# DigiSim

> DigiSim is a digital logic circuit simulator and educational platform with an Angular frontend, supporting circuit design from basic gates to CPU architecture with real-time simulation and subscription-based component access.

## Core Features

**Circuit Builder**: Drag-and-drop interface with 50+ logic components
**Simulation Engines**: Event-driven and iterative simulators for accurate circuit behavior
**Educational Templates**: Structured learning from logic fundamentals to CPU design
**Subscription Tiers**: FREE (basic gates), BASIC (sequential logic), PROFESSIONAL (CPU components)
**Export System**: PNG export and simulation file formats

## Component Library

**Logic Gates**: AND, OR, NOT, NAND, NOR, XOR, XNOR, Buffer
**Sequential**: D/JK/T Flip-flops, Latches, Registers, Counters
**Arithmetic**: 8-bit ALU, Binary Adders, Comparators
**Memory**: RAM, ROM, Register files
**I/O**: Switches, Lights, 7-Segment Display, Oscilloscope
**CPU**: Program Counter, Instruction Register, Assembly Loader

## Architecture

**Frontend**: Angular 20+ with TypeScript, Material Design 3
**Backend**: Protobuf APIs for auth, circuits, templates, subscriptions
**Simulation**: EventDrivenSimulatorService with component state management
**Storage**: Circuit files with JSON serialization and metadata

## Key Services

- **WorkspaceService**: Circuit management and component operations
- **ComponentPermissionService**: Subscription-based access control
- **TemplateCircuitService**: Educational circuit templates
- **CircuitFileService**: Save/load with AI summaries

## Educational Framework

1. **Logic Fundamentals**: Basic gates and truth tables
2. **Combinational Circuits**: Adders, multiplexers, encoders
3. **Sequential Logic**: Flip-flops, counters, state machines
4. **Memory Systems**: Registers, RAM, ROM
5. **CPU Architecture**: Instruction execution and processor design

## API Endpoints

**Auth**: `/api/auth/{email,google,apple}/signin`, `/api/auth/refresh`
**Circuits**: `/api/digisim/circuits/{save,list,delete}`
**Templates**: `/api/digisim/templates/{list,featured}`
**Subscription**: `/api/subscription/{status,create,cancel}`

## Technical Stack

**Build**: Angular CLI 20.3.7, TypeScript, SCSS
**Testing**: Karma/Jasmine, E2E testing
**Deployment**: Optimized production builds with environment configs