Core Java + AI Development Course Tracker

A modern, production-grade learning management and lecture progress tracker tailored for deep syllabus tracking, daily planning, and streak consistency.

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🌟 Overview

Core Java + AI Development Course Tracker is an interactive, privacy-first web application engineered to track large curriculum courses. Built with React 19 and Vite 8, all user progress, daily schedules, streak histories, and configuration settings are stored 100% locally in your browser's localStorage—no account creation, telemetry, or backend database required.

The application comes preloaded with the flagship Core Java + AI Development (Interview Prep. & Projects) curriculum (150 lectures / ~131 hours across 18 comprehensive sections), featuring full support for importing, adding, and replacing custom course XMLs.

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🚀 Key Features

📅 Smart Daily Target & Frozen Auto-Plan

• Zero-Configuration Setup: Launches immediately with a balanced 1.5h daily target and expands Section 1 by default.
• Auto-Plan Mode: Automatically calculates and selects the optimal next lectures in syllabus order to meet your daily target.
• Daily Plan Freeze: Once generated, the day's plan remains locked in localStorage for that date. Refreshing the browser or checking off lectures will not mutate your planned schedule until a new calendar day begins.
• Smart Lecture State: Completed lectures display a crisp COMPLETED pill badge, row dimming, and strikethrough title while hiding the "Mark as Today" plan toggle to eliminate visual clutter.

📊 Modern Per-Section Progress Sidebar

• Interactive Section Cards: Displays live watched ratios (e.g. 3/7 lectures), remaining section duration (1h 46m left), and dynamic progress bars with amber-to-green gradient transitions.
• One-Click Section Navigation: Clicking any section card smoothly scrolls to and expands that specific section in the syllabus.
• Sticky Dual-Panel: Today's Plan and Section Progress scroll alongside the main curriculum, remaining visible without having to scroll back to the top of long syllabi.

🔄 Multi-Course Lifecycle & XML Importer

• Single Built-in Flagship Course: Pre-configured with Core Java + AI Development.
• Flexible Course Management:
  • Add Course Alongside: Import any custom course XML to track multiple curriculums concurrently without losing existing data.
  • Replace Course: Cleanly replace an existing course with a new XML syllabus.
• Data Isolation: Each course maintains isolated namespaces in localStorage for watched lectures, daily plans, streak history, settings, and start dates. Switching courses never mixes progress.
• Safe Course Deletion: Destructive actions and course replacements are guarded by a 6-character alphanumeric PIN confirmation modal where the confirm button is strictly disabled until the exact code matches.

🔥 Consistency & Streak Calendar

• GitHub-Style Contribution Heatmap: Visualizes your daily watch time with varying intensity of amber cells.
• Practice Days: Allows logging non-video study sessions (coding exercises, interview prep, revision) to preserve streaks. Requires a reflective 10+ word note and confirmation code.
• Historical Logging: Retroactively log practice sessions on past inactive days directly from the calendar modal.
• Course Completion Projection: Calculates estimated finish dates based on your actual start date, remaining course duration, and daily pace.

🧠 Daily AI Motivation (Optional)

• Features an uplifting daily encouragement popup.
• Bring your own OpenAI API key in Settings for dynamic, AI-generated daily messages, with seamless automatic fallback to built-in motivational quotes if no API key is provided.

🛡️ Privacy & Storage Management

• Data Export & Backup: Export your entire application state (all courses, progress, plans, and history) into a portable JSON backup file.
• Data Restore: Import backup snapshots with safety validation.
• Danger Zone Factory Reset: Cleanly wipe all stored data and restore a pristine default installation.

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🛠️ Technology Stack

Layer	Technologies Used
Frontend Framework	React 19
Build Tool & Dev Server	Vite 8
Styling & Design System	Vanilla CSS3 (Custom Design Tokens, Glassmorphism, CSS Grid & Flexbox)
Code Quality & Linter	Oxlint
Testing Suite	Node.js Native Test Runner (node:test) with custom localStorage mock
Storage Engine	Browser localStorage (Namespaced JSON keys)

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📦 Getting Started

Prerequisites

• Node.js: v18.0.0 or higher
• npm: v9.0.0 or higher

Installation

1. Clone the repository:

   git clone https://github.com/sagardhadke/corejava-ai.git
   cd corejava-ai

2. Install dependencies:

   npm install

3. Start the local development server:

   npm run dev

   Open http://localhost:5173 in your browser.

4. Build for production:

   npm run build

5. Preview production bundle:

   npm run preview

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🧪 Testing & Quality Assurance

The application includes an automated integration test suite covering the course management system, data isolation, replacement logic, and edge cases:

npm test

Test Suite Coverage (14/14 Passing)

• Fresh install initializes with single built-in Core Java + AI course
• Adding custom XML course alongside preserves default course
• Course switching persists active state and synchronizes UI
• Multi-course progress data isolation across localStorage
• Course replacement completely removes target course and purges all 5 data keys
• Replaced courses do not resurrect on simulated reload or registry refresh
• Replacing custom courses with new custom courses works cleanly
• Course deletion enforces minimum 1-course safeguard
• Deleting a course purges all associated keys and frees storage space
• Deleting active course automatically falls back to the remaining course
• Factory reset purges all custom keys and restores default configuration
• Graceful recovery and fallback upon encountering corrupt localStorage registry
• Stale/orphan course IDs in registry are filtered automatically
• Complete backup export and restore preserves all courses and progress

Linting

npm run lint

Uses oxlint for high-performance static analysis with zero warnings and zero errors.

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📑 Course XML Format

Custom courses can be imported at runtime via Settings → Memory & Courses → Import course from XML. The XML parser expects the following schema:

<?xml version="1.0" encoding="UTF-8"?>
<course>
  <title>Your Course Title Here</title>
  <sections>
    <section number="01" title="Fundamentals &amp; Setup">
      <items>
        <item type="video" title="Introduction to Architecture" duration="15m30s" />
        <item type="video" title="Environment Configuration" duration="28m45s" />
        <item type="pdf" title="Cheatsheet" /> <!-- Non-video items are preserved without affecting duration -->
      </items>
    </section>
    <section number="02" title="Advanced Concepts">
      <items>
        <item type="video" title="Memory Model &amp; Garbage Collection" duration="42m10s" />
      </items>
    </section>
  </sections>
</course>

Note: Durations can be formatted as Xh Ym Zs, Xh Ym, Ym Zs, or Xm. Ampersands in titles should be escaped as &.

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🗄️ LocalStorage Data Architecture

All course data is stored under namespaced keys to guarantee zero cross-talk between curriculums:

Key Pattern	Structure / Purpose
jct_course_registry_v1	{ courseIds: string[], activeCourseId: string, customCourses: Record<string, Course> }
jct_watched__<courseId>	{ [lectureId: string]: boolean } — Map of completed lecture IDs
jct_today_plan__<courseId>	{ date: string, ids: string[], auto: boolean } — Frozen daily schedule
jct_settings__<courseId>	{ dailySec: number, autoPlan: boolean, streakMode: "target" | "any" }
jct_history__<courseId>	{ [dateKey: string]: { watchedSec, watchedCount, lectureIds, isPractice, practiceNote } }
jct_start_date__<courseId>	"YYYY-MM-DD" — Custom start date for completion estimation
jct_motivation_shown_v1	{ date: string } — Global daily flag for motivation popup
jct_openai_api_key_v1	string — User-provided OpenAI API key (client-side only)