feat: support custom local study plans via json

.leetcode

@@ -7,6 +7,11 @@
     {
       "slug": "30-days-of-javascript",
       "name": "30 Days of JavaScript"
+    },
+    {
+      "slug": "neetcode-150",
+      "name": "NeetCode 150",
+      "path": "data/neetcode-150.json"
     }
   ],
   "problemLists": [

README.md

@@ -258,7 +258,10 @@ Any setting above can be overridden per-workspace in the `.leetcode` file. Works
 
 ```json
 {
-  "studyPlans": [{ "slug": "top-interview-150", "name": "Top Interview 150" }],
+  "studyPlans": [
+    { "slug": "top-interview-150", "name": "Top Interview 150" },
+    { "slug": "my-custom-list", "name": "My Custom List", "path": "data/custom-list.json" }
+  ],
   "problemLists": [{ "slug": "graph", "name": "Graph" }],
   "activeStudyPlan": "top-interview-150",
   "activeProblemList": "graph",
@@ -268,6 +271,21 @@ Any setting above can be overridden per-workspace in the `.leetcode` file. Works
 }
 ```
 
+### Custom Study Plans
+
+You can load your own custom-categorized study plans (like NeetCode 150) without relying on LeetCode's backend. 
+
+Simply add the `path` property to a study plan entry in your `.leetcode` config and point it to a local JSON file in your workspace:
+
+```json
+{
+  "Arrays & Hashing": ["contains-duplicate", "valid-anagram"],
+  "Two Pointers": ["valid-palindrome"]
+}
+```
+
+The extension will read this JSON file and instantly render it in the Study Plans sidebar as a fully categorized tree view.
+
 ## Requirements
 
 - VS Code or Cursor **1.85+**

src/modules/LeetcodeConfig.ts

@@ -9,7 +9,7 @@ export type ActiveListSource = "studyPlan" | "problemList";
 
 /** Schema for .leetcode config file. Overrides VS Code settings for this workspace. */
 export interface LeetcodeConfig {
-  studyPlans?: Array<{ slug: string; name: string }>;
+  studyPlans?: Array<{ slug: string; name: string; path?: string }>;
   /** LeetCode problem-list slugs (e.g. graph → /problem-list/graph/). */
   problemLists?: Array<{ slug: string; name: string }>;
   /** Default study plan slug for the Study Plans sidebar (must match `studyPlans`). */
@@ -79,21 +79,24 @@ const DEFAULTS: Required<
     "Explain my solution code for this LeetCode problem. Respond with: (1) Intuition — core idea in plain language; (2) Step-by-step dry run — walk through the algorithm with a small example, including loop/state changes; (3) Time and space complexity with brief justification. Do not rewrite the full solution unless needed for clarity.",
 };
 
-function isValidStudyPlanEntry(obj: unknown): obj is { slug: string; name: string } {
+function isValidStudyPlanEntry(obj: unknown): obj is { slug: string; name: string; path?: string } {
   return (
     typeof obj === "object" &&
     obj !== null &&
     typeof (obj as { slug?: unknown }).slug === "string" &&
-    typeof (obj as { name?: unknown }).name === "string"
+    typeof (obj as { name?: unknown }).name === "string" &&
+    ((obj as { path?: unknown }).path === undefined || typeof (obj as { path?: unknown }).path === "string")
   );
 }
 
-function parseStudyPlans(raw: unknown): Array<{ slug: string; name: string }> {
+function parseStudyPlans(raw: unknown): Array<{ slug: string; name: string; path?: string }> {
   if (!Array.isArray(raw)) return DEFAULTS.studyPlans;
-  const result: Array<{ slug: string; name: string }> = [];
+  const result: Array<{ slug: string; name: string; path?: string }> = [];
   for (const item of raw) {
     if (isValidStudyPlanEntry(item)) {
-      result.push({ slug: item.slug, name: item.name });
+      const entry: { slug: string; name: string; path?: string } = { slug: item.slug, name: item.name };
+      if (item.path !== undefined) entry.path = item.path;
+      result.push(entry);
     }
   }
   return result.length > 0 ? result : DEFAULTS.studyPlans;
@@ -347,7 +350,7 @@ export function getEffectiveConfig(
 ): LeetcodeConfig & { internalApiUrl: string; problemViewMode: "ui" | "text" } {
   const vscodeConfig = vscode.workspace.getConfiguration("leetcodePractice");
   const leetcode = parseLeetcodeConfig(workspaceFolders);
-  const studyPlans = leetcode.studyPlans ?? vscodeConfig.get<Array<{ slug: string; name: string }>>("studyPlans") ?? DEFAULTS.studyPlans;
+  const studyPlans = leetcode.studyPlans ?? vscodeConfig.get<Array<{ slug: string; name: string; path?: string }>>("studyPlans") ?? DEFAULTS.studyPlans;
   const problemLists =
     leetcode.problemLists ?? vscodeConfig.get<Array<{ slug: string; name: string }>>("problemLists") ?? DEFAULTS.problemLists;
   const vsActiveSource = vscodeConfig.get<string>("activeListSource");

src/modules/ProblemsProvider.ts

@@ -7,7 +7,7 @@ import {
   type ProblemListItem,
   type StudyPlanGroup,
 } from "./LeetCode";
-import { NO_PROBLEM_LIST_SENTINEL } from "./LeetcodeConfig";
+import { NO_PROBLEM_LIST_SENTINEL, getEffectiveConfig } from "./LeetcodeConfig";
 const STATUS_KEY = "leetcode-practice.problemStatus";
 
 export type ProblemStatus = "solved" | "attempting";
@@ -248,7 +248,41 @@ export class ProblemsTreeProvider implements vscode.TreeDataProvider<ProblemTree
           this.groups = problems.length > 0 ? [{ category, problems }] : [];
           }
         } else {
-          this.groups = await this.leetcode.getStudyPlanProblemListGrouped(planSlug);
+          const lcexCfg = getEffectiveConfig(vscode.workspace.workspaceFolders ?? []);
+          const planConfig = lcexCfg.studyPlans?.find((p) => p.slug === planSlug);
+
+          if (planConfig?.path) {
+            let localPath = "";
+            for (const f of vscode.workspace.workspaceFolders ?? []) {
+              const candidate = path.resolve(f.uri.fsPath, planConfig.path);
+              if (fs.existsSync(candidate)) {
+                localPath = candidate;
+                break;
+              }
+            }
+            if (localPath) {
+              try {
+                const raw = fs.readFileSync(localPath, "utf-8");
+                const customPlan = JSON.parse(raw) as Record<string, string[]>;
+
+                const fullProvider = new ProblemsTreeProvider("problemset", this.memento, this.storagePath);
+                const allProblems = await fullProvider.getProblemList();
+                const bySlug = new Map(allProblems.map(p => [p.titleSlug, p]));
+
+                this.groups = Object.entries(customPlan).map(([category, slugs]) => ({
+                  category,
+                  problems: slugs.map(slug => bySlug.get(slug)).filter((p): p is ProblemListItem => !!p)
+                })).filter(g => g.problems.length > 0);
+              } catch (e) {
+                console.error(`Failed to load custom study plan from ${localPath}`, e);
+                this.groups = [];
+              }
+            } else {
+              this.groups = [];
+            }
+          } else {
+            this.groups = await this.leetcode.getStudyPlanProblemListGrouped(planSlug);
+          }
         }
         if (this.groups.length > 0) {
           try {