feat: wip import resource

packages/server/src/services/Import/ImportFilePreview.ts

@@ -1,11 +1,98 @@
-import { Service } from 'typedi';
+import { Inject, Service } from 'typedi';
+import { first, omit } from 'lodash';
+import { ServiceError } from '@/exceptions';
+import { ERRORS, getUnmappedSheetColumns } from './_utils';
+import HasTenancyService from '../Tenancy/TenancyService';
+import { ImportFileCommon } from './ImportFileCommon';
+import { ImportFileDataTransformer } from './ImportFileDataTransformer';
+import ResourceService from '../Resource/ResourceService';
 
 @Service()
 export class ImportFilePreview {
+  @Inject()
+  private tenancy: HasTenancyService;
+
+  @Inject()
+  private resource: ResourceService;
+
+  @Inject()
+  private importFileCommon: ImportFileCommon;
+
+  @Inject()
+  private importFileParser: ImportFileDataTransformer;
+
   /**
+   *
+   * - Returns the passed rows and will be in inserted.
+   * - Returns the passed rows will be overwritten.
+   * - Returns the rows errors from the validation.
+   * - Returns the unmapped fields.
    *
    * @param {number} tenantId
    * @param {number} importId
    */
-  public preview(tenantId: number, importId: number) {}
+  public async preview(tenantId: number, importId: number) {
+    const { Import } = this.tenancy.models(tenantId);
+
+    const importFile = await Import.query()
+      .findOne('importId', importId)
+      .throwIfNotFound();
+
+    // Throw error if the import file is not mapped yet.
+    if (!importFile.isMapped) {
+      throw new ServiceError(ERRORS.IMPORT_FILE_NOT_MAPPED);
+    }
+    const buffer = await this.importFileCommon.readImportFile(
+      importFile.filename
+    );
+    const jsonData = this.importFileCommon.parseXlsxSheet(buffer);
+
+    const importableFields = this.resource.getResourceImportableFields(
+      tenantId,
+      importFile.resource
+    );
+    // Prases the sheet json data.
+    const parsedData = this.importFileParser.transformSheetData(
+      importFile,
+      importableFields,
+      jsonData
+    );
+    const knex = this.tenancy.knex(tenantId);
+    const trx = await knex.transaction({ isolationLevel: 'read uncommitted' });
+
+    // Runs the importing operation with ability to return errors that will happen.
+    const asyncOpers = await this.importFileCommon.import(
+      tenantId,
+      importableFields,
+      parsedData,
+      trx
+    );
+    // Filter out the operations that have successed.
+    const successAsyncOpers = asyncOpers.filter((oper) => !oper);
+    const errors = asyncOpers.filter((oper) => oper);
+
+    // Rollback all the successed transactions.
+    await trx.rollback();
+
+    const header = Object.keys(first(jsonData));
+    const mapping = importFile.mappingParsed;
+
+    const unmappedColumns = getUnmappedSheetColumns(header, mapping);
+    const totalCount = parsedData.length;
+
+    const createdCount = successAsyncOpers.length;
+    const errorsCount = errors.length;
+    const skippedCount = errorsCount;
+
+    return {
+      createdCount,
+      skippedCount,
+      totalCount,
+      errorsCount,
+      errors,
+      unmappedColumns: unmappedColumns,
+      unmappedColumnsCount: unmappedColumns.length,
+    };
+  }
+
 }