import { Injectable, Logger } from '@nestjs/common';
import { OracleDBService } from 'src/db/db.service';
import * as oracledb from 'oracledb';
import { InsertRegionsDto, UpdateRegionDto } from './region.dto';
import { BadRequestException } from 'src/exceptions/badRequest.exception';
import { InternalServerException } from 'src/exceptions/internalServerError.exception';

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

  constructor(private readonly oracleDBService: OracleDBService) { }

  async insertRegions(body: InsertRegionsDto) {
    let connection;
    try {
      connection = await this.oracleDBService.getConnection();
      if (!connection) {
        throw new InternalServerException();
      }

      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();

      if (fres[0].ERRORMESG) {
        this.logger.warn(fres[0].ERRORMESG);
        throw new BadRequestException(fres[0].ERRORMESG)
      }

      return fres;
    } catch (error) {
      if (error instanceof BadRequestException) {
        this.logger.warn(error.message);
        throw error;
      }
      this.logger.error('insertRegions failed', error.stack || error);
      throw new InternalServerException();
    } finally {
      if (connection) {
        try {
          await connection.close();
        } catch (closeErr) {
          this.logger.error('Failed to close DB connection', closeErr);
        }
      }
    }
  }

  async updateRegions(body: UpdateRegionDto) {
    let connection;
    try {
      connection = await this.oracleDBService.getConnection();
      if (!connection) {
        throw new InternalServerException();
      }

      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();

      if (fres[0].ERRORMESG) {
        this.logger.warn(fres[0].ERRORMESG);
        throw new BadRequestException(fres[0].ERRORMESG)
      }

      return fres;
    } catch (error) {
      if (error instanceof BadRequestException) {
        this.logger.warn(error.message);
        throw error;
      }
      this.logger.error('updateRegions failed', error.stack || error);
      throw new InternalServerException();
    } finally {
      if (connection) {
        try {
          await connection.close();
        } catch (closeErr) {
          this.logger.error('Failed to close DB connection', closeErr);
        }
      }
    }
  }

  async getRegions() {
    let connection;
    let rows = [];
    try {

      connection = await this.oracleDBService.getConnection();
      if (!connection) {
        throw new InternalServerException()
      }

      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 BadRequestException();
      }

      return rows;
    } catch (error) {
      if (error instanceof BadRequestException) {
        this.logger.warn(error.message);
        throw error;
      }
      else if (error.message === "NJS-107: invalid cursor") {
        this.logger.warn(error.message);
        throw new BadRequestException();
      }
      this.logger.error('GETBASICFEERATES failed', error.stack || error);
      throw new InternalServerException();
    } finally {
      if (connection) {
        try {
          await connection.close();
        } catch (closeErr) {
          this.logger.error('Failed to close DB connection', closeErr);
        }
      }
    }
  }
}