feat(knowledge): add link resolution service

- Add resolveLinksFromContent() to parse wiki links from content and resolve them
- Add getBacklinks() to find all entries that link to a target entry
- Import parseWikiLinks from utils for content parsing
- Export new types: ResolvedLink, Backlink
- Add comprehensive tests for new functionality (27 tests total)

apps/api/src/knowledge/services/link-resolution.service.ts

@@ -1,5 +1,6 @@
 import { Injectable } from "@nestjs/common";
 import { PrismaService } from "../../prisma/prisma.service";
+import { parseWikiLinks, WikiLink } from "../utils/wiki-link-parser";
 
 /**
  * Represents a knowledge entry that matches a link target
@@ -9,6 +10,32 @@ export interface ResolvedEntry {
   title: string;
 }
 
+/**
+ * Represents a resolved wiki link with entry information
+ */
+export interface ResolvedLink {
+  /** The parsed wiki link */
+  link: WikiLink;
+  /** The resolved entry ID, or null if not found */
+  entryId: string | null;
+}
+
+/**
+ * Represents a backlink - an entry that links to a target entry
+ */
+export interface Backlink {
+  /** The source entry ID */
+  sourceId: string;
+  /** The source entry title */
+  sourceTitle: string;
+  /** The source entry slug */
+  sourceSlug: string;
+  /** The link text used to reference the target */
+  linkText: string;
+  /** The display text shown for the link */
+  displayText: string;
+}
+
 /**
  * Service for resolving wiki-style links to knowledge entries
  *
@@ -165,4 +192,72 @@ export class LinkResolutionService {
 
     return matches;
   }
+
+  /**
+   * Parse wiki links from content and resolve them to knowledge entries
+   *
+   * @param content - The markdown content containing wiki links
+   * @param workspaceId - The workspace scope for resolution
+   * @returns Array of resolved links with entry IDs (or null if not found)
+   */
+  async resolveLinksFromContent(
+    content: string,
+    workspaceId: string
+  ): Promise<ResolvedLink[]> {
+    // Parse wiki links from content
+    const parsedLinks = parseWikiLinks(content);
+
+    if (parsedLinks.length === 0) {
+      return [];
+    }
+
+    // Resolve each link
+    const resolvedLinks: ResolvedLink[] = [];
+
+    for (const link of parsedLinks) {
+      const entryId = await this.resolveLink(workspaceId, link.target);
+      resolvedLinks.push({
+        link,
+        entryId,
+      });
+    }
+
+    return resolvedLinks;
+  }
+
+  /**
+   * Get all entries that link TO a specific entry (backlinks)
+   *
+   * @param entryId - The target entry ID
+   * @returns Array of backlinks with source entry information
+   */
+  async getBacklinks(entryId: string): Promise<Backlink[]> {
+    // Find all links where this entry is the target
+    const links = await this.prisma.knowledgeLink.findMany({
+      where: {
+        targetId: entryId,
+        resolved: true,
+      },
+      include: {
+        source: {
+          select: {
+            id: true,
+            title: true,
+            slug: true,
+          },
+        },
+      },
+      orderBy: {
+        createdAt: "desc",
+      },
+    });
+
+    return links.map((link) => ({
+      sourceId: link.source.id,
+      sourceTitle: link.source.title,
+      sourceSlug: link.source.slug,
+      linkText: link.linkText,
+      displayText: link.displayText,
+    }));
+  }
 }