Requirements list created

requirements.md

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+# AG Beats - Requirements Specification
+
+AG Beats is a web-based, collaborative drum machine and bass sequencer that allowing multiple users to compose music together in real-time.
+
+## 1. Functional Requirements
+
+### 1.1 Step Sequencer
+- **Instruments**: Support for 5 drum tracks (Kick, Snare, Hi-Hat, Open Hat, Ride).
+- **Step Configuration**:
+  - Adjustable sequence length from 4 to 64 steps (increments of 4).
+  - Default length: 16 steps.
+- **Grid Interaction**:
+  - Toggle notes on/off for each instrument per step.
+  - Support for "drag-to-toggle" to quickly fill or clear steps in a row.
+- **Bass Line**:
+  - 2-octave bass sequencer (C2 to B3).
+  - Selectable notes per step (supports polyphony).
+  - Visual distinction between natural and sharp notes.
+
+### 1.2 Audio Engine
+- **Synthesis**: Real-time sound generation using the Web Audio API.
+  - Integrated synthesizers for Kick, Snare, and Hi-Hats.
+  - Sine-wave based bass synthesizer.
+- **Sample Support**: Capability to load and play audio samples for instruments.
+- **Playback Controls**:
+  - Global Play/Stop functionality.
+  - Tempo (BPM) control range: 40 to 240 BPM (Default: 76 BPM).
+  - Real-time step highlighting during playback.
+- **Mixer**:
+  - Individual "Mute" toggle for each drum track.
+  - Master volume control for the Drum section.
+  - Master volume control for the Bass section.
+- **Interactive Preview**: Trigger individual drum sounds or bass notes by clicking their respective labels (outside of playback).
+
+### 1.3 Real-time Collaboration
+- **Presence**:
+  - Real-time visibility of other connected users' cursors with unique colors.
+  - Synchronization of connected user list.
+- **State Synchronization**:
+  - Instant broadcasting of all grid changes (drums and bass).
+  - Synchronization of playback state (start/stop), tempo, steps, mutes, and volumes.
+  - Shared "Clear" and "Import" actions across the session.
+- **Stability**: Support for "Synchronizing" state when a new user joins an existing session.
+
+### 1.4 Session & Data Management
+- **Named Sessions**: Support for multiple concurrent sessions identified by a `sessionId` URL parameter.
+- **Session Sharing**: One-click functionality to copy the current session URL to the clipboard.
+- **Persistence**: Session state is maintained in-memory on the server for the duration of the session.
+- **Import/Export**:
+  - Export current pattern as a `.json` file.
+  - Import patterns from previously exported `.json` files.
+
+## 2. Technical Stack
+- **Frontend**: React 19, TypeScript, Tailwind CSS (via CDN).
+- **Backend**: Node.js with Express and WebSocket (`ws`).
+- **Communication**: WebSockets for real-time state synchronization and cursor presence.
+- **Audio**: Web Audio API for low-latency synthesis and playback.
+
+## 3. User Interface & Experience
+- **Responsive Design**: Mobile-friendly layout with horizontal scrolling for large sequences.
+- **Modern Aesthetics**: Sleek, slate-based color palette with vibrant accents (Orange for drums, Purple for bass).
+- **Interactive Feedback**:
+  - Hover effects on sequencer cells.
+  - Confirmation modals for destructive actions (e.g., Clear Pattern).
+  - Scroll-wheel support for tempo adjustment.
+  - Sticky labels for easy navigation in large grids.
+
+## 4. Constraints & Limits
+- **Tempo Range**: 40 - 240 BPM.
+- **Sequence Steps**: 4 - 64 steps (must be multiple of 4).
+- **Instruments**: Fixed set of 5 drum instruments.
+- **Storage**: State is currently ephemeral (in-memory) and lost if the server restarts or the last user leaves the session.