feat: add PDF repair check functionality

packages/repair/src/PDFRepair.ts

@@ -1,14 +1,25 @@
 import { PDFDocument } from "@peculiarventures/pdf-doc";
 import { PDFRepairRegistry, IRepairRule, globalRepairRegistry } from "./PDFRepairRegistry";
+import { PDFRepairStatus } from "./PDFRepairStatus";
 
 /**
  * An object that records repair notes for a PDF file. The keys are rule IDs and the values are arrays of strings
  * containing the repair notes.
  */
-interface RepairNotes {
+export interface RepairNotes {
   [key: string]: string[];
 }
 
+export interface RepairCheckRule {
+  status: PDFRepairStatus;
+  description: string;
+}
+
+export interface RepairCheck {
+  status: PDFRepairStatus;
+  rules: Record<string, RepairCheckRule>;
+}
+
 /**
  * A class for repairing PDF documents by applying a set of rules to them.
  */
@@ -39,4 +50,29 @@ export class PDFRepair {
 
     return repairNotes;
   }
+
+  /**
+   * Checks if a PDF document needs to be repaired.
+   * @param doc - The PDF document to check.
+   * @returns
+   */
+  async checkDocument(doc: PDFDocument): Promise<RepairCheck> {
+    const check: RepairCheck = {
+      status: PDFRepairStatus.notNeeded,
+      rules: {},
+    };
+
+    for (const rule of this.rules) {
+      const status = await rule.check(doc);
+      if (check.status !== PDFRepairStatus.requireClone && status !== PDFRepairStatus.notNeeded) {
+        check.status = status;
+      }
+      check.rules[rule.id] = {
+        status,
+        description: rule.description,
+      };
+    }
+
+    return check;
+  }
 }

packages/repair/src/PDFRepairRegistry.ts

@@ -1,4 +1,5 @@
 import { PDFDocument } from "@peculiarventures/pdf-doc";
+import { PDFRepairStatus } from "./PDFRepairStatus";
 
 /**
  * An interface representing a repair rule for a PDF document.
@@ -18,6 +19,12 @@ export interface IRepairRule {
    * @returns A string representing the repair note generated by the rule, or null if no repair was performed.
    */
   apply: (doc: PDFDocument) => Promise<string[]>;
+  /**
+   * Checks if the repair rule is applicable to a PDF document.
+   * @param doc
+   * @returns An enum value indicating the repair status of the PDF document.
+   */
+  check: (doc: PDFDocument) => Promise<PDFRepairStatus>;
 }
 
 /**

packages/repair/src/PDFRepairStatus.ts

@@ -0,0 +1,19 @@
+
+/**
+ * Represents the repair status of a PDF document.
+ */
+export enum PDFRepairStatus {
+  /**
+   * The PDF document is not repairable. It is either corrupt or malformed.
+   * The document should be fixed via the `PDFDocument.clone()` method.
+   */
+  requireClone = "RequireClone",
+  /**
+   * The PDF document is repairable and doesn't need to be rewritten.
+   */
+  repairable = "Repairable",
+  /**
+   * The PDF document is correctly formatted and does not need to be repaired.
+   */
+  notNeeded = "NotNeeded",
+}