Add configurable minimum sentence length for N+1 targets

src/config/config.test.ts

@@ -137,6 +137,55 @@ test("accepts valid ankiConnect n+1 behavior values", () => {
   assert.equal(config.ankiConnect.nPlusOne.refreshMinutes, 120);
 });
 
+test("validates ankiConnect n+1 minimum sentence word count", () => {
+  const dir = makeTempDir();
+  fs.writeFileSync(
+    path.join(dir, "config.jsonc"),
+    `{
+      "ankiConnect": {
+        "nPlusOne": {
+          "minSentenceWords": 0
+        }
+      }
+    }`,
+    "utf-8",
+  );
+
+  const service = new ConfigService(dir);
+  const config = service.getConfig();
+  const warnings = service.getWarnings();
+
+  assert.equal(
+    config.ankiConnect.nPlusOne.minSentenceWords,
+    DEFAULT_CONFIG.ankiConnect.nPlusOne.minSentenceWords,
+  );
+  assert.ok(
+    warnings.some(
+      (warning) => warning.path === "ankiConnect.nPlusOne.minSentenceWords",
+    ),
+  );
+});
+
+test("accepts valid ankiConnect n+1 minimum sentence word count", () => {
+  const dir = makeTempDir();
+  fs.writeFileSync(
+    path.join(dir, "config.jsonc"),
+    `{
+      "ankiConnect": {
+        "nPlusOne": {
+          "minSentenceWords": 4
+        }
+      }
+    }`,
+    "utf-8",
+  );
+
+  const service = new ConfigService(dir);
+  const config = service.getConfig();
+
+  assert.equal(config.ankiConnect.nPlusOne.minSentenceWords, 4);
+});
+
 test("validates ankiConnect n+1 match mode values", () => {
   const dir = makeTempDir();
   fs.writeFileSync(
@@ -328,5 +377,6 @@ test("template generator includes known keys", () => {
   assert.match(output, /"nPlusOne"\s*:\s*\{/);
   assert.match(output, /"nPlusOne": "#c6a0f6"/);
   assert.match(output, /"knownWord": "#a6da95"/);
+  assert.match(output, /"minSentenceWords": 3/);
   assert.match(output, /auto-generated from src\/config\/definitions.ts/);
 });

src/config/definitions.ts

@@ -128,6 +128,7 @@ export const DEFAULT_CONFIG: ResolvedConfig = {
       refreshMinutes: 1440,
       matchMode: "headword",
       decks: [],
+      minSentenceWords: 3,
       nPlusOne: "#c6a0f6",
       knownWord: "#a6da95",
     },
@@ -333,6 +334,13 @@ export const CONFIG_OPTION_REGISTRY: ConfigOptionRegistryEntry[] = [
     defaultValue: DEFAULT_CONFIG.ankiConnect.nPlusOne.refreshMinutes,
     description: "Minutes between known-word cache refreshes.",
   },
+  {
+    path: "ankiConnect.nPlusOne.minSentenceWords",
+    kind: "number",
+    defaultValue: DEFAULT_CONFIG.ankiConnect.nPlusOne.minSentenceWords,
+    description:
+      "Minimum sentence word count required for N+1 targeting (default: 3).",
+  },
   {
     path: "ankiConnect.nPlusOne.decks",
     kind: "array",

src/config/service.ts

@@ -698,6 +698,32 @@ export class ConfigService {
           DEFAULT_CONFIG.ankiConnect.nPlusOne.refreshMinutes;
       }
 
+      const nPlusOneMinSentenceWords = asNumber(
+        nPlusOneConfig.minSentenceWords,
+      );
+      const hasValidNPlusOneMinSentenceWords =
+        nPlusOneMinSentenceWords !== undefined &&
+        Number.isInteger(nPlusOneMinSentenceWords) &&
+        nPlusOneMinSentenceWords > 0;
+      if (nPlusOneMinSentenceWords !== undefined) {
+        if (hasValidNPlusOneMinSentenceWords) {
+          resolved.ankiConnect.nPlusOne.minSentenceWords =
+            nPlusOneMinSentenceWords;
+        } else {
+          warn(
+            "ankiConnect.nPlusOne.minSentenceWords",
+            nPlusOneConfig.minSentenceWords,
+            resolved.ankiConnect.nPlusOne.minSentenceWords,
+            "Expected a positive integer.",
+          );
+          resolved.ankiConnect.nPlusOne.minSentenceWords =
+            DEFAULT_CONFIG.ankiConnect.nPlusOne.minSentenceWords;
+        }
+      } else {
+        resolved.ankiConnect.nPlusOne.minSentenceWords =
+          DEFAULT_CONFIG.ankiConnect.nPlusOne.minSentenceWords;
+      }
+
       const nPlusOneMatchMode = asString(nPlusOneConfig.matchMode);
       const legacyNPlusOneMatchMode = asString(behavior.nPlusOneMatchMode);
       const hasValidNPlusOneMatchMode =