();
            this.createAction = metadata.getCreateAction();
            this.updateAction = metadata.getUpdateAction();
            this.removeable = metadata.isRemoveable();
            this.userCredentialMetadatas = userCredentialMetadatas;
        }

        public String getCategory() {
            return category;
        }
        
        public String getType() {
            return type;
        }

        public String getDisplayName() {
            return displayName;
        }

        public String getHelptext() {
            return helptext;
        }

        public String getIconCssClass() {
            return iconCssClass;
        }

        public String getCreateAction() {
            return createAction;
        }

        public String getUpdateAction() {
            return updateAction;
        }

        public boolean isRemoveable() {
            return removeable;
        }

        public List<CredentialMetadataRepresentation> getUserCredentialMetadatas() {
            return userCredentialMetadatas;
        }

        @JsonIgnore
        public CredentialTypeMetadata getMetadata() {
            return metadata;
        }
    }


    /**
     * Retrieve the stream of credentials available to the current logged in user. It will return only credentials of enabled types,
     * which user can use to authenticate in some authentication flow.
     *
     * @param type Allows to filter just single credential type, which will be specified as this parameter. If null, it will return all credential types
     * @param userCredentials specifies if user credentials should be returned. If true, they will be returned in the "userCredentials" attribute of
     *                        particular credential. Defaults to true.
     * @return
     */
    @GET
    @NoCache
    @Produces(javax.ws.rs.core.MediaType.APPLICATION_JSON)
    public Stream<CredentialContainer> credentialTypes(@QueryParam(TYPE) String type,
                                                     @QueryParam(USER_CREDENTIALS) Boolean userCredentials) {
        auth.requireOneOf(AccountRoles.MANAGE_ACCOUNT, AccountRoles.VIEW_PROFILE);

        boolean includeUserCredentials = userCredentials == null || userCredentials;

        List<CredentialProvider> credentialProviders = session.getKeycloakSessionFactory().getProviderFactoriesStream(CredentialProvider.class)
                .filter(f -> Types.supports(CredentialProvider.class, f, CredentialProviderFactory.class))
                .map(f -> session.getProvider(CredentialProvider.class, f.getId()))
                .collect(Collectors.toList());
        Set<String> enabledCredentialTypes = getEnabledCredentialTypes(credentialProviders);

        Stream<CredentialModel> modelsStream = includeUserCredentials ? user.credentialManager().getStoredCredentialsStream() : Stream.empty();
        List<CredentialModel> models = modelsStream.collect(Collectors.toList());

        Function<CredentialProvider, CredentialContainer> toCredentialContainer = (credentialProvider) -> {
            CredentialTypeMetadataContext ctx = CredentialTypeMetadataContext.builder()
                    .user(user)
                    .build(session);
            CredentialTypeMetadata metadata = credentialProvider.getCredentialTypeMetadata(ctx);

            List<CredentialMetadataRepresentation> userCredentialMetadataModels = null;

            if (includeUserCredentials) {
                List<CredentialModel> modelsOfType = models.stream()
                        .filter(credentialModel -> credentialProvider.getType().equals(credentialModel.getType()))
                        .collect(Collectors.toList());


                List<CredentialMetadata> credentialMetadataList = modelsOfType.stream()
                        .map(m -> {
                            return credentialProvider.getCredentialMetadata(
                                    credentialProvider.getCredentialFromModel(m), metadata
                            );
                        }).collect(Collectors.toList());

                // Don't return secrets from REST endpoint
                credentialMetadataList.stream().forEach(md -> md.getCredentialModel().setSecretData(null));
                userCredentialMetadataModels = credentialMetadataList.stream().map(ModelToRepresentation::toRepresentation).collect(Collectors.toList());

                if (userCredentialMetadataModels.isEmpty() &&
                        user.credentialManager().isConfiguredFor(credentialProvider.getType())) {
                    // In case user is federated in the userStorage, he may have credential configured on the userStorage side. We're
                    // creating "dummy" credential representing the credential provided by userStorage
                    CredentialMetadataRepresentation metadataRepresentation = new CredentialMetadataRepresentation();
                    CredentialRepresentation credential = createUserStorageCredentialRepresentation(credentialProvider.getType());
                    metadataRepresentation.setCredential(credential);
                    userCredentialMetadataModels = Collections.singletonList(metadataRepresentation);
                }

                // In case that there are no userCredentials AND there are not required actions for setup new credential,
                // we won't include credentialType as user won't be able to do anything with it
                if (userCredentialMetadataModels.isEmpty() && metadata.getCreateAction() == null && metadata.getUpdateAction() == null) {
                    return null;
                }
            }

            return new CredentialContainer(metadata, userCredentialMetadataModels);
        };

        return credentialProviders.stream()
                .filter(p -> type == null || Objects.equals(p.getType(), type))
                .filter(p -> enabledCredentialTypes.contains(p.getType()))
                .map(toCredentialContainer)
                .filter(Objects::nonNull)
                .sorted(Comparator.comparing(CredentialContainer::getMetadata));
    }

    // Going through all authentication flows and their authentication executions to see if there is any authenticator of the corresponding
    // credential type.
    private Set<String> getEnabledCredentialTypes(List<CredentialProvider> credentialProviders) {
        Stream<String> enabledCredentialTypes = realm.getAuthenticationFlowsStream()
                .filter(((Predicate<AuthenticationFlowModel>) this::isFlowEffectivelyDisabled).negate())
                .flatMap(flow ->
                        realm.getAuthenticationExecutionsStream(flow.getId())
                                .filter(exe -> Objects.nonNull(exe.getAuthenticator()) && exe.getRequirement() != DISABLED)
                                .map(exe -> (AuthenticatorFactory) session.getKeycloakSessionFactory()
                                        .getProviderFactory(Authenticator.class, exe.getAuthenticator()))
                                .filter(Objects::nonNull)
                                .map(AuthenticatorFactory::getReferenceCategory)
                                .filter(Objects::nonNull)
                );

        Set<String> credentialTypes = credentialProviders.stream()
                .map(CredentialProvider::getType)
                .collect(Collectors.toSet());

        return enabledCredentialTypes.filter(credentialTypes::contains).collect(Collectors.toSet());
    }

    // Returns true if flow is effectively disabled - either it's execution or some parent execution is disabled
    private boolean isFlowEffectivelyDisabled(AuthenticationFlowModel flow) {
        while (!flow.isTopLevel()) {
            AuthenticationExecutionModel flowExecution = realm.getAuthenticationExecutionByFlowId(flow.getId());
            if (flowExecution == null) return false; // Can happen under some corner cases
            if (DISABLED == flowExecution.getRequirement()) return true;
            if (flowExecution.getParentFlow() == null) return false;

            // Check parent flow
            flow = realm.getAuthenticationFlowById(flowExecution.getParentFlow());
            if (flow == null) return false;
        }

        return false;
    }

    /**
     * Remove a credential of current user
     *
     * @param credentialId ID of the credential, which will be removed
     */
    @Path("{credentialId}")
    @DELETE
    @NoCache
    public void removeCredential(final @PathParam("credentialId") String credentialId) {
        auth.require(AccountRoles.MANAGE_ACCOUNT);
        CredentialModel credential = user.credentialManager().getStoredCredentialById(credentialId);
        if (credential == null) {
            throw new NotFoundException("Credential not found");
        }
        user.credentialManager().removeStoredCredentialById(credentialId);
    }


    /**
     * Update a user label of specified credential of current user
     *
     * @param credentialId ID of the credential, which will be updated
     * @param userLabel new user label as JSON string
     */
    @PUT
    @Consumes(MediaType.APPLICATION_JSON)
    @Path("{credentialId}/label")
    @NoCache
    public void setLabel(final @PathParam("credentialId") String credentialId, String userLabel) {
        auth.require(AccountRoles.MANAGE_ACCOUNT);
        CredentialModel credential = user.credentialManager().getStoredCredentialById(credentialId);
        if (credential == null) {
            throw new NotFoundException("Credential not found");
        }

        try {
            String label = JsonSerialization.readValue(userLabel, String.class);
            user.credentialManager().updateCredentialLabel(credentialId, label);
        } catch (IOException ioe) {
            throw new ErrorResponseException(ErrorResponse.error(Messages.INVALID_REQUEST, Response.Status.BAD_REQUEST));
        }
    }

    // TODO: This is kept here for now and commented.
//    /**
//     * Move a credential to a position behind another credential
//     * @param credentialId The credential to move
//     */
//    @Path("{credentialId}/moveToFirst")
//    @POST
//    public void moveToFirst(final @PathParam("credentialId") String credentialId){
//        moveCredentialAfter(credentialId, null);
//    }
//
//    /**
//     * Move a credential to a position behind another credential
//     * @param credentialId The credential to move
//     * @param newPreviousCredentialId The credential that will be the previous element in the list. If set to null, the moved credential will be the first element in the list.
//     */
//    @Path("{credentialId}/moveAfter/{newPreviousCredentialId}")
//    @POST
//    public void moveCredentialAfter(final @PathParam("credentialId") String credentialId, final @PathParam("newPreviousCredentialId") String newPreviousCredentialId){
//        auth.require(AccountRoles.MANAGE_ACCOUNT);
//        session.userCredentialManager().moveCredentialTo(realm, user, credentialId, newPreviousCredentialId);
//    }

}
