Implemented logic to output diagnostics log by adding additional outp…

…ut flag

src/core/parser.ts

@@ -12,6 +12,22 @@ import { red, yellow, green, cyan } from 'chalk';
 import type { Diagnostic } from '@asyncapi/parser/cjs';
 import type Command from './base';
 import type { Specification } from './models/SpecificationFile';
+import { promises } from 'fs';
+import path from 'path';
+
+const { writeFile } = promises;
+
+type DiagnosticsFormat = 'stylish' | 'json' | 'junit' | 'html' | 'text' | 'teamcity' | 'pretty';
+
+const formatExtensions: Record<DiagnosticsFormat, string> = {
+  stylish: '.txt',
+  json: '.json',
+  junit: '.xml',
+  html: '.html',
+  text: '.txt',
+  teamcity: '.txt',
+  pretty: '.txt',
+};
 
 export type SeverityKind = 'error' | 'warn' | 'info' | 'hint';
 
@@ -56,13 +72,18 @@ export function validationFlags({ logDiagnostics = true }: ValidationFlagsOption
       options: ['error', 'warn', 'info', 'hint'] as const,
       default: 'error',
     })(),
+    'output': Flags.string({
+      description: 'The output file name. Omitting this flag the result will be printed in the console.',
+      char: 'o' 
+    })
   };
 }
 
 export interface ValidateOptions {
   'log-diagnostics'?: boolean;
   'diagnostics-format'?: `${OutputFormat}`;
   'fail-severity'?: SeverityKind;
+  'output'?: string;
 }
 
 export async function validate(command: Command, specFile: Specification, options: ValidateOptions = {}) {
@@ -86,14 +107,24 @@ function logDiagnostics(diagnostics: Diagnostic[], command: Command, specFile: S
     if (hasFailSeverity(diagnostics, failSeverity)) {
       if (logDiagnostics) {
         command.logToStderr(`\n${sourceString} and/or referenced documents have governance issues.`);
-        command.logToStderr(formatOutput(diagnostics, diagnosticsFormat, failSeverity));
+        const diagnosticsOutput = formatOutput(diagnostics, diagnosticsFormat, failSeverity);
+        if (options.output) {
+          writeValidationDiagnostic(options.output, command, diagnosticsFormat, diagnosticsOutput);
+        } else {
+          command.log(diagnosticsOutput);
+        }
       }
       return ValidationStatus.INVALID;
     }
 
     if (logDiagnostics) {
       command.log(`\n${sourceString} is valid but has (itself and/or referenced documents) governance issues.`);
-      command.log(formatOutput(diagnostics, diagnosticsFormat, failSeverity));
+      const diagnosticsOutput = formatOutput(diagnostics, diagnosticsFormat, failSeverity);
+      if (options.output) {
+        writeValidationDiagnostic(options.output, command, diagnosticsFormat, diagnosticsOutput);
+      } else {
+        command.log(diagnosticsOutput);
+      }
     }
   } else if (logDiagnostics) {
     command.log(`\n${sourceString} is valid! ${sourceString} and referenced documents don't have governance issues.`);
@@ -145,3 +176,18 @@ function hasFailSeverity(diagnostics: Diagnostic[], failSeverity: SeverityKind)
   const diagnosticSeverity = getDiagnosticSeverity(failSeverity);
   return diagnostics.some(diagnostic => diagnostic.severity <= diagnosticSeverity);
 }
+
+async function writeValidationDiagnostic(outputPath: string, command: Command, format: DiagnosticsFormat, formatOutput: string){
+  const expectedExtension = formatExtensions[format];
+  const actualExtension = path.extname(outputPath);
+
+  // Validate file extension against diagnostics format
+  if (expectedExtension && (actualExtension !== expectedExtension)) {
+    command.logToStderr(`Invalid file extension for format "${format}". Expected extension: "${expectedExtension}"`);
+  } else {
+    await writeFile(path.resolve(process.cwd(), outputPath), formatOutput, {
+      encoding: 'utf-8',
+    }).catch(err => console.log(err));
+  }
+
+}