Add to readFile functionality for png badges

app/lib/import.ts

@@ -3,14 +3,101 @@ import * as RNFS from 'react-native-fs';
 
 import { ProfileRecord } from '../model';
 import { CredentialImportReport } from '../types/credential';
-
+import { Buffer } from '@craftzdog/react-native-buffer';
 export type ReportDetails = Record<string, string[]>;
 
 export async function readFile(path: string): Promise<string> {
-  const decodedPath = path.replace(/%20/g, ' ');
-  return RNFS.readFile(decodedPath, 'utf8');
+  let fileContent: string = '';
+  let openBadgeCredential = '';
+  try {
+    // Extract the file extension from the resolved/provided path
+    const fileExtension = getFileExtension(path);
+
+    if (fileExtension === 'png') {    
+      // Read the PNG file as base64
+      const base64Image = await RNFS.readFile(path, 'base64');
+
+      const decodedString = Buffer.from(base64Image, 'base64').toString('utf8');
+
+      // Search for keyword and extract the object following it
+      const keyword = 'openbadgecredential';  
+      const keywordIndex = decodedString.indexOf(keyword);
+
+      // Check if the keyword is found
+      if (keywordIndex !== -1) {
+        // Extract the portion of the string after the keyword
+        const startIndex = keywordIndex + keyword.length;
+
+        // Find start of the object
+        const objectStart = decodedString.indexOf('{', startIndex);
+
+        if (objectStart !== -1) {
+          // Find matching closing brace
+          let braceCount = 0;
+          let objectEnd = objectStart;
+
+          while (objectEnd < decodedString.length) {
+            if (decodedString[objectEnd] === '{') {
+              braceCount++;
+            } else if (decodedString[objectEnd] === '}') {
+              braceCount--;
+            }
+
+            // When brace count goes back to zero = found the end of object
+            if (braceCount === 0) {
+              break;
+            }
+
+            objectEnd++;
+          }
+
+          // Slice string to capture the entire object (including braces)
+          const objectString = decodedString.slice(objectStart, objectEnd + 1);
+
+          // Parse object
+          try {
+            const parsedObject = JSON.parse(objectString);
+            openBadgeCredential = JSON.stringify(parsedObject, null, 2);
+          } catch (error) {
+            console.error('Failed to parse JSON:', error);
+          }
+        } 
+      } else {
+        console.log('Keyword not found');
+      }
+
+      fileContent = openBadgeCredential;
+
+    } else {
+      // For other file types (text, etc.), read as UTF-8
+      const decodedPath = path.replace(/%20/g, ' ');
+      fileContent = await RNFS.readFile(decodedPath, 'utf8');
+    }
+
+  } catch (error) {
+    console.error('Error reading file:', error);
+    fileContent = '';  // Handle error, fallback value
+  }
+
+  if (fileContent === undefined) {
+    throw new Error('File content could not be determined');
+  }
+
+  return fileContent;
 }
 
+// Utility function to extract file extension
+function getFileExtension(path: string): string {
+  // Check if the path ends with a file extension like ".png"
+  const regex = /(?:\.([^.]+))?$/;
+  const match = path.match(regex);
+  if (match && match[1]) {
+    return match[1].toLowerCase(); // Return the extension in lowercase (e.g., png, jpg)
+  }
+  return ''; // If no extension found, return an empty string
+}
+
+
 export async function pickAndReadFile(): Promise<string> {
   const { uri } = await DocumentPicker.pickSingle({
     type: DocumentPicker.types.allFiles,