import { HttpException, HttpStatus, Injectable, Optional, Inject } from '@nestjs/common';
import { InjectModel } from '@nestjs/mongoose';
import { FilterQuery, Model, Types } from 'mongoose';
import { BaseResponseDTO } from 'src/common/dto/base-response.dto';
import { Role } from 'src/common/types/role.type';
import { AdminDocument, AdminModel } from 'src/database/model/admin.model';
import { SessionModel } from 'src/database/model/sessions.model';
import { UserModel } from 'src/database/model/user.model';
import { ReassignedLogsModel } from 'src/database/model/reassigned-logs.model';
import { ChatService } from 'src/socket/support-management/chat.service';
import { RedisService } from 'src/common/helpers/redis.service';
import { CreateAdminDto } from './dto/create-admin.dto';
import { EditProfileDto } from './dto/edit-profile.dto';
import { createExpertDto } from './dto/create-new-expert.dto';
import * as crypto from 'node:crypto';

@Injectable()
export class AdminService {
  constructor(
    @InjectModel(AdminModel.name)
    private readonly adminModel: Model<AdminModel>,
    @InjectModel(SessionModel.name)
    private readonly sessionModel: Model<SessionModel>,
    @InjectModel(UserModel.name)
    private readonly userModel: Model<UserModel>,
    @InjectModel(ReassignedLogsModel.name)
    private readonly reassignedLogsModel: Model<ReassignedLogsModel>,
    @Optional() @Inject(ChatService)
    private readonly chatService: ChatService | null,
    private readonly redisService: RedisService,
  ) {}

  async create(createAdminDto: CreateAdminDto, role: Role.Admin | Role.Expert | Role.Supervisor) {
    return await this.adminModel.create({
      ...createAdminDto,
      username: createAdminDto.email,
      role: role,
    });
  }

  async findOneAdmin(query: FilterQuery<AdminModel>): Promise<AdminDocument> {
    return await this.adminModel.findOne(query);
  }

  async getProfile(adminIdentity): Promise<any> {
    try {
      const admin = await this.adminModel
        .findOne(
          {
            _id: new Types.ObjectId(adminIdentity.userData._id),
            isActive: true,
          },
          { password: 0, resetToken: 0 },
        )
        .populate('avatar');

      if (!admin) throw new HttpException('not_found', HttpStatus.NOT_FOUND);

      // Use expert's email to find sessions (expert field stores email)
      const expertEmail = admin.email;

      // Calculate total answered: sessions where expert actually connected (connectedToExpert === true)
      // and the expert field matches this expert's email
      const answeredSessions = await this.sessionModel.find({
        expert: expertEmail,
        connectedToExpert: true,
        onlineStartDate: { $exists: true },
      });

      // Calculate activity time (sum of all answered session durations in seconds)
      const activityTime = Math.round(
        answeredSessions.reduce((total, session) => {
          if (session.onlineStartDate && session.onlineEndDate) {
            const duration =
              (session.onlineEndDate.getTime() -
                session.onlineStartDate.getTime()) /
              1000;
            // Only add positive durations to avoid negative activity time
            return total + (duration > 0 ? duration : 0);
          }
          return total;
        }, 0),
      );

      // Calculate total answered (sessions where expert connected)
      const totalAnswered = answeredSessions.length;

      // Calculate total not answered: count from reassigned_logs where this expert missed the chat
      // (reassigned from them, meaning they were online but didn't answer)
      const totalNotAnswered = await this.reassignedLogsModel.countDocuments({
        from: expertEmail,
      });

      // Calculate total sessions (answered + not answered)
      const totalSessions = totalAnswered + totalNotAnswered;

      // Calculate total rate (average of all non-null rates from answered sessions)
      const rates = answeredSessions
        .filter(
          (session) =>
            session.expertRate !== null && session.expertRate !== undefined,
        )
        .map((session) => session.expertRate);
      const totalRate =
        rates.length > 0
          ? parseFloat((rates.reduce((sum, rate) => sum + rate, 0) / rates.length).toFixed(2))
          : 0;

      return new BaseResponseDTO(HttpStatus.OK, 'SUCCESS', {
        _id: admin._id,
        name: admin.name,
        family: admin.family,
        mobile: admin.mobile,
        email: admin.email,
        username: admin.username,
        role: admin.role,
        isActive: admin.isActive,
        avatar: admin.avatar
          ? `https://${process.env.BASEURL}/${(admin.avatar as any).filePath}`
          : null,
        birthDate: admin.birthDate,
        reports: {
          activityTime,
          totalSessions,
          totalAnswered,
          totalNotAnswered,
          totalRate,
          currentNotActive: 0, // Will be implemented later
        },
      });
    } catch (err) {
      console.log(err);
      throw new HttpException(err.message, HttpStatus.BAD_REQUEST);
    }
  }

  async createNewExpert(body:createExpertDto,adminIdentity:any){
    try {
      const existingExpert = await this.adminModel.findOne<AdminModel | null>({ // Explicitly type existingExpert as AdminModel | null
        $or: [{ email: body.email }, { mobile: body.mobile }],
      });

      if (existingExpert) {
        throw new HttpException('Expert with this email or mobile already exists', HttpStatus.BAD_REQUEST);
      }
      const hashedPassword = crypto.createHash('sha256').update(body.password).digest('hex');

      const newExpert = await this.adminModel.create({
        email: body.email,
        password: hashedPassword,
        mobile: body.mobile,
        name: body.name,
        family: body.family,
        role: 'expert',
        username: body.email, // Set username to email
      });

      // Exclude password from the returned object
      const { password, ...expertWithoutPassword } = newExpert.toObject();

      return new BaseResponseDTO(HttpStatus.CREATED, 'Expert created successfully', expertWithoutPassword);
    } catch (err) {
      console.log(err);
      throw new HttpException(err.message, HttpStatus.BAD_REQUEST);
    }
  }

  async modifyProfile(body: EditProfileDto, adminIdentity: any) {
    const admin = await this.adminModel.findOne({
      _id: new Types.ObjectId(adminIdentity.userData._id),
      isActive: true,
    });

    if (!admin) {
      throw new HttpException('not_found', HttpStatus.NOT_FOUND);
    }

    const updatePayload: any = { ...body };

    const updatedUser = await this.adminModel
      .findByIdAndUpdate(adminIdentity.userData._id, updatePayload, {
        new: true,
        projection: {
          _id: 1,
          role: 1,
          mobile: 1,
          email: 1,
          username: 1,
          name: 1,
          family: 1,
          createdAt: 1,
          updatedAt: 1,
          birthDate: 1,
          birthday: 1,
          avatar: 1,
        },
      })
      .populate('avatar');

    return updatedUser;
  }

  async toggleExpertActivation(expertId: string): Promise<BaseResponseDTO> {
    try {
      const expert = await this.adminModel.findOne({
        _id: new Types.ObjectId(expertId),
        role: Role.Expert,
      });

      if (!expert) {
        throw new HttpException('Expert not found', HttpStatus.NOT_FOUND);
      }

      expert.isActive = !expert.isActive;
      await expert.save();

      const message = expert.isActive ? 'Expert activated successfully' : 'Expert deactivated successfully';
      const { password, ...expertWithoutPassword } = expert.toObject();
      return new BaseResponseDTO(HttpStatus.OK, message, expertWithoutPassword);
    } catch (err) {
      console.log(err);
      throw new HttpException(err.message, HttpStatus.BAD_REQUEST);
    }
  }

  async getDashboard(): Promise<BaseResponseDTO> {
    try {
      const redisClient = this.redisService.getClient();
      const ONLINE_EXPERTS_KEY = 'onlineExperts';
      const ROOMS_HASH_KEY = 'rooms:active';
      const WAITING_QUEUE_KEY = 'waitingQueue';
      const WAITING_USERS_KEY = 'waiting_users';

      // Get all experts from Redis onlineExperts hash
      let allExpertsFromRedis: any[] = [];
      try {
        const onlineExpertsEntries = await redisClient.hgetall(ONLINE_EXPERTS_KEY);
        allExpertsFromRedis = Object.values(onlineExpertsEntries)
          .map((v) => {
            try {
              return JSON.parse(v as string);
            } catch {
              return null;
            }
          })
          .filter((expert: any) => expert);
      } catch (err) {
        console.error('Error getting experts from Redis:', err);
      }

      // 1. تعداد کارشناس در حال مکالمه - Number of experts currently in conversation
      // Experts who have activeSessions > 0
      const expertsInConversation = allExpertsFromRedis.filter(
        (expert: any) => expert.activeSessions > 0
      );
      const expertsInConversationCount = expertsInConversation.length;

      // 2. تعداد کارشناس آنلاین - Number of online experts
      // Experts who are marked as online OR have active sessions (if in conversation, they should be online)
      const onlineExpertIds = new Set<string>();
      allExpertsFromRedis.forEach((expert: any) => {
        if (expert.isOnline === true || expert.activeSessions > 0) {
          onlineExpertIds.add(expert.expertId);
        }
      });
      const onlineExpertsCount = onlineExpertIds.size;

      // 3. تعداد کاربر در حال مکاتبه با کارشناس - Number of users currently chatting with expert
      // Each room in rooms:active represents one active chat session
      // Since each user can only have one active expert session, counting active rooms = counting unique users
      let usersWithExpert = 0;
      try {
        if (this.chatService) {
          const activeRooms = await this.chatService.getActiveRooms();
          usersWithExpert = activeRooms ? activeRooms.length : 0;
        } else {
          // Fallback: get directly from Redis if chatService is not available
          const roomsEntries = await redisClient.hgetall(ROOMS_HASH_KEY);
          const activeRooms = Object.values(roomsEntries)
            .map((v) => {
              try {
                return JSON.parse(v as string);
              } catch {
                return null;
              }
            })
            .filter((room: any) => room && room.isActive);
          
          usersWithExpert = activeRooms.length;
        }
      } catch (err) {
        console.error('Error getting users with expert from Redis:', err);
      }

      // 4. تعداد کاربر در انتظار ارتباط با کارشناس - Number of users waiting to connect with expert
      // Get from Redis waitingQueue list and waiting_users hash
      let waitingUsersCount = 0;
      try {
        const waitingQueueLength = await redisClient.llen(WAITING_QUEUE_KEY);
        const waitingUsersKeys = await redisClient.hkeys(WAITING_USERS_KEY);
        waitingUsersCount = waitingQueueLength + waitingUsersKeys.length;
      } catch (err) {
        console.error('Error getting waiting users from Redis:', err);
      }

      // 5. تعداد کاربر چت بات - Number of chatbot users (total unique users with sessions)
      const totalChatbotUsers = await this.sessionModel.distinct('userId').then(ids => ids.length);

      // 6. تعداد کاربر بیمه گذار چت بات - Number of insurance holder chatbot users
      // Users with nationalCode who have sessions
      const usersWithSessions = await this.sessionModel.distinct('userId');
      const insuranceHolderUsers = await this.userModel.countDocuments({
        _id: { $in: usersWithSessions },
        nationalCode: { $exists: true, $nin: [null, ''] },
      });

      return new BaseResponseDTO(HttpStatus.OK, 'SUCCESS', {
        expertsInConversation: expertsInConversationCount,
        onlineExperts: onlineExpertsCount,
        usersWithExpert: usersWithExpert,
        waitingUsers: waitingUsersCount,
        totalChatbotUsers: totalChatbotUsers,
        insuranceHolderUsers: insuranceHolderUsers,
      });
    } catch (err) {
      console.error('Error in getDashboard:', err);
      throw new HttpException(
        err.message || 'Failed to fetch dashboard data',
        HttpStatus.INTERNAL_SERVER_ERROR,
      );
    }
  }
}