Widerhall/src/main/java/de/srsoftware/widerhall/data/ListMember.java

package de.srsoftware.widerhall.data;

import de.srsoftware.widerhall.Util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.*;

import static de.srsoftware.widerhall.Constants.*;
import static de.srsoftware.widerhall.Util.t;

/**
 * @author Stephan Richter
 * This class embodies the ListMembers table
 */
public class ListMember {
    public static final String TABLE_NAME = "ListMembers";
    public static final int STATE_OWNER = 1;
    public static final int STATE_SUBSCRIBER = 2;
    public static final int STATE_AWAITING_CONFIRMATION = 4;
    public static final int STATE_MODERATOR = 8;
    private static final Logger LOG = LoggerFactory.getLogger(ListMember.class);
    private static final String LIST_EMAIL = "list_email";
    private static final String USER_EMAIL = "user_email";
    private static final String STATE = "state";

    private MailingList list;
    private User user;
    private final String token;
    private final int state;

    /**
     * create a new list member object
     * @param list
     * @param user
     * @param state
     * @param token
     */
    public ListMember(MailingList list, User user, int state, String token){
        this.list = list;
        this.user = user;
        this.state = state;
        this.token = token;
    }

    public String addNewModerator(String userEmail) {
        if (!isAllowedToEditMods()) return t("You are not allowed to nominate new mods for {}",list.email());
        User moderator = null;
        try {
            moderator = User.load(userEmail);
        } catch (SQLException e) {
            LOG.warn("Failed to load user for {}",userEmail,e);
            return t("Failed to load user for {}",userEmail);
        }
        if (moderator == null) return t("No such user: {}",userEmail);

        ListMember member = null;
        try {
            member = ListMember.load(list,moderator);
        } catch (SQLException e) {
            LOG.warn("Failed to load list member for {}/{}",moderator.email(),list.email(),e);
            return t("Failed to load list member for {}/{}",moderator.email(),list.email());
        }
        try {
            if (member == null) {
                ListMember.create(list, moderator, ListMember.STATE_MODERATOR);
            } else {
                member.setState(ListMember.STATE_MODERATOR);
            }
        } catch (SQLException e) {
            LOG.warn("Failed to make {} a moderator of {}",moderator.email(),list.email(),e);
            return t("Failed to make {} a moderator of {}",moderator.email(),list.email());
        }
        return null;
    }

    /**
     * tries to confirm the token:
     * This method loads the list member, that is assigned with the token.
     * If no db entry is found for the token, null is returned.
     * If an entry is found, the respective User object is loaded.
     * If no User object is assigned, null is returned.
     * If a matching User object is present, the member's state is altered from AWAITING_CONFIRMATION to SUBSCRIBER and the token is dropped.
     * @param token
     * @return
     * @throws SQLException
     */
    public static User confirm(String token) throws SQLException {
        var rs = Database.open().select(TABLE_NAME).where(TOKEN,token).compile().exec();
        if (rs.next()){
            var lm = ListMember.from(rs);
            rs.close();
            if (lm.user != null){
                int newState = lm.state ^ STATE_AWAITING_CONFIRMATION | STATE_SUBSCRIBER;
                Database.open()
                        .update(TABLE_NAME)
                        .set(TOKEN,null)
                        .set(STATE, newState) //drop confirmation state, set subscriber state
                        .where(LIST_EMAIL,lm.list.email())
                        .where(USER_EMAIL,lm.user.email())
                        .compile()
                        .run();
            }
            return lm.user;
        }
        return null;
    }


    /**
     * Create a new list member entry in the database.
     * If the member has the state AWAITING_CONFIRMATION, a token is assigned with the member, too.
     * @param list
     * @param user
     * @param state
     * @return
     * @throws SQLException
     */
    public static ListMember create(MailingList list, User user, int state) throws SQLException {
        String token = null;
        if ((state & STATE_AWAITING_CONFIRMATION) > 0){
            token = Util.sha256(String.join("/",list.email(),user.email(),user.salt()));
        }
        return new ListMember(list,user,state,token).save();
    }

    /**
     * create the table for ListMember objects
     * @throws SQLException
     */
    public static void createTable() throws SQLException {
        var sql = new StringBuilder()
                .append("CREATE TABLE ").append(TABLE_NAME)
                .append(" (")
                .append(LIST_EMAIL).append(" ").append(VARCHAR).append(", ")
                .append(USER_EMAIL).append(" ").append(VARCHAR).append(", ")
                .append(STATE).append(" ").append(INT).append(", ")
                .append(TOKEN).append(" ").append(VARCHAR).append(", ")
                .append("PRIMARY KEY (").append(LIST_EMAIL).append(", ").append(USER_EMAIL).append("));");
        Database.open().query(sql).compile().run();
    }

    public String dropMember(String userEmail) {
        if (!isModerator()) return t("You are not allowed to remove members of {}",list.email());
        User user = null;
        try {
            user = User.load(userEmail);
        } catch (SQLException e) {
            LOG.warn("Failed to load user for {}",userEmail,e);
            return t("Failed to load user for {}",userEmail);
        }
        if (user == null) return t("No such user: {}",userEmail);

        ListMember member = null;
        try {
            member = ListMember.load(list,user);
        } catch (SQLException e) {
            LOG.warn("Failed to load list member for {}/{}",user.email(),list.email(),e);
            return t("Failed to load list member for {}/{}",user.email(),list.email());
        }

        if (member == null) return t("{} is no member of {}",user.email(),list.email());
        if (member.isOwner()) return t("You are not allowed to remvoe the list owner!");

        try {
            member.unsubscribe();
        } catch (SQLException e) {
            LOG.warn("Failed to un-subscribe {} from {}",user.email(),list.email(),e);
            return t("Failed to un-subscribe {} from {}",user.email(),list.email());
        }
        return null;
    }

    public String dropModerator(String userEmail) {
        if (!isAllowedToEditMods()) return t("You are not allowed to edit mods of {}",list.email());
        User moderator = null;
        try {
            moderator = User.load(userEmail);
        } catch (SQLException e) {
            LOG.warn("Failed to load user for {}",userEmail,e);
            return t("Failed to load user for {}",userEmail);
        }
        if (moderator == null) return t("No such user: {}",userEmail);

        ListMember member = null;
        try {
            member = ListMember.load(list,moderator);
        } catch (SQLException e) {
            LOG.warn("Failed to load list member for {}/{}",moderator.email(),list.email(),e);
            return t("Failed to load list member for {}/{}",moderator.email(),list.email());
        }
        try {
            if (member == null) {
                ListMember.create(list, moderator, ListMember.STATE_SUBSCRIBER);
            } else {
                member.setState(ListMember.STATE_SUBSCRIBER);
            }
        } catch (SQLException e) {
            LOG.warn("Failed to make {} a subscriber of {}",moderator.email(),list.email(),e);
            return t("Failed to make {} a subscriber of {}",moderator.email(),list.email());
        }
        return null;
    }

    /**
     * create a new ListMember object from a ResultSet
     * @param rs
     * @return
     * @throws SQLException
     */
    public static ListMember from(ResultSet rs) throws SQLException {
        return new ListMember(
                MailingList.load(rs.getString(LIST_EMAIL)),
                User.load(rs.getString(USER_EMAIL)),
                rs.getInt(STATE),
                rs.getString(TOKEN));
    }

    /**
     * test, if the current object has a given state
     * @param testState
     * @return
     */
    public boolean hasState(int testState) {
        return (state & testState) > 0;
    }

    public boolean isAllowedToEditMods(){
        if (isOwner()) return true;
        if (isModerator()) return list.modsMayEditMods();
        return false;
    }

    public boolean isAwaiting(){
        return hasState(STATE_AWAITING_CONFIRMATION);
    }

    public boolean isModerator() {
        return hasState(STATE_OWNER|STATE_MODERATOR);
    }

    public boolean isOwner(){
        return hasState(STATE_OWNER);
    }

    public boolean isSubscriber(){
        return hasState(STATE_SUBSCRIBER|STATE_MODERATOR|STATE_OWNER);
    }

    public MailingList list(){
        return list;
    }
    /**
     * return a set of list emails of MailingLists the given user attends
     * @param user
     * @return
     */
    public static Set<ListMember> listsOf(User user) {
        var listEmails = new HashSet<String>();
        try {
            var request = Database.open()
                    .select(TABLE_NAME);
            if (!user.hashPermission(User.PERMISSION_ADMIN)) request = request.where(USER_EMAIL, user.email());
            var rs = request.compile().exec();
            while (rs.next()) listEmails.add(rs.getString(LIST_EMAIL));
        } catch (SQLException e) {
            LOG.warn("Collecting lists of {} failed: ",user.email(),e);
        }
        var lists = MailingList.loadAll(listEmails);
        var result = new HashSet<ListMember>();
        try {
            for (var ml : lists) result.add(ListMember.load(ml,user));
        } catch (SQLException e) {
            e.printStackTrace();
        }

        return result;
    }

    /**
     * return a set of list emails of MailingLists owned by the given user
     * @param user
     * @return
     */
    public static Set<String> listsOwnedBy(User user) {
        var list = new HashSet<String>();
        try {
            var request = Database.open().select(TABLE_NAME, LIST_EMAIL, STATE+" & "+STATE_OWNER+" as "+STATE);
            if (!user.hashPermission(User.PERMISSION_ADMIN)) request = request.where(USER_EMAIL, user.email()).where(STATE, STATE_OWNER);
            var rs = request.compile().exec();
            while (rs.next()) list.add(rs.getString(LIST_EMAIL));
        } catch (SQLException e) {
            LOG.warn("Collecting lists of {} failed: ",user.email(),e);
        }
        return list;
    }

    /**
     * load the list member specified by a MailingList and as User object
     * @param list
     * @param user
     * @return
     * @throws SQLException
     */
    public static ListMember load(MailingList list,User user) throws SQLException {
        var rs = Database
                .open()
                .select(TABLE_NAME)
                .where(LIST_EMAIL,list.email())
                .where(USER_EMAIL,user.email())
                .compile()
                .exec();
        try {
            if (rs.next()) return ListMember.from(rs);
        } finally {
            rs.close();
        }
        return null;
    }


    public static Set<ListMember> of(MailingList list) throws SQLException {
        var rs = Database.open().select(TABLE_NAME).where(LIST_EMAIL,list.email()).compile().exec();
        var set = new HashSet<ListMember>();
        try {
            while (rs.next()) set.add(ListMember.from(rs));
        } finally {
            rs.close();
        }
        return set;
    }

    public Map<String,Object> safeMap(){
        return Map.of(
                EMAIL,user.email(),
                NAME,user.name(),
                STATE,stateText()
        );
    }

    /**
     * Save the current ListMember object to the database
     * @return
     * @throws SQLException
     */
    private ListMember save() throws SQLException {
        var req = Database.open()
                .insertInto(TABLE_NAME)
                .set(LIST_EMAIL,list.email())
                .set(USER_EMAIL,user.email())
                .set(STATE,state);
        if (token != null) req.set(TOKEN,token);
        req.compile().run();
        return this;
    }

    public ListMember setState(int newState) throws SQLException {
        Database.open()
                .update(TABLE_NAME)
                .set(STATE,newState)
                .where(USER_EMAIL,user.email())
                .where(LIST_EMAIL,list.email())
                .compile()
                .run();
        return this;
    }

    /**
     * convert state flag to readable text
     * @return
     */
    public String stateText() {
        var words = new ArrayList<String>();
        if (isAwaiting()) words.add("awaiting confirmation");
        if (isModerator()) words.add("moderator");
        if (isOwner()) words.add("owner");
        if (isSubscriber()) words.add("subscriber");
        return String.join(", ",words);
    }

    /**
     * get the token of the current list member
     * @return
     */
    public String token() {
        return token;
    }

    /**
     * unsubscribe a list member
     * @throws SQLException
     */
    public void unsubscribe() throws SQLException {
        var db = Database.open();
        var rs = db.select(TABLE_NAME)
                .where(LIST_EMAIL,list.email())
                .where(USER_EMAIL,user.email())
                .compile()
                .exec();
        while (rs.next()){
            int state = Util.unset(rs.getInt(STATE),STATE_SUBSCRIBER,STATE_MODERATOR,STATE_AWAITING_CONFIRMATION); // drop subscription and awaiting flags
            var req = state < 1 ? db.deleteFrom(TABLE_NAME) : db.update(TABLE_NAME).set(STATE,state).set(TOKEN,null);
            req.where(LIST_EMAIL,list.email()).where(USER_EMAIL,user.email()).compile().run();
        }
    }

    public User user(){
        return user;
    }
}