import { Injectable } from '@nestjs/common';
import { OracleDBService } from 'src/db/db.service';
import * as oracledb from 'oracledb';
import { InsertRegionsDto, UpdateRegionDto } from './region.dto';

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

  async insertRegions(body: InsertRegionsDto) {
    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.InsertNewRegion(:p_region,:p_name,:p_cursor);
                END;`,
        {
          p_region: {
            val: body.p_region,
            type: oracledb.DB_TYPE_VARCHAR,
          },
          p_name: {
            val: body.p_name,
            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();

      return fres;
    } catch (err) {
      if (err instanceof Error) {
        return { error: err.message };
      } else {
        return { error: 'An unknown error occurred' };
      }
    }
  }

  async updateRegions(body: UpdateRegionDto) {
    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.UpdateRegion(:p_regionID,:p_name,:p_cursor);
                END;`,
        {
          p_regionID: {
            val: body.p_regionID,
            type: oracledb.DB_TYPE_NUMBER,
          },
          p_name: {
            val: body.p_name,
            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();

      return fres;
    } catch (err) {
      if (err instanceof Error) {
        return { error: err.message };
      } else {
        return { error: 'An unknown error occurred' };
      }
    }
  }

  async getRegions() {
    let connection;
    let rows = [];
    try {
      try {
        connection = await this.oracleDBService.getConnection();
      } catch (err) {
        console.log('DB ERROR:  ', err);
        return { error: 'Error while connecting to DB' };
      }
      const result = await connection.execute(
        `BEGIN
                        USCIB_Managed_Pkg.GetRegions(:p_cursor);
                    END;`,
        {
          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);
          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' };
      }
    }
  }
}