apps/api/src/knowledge/knowledge.module.ts

@@ -3,11 +3,12 @@ import { PrismaModule } from "../prisma/prisma.module";
 import { AuthModule } from "../auth/auth.module";
 import { KnowledgeService } from "./knowledge.service";
 import { KnowledgeController } from "./knowledge.controller";
+import { LinkResolutionService } from "./services/link-resolution.service";
 
 @Module({
   imports: [PrismaModule, AuthModule],
   controllers: [KnowledgeController],
-  providers: [KnowledgeService],
-  exports: [KnowledgeService],
+  providers: [KnowledgeService, LinkResolutionService],
+  exports: [KnowledgeService, LinkResolutionService],
 })
 export class KnowledgeModule {}

apps/api/src/knowledge/services/index.ts

@@ -0,0 +1,2 @@
+export { LinkResolutionService } from "./link-resolution.service";
+export type { ResolvedEntry } from "./link-resolution.service";

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

@@ -0,0 +1,406 @@
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { Test, TestingModule } from "@nestjs/testing";
+import { LinkResolutionService } from "./link-resolution.service";
+import { PrismaService } from "../../prisma/prisma.service";
+
+describe("LinkResolutionService", () => {
+  let service: LinkResolutionService;
+  let prisma: PrismaService;
+
+  const workspaceId = "workspace-123";
+
+  const mockEntries = [
+    {
+      id: "entry-1",
+      workspaceId,
+      slug: "typescript-guide",
+      title: "TypeScript Guide",
+      content: "...",
+      contentHtml: "...",
+      summary: null,
+      status: "PUBLISHED",
+      visibility: "WORKSPACE",
+      createdAt: new Date(),
+      updatedAt: new Date(),
+      createdBy: "user-1",
+      updatedBy: "user-1",
+    },
+    {
+      id: "entry-2",
+      workspaceId,
+      slug: "react-hooks",
+      title: "React Hooks",
+      content: "...",
+      contentHtml: "...",
+      summary: null,
+      status: "PUBLISHED",
+      visibility: "WORKSPACE",
+      createdAt: new Date(),
+      updatedAt: new Date(),
+      createdBy: "user-1",
+      updatedBy: "user-1",
+    },
+    {
+      id: "entry-3",
+      workspaceId,
+      slug: "react-hooks-advanced",
+      title: "React Hooks Advanced",
+      content: "...",
+      contentHtml: "...",
+      summary: null,
+      status: "PUBLISHED",
+      visibility: "WORKSPACE",
+      createdAt: new Date(),
+      updatedAt: new Date(),
+      createdBy: "user-1",
+      updatedBy: "user-1",
+    },
+  ];
+
+  const mockPrismaService = {
+    knowledgeEntry: {
+      findUnique: vi.fn(),
+      findFirst: vi.fn(),
+      findMany: vi.fn(),
+    },
+  };
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        LinkResolutionService,
+        {
+          provide: PrismaService,
+          useValue: mockPrismaService,
+        },
+      ],
+    }).compile();
+
+    service = module.get<LinkResolutionService>(LinkResolutionService);
+    prisma = module.get<PrismaService>(PrismaService);
+
+    vi.clearAllMocks();
+  });
+
+  describe("resolveLink", () => {
+    describe("Exact title match", () => {
+      it("should resolve link by exact title match", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(
+          mockEntries[0]
+        );
+
+        const result = await service.resolveLink(
+          workspaceId,
+          "TypeScript Guide"
+        );
+
+        expect(result).toBe("entry-1");
+        expect(mockPrismaService.knowledgeEntry.findFirst).toHaveBeenCalledWith(
+          {
+            where: {
+              workspaceId,
+              title: "TypeScript Guide",
+            },
+            select: {
+              id: true,
+            },
+          }
+        );
+      });
+
+      it("should be case-sensitive for exact title match", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findUnique.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([]);
+
+        const result = await service.resolveLink(
+          workspaceId,
+          "typescript guide"
+        );
+
+        expect(result).toBeNull();
+      });
+    });
+
+    describe("Slug match", () => {
+      it("should resolve link by slug", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findUnique.mockResolvedValueOnce(
+          mockEntries[0]
+        );
+
+        const result = await service.resolveLink(
+          workspaceId,
+          "typescript-guide"
+        );
+
+        expect(result).toBe("entry-1");
+        expect(mockPrismaService.knowledgeEntry.findUnique).toHaveBeenCalledWith(
+          {
+            where: {
+              workspaceId_slug: {
+                workspaceId,
+                slug: "typescript-guide",
+              },
+            },
+            select: {
+              id: true,
+            },
+          }
+        );
+      });
+
+      it("should prioritize exact title match over slug match", async () => {
+        // If exact title matches, slug should not be checked
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(
+          mockEntries[0]
+        );
+
+        const result = await service.resolveLink(
+          workspaceId,
+          "TypeScript Guide"
+        );
+
+        expect(result).toBe("entry-1");
+        expect(mockPrismaService.knowledgeEntry.findUnique).not.toHaveBeenCalled();
+      });
+    });
+
+    describe("Fuzzy title match", () => {
+      it("should resolve link by case-insensitive fuzzy match", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findUnique.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([
+          mockEntries[0],
+        ]);
+
+        const result = await service.resolveLink(
+          workspaceId,
+          "typescript guide"
+        );
+
+        expect(result).toBe("entry-1");
+        expect(mockPrismaService.knowledgeEntry.findMany).toHaveBeenCalledWith({
+          where: {
+            workspaceId,
+            title: {
+              mode: "insensitive",
+              equals: "typescript guide",
+            },
+          },
+          select: {
+            id: true,
+            title: true,
+          },
+        });
+      });
+
+      it("should return null when fuzzy match finds multiple results", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findUnique.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([
+          mockEntries[1],
+          mockEntries[2],
+        ]);
+
+        const result = await service.resolveLink(workspaceId, "react hooks");
+
+        expect(result).toBeNull();
+      });
+
+      it("should return null when no match is found", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findUnique.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([]);
+
+        const result = await service.resolveLink(
+          workspaceId,
+          "Non-existent Entry"
+        );
+
+        expect(result).toBeNull();
+      });
+    });
+
+    describe("Workspace scoping", () => {
+      it("should only resolve links within the specified workspace", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findUnique.mockResolvedValueOnce(null);
+        mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([]);
+
+        await service.resolveLink("different-workspace", "TypeScript Guide");
+
+        expect(mockPrismaService.knowledgeEntry.findFirst).toHaveBeenCalledWith(
+          expect.objectContaining({
+            where: expect.objectContaining({
+              workspaceId: "different-workspace",
+            }),
+          })
+        );
+      });
+    });
+
+    describe("Edge cases", () => {
+      it("should handle empty string input", async () => {
+        const result = await service.resolveLink(workspaceId, "");
+
+        expect(result).toBeNull();
+        expect(mockPrismaService.knowledgeEntry.findFirst).not.toHaveBeenCalled();
+      });
+
+      it("should handle null input", async () => {
+        const result = await service.resolveLink(workspaceId, null as any);
+
+        expect(result).toBeNull();
+        expect(mockPrismaService.knowledgeEntry.findFirst).not.toHaveBeenCalled();
+      });
+
+      it("should handle whitespace-only input", async () => {
+        const result = await service.resolveLink(workspaceId, "   ");
+
+        expect(result).toBeNull();
+        expect(mockPrismaService.knowledgeEntry.findFirst).not.toHaveBeenCalled();
+      });
+
+      it("should trim whitespace from target before resolving", async () => {
+        mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(
+          mockEntries[0]
+        );
+
+        const result = await service.resolveLink(
+          workspaceId,
+          "  TypeScript Guide  "
+        );
+
+        expect(result).toBe("entry-1");
+        expect(mockPrismaService.knowledgeEntry.findFirst).toHaveBeenCalledWith(
+          expect.objectContaining({
+            where: expect.objectContaining({
+              title: "TypeScript Guide",
+            }),
+          })
+        );
+      });
+    });
+  });
+
+  describe("resolveLinks", () => {
+    it("should resolve multiple links in batch", async () => {
+      // First link: "TypeScript Guide" -> exact title match
+      // Second link: "react-hooks" -> slug match
+      mockPrismaService.knowledgeEntry.findFirst.mockImplementation(
+        async ({ where }: any) => {
+          if (where.title === "TypeScript Guide") {
+            return mockEntries[0];
+          }
+          return null;
+        }
+      );
+
+      mockPrismaService.knowledgeEntry.findUnique.mockImplementation(
+        async ({ where }: any) => {
+          if (where.workspaceId_slug?.slug === "react-hooks") {
+            return mockEntries[1];
+          }
+          return null;
+        }
+      );
+
+      mockPrismaService.knowledgeEntry.findMany.mockResolvedValue([]);
+
+      const targets = ["TypeScript Guide", "react-hooks"];
+      const result = await service.resolveLinks(workspaceId, targets);
+
+      expect(result).toEqual({
+        "TypeScript Guide": "entry-1",
+        "react-hooks": "entry-2",
+      });
+    });
+
+    it("should handle empty array", async () => {
+      const result = await service.resolveLinks(workspaceId, []);
+
+      expect(result).toEqual({});
+      expect(mockPrismaService.knowledgeEntry.findFirst).not.toHaveBeenCalled();
+    });
+
+    it("should handle unresolved links", async () => {
+      mockPrismaService.knowledgeEntry.findFirst.mockResolvedValue(null);
+      mockPrismaService.knowledgeEntry.findUnique.mockResolvedValue(null);
+      mockPrismaService.knowledgeEntry.findMany.mockResolvedValue([]);
+
+      const result = await service.resolveLinks(workspaceId, [
+        "Non-existent",
+        "Another-Non-existent",
+      ]);
+
+      expect(result).toEqual({
+        "Non-existent": null,
+        "Another-Non-existent": null,
+      });
+    });
+
+    it("should deduplicate targets", async () => {
+      mockPrismaService.knowledgeEntry.findFirst.mockResolvedValueOnce(
+        mockEntries[0]
+      );
+
+      const result = await service.resolveLinks(workspaceId, [
+        "TypeScript Guide",
+        "TypeScript Guide",
+      ]);
+
+      expect(result).toEqual({
+        "TypeScript Guide": "entry-1",
+      });
+      // Should only be called once for the deduplicated target
+      expect(mockPrismaService.knowledgeEntry.findFirst).toHaveBeenCalledTimes(
+        1
+      );
+    });
+  });
+
+  describe("getAmbiguousMatches", () => {
+    it("should return multiple entries that match case-insensitively", async () => {
+      mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([
+        { id: "entry-2", title: "React Hooks" },
+        { id: "entry-3", title: "React Hooks Advanced" },
+      ]);
+
+      const result = await service.getAmbiguousMatches(
+        workspaceId,
+        "react hooks"
+      );
+
+      expect(result).toHaveLength(2);
+      expect(result).toEqual([
+        { id: "entry-2", title: "React Hooks" },
+        { id: "entry-3", title: "React Hooks Advanced" },
+      ]);
+    });
+
+    it("should return empty array when no matches found", async () => {
+      mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([]);
+
+      const result = await service.getAmbiguousMatches(
+        workspaceId,
+        "Non-existent"
+      );
+
+      expect(result).toEqual([]);
+    });
+
+    it("should return single entry if only one match", async () => {
+      mockPrismaService.knowledgeEntry.findMany.mockResolvedValueOnce([
+        { id: "entry-1", title: "TypeScript Guide" },
+      ]);
+
+      const result = await service.getAmbiguousMatches(
+        workspaceId,
+        "typescript guide"
+      );
+
+      expect(result).toHaveLength(1);
+    });
+  });
+});

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

@@ -0,0 +1,168 @@
+import { Injectable } from "@nestjs/common";
+import { PrismaService } from "../../prisma/prisma.service";
+
+/**
+ * Represents a knowledge entry that matches a link target
+ */
+export interface ResolvedEntry {
+  id: string;
+  title: string;
+}
+
+/**
+ * Service for resolving wiki-style links to knowledge entries
+ *
+ * Resolution strategy (in order of priority):
+ * 1. Exact title match (case-sensitive)
+ * 2. Slug match
+ * 3. Fuzzy title match (case-insensitive)
+ *
+ * Supports workspace scoping via RLS
+ */
+@Injectable()
+export class LinkResolutionService {
+  constructor(private readonly prisma: PrismaService) {}
+
+  /**
+   * Resolve a single link target to a knowledge entry ID
+   *
+   * @param workspaceId - The workspace scope
+   * @param target - The link target (title or slug)
+   * @returns The entry ID if resolved, null if not found or ambiguous
+   */
+  async resolveLink(
+    workspaceId: string,
+    target: string
+  ): Promise<string | null> {
+    // Validate input
+    if (!target || typeof target !== "string") {
+      return null;
+    }
+
+    // Trim whitespace
+    const trimmedTarget = target.trim();
+
+    // Reject empty or whitespace-only strings
+    if (trimmedTarget.length === 0) {
+      return null;
+    }
+
+    // 1. Try exact title match (case-sensitive)
+    const exactMatch = await this.prisma.knowledgeEntry.findFirst({
+      where: {
+        workspaceId,
+        title: trimmedTarget,
+      },
+      select: {
+        id: true,
+      },
+    });
+
+    if (exactMatch) {
+      return exactMatch.id;
+    }
+
+    // 2. Try slug match
+    const slugMatch = await this.prisma.knowledgeEntry.findUnique({
+      where: {
+        workspaceId_slug: {
+          workspaceId,
+          slug: trimmedTarget,
+        },
+      },
+      select: {
+        id: true,
+      },
+    });
+
+    if (slugMatch) {
+      return slugMatch.id;
+    }
+
+    // 3. Try fuzzy match (case-insensitive)
+    const fuzzyMatches = await this.prisma.knowledgeEntry.findMany({
+      where: {
+        workspaceId,
+        title: {
+          mode: "insensitive",
+          equals: trimmedTarget,
+        },
+      },
+      select: {
+        id: true,
+        title: true,
+      },
+    });
+
+    // Return null if no matches or multiple matches (ambiguous)
+    if (fuzzyMatches.length === 0) {
+      return null;
+    }
+
+    if (fuzzyMatches.length > 1) {
+      // Ambiguous match - multiple entries with similar titles
+      return null;
+    }
+
+    return fuzzyMatches[0].id;
+  }
+
+  /**
+   * Resolve multiple link targets in batch
+   *
+   * @param workspaceId - The workspace scope
+   * @param targets - Array of link targets
+   * @returns Map of target to resolved entry ID (null if not found)
+   */
+  async resolveLinks(
+    workspaceId: string,
+    targets: string[]
+  ): Promise<Record<string, string | null>> {
+    const result: Record<string, string | null> = {};
+
+    // Deduplicate targets
+    const uniqueTargets = Array.from(new Set(targets));
+
+    // Resolve each target
+    for (const target of uniqueTargets) {
+      const resolved = await this.resolveLink(workspaceId, target);
+      result[target] = resolved;
+    }
+
+    return result;
+  }
+
+  /**
+   * Get all entries that could match a link target (for disambiguation UI)
+   *
+   * @param workspaceId - The workspace scope
+   * @param target - The link target
+   * @returns Array of matching entries
+   */
+  async getAmbiguousMatches(
+    workspaceId: string,
+    target: string
+  ): Promise<ResolvedEntry[]> {
+    const trimmedTarget = target.trim();
+
+    if (trimmedTarget.length === 0) {
+      return [];
+    }
+
+    const matches = await this.prisma.knowledgeEntry.findMany({
+      where: {
+        workspaceId,
+        title: {
+          mode: "insensitive",
+          equals: trimmedTarget,
+        },
+      },
+      select: {
+        id: true,
+        title: true,
+      },
+    });
+
+    return matches;
+  }
+}