Add SQLite baseline store for log comparison and anomaly detection

Captures a rich fingerprint of log analysis (level distribution, crashes,
components, timestamp density, sample lines) into ~/.logan/baselines.db.
Users can save baselines from known-good logs and compare new logs against
them to detect level shifts, new crashes, error rate spikes, missing
components, and activity pattern changes. Includes UI in analysis panel,
4 HTTP API endpoints, 4 MCP tools, and 45 tests.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ozgesolidkey

package-lock.json

@@ -31,6 +31,7 @@
   },
   "devDependencies": {
     "@electron/rebuild": "^3.7.2",
+    "@types/better-sqlite3": "^7.6.13",
     "@types/diff": "^7.0.2",
     "@types/node": "^20.10.0",
     "@types/ssh2": "^1.15.5",
@@ -41,6 +42,7 @@
   },
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.26.0",
+    "better-sqlite3": "^12.6.2",
     "diff": "^8.0.3",
     "marked": "^17.0.1",
     "node-pty": "^1.1.0",

package.json

@@ -5,6 +5,8 @@ import * as os from 'os';
 import { BrowserWindow } from 'electron';
 import { SearchOptions, Bookmark, Highlight } from '../shared/types';
 import { FileHandler } from './fileHandler';
+import { BaselineStore, buildFingerprint } from './baselineStore';
+import { AnalysisResult } from './analyzers/types';
 
 const API_PORT = 19532;
 const PORT_FILE = path.join(os.homedir(), '.logan', 'mcp-port');
@@ -27,6 +29,8 @@ export interface ApiContext {
   addHighlight(highlight: Highlight): any;
   detectTimeGaps(options: any): Promise<any>;
   navigateToLine(lineNumber: number): void;
+  getBaselineStore(): BaselineStore;
+  getAnalysisResult(): AnalysisResult | null;
 }
 
 let server: http.Server | null = null;
@@ -121,6 +125,12 @@ export function startApiServer(ctx: ApiContext): void {
           return;
         }
 
+        if (url === '/api/baselines') {
+          const baselines = ctx.getBaselineStore().list();
+          sendJson(res, { success: true, baselines });
+          return;
+        }
+
         sendError(res, 'Not found', 404);
         return;
       }
@@ -228,6 +238,44 @@ export function startApiServer(ctx: ApiContext): void {
           return;
         }
 
+        if (url === '/api/baseline-save') {
+          const filePath = ctx.getCurrentFilePath();
+          const handler = ctx.getFileHandler();
+          const analysisResult = ctx.getAnalysisResult();
+          if (!filePath || !handler) return sendError(res, 'No file open');
+          if (!analysisResult) return sendError(res, 'Run analysis first');
+          const fp = buildFingerprint(filePath, analysisResult, handler);
+          const id = ctx.getBaselineStore().save(
+            body.name || 'Unnamed baseline',
+            body.description || '',
+            body.tags || [],
+            fp
+          );
+          sendJson(res, { success: true, id });
+          return;
+        }
+
+        if (url === '/api/baseline-compare') {
+          const filePath = ctx.getCurrentFilePath();
+          const handler = ctx.getFileHandler();
+          const analysisResult = ctx.getAnalysisResult();
+          if (!filePath || !handler) return sendError(res, 'No file open');
+          if (!analysisResult) return sendError(res, 'Run analysis first');
+          if (!body.baselineId) return sendError(res, 'baselineId required');
+          const fp = buildFingerprint(filePath, analysisResult, handler);
+          const report = ctx.getBaselineStore().compare(fp, body.baselineId);
+          if (!report) return sendError(res, 'Baseline not found');
+          sendJson(res, { success: true, report });
+          return;
+        }
+
+        if (url === '/api/baseline-delete') {
+          if (!body.baselineId) return sendError(res, 'baselineId required');
+          const ok = ctx.getBaselineStore().delete(body.baselineId);
+          sendJson(res, { success: ok, error: ok ? undefined : 'Baseline not found' });
+          return;
+        }
+
         sendError(res, 'Not found', 404);
         return;
       }