import { Injectable, Logger, OnModuleInit } from "@nestjs/common";
import { InjectModel } from "@nestjs/mongoose";
import { FilterQuery, Model, UpdateQuery } from "mongoose";
import { ClientModel, ClientDocument } from "../schema/client.schema";

@Injectable()
export class ClientDbService implements OnModuleInit {
  private readonly logger = new Logger(ClientDbService.name);

  constructor(
    @InjectModel(ClientModel.name)
    private readonly clientModel: Model<ClientModel>,
  ) {}

  async onModuleInit(): Promise<void> {
    await this.dropLegacyPropertyUniqueIndex();
  }

  /**
   * `property` was once declared `unique: true` in the schema. Production keeps
   * `autoIndex: false`, so the stale unique index remained and rejected a second
   * client with a missing/null SMS key (E11000 duplicate key).
   */
  private async dropLegacyPropertyUniqueIndex(): Promise<void> {
    try {
      const indexes = await this.clientModel.collection.indexes();
      for (const index of indexes) {
        if (!index.unique || !index.name || index.name === "_id_") continue;

        const keys = Object.keys(index.key ?? {});
        const isLegacyPropertyIndex =
          keys.length === 1 &&
          (keys[0] === "property" || keys[0] === "property.smsApiKey");

        if (!isLegacyPropertyIndex) continue;

        await this.clientModel.collection.dropIndex(index.name);
        this.logger.warn(
          `Dropped legacy unique index on clients.${keys[0]}: ${index.name}`,
        );
      }
    } catch (err) {
      this.logger.error("Failed to drop legacy client property index", err);
    }
  }

  async create(client: ClientModel): Promise<ClientModel> {
    return await this.clientModel.create(client);
  }

  async find(client: FilterQuery<ClientModel>): Promise<ClientDocument> {
    return await this.clientModel.findOne(client);
  }

  async findOne(client: FilterQuery<ClientModel>) {
    return this.clientModel.findOne(client);
  }

  async findAll(): Promise<ClientModel[]> {
    return await this.clientModel.find();
  }

  async findByIdAndUpdate(
    id: string,
    update: UpdateQuery<ClientModel>,
  ): Promise<ClientModel | null> {
    return this.clientModel
      .findByIdAndUpdate(id, update, { new: true })
      .lean()
      .exec();
  }
}