package io.papermc.paper.adventure;

import io.papermc.paper.chat.ChatRenderer;
import io.papermc.paper.event.player.AbstractChatEvent;
import io.papermc.paper.event.player.AsyncChatEvent;
import io.papermc.paper.event.player.ChatEvent;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.BitSet;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.function.Function;
import net.kyori.adventure.audience.Audience;
import net.kyori.adventure.audience.ForwardingAudience;
import net.kyori.adventure.key.Key;
import net.kyori.adventure.text.Component;
import net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer;
import net.minecraft.ChatFormatting;
import net.minecraft.Optionull;
import net.minecraft.Util;
import net.minecraft.core.registries.Registries;
import net.minecraft.network.chat.ChatType;
import net.minecraft.network.chat.OutgoingChatMessage;
import net.minecraft.network.chat.PlayerChatMessage;
import net.minecraft.resources.ResourceKey;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.server.MinecraftServer;
import net.minecraft.server.level.ServerPlayer;
import org.bukkit.command.ConsoleCommandSender;
import org.bukkit.craftbukkit.CraftWorld;
import org.bukkit.craftbukkit.entity.CraftPlayer;
import org.bukkit.craftbukkit.util.LazyPlayerSet;
import org.bukkit.craftbukkit.util.Waitable;
import org.bukkit.entity.Player;
import org.bukkit.event.Event;
import org.bukkit.event.HandlerList;
import org.bukkit.event.player.AsyncPlayerChatEvent;
import org.bukkit.event.player.PlayerChatEvent;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.framework.qual.DefaultQualifier;
import org.intellij.lang.annotations.Subst;

import static net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer.legacySection;

@DefaultQualifier(NonNull.class)
public final class ChatProcessor {
    static final ResourceKey<ChatType> PAPER_RAW = ResourceKey.create(Registries.CHAT_TYPE, ResourceLocation.fromNamespaceAndPath(ResourceLocation.PAPER_NAMESPACE, "raw"));
    static final String DEFAULT_LEGACY_FORMAT = "<%1$s> %2$s"; // copied from PlayerChatEvent/AsyncPlayerChatEvent
    final MinecraftServer server;
    final ServerPlayer player;
    final PlayerChatMessage message;
    final boolean async;
    final String craftbukkit$originalMessage;
    final Component paper$originalMessage;
    final OutgoingChatMessage outgoing;

    static final int MESSAGE_CHANGED = 1;
    static final int FORMAT_CHANGED = 2;
    static final int SENDER_CHANGED = 3; // Not used
    private final BitSet flags = new BitSet(3);

    public ChatProcessor(final MinecraftServer server, final ServerPlayer player, final PlayerChatMessage message, final boolean async) {
        this.server = server;
        this.player = player;
        this.message = message;
        this.async = async;
        this.craftbukkit$originalMessage = message.unsignedContent() != null ? LegacyComponentSerializer.legacySection().serialize(PaperAdventure.asAdventure(message.unsignedContent())) : message.signedContent();
        this.paper$originalMessage = PaperAdventure.asAdventure(this.message.decoratedContent());
        this.outgoing = OutgoingChatMessage.create(this.message);
    }

    @SuppressWarnings("deprecated")
    public void process() {
        final boolean listenersOnAsyncEvent = canYouHearMe(AsyncPlayerChatEvent.getHandlerList());
        final boolean listenersOnSyncEvent = canYouHearMe(PlayerChatEvent.getHandlerList());
        if (listenersOnAsyncEvent || listenersOnSyncEvent) {
            final CraftPlayer player = this.player.getBukkitEntity();
            final AsyncPlayerChatEvent ae = new AsyncPlayerChatEvent(this.async, player, this.craftbukkit$originalMessage, new LazyPlayerSet(this.server));
            this.post(ae);
            if (listenersOnSyncEvent) {
                final PlayerChatEvent se = new PlayerChatEvent(player, ae.getMessage(), ae.getFormat(), ae.getRecipients());
                se.setCancelled(ae.isCancelled()); // propagate cancelled state
                this.queueIfAsyncOrRunImmediately(new Waitable<Void>() {
                    @Override
                    protected Void evaluate() {
                        ChatProcessor.this.post(se);
                        return null;
                    }
                });
                this.readLegacyModifications(se.getMessage(), se.getFormat(), se.getPlayer());
                this.processModern(
                    this.modernRenderer(se.getFormat()),
                    this.viewersFromLegacy(se.getRecipients()),
                    this.modernMessage(se.getMessage()),
                    se.getPlayer(),
                    se.isCancelled()
                );
            } else {
                this.readLegacyModifications(ae.getMessage(), ae.getFormat(), ae.getPlayer());
                this.processModern(
                    this.modernRenderer(ae.getFormat()),
                    this.viewersFromLegacy(ae.getRecipients()),
                    this.modernMessage(ae.getMessage()),
                    ae.getPlayer(),
                    ae.isCancelled()
                );
            }
        } else {
            this.processModern(
                defaultRenderer(),
                new LazyChatAudienceSet(this.server),
                this.paper$originalMessage,
                this.player.getBukkitEntity(),
                false
            );
        }
    }

    private ChatRenderer modernRenderer(final String format) {
        if (this.flags.get(FORMAT_CHANGED)) {
            return legacyRenderer(format);
        } else {
            return defaultRenderer();
        }
    }

    private Component modernMessage(final String legacyMessage) {
        if (this.flags.get(MESSAGE_CHANGED)) {
            return legacySection().deserialize(legacyMessage);
        } else {
            return this.paper$originalMessage;
        }
    }

    private void readLegacyModifications(final String message, final String format, final Player playerSender) {
        this.flags.set(MESSAGE_CHANGED, !message.equals(this.craftbukkit$originalMessage));
        this.flags.set(FORMAT_CHANGED, !format.equals(DEFAULT_LEGACY_FORMAT));
        this.flags.set(SENDER_CHANGED, playerSender != this.player.getBukkitEntity());
    }

    private void processModern(final ChatRenderer renderer, final Set<Audience> viewers, final Component message, final Player player, final boolean cancelled) {
        final PlayerChatMessage.AdventureView signedMessage = this.message.adventureView();
        final AsyncChatEvent ae = new AsyncChatEvent(this.async, player, viewers, renderer, message, this.paper$originalMessage, signedMessage);
        ae.setCancelled(cancelled); // propagate cancelled state
        this.post(ae);
        final boolean listenersOnSyncEvent = canYouHearMe(ChatEvent.getHandlerList());
        if (listenersOnSyncEvent) {
            this.queueIfAsyncOrRunImmediately(new Waitable<Void>() {
                @Override
                protected Void evaluate() {
                    final ChatEvent se = new ChatEvent(player, ae.viewers(), ae.renderer(), ae.message(), ChatProcessor.this.paper$originalMessage/*, ae.usePreviewComponent()*/, signedMessage);
                    se.setCancelled(ae.isCancelled()); // propagate cancelled state
                    ChatProcessor.this.post(se);
                    ChatProcessor.this.readModernModifications(se, renderer);
                    ChatProcessor.this.complete(se);
                    return null;
                }
            });
        } else {
            this.readModernModifications(ae, renderer);
            this.complete(ae);
        }
    }

    private void readModernModifications(final AbstractChatEvent chatEvent, final ChatRenderer originalRenderer) {
        this.flags.set(MESSAGE_CHANGED, !chatEvent.message().equals(this.paper$originalMessage));
        if (originalRenderer != chatEvent.renderer()) { // don't set to false if it hasn't changed
            this.flags.set(FORMAT_CHANGED, true);
        }
    }

    private void complete(final AbstractChatEvent event) {
        if (event.isCancelled()) {
            return;
        }

        final CraftPlayer player = ((CraftPlayer) event.getPlayer());
        final Component displayName = displayName(player);
        final Component message = event.message();
        final ChatRenderer renderer = event.renderer();

        final Set<Audience> viewers = event.viewers();
        final ResourceKey<ChatType> chatTypeKey = renderer instanceof ChatRenderer.Default ? ChatType.CHAT : PAPER_RAW;
        final ChatType.Bound chatType = ChatType.bind(chatTypeKey, this.player.level().registryAccess(), PaperAdventure.asVanilla(displayName(player)));

        OutgoingChat outgoingChat = viewers instanceof LazyChatAudienceSet lazyAudienceSet && lazyAudienceSet.isLazy() ? new ServerOutgoingChat() : new ViewersOutgoingChat();
        if (this.flags.get(FORMAT_CHANGED)) {
            if (renderer instanceof ChatRenderer.ViewerUnaware unaware) {
                outgoingChat.sendFormatChangedViewerUnaware(player, PaperAdventure.asVanilla(unaware.render(player, displayName, message)), viewers, chatType);
            } else {
                outgoingChat.sendFormatChangedViewerAware(player, displayName, message, renderer, viewers, chatType);
            }
        } else if (this.flags.get(MESSAGE_CHANGED)) {
            if (!(renderer instanceof ChatRenderer.ViewerUnaware unaware)) {
                throw new IllegalStateException("BUG: This should be a ViewerUnaware renderer at this point");
            }
            final Component renderedComponent = chatTypeKey == ChatType.CHAT ? message : unaware.render(player, displayName, message);
            outgoingChat.sendMessageChanged(player, PaperAdventure.asVanilla(renderedComponent), viewers, chatType);
        } else {
            outgoingChat.sendOriginal(player, viewers, chatType);
        }
    }

    interface OutgoingChat {
        default void sendFormatChangedViewerUnaware(CraftPlayer player, net.minecraft.network.chat.Component renderedMessage, Set<Audience> viewers, ChatType.Bound chatType) {
            this.sendMessageChanged(player, renderedMessage, viewers, chatType);
        }

        void sendFormatChangedViewerAware(CraftPlayer player, Component displayName, Component message, ChatRenderer renderer, Set<Audience> viewers, ChatType.Bound chatType);

        void sendMessageChanged(CraftPlayer player, net.minecraft.network.chat.Component renderedMessage, Set<Audience> viewers, ChatType.Bound chatType);

        void sendOriginal(CraftPlayer player, Set<Audience> viewers, ChatType.Bound chatType);
    }

    final class ServerOutgoingChat implements OutgoingChat {
        @Override
        public void sendFormatChangedViewerAware(CraftPlayer player, Component displayName, Component message, ChatRenderer renderer, Set<Audience> viewers, ChatType.Bound chatType) {
            ChatProcessor.this.server.getPlayerList().broadcastChatMessage(ChatProcessor.this.message, ChatProcessor.this.player, chatType, viewer -> PaperAdventure.asVanilla(renderer.render(player, displayName, message, viewer)));
        }

        @Override
        public void sendMessageChanged(CraftPlayer player, net.minecraft.network.chat.Component renderedMessage, Set<Audience> viewers, ChatType.Bound chatType) {
            ChatProcessor.this.server.getPlayerList().broadcastChatMessage(ChatProcessor.this.message.withUnsignedContent(renderedMessage), ChatProcessor.this.player, chatType);
        }

        @Override
        public void sendOriginal(CraftPlayer player, Set<Audience> viewers, ChatType.Bound chatType) {
            ChatProcessor.this.server.getPlayerList().broadcastChatMessage(ChatProcessor.this.message, ChatProcessor.this.player, chatType);
        }
    }

    final class ViewersOutgoingChat implements OutgoingChat {
        @Override
        public void sendFormatChangedViewerAware(CraftPlayer player, Component displayName, Component message, ChatRenderer renderer, Set<Audience> viewers, ChatType.Bound chatType) {
            this.broadcastToViewers(viewers, chatType, v -> PaperAdventure.asVanilla(renderer.render(player, displayName, message, v)));
        }

        @Override
        public void sendMessageChanged(CraftPlayer player, net.minecraft.network.chat.Component renderedMessage, Set<Audience> viewers, ChatType.Bound chatType) {
            this.broadcastToViewers(viewers, chatType, $ -> renderedMessage);
        }

        @Override
        public void sendOriginal(CraftPlayer player, Set<Audience> viewers, ChatType.Bound chatType) {
            this.broadcastToViewers(viewers, chatType, null);
        }

        private void broadcastToViewers(Collection<Audience> viewers, final ChatType.Bound chatType, final @Nullable Function<Audience, net.minecraft.network.chat.Component> msgFunction) {
            for (Audience viewer : viewers) {
                if (acceptsNative(viewer)) {
                    this.sendNative(viewer, chatType, msgFunction);
                } else {
                    final net.minecraft.network.chat.@Nullable Component unsigned = Optionull.map(msgFunction, f -> f.apply(viewer));
                    final PlayerChatMessage msg = unsigned == null ? ChatProcessor.this.message : ChatProcessor.this.message.withUnsignedContent(unsigned);
                    viewer.sendMessage(msg.adventureView(), this.adventure(chatType));
                }
            }
        }

        private static final Map<String, net.kyori.adventure.chat.ChatType> BUILT_IN_CHAT_TYPES = Util.make(() -> {
            final Map<String, net.kyori.adventure.chat.ChatType> map = new HashMap<>();
            for (final Field declaredField : net.kyori.adventure.chat.ChatType.class.getDeclaredFields()) {
                if (Modifier.isStatic(declaredField.getModifiers()) && declaredField.getType().equals(ChatType.class)) {
                    try {
                        final net.kyori.adventure.chat.ChatType type = (net.kyori.adventure.chat.ChatType) declaredField.get(null);
                        map.put(type.key().asString(), type);
                    } catch (final ReflectiveOperationException ignore) {
                    }
                }
            }
            return map;
        });

        private net.kyori.adventure.chat.ChatType.Bound adventure(ChatType.Bound chatType) {
            @Subst("key:value") final String stringKey = Objects.requireNonNull(
                chatType.chatType().unwrapKey().orElseThrow().location(),
                () -> "No key for '%s' in CHAT_TYPE registry.".formatted(chatType)
            ).toString();
            net.kyori.adventure.chat.@Nullable ChatType adventure = BUILT_IN_CHAT_TYPES.get(stringKey);
            if (adventure == null) {
                adventure = net.kyori.adventure.chat.ChatType.chatType(Key.key(stringKey));
            }
            return adventure.bind(
                PaperAdventure.asAdventure(chatType.name()),
                chatType.targetName().map(PaperAdventure::asAdventure).orElse(null)
            );
        }

        private static boolean acceptsNative(final Audience viewer) {
            if (viewer instanceof Player || viewer instanceof ConsoleCommandSender) {
                return true;
            }
            if (viewer instanceof ForwardingAudience.Single single) {
                return acceptsNative(single.audience());
            }
            return false;
        }

        private void sendNative(final Audience viewer, final ChatType.Bound chatType, final @Nullable Function<Audience, net.minecraft.network.chat.Component> msgFunction) {
            if (viewer instanceof ConsoleCommandSender) {
                this.sendToServer(chatType, msgFunction);
            } else if (viewer instanceof CraftPlayer craftPlayer) {
                craftPlayer.getHandle().sendChatMessage(ChatProcessor.this.outgoing, ChatProcessor.this.player.shouldFilterMessageTo(craftPlayer.getHandle()), chatType, Optionull.map(msgFunction, f -> f.apply(viewer)));
            } else if (viewer instanceof ForwardingAudience.Single single) {
                this.sendNative(single.audience(), chatType, msgFunction);
            } else {
                throw new IllegalStateException("Should only be a Player or Console or ForwardingAudience.Single pointing to one!");
            }
        }

        private void sendToServer(final ChatType.Bound chatType, final @Nullable Function<Audience, net.minecraft.network.chat.Component> msgFunction) {
            final PlayerChatMessage toConsoleMessage = msgFunction == null ? ChatProcessor.this.message : ChatProcessor.this.message.withUnsignedContent(msgFunction.apply(ChatProcessor.this.server.console));
            ChatProcessor.this.server.logChatMessage(toConsoleMessage.decoratedContent(), chatType, ChatProcessor.this.server.getPlayerList().verifyChatTrusted(toConsoleMessage) ? null : "Not Secure");
        }
    }

    private Set<Audience> viewersFromLegacy(final Set<Player> recipients) {
        if (recipients instanceof LazyPlayerSet lazyPlayerSet && lazyPlayerSet.isLazy()) {
            return new LazyChatAudienceSet(this.server);
        }
        final HashSet<Audience> viewers = new HashSet<>(recipients);
        viewers.add(this.server.console);
        return viewers;
    }

    static String legacyDisplayName(final CraftPlayer player) {
        if (((org.bukkit.craftbukkit.CraftWorld) player.getWorld()).getHandle().paperConfig().scoreboards.useVanillaWorldScoreboardNameColoring) {
            return legacySection().serialize(player.teamDisplayName()) + ChatFormatting.RESET;
        }
        return player.getDisplayName();
    }

    static Component displayName(final CraftPlayer player) {
        if (((CraftWorld) player.getWorld()).getHandle().paperConfig().scoreboards.useVanillaWorldScoreboardNameColoring) {
            return player.teamDisplayName();
        }
        return player.displayName();
    }

    private static ChatRenderer.Default defaultRenderer() {
        return (ChatRenderer.Default) ChatRenderer.defaultRenderer();
    }

    private static ChatRenderer legacyRenderer(final String format) {
        if (DEFAULT_LEGACY_FORMAT.equals(format)) {
            return defaultRenderer();
        }
        return ChatRenderer.viewerUnaware((player, sourceDisplayName, message) -> legacySection().deserialize(legacyFormat(format, player, legacySection().serialize(message))));
    }

    static String legacyFormat(final String format, Player player, String message) {
        return String.format(format, legacyDisplayName((CraftPlayer) player), message);
    }

    private void queueIfAsyncOrRunImmediately(final Waitable<Void> waitable) {
        if (this.async) {
            this.server.processQueue.add(waitable);
        } else {
            waitable.run();
        }
        try {
            waitable.get();
        } catch (final InterruptedException e) {
            Thread.currentThread().interrupt(); // tag, you're it
        } catch (final ExecutionException e) {
            throw new RuntimeException("Exception processing chat", e.getCause());
        }
    }

    private void post(final Event event) {
        this.server.server.getPluginManager().callEvent(event);
    }

    static boolean canYouHearMe(final HandlerList handlers) {
        return handlers.getRegisteredListeners().length > 0;
    }
}
