package net.frozenorb.apiv3.model;

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.google.common.base.Charsets;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.hash.Hashing;
import com.mongodb.async.SingleResultCallback;
import com.mongodb.async.client.MongoCollection;
import com.mongodb.client.result.UpdateResult;
import fr.javatic.mongo.jacksonCodec.Entity;
import fr.javatic.mongo.jacksonCodec.objectId.Id;
import io.vertx.core.CompositeFuture;
import io.vertx.core.Future;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.Setter;
import net.frozenorb.apiv3.APIv3;
import net.frozenorb.apiv3.serialization.gson.ExcludeFromReplies;
import net.frozenorb.apiv3.serialization.jackson.UuidJsonDeserializer;
import net.frozenorb.apiv3.serialization.jackson.UuidJsonSerializer;
import net.frozenorb.apiv3.unsorted.BlockingCallback;
import net.frozenorb.apiv3.util.MojangUtils;
import net.frozenorb.apiv3.util.PermissionUtils;
import net.frozenorb.apiv3.util.SyncUtils;
import net.frozenorb.apiv3.util.UuidUtils;
import org.bson.Document;

import java.time.Instant;
import java.util.*;

@Entity
@AllArgsConstructor
public final class User {

    private static final MongoCollection<User> usersCollection = APIv3.getDatabase().getCollection("users", User.class);

    @Getter @Id @JsonSerialize(using=UuidJsonSerializer.class) @JsonDeserialize(using=UuidJsonDeserializer.class) private UUID id;
    @Getter private String lastUsername;
    @Getter @ExcludeFromReplies private Map<String, Instant> aliases = new HashMap<>();
    @Getter @ExcludeFromReplies @Setter private String totpSecret;
    @Getter @ExcludeFromReplies @Setter private String emailToken;
    @Getter @ExcludeFromReplies @Setter private Instant emailTokenSetAt;
    @Getter @ExcludeFromReplies private String password;
    @Getter @Setter private String email;
    @Getter private String phoneNumber;
    @Getter private String lastSeenOn;
    @Getter private Instant lastSeenAt;
    @Getter private Instant firstSeenAt;
    @Getter private boolean online;

    public static User findByIdSync(String id) {
        UUID uuid;

        try {
            uuid = UUID.fromString(id);
        } catch (NullPointerException | IllegalArgumentException ex) {
            return null;
        }

        return findByIdSync(uuid);
    }

    public static User findByIdSync(UUID id) {
        if (UuidUtils.isAcceptableUuid(id)) {
            return SyncUtils.blockOne(usersCollection.find(new Document("_id", id)));
        } else {
            return null;
        }
    }

    public static User findByEmailTokenSync(String emailToken) {
        return SyncUtils.blockOne(usersCollection.find(new Document("emailToken", emailToken)));
    }

    public static User findByLastUsernameSync(String lastUsername) {
        return SyncUtils.blockOne(usersCollection.find(new Document("lastUsername", lastUsername)));
    }

    public static void findById(String id, SingleResultCallback<User> callback) {
        try {
            UUID uuid = UUID.fromString(id);
            findById(uuid, callback);
        } catch (IllegalArgumentException ex) { // from UUID parsing
            callback.onResult(null, ex);
        }
    }

    public static void findById(UUID id, SingleResultCallback<User> callback) {
        if (UuidUtils.isAcceptableUuid(id)) {
            usersCollection.find(new Document("_id", id)).first(callback);
        } else {
            callback.onResult(null, null);
        }
    }

    public static void findByIdGrouped(Iterable<UUID> search, SingleResultCallback<Map<UUID, User>> callback) {
        usersCollection.find(new Document("_id", new Document("$in", search))).into(new ArrayList<>(), (users, error) -> {
            if (error != null) {
                callback.onResult(null, error);
            } else {
                Map<UUID, User> result = new HashMap<>();

                for (UUID user : search) {
                    result.put(user, null);
                }

                for (User user : users) {
                    result.put(user.getId(), user);
                }

                callback.onResult(result, null);
            }
        });
    }

    public static void findByLastUsername(String lastUsername, SingleResultCallback<User> callback) {
        usersCollection.find(new Document("lastUsername", lastUsername)).first(callback);
    }

    public User() {} // For Jackson

    // TODO: THIS IS CURRENTLY BLOCKING. MAYBE FOR THE HEARTBEAT WE CAN DO SOMETHING
    // TO MAKE IT NOT SO BLOCKING
    public User(UUID id, String lastUsername) {
        this.id = id;
        this.lastUsername = ""; // Intentional, so updateUsername actually does something.
        this.aliases = new HashMap<>();
        this.lastSeenAt = Instant.now();
        this.firstSeenAt = Instant.now();

        updateUsername(lastUsername);
    }

    public boolean hasPermissionAnywhere(String permission) {
        Map<String, Boolean> globalPermissions = getGlobalPermissions();
        return globalPermissions.containsKey(permission) && globalPermissions.get(permission);
    }

    // TODO: ASYNC
    public Map<String, Boolean> getGlobalPermissions() {
        Map<String, Boolean> globalPermissions = PermissionUtils.getDefaultPermissions(getHighestRankAnywhere());

        for (Map.Entry<ServerGroup, Rank> serverGroupEntry : getHighestRanks().entrySet()) {
            ServerGroup serverGroup = serverGroupEntry.getKey();
            Rank rank = serverGroupEntry.getValue();

            globalPermissions = PermissionUtils.mergePermissions(
                    globalPermissions,
                    serverGroup.calculatePermissions(rank)
            );
        }

        return ImmutableMap.copyOf(globalPermissions);
    }

    // TODO: Clean
    public boolean seenOnServer(Server server) {
        if (online && server.getId().equals(this.lastSeenOn)) {
            return false;
        }

        this.lastSeenOn = server.getId();

        if (!online) {
            this.lastSeenAt = Instant.now();
        }

        this.online = true;
        return true;
    }

    public void leftServer() {
        this.lastSeenAt = Instant.now();
        this.online = false;
    }

    public void updateUsername(String newUsername) {
        if (!newUsername.equals(lastUsername)) {
            this.lastUsername = newUsername;

            User withNewUsername;

            while ((withNewUsername = User.findByLastUsernameSync(newUsername)) != null) {
                BlockingCallback<String> callback = new BlockingCallback<>();
                MojangUtils.getName(withNewUsername.getId(), callback);
                withNewUsername.updateUsername(callback.get());
            }
        }

        this.aliases.put(newUsername, Instant.now());
    }

    public void setPassword(String input) {
        this.password = Hashing
                .sha256()
                .hashString(input + "$" + id.toString(), Charsets.UTF_8)
                .toString();
    }

    public boolean checkPassword(String input) {
        String hashed = Hashing
                .sha256()
                .hashString(input + "$" + id.toString(), Charsets.UTF_8)
                .toString();

        return password != null && hashed.equals(password);
    }

    public Rank getHighestRankAnywhere() {
        return getHighestRankScoped(null, Grant.findByUserSync(this));
    }

    // TODO: Clean
    // This is only used to help batch requests to mongo
    public Rank getHighestRankScoped(ServerGroup serverGroup, Iterable<Grant> grants) {
        Rank highest = null;

        for (Grant grant : grants) {
            if (!grant.isActive() || (serverGroup != null && !grant.appliesOn(serverGroup))) {
                continue;
            }

            Rank rank = Rank.findById(grant.getRank());

            if (highest == null || rank.getWeight() > highest.getWeight()) {
                highest = rank;
            }
        }

        if (highest != null) {
            return highest;
        } else {
            return Rank.findById("default");
        }
    }

    // TODO: Clean
    public Map<ServerGroup, Rank> getHighestRanks() {
        Map<ServerGroup, Rank> highestRanks = new HashMap<>();
        Rank defaultRank = Rank.findById("default");
        List<Grant> userGrants = Grant.findByUserSync(this);

        for (ServerGroup serverGroup : ServerGroup.findAll()) {
            Rank highest = defaultRank;

            for (Grant grant : userGrants) {
                if (!grant.isActive() || !grant.appliesOn(serverGroup)) {
                    continue;
                }

                Rank rank = Rank.findById(grant.getRank());

                if (highest == null || rank.getWeight() > highest.getWeight()) {
                    highest = rank;
                }
            }

            highestRanks.put(serverGroup, highest);
        }

        return highestRanks;
    }

    public void getLoginInfo(Server server, String userIp, SingleResultCallback<Map<String, Object>> callback) {
        Future<Iterable<Punishment>> punishmentsFuture = Future.future();
        Future<Iterable<IpBan>> ipBansFuture = Future.future();
        Future<Iterable<Grant>> grantsFuture = Future.future();

        Punishment.findByUserAndType(this, ImmutableSet.of(
                Punishment.PunishmentType.BLACKLIST,
                Punishment.PunishmentType.BAN,
                Punishment.PunishmentType.MUTE
        ), (punishments, error) -> {
            if (error != null) {
                punishmentsFuture.fail(error);
            } else {
                punishmentsFuture.complete(punishments);
            }
        });

        if (userIp != null) {
            IpBan.findByIp(userIp, (ipBans, error) -> {
                if (error != null) {
                    ipBansFuture.fail(error);
                } else {
                    ipBansFuture.complete(ipBans);
                }
            });
        } else {
            ipBansFuture.complete(ImmutableSet.of());
        }

        Grant.findByUser(this, (grants, error) -> {
            if (error != null) {
                grantsFuture.fail(error);
            } else {
                grantsFuture.complete(grants);
            }
        });

        CompositeFuture.all(punishmentsFuture, ipBansFuture, grantsFuture).setHandler((result) -> {
            if (result.succeeded()) {
                Iterable<Punishment> punishments = result.result().result(0);
                Iterable<IpBan> ipBans = result.result().result(1);
                Iterable<Grant> grants = result.result().result(2);

                callback.onResult(createLoginInfo(server, punishments, ipBans, grants), null);
            } else {
                callback.onResult(null, result.cause());
            }
        });
    }

    // This is only used to help batch requests to mongo
    public Map<String, Object> createLoginInfo(Server server, Iterable<Punishment> punishments, Iterable<IpBan> ipBans, Iterable<Grant> grants) {
        Punishment activeMute = null;
        Punishment activeBan = null;
        IpBan activeIpBan = null;

        for (Punishment punishment : punishments) {
            if (!punishment.isActive()) {
                continue;
            }

            if (punishment.getType() == Punishment.PunishmentType.MUTE) {
                activeMute = punishment;
            } else if (punishment.getType() == Punishment.PunishmentType.BAN || punishment.getType() == Punishment.PunishmentType.BLACKLIST) {
                activeBan = punishment;
            }
        }

        for (IpBan ipBan : ipBans) {
            if (ipBan.isActive()) {
                activeIpBan = ipBan;
                break;
            }
        }

        Rank highestRank = getHighestRankScoped(ServerGroup.findById(server.getServerGroup()), grants);
        Map<String, Object> access = ImmutableMap.of(
                "allowed", true,
                "message", "Public server"
        );

        if (activeBan != null) {
            access = ImmutableMap.of(
                    "allowed", false,
                    "message", activeBan.getAccessDenialReason(),
                    "activeBanId", activeBan.getId()
            );
        } else if (activeIpBan != null) {
            // TODO: ASYNC
            BlockingCallback<String> callback = new BlockingCallback<>();
            activeIpBan.getAccessDenialReason(callback);
            String reason = callback.get();

            access = ImmutableMap.of(
                    "allowed", false,
                    "message", reason,
                    "activeIpBanId", activeIpBan.getId()
            );
        }

        // Generics are weird, yes we have to do this.
        ImmutableMap.Builder<String, Object> result = ImmutableMap.<String, Object>builder()
                .put("user", this)
                .put("access", access)
                .put("rank", highestRank.getId())
                .put("totpSetup", getTotpSecret() != null);

        if (activeMute != null) {
            result.put("mute", activeMute);
        }

        return result.build();
    }

    public void insert() {
        BlockingCallback<Void> callback = new BlockingCallback<>();
        usersCollection.insertOne(this, callback);
        callback.get();
    }

    public void save() {
        BlockingCallback<UpdateResult> callback = new BlockingCallback<>();
        save(callback);
        callback.get();
    }

    public void save(SingleResultCallback<UpdateResult> callback) {
        usersCollection.replaceOne(new Document("_id", id), this, callback);
    }

}