# Documentation Plan

## 🎯 **Objective**

Create comprehensive, user-friendly documentation that covers all aspects of apt-ostree, from basic usage to advanced development, ensuring users and developers can effectively use and contribute to the system.

## 📚 **Documentation Structure**

### **1. User Documentation**
- **Quick Start Guide**: Get up and running in minutes
- **User Manual**: Complete user reference
- **Troubleshooting**: Common issues and solutions
- **Examples**: Real-world usage scenarios

### **2. Developer Documentation**
- **Architecture Guide**: System design and components
- **API Reference**: Complete interface documentation
- **Development Guide**: Contributing to apt-ostree
- **Testing Guide**: Testing strategies and examples

### **3. Administrator Documentation**
- **Installation Guide**: System deployment
- **Configuration Guide**: System customization
- **Security Guide**: Security policies and hardening
- **Maintenance Guide**: System upkeep and monitoring

## 📖 **User Documentation**

### **Quick Start Guide**
```markdown
# Quick Start Guide

## Installation
```bash
# Debian/Ubuntu
sudo apt update
sudo apt install apt-ostree

# From source
git clone https://github.com/your-org/apt-ostree.git
cd apt-ostree
cargo build --release
sudo cp target/release/apt-ostree /usr/local/bin/
```

## First Steps
```bash
# Check system status
apt-ostree status

# Search for packages
apt-ostree search nginx

# Install a package
sudo apt-ostree install nginx

# Check system health
apt-ostree metrics
```

## Basic Operations
- **System upgrade**: `apt-ostree upgrade`
- **Package management**: `apt-ostree install/remove`
- **System rollback**: `apt-ostree rollback`
- **Live updates**: `apt-ostree apply-live`
```

### **User Manual**
```markdown
# User Manual

## Table of Contents
1. [Introduction](introduction.md)
2. [Getting Started](getting-started.md)
3. [Basic Commands](basic-commands.md)
4. [Package Management](package-management.md)
5. [System Operations](system-operations.md)
6. [Advanced Features](advanced-features.md)
7. [Troubleshooting](troubleshooting.md)
8. [Reference](reference.md)

## Command Reference
### Core Commands
- `status` - System status and information
- `upgrade` - System upgrade operations
- `rollback` - System rollback functionality
- `deploy` - Deployment management
- `rebase` - Tree rebasing operations

### Package Management
- `install` - Install packages
- `uninstall` - Remove packages
- `search` - Search for packages
- `override` - Package override management

### System Management
- `initramfs` - Initramfs management
- `kargs` - Kernel argument management
- `reload` - Reload configuration
- `cancel` - Cancel operations

### Advanced Commands
- `compose` - Tree composition
- `db` - Database operations
- `reset` - System reset
- `refresh-md` - Refresh metadata

### Live Updates
- `apply-live` - Apply live updates
- `usroverlay` - User overlay management

### Utility Commands
- `cleanup` - System cleanup
- `finalize-deployment` - Finalize deployment
- `metrics` - System metrics
```

### **Troubleshooting Guide**
```markdown
# Troubleshooting Guide

## Common Issues

### Package Installation Failures
**Problem**: Package installation fails with dependency errors
**Solution**: 
```bash
# Check package dependencies
apt-ostree search <package-name>

# Verify system state
apt-ostree status

# Try with dependency resolution
apt-ostree install <package-name> --resolve-deps
```

### System Upgrade Issues
**Problem**: System upgrade fails or hangs
**Solution**:
```bash
# Check for active transactions
apt-ostree transaction list

# Cancel stuck operations
apt-ostree cancel

# Verify system integrity
apt-ostree db verify
```

### Permission Errors
**Problem**: Operation fails with permission denied
**Solution**:
```bash
# Use sudo for privileged operations
sudo apt-ostree install <package-name>

# Check Polkit authorization
pkaction --action-id org.projectatomic.aptostree1.install

# Verify user permissions
apt-ostree security check-user
```

## Error Codes
- **E001**: Permission denied
- **E002**: Package not found
- **E003**: Dependency conflict
- **E004**: System state error
- **E005**: Network error
- **E006**: Disk space error
- **E007**: Transaction error
- **E008**: Security violation

## Recovery Procedures
1. **System Rollback**: `apt-ostree rollback`
2. **Transaction Cleanup**: `apt-ostree cleanup`
3. **Database Repair**: `apt-ostree db repair`
4. **System Reset**: `apt-ostree reset`
```

## 🛠️ **Developer Documentation**

### **Architecture Guide**
```markdown
# Architecture Guide

## System Overview
apt-ostree is a hybrid image/package system that combines OSTree for atomic updates with APT for package management.

## Component Architecture
```
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   CLI Client    │    │  System Daemon  │    │   OSTree Repo   │
│  (apt-ostree)   │◄──►│ (apt-ostreed)   │◄──►│                 │
└─────────────────┘    └─────────────────┘    └─────────────────┘
         │                       │                       │
         │                       │                       │
         ▼                       ▼                       ▼
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   APT Cache     │    │  Transaction    │    │  Package Store  │
│                 │    │   Manager       │    │                 │
└─────────────────┘    └─────────────────┘    └─────────────────┘
```

## Core Components

### CLI Client
- **Purpose**: User interface and command processing
- **Responsibilities**: Argument parsing, command dispatch, output formatting
- **Communication**: DBus interface with daemon

### System Daemon
- **Purpose**: Background service for system operations
- **Responsibilities**: Package management, transaction processing, system operations
- **Interfaces**: DBus API, system integration

### Transaction Manager
- **Purpose**: Atomic operation coordination
- **Responsibilities**: Transaction lifecycle, rollback support, state management
- **Features**: ACID properties, conflict resolution

### Package Manager
- **Purpose**: APT integration and package operations
- **Responsibilities**: Dependency resolution, package installation, cache management
- **Features**: Parallel operations, intelligent caching
```

### **API Reference**
```markdown
# API Reference

## DBus Interface

### org.projectatomic.aptostree1

#### Methods

##### get_system_status()
Returns the current system status and deployment information.

**Parameters**: None
**Returns**: `String` - JSON-formatted system status
**Errors**: 
- `org.freedesktop.DBus.Error.AccessDenied`: Insufficient permissions
- `org.freedesktop.DBus.Error.Failed`: Operation failed

**Example**:
```bash
dbus-send --system --dest=org.projectatomic.aptostree1 \
    --print-reply /org/projectatomic/aptostree1 \
    org.projectatomic.aptostree1.get_system_status
```

##### install_packages(packages: Array<String>)
Installs the specified packages.

**Parameters**:
- `packages`: Array of package names to install

**Returns**: `String` - Transaction ID
**Errors**:
- `org.freedesktop.DBus.Error.AccessDenied`: Insufficient permissions
- `org.freedesktop.DBus.Error.InvalidArgs`: Invalid package names
- `org.freedesktop.DBus.Error.Failed`: Installation failed

**Example**:
```bash
dbus-send --system --dest=org.projectatomic.aptostree1 \
    --print-reply /org/projectatomic/aptostree1 \
    org.projectatomic.aptostree1.install_packages \
    array:string:"nginx","vim"
```

#### Properties

##### SystemStatus (read)
Current system status information.

**Type**: `String`
**Access**: Read
**Description**: JSON-formatted system status

##### PackageCount (read)
Total number of installed packages.

**Type**: `UInt32`
**Access**: Read
**Description**: Count of installed packages

#### Signals

##### package_installed(package: String, version: String)
Emitted when a package is successfully installed.

**Parameters**:
- `package`: Name of the installed package
- `version`: Version of the installed package

##### transaction_completed(transaction_id: String, success: Boolean)
Emitted when a transaction completes.

**Parameters**:
- `transaction_id`: ID of the completed transaction
- `success`: Whether the transaction succeeded
```

### **Development Guide**
```markdown
# Development Guide

## Setting Up Development Environment

### Prerequisites
- Rust 1.70+
- Cargo
- Git
- Build tools (gcc, make, pkg-config)

### Development Setup
```bash
# Clone repository
git clone https://github.com/your-org/apt-ostree.git
cd apt-ostree

# Install dependencies
sudo apt update
sudo apt install build-essential pkg-config libostree-dev libapt-pkg-dev

# Build project
cargo build

# Run tests
cargo test

# Run linter
cargo clippy

# Format code
cargo fmt
```

## Project Structure
```
src/
├── main.rs              # CLI entry point
├── lib.rs               # Library exports
├── daemon/              # Daemon implementation
│   ├── mod.rs           # Daemon module
│   ├── main.rs          # Daemon entry point
│   ├── dbus.rs          # DBus interface
│   ├── transaction.rs   # Transaction management
│   ├── ostree.rs        # OSTree operations
│   ├── apt.rs           # APT integration
│   ├── security.rs      # Security management
│   ├── sysroot.rs       # Sysroot operations
│   └── os.rs            # OS interface
├── client/               # Client implementation
│   ├── mod.rs           # Client module
│   ├── dbus.rs          # DBus client
│   └── transaction.rs   # Transaction client
└── lib/                  # Core library
    ├── error.rs          # Error handling
    ├── logging.rs        # Logging system
    ├── security.rs       # Security utilities
    └── system.rs         # System utilities
```

## Coding Standards

### Rust Conventions
- Follow Rust naming conventions
- Use meaningful variable and function names
- Implement proper error handling with `Result<T, E>`
- Use async/await for asynchronous operations
- Implement comprehensive testing

### Code Organization
- Keep functions small and focused
- Use modules for logical grouping
- Implement proper error propagation
- Add comprehensive documentation comments

### Testing Requirements
- Unit tests for all public functions
- Integration tests for workflows
- Performance benchmarks for critical paths
- Security tests for validation functions

## Contributing

### Development Workflow
1. Fork the repository
2. Create a feature branch
3. Implement your changes
4. Add tests for new functionality
5. Update documentation
6. Submit a pull request

### Code Review Process
- All changes require code review
- Tests must pass before merge
- Documentation must be updated
- Security implications must be reviewed

### Release Process
1. Update version numbers
2. Update changelog
3. Run full test suite
4. Create release tag
5. Build and package
6. Deploy to repositories
```

## 🔧 **Administrator Documentation**

### **Installation Guide**
```markdown
# Installation Guide

## System Requirements

### Supported Distributions
- Debian 13+ (Trixie)
- Ubuntu 25.04+ (Noble Numbat)

### Hardware Requirements
- **CPU**: x86_64 or ARM64
- **Memory**: 2GB RAM minimum, 4GB recommended
- **Storage**: 10GB free space minimum
- **Network**: Internet connection for package downloads

### Dependencies
- OSTree 2023.1+
- APT 2.6+
- Systemd 250+
- Polkit 0.120+

## Installation Methods

### Package Installation (Recommended)
```bash
# Add repository
echo "deb https://apt.example.com/apt-ostree stable main" | \
    sudo tee /etc/apt/sources.list.d/apt-ostree.list

# Add GPG key
wget -qO - https://apt.example.com/apt-ostree.gpg.key | \
    sudo apt-key add -

# Update package list
sudo apt update

# Install apt-ostree
sudo apt install apt-ostree apt-ostreed
```

### Source Installation
```bash
# Install build dependencies
sudo apt install build-essential pkg-config \
    libostree-dev libapt-pkg-dev libpolkit-gobject-1-dev

# Clone and build
git clone https://github.com/your-org/apt-ostree.git
cd apt-ostree
cargo build --release

# Install binaries
sudo cp target/release/apt-ostree /usr/local/bin/
sudo cp target/release/apt-ostreed /usr/local/bin/

# Install systemd services
sudo cp daemon/systemd/*.service /etc/systemd/system/
sudo cp daemon/systemd/*.socket /etc/systemd/system/

# Install Polkit policy
sudo cp daemon/polkit/*.policy /usr/share/polkit-1/actions/

# Enable and start services
sudo systemctl daemon-reload
sudo systemctl enable apt-ostreed.socket
sudo systemctl start apt-ostreed.socket
```

## Post-Installation

### Verify Installation
```bash
# Check binary installation
apt-ostree --version
apt-ostreed --version

# Check service status
sudo systemctl status apt-ostreed.socket

# Test basic functionality
apt-ostree status
```

### Initial Configuration
```bash
# Create configuration directory
sudo mkdir -p /etc/apt-ostree

# Create configuration file
sudo tee /etc/apt-ostree/config.toml > /dev/null <<EOF
[system]
ostree_repo = "/var/lib/apt-ostree"
cache_dir = "/var/cache/apt-ostree"
log_level = "info"

[security]
require_authentication = true
allowed_users = ["root", "sudo"]
policy_file = "/etc/apt-ostree/policy.conf"

[logging]
file_path = "/var/log/apt-ostree.log"
max_file_size = "100MB"
max_files = 7
format = "json"
EOF

# Set permissions
sudo chown root:root /etc/apt-ostree/config.toml
sudo chmod 644 /etc/apt-ostree/config.toml
```

## Troubleshooting

### Common Issues
- **Service won't start**: Check dependencies and permissions
- **Permission denied**: Verify Polkit configuration
- **Network errors**: Check firewall and proxy settings
- **Storage errors**: Verify disk space and permissions
```

## 📊 **Documentation Metrics**

### **Completeness Goals**
- **User Documentation**: 100% command coverage
- **Developer Documentation**: 100% API coverage
- **Administrator Documentation**: 100% deployment coverage
- **Examples**: 50+ practical examples

### **Quality Goals**
- **Readability**: Clear, concise language
- **Accuracy**: 100% technical accuracy
- **Completeness**: No missing information
- **Maintainability**: Easy to update and extend

## 🔧 **Implementation Plan**

### **Phase 1: Foundation (Week 5)**
- [ ] Create documentation structure
- [ ] Write user quick start guide
- [ ] Document basic commands
- [ ] Create troubleshooting guide

### **Phase 2: Core Documentation (Week 5)**
- [ ] Complete user manual
- [ ] Write architecture guide
- [ ] Document API reference
- [ ] Create development guide

### **Phase 3: Advanced Documentation (Week 6)**
- [ ] Write administrator guides
- [ ] Create configuration examples
- [ ] Document security policies
- [ ] Add performance tuning guides

### **Phase 4: Validation (Week 6)**
- [ ] User documentation review
- [ ] Technical accuracy validation
- [ ] Usability testing
- [ ] Final documentation review

## 🔗 **Related Documentation**

- [Architecture Overview](../architecture/overview.md)
- [CLI Commands](../architecture/cli-command-structure.md)
- [Package Management](../architecture/apt-library-analysis.md)
- [Security Model](../security/security-hardening.md)
- [Performance Optimization](../optimization/performance-optimization.md)
