import { Injectable } from '@nestjs/common';
import * as oracledb from 'oracledb';
import { OracleDBService } from 'src/db/db.service';
import {
  CreateCarnetSequenceDTO,
  GetCarnetSequenceDTO,
} from './carnet-sequence.dto';

@Injectable()
export class CarnetSequenceService {
  constructor(private readonly oracleDBService: OracleDBService) {}

  async createCarnetSequence(body: CreateCarnetSequenceDTO) {
    let connection;
    try {
      connection = await this.oracleDBService.getConnection();
      if (!connection) {
        throw new Error('No DB Connected');
      }

      const result = await connection.execute(
        `BEGIN
                   USCIB_Managed_Pkg.CreateCarnetSequence(
                    :p_spid,
                    :p_regionid,
                    :p_startnumber,
                    :p_endnumber,
                    :p_carnettype,
                    :p_cursor);
                 END;`,
        {
          p_spid: {
            val: body.p_spid,
            type: oracledb.DB_TYPE_NUMBER,
          },
          p_regionid: {
            val: body.p_regionid,
            type: oracledb.DB_TYPE_NUMBER,
          },
          p_startnumber: {
            val: body.p_startnumber,
            type: oracledb.DB_TYPE_NUMBER,
          },
          p_endnumber: {
            val: body.p_endnumber,
            type: oracledb.DB_TYPE_NUMBER,
          },
          p_carnettype: {
            val: body.p_carnettype,
            type: oracledb.DB_TYPE_VARCHAR,
          },
          p_cursor: {
            type: oracledb.CURSOR,
            dir: oracledb.BIND_OUT,
          },
        },
        {
          outFormat: oracledb.OUT_FORMAT_OBJECT,
        },
      );

      await connection.commit();

      const fres = await result.outBinds.p_cursor.getRows();

      await result.outBinds.p_cursor.close();

      return fres;
    } catch (err) {
      if (err instanceof Error) {
        return { error: err.message };
      } else {
        return { error: 'An unknown error occurred' };
      }
    }
    finally {
      if (connection) {
        try {
          await connection.close();
        } catch (closeErr) {
          console.error('Failed to close connection:', closeErr);
        }
      }
    }
  }

  async getCarnetSequence(body: GetCarnetSequenceDTO) {
    let connection;
    let rows = [];
    try {
      // Connect to the Oracle database using oracledb
      connection = await this.oracleDBService.getConnection();
      if (!connection) {
        throw new Error('No DB Connected');
      }

      const result = await connection.execute(
        `BEGIN
                    USCIB_Managed_Pkg.GetCarnetSequence(:p_spid,:p_cursor);
                END;`,
        {
          p_spid: {
            val: body.p_spid,
            type: oracledb.DB_TYPE_NUMBER,
          },
          p_cursor: {
            type: oracledb.CURSOR,
            dir: oracledb.BIND_OUT,
          },
        },
        {
          outFormat: oracledb.OUT_FORMAT_OBJECT,
        },
      );

      if (result.outBinds && result.outBinds.p_cursor) {
        const cursor = result.outBinds.p_cursor;
        let rowsBatch;

        do {
          rowsBatch = await cursor.getRows(100); // Fetch 100 rows at a time
          rows = rows.concat(rowsBatch);
        } while (rowsBatch.length > 0);

        await cursor.close();
      } else {
        throw new Error('No cursor returned from the stored procedure');
      }

      return rows;
    } catch (err) {
      if (err instanceof Error) {
        return { error: err.message };
      } else {
        return { error: 'An unknown error occurred' };
      }
    }
    finally {
      if (connection) {
        try {
          await connection.close();
        } catch (closeErr) {
          console.error('Failed to close connection:', closeErr);
        }
      }
    }
  }
}