package com.xuqm.im.service;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.xuqm.common.exception.BusinessException;
import com.xuqm.im.cluster.ImClusterPublisher;
import com.xuqm.im.entity.ImGroupEntity;
import com.xuqm.im.entity.ImMessageEntity;
import com.xuqm.im.entity.WebhookConfigEntity;
import com.xuqm.im.model.ConversationView;
import com.xuqm.im.model.SendMessageRequest;
import com.xuqm.im.repository.WebhookConfigRepository;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import com.xuqm.im.repository.ImMessageRepository;
import java.util.List;
import java.util.Objects;
import java.util.UUID;

@Service
public class MessageService {

    private final ImMessageRepository messageRepository;
    private final WebhookConfigRepository webhookRepository;
    private final KeywordFilterService keywordFilterService;
    private final ImClusterPublisher clusterPublisher;
    private final ImGroupService groupService;
    private final BlacklistService blacklistService;
    private final ConversationStateService conversationStateService;
    private final ObjectMapper objectMapper;

    @Value("${im.webhook-timeout-ms:3000}")
    private int webhookTimeoutMs;

    public MessageService(ImMessageRepository messageRepository,
                          WebhookConfigRepository webhookRepository,
                          KeywordFilterService keywordFilterService,
                          ImClusterPublisher clusterPublisher,
                          ImGroupService groupService,
                          BlacklistService blacklistService,
                          ConversationStateService conversationStateService,
                          ObjectMapper objectMapper) {
        this.messageRepository = messageRepository;
        this.webhookRepository = webhookRepository;
        this.keywordFilterService = keywordFilterService;
        this.clusterPublisher = clusterPublisher;
        this.groupService = groupService;
        this.blacklistService = blacklistService;
        this.conversationStateService = conversationStateService;
        this.objectMapper = objectMapper;
    }

    public ImMessageEntity send(String appId, String fromUserId, SendMessageRequest req) {
        String content = req.content();
        if (req.msgType() == ImMessageEntity.MsgType.TEXT) {
            content = keywordFilterService.filter(appId, content);
            if (content == null) {
                throw new BusinessException("消息包含违禁内容");
            }
        }
        ImGroupEntity group = null;
        if (req.chatType() == ImMessageEntity.ChatType.GROUP) {
            group = groupService.get(req.toId());
            if (!groupService.memberIds(group).contains(fromUserId)) {
                throw new BusinessException(403, "不在群内");
            }
            if (groupService.isMemberMuted(req.toId(), fromUserId)) {
                throw new BusinessException(403, "当前用户已被禁言");
            }
        } else if (blacklistService.isEitherBlocked(appId, fromUserId, req.toId())) {
            throw new BusinessException(403, "已被拉黑，无法发送消息");
        }

        ImMessageEntity message = new ImMessageEntity();
        message.setId(UUID.randomUUID().toString());
        message.setAppId(appId);
        message.setFromUserId(fromUserId);
        message.setToId(req.toId());
        message.setChatType(req.chatType());
        message.setMsgType(req.msgType());
        message.setContent(content);
        message.setStatus(ImMessageEntity.MsgStatus.SENT);
        message.setMentionedUserIds(req.mentionedUserIds());
        message.setCreatedAt(LocalDateTime.now());
        messageRepository.save(message);

        String destination = req.chatType() == ImMessageEntity.ChatType.SINGLE
                ? "/user/" + req.toId() + "/queue/messages"
                : "/topic/group/" + req.toId();
        clusterPublisher.publish(destination, message);
        if (req.chatType() == ImMessageEntity.ChatType.SINGLE && !fromUserId.equals(req.toId())) {
            clusterPublisher.publish("/user/" + fromUserId + "/queue/messages", message);
            conversationStateService.clearHiddenForUsers(appId, req.toId(), req.chatType().name(), List.of(fromUserId, req.toId()));
        } else if (req.chatType() == ImMessageEntity.ChatType.GROUP) {
            conversationStateService.clearHiddenForUsers(appId, req.toId(), req.chatType().name(), groupService.memberIds(group));
        }

        dispatchWebhooks(appId, message);
        return message;
    }

    public ImMessageEntity revoke(String appId, String messageId, String requestUserId) {
        ImMessageEntity message = messageRepository.findById(messageId)
                .orElseThrow(() -> new BusinessException(404, "消息不存在"));
        if (!message.getAppId().equals(appId)) {
            throw new BusinessException(403, "无权操作");
        }
        if (!message.getFromUserId().equals(requestUserId)) {
            throw new BusinessException(403, "只能撤回自己发送的消息");
        }
        message.setStatus(ImMessageEntity.MsgStatus.REVOKED);
        message.setMsgType(ImMessageEntity.MsgType.REVOKED);
        ImMessageEntity saved = messageRepository.save(message);

        if (saved.getChatType() == ImMessageEntity.ChatType.SINGLE) {
            clusterPublisher.publish("/user/" + saved.getToId() + "/queue/messages", saved);
            if (!saved.getFromUserId().equals(saved.getToId())) {
                clusterPublisher.publish("/user/" + saved.getFromUserId() + "/queue/messages", saved);
            }
        } else {
            clusterPublisher.publish("/topic/group/" + saved.getToId(), saved);
        }
        return saved;
    }

    public Page<ImMessageEntity> history(String appId, String userId, String toId, int page, int size) {
        return messageRepository.findSingleConversation(
                appId, userId, toId, PageRequest.of(page, size));
    }

    public Page<ImMessageEntity> groupHistory(String appId, String groupId, String userId, int page, int size) {
        ImGroupEntity group = groupService.get(groupId);
        if (!groupService.memberIds(group).contains(userId)) {
            throw new BusinessException(403, "不在群内");
        }
        return messageRepository.findGroupHistory(appId, groupId, PageRequest.of(page, size));
    }

    public List<ImMessageRepository.ConversationSummary> conversations(String appId, String userId, int size) {
        return messageRepository.findConversations(appId, userId, size);
    }

    public List<ConversationView> conversationViews(String appId, String userId, int size) {
        int fetchSize = Math.max(size * 3, size);
        return messageRepository.findConversations(appId, userId, fetchSize).stream()
                .map(summary -> toConversationView(appId, userId, summary))
                .filter(Objects::nonNull)
                .limit(size)
                .toList();
    }

    private ConversationView toConversationView(
            String appId,
            String userId,
            ImMessageRepository.ConversationSummary summary
    ) {
        String targetId = summary.getTargetId();
        String chatType = summary.getChatType();
        var state = conversationStateService.find(appId, userId, targetId, chatType);
        if (state != null && state.isHidden()) {
            return null;
        }
        Page<ImMessageEntity> page = chatType.equals("GROUP")
                ? messageRepository.findGroupHistory(appId, targetId, PageRequest.of(0, 1))
                : messageRepository.findSingleConversation(appId, userId, targetId, PageRequest.of(0, 1));
        ImMessageEntity lastMessage = page.getContent().stream().findFirst().orElse(null);
        LocalDateTime lastReadAt = state == null ? null : state.getLastReadAt();
        long unreadCount = chatType.equals("GROUP")
                ? messageRepository.countUnreadGroupConversation(appId, userId, targetId, lastReadAt)
                : messageRepository.countUnreadSingleConversation(appId, userId, targetId, lastReadAt);
        return new ConversationView(
                targetId,
                chatType,
                lastMessage != null ? lastMessage.getContent() : null,
                lastMessage != null ? lastMessage.getMsgType().name() : null,
                toEpochMillis(lastMessage != null ? lastMessage.getCreatedAt() : summary.getLastTime()),
                (int) unreadCount,
                state != null && state.isMuted(),
                state != null && state.isPinned()
        );
    }

    private long toEpochMillis(LocalDateTime time) {
        return time == null ? 0L : time.toInstant(ZoneOffset.UTC).toEpochMilli();
    }

    @Async
    protected void dispatchWebhooks(String appId, ImMessageEntity message) {
        List<WebhookConfigEntity> webhooks = webhookRepository.findByAppIdAndEnabledTrue(appId);
        if (webhooks.isEmpty()) return;

        try {
            String body = objectMapper.writeValueAsString(message);
            HttpClient client = HttpClient.newHttpClient();
            for (WebhookConfigEntity webhook : webhooks) {
                try {
                    HttpRequest request = HttpRequest.newBuilder()
                            .uri(URI.create(webhook.getUrl()))
                            .header("Content-Type", "application/json")
                            .POST(HttpRequest.BodyPublishers.ofString(body))
                            .build();
                    client.send(request, HttpResponse.BodyHandlers.ofString());
                } catch (Exception ignored) {
                }
            }
        } catch (Exception ignored) {
        }
    }
}