# Unit 09 — Android / Termux Deployment

## Goal
Automated setup script and instructions for running the provisioning stack on Android via Termux (no root required for basic operation).

## Files
- `android/README.md`
- `android/termux_setup.sh`

---

## Constraints & Differences from Raspberry Pi

| Feature | Raspberry Pi | Android (Termux) |
|---------|-------------|-----------------|
| WiFi AP | hostapd (full control) | Android Settings hotspot (limited) |
| DNS hijacking | dnsmasq full control | Limited without root |
| Port 80 | Direct | Need port >1024 or root; use 8080 |
| Captive portal trigger | iptables redirect | Relies on OS captive portal detection |
| Systemd | Yes | No — use Termux boot scripts |

---

## `android/termux_setup.sh`

```bash
#!/data/data/com.termux/files/usr/bin/bash
set -euo pipefail

echo "=== eSIM Provisioning Server — Termux Setup ==="

# Update Termux packages
pkg update -y && pkg upgrade -y

# Install core dependencies
pkg install -y python python-pip nginx

# Install Python dependencies
pip install flask cryptography pymongo pyyaml requests

# Create directory structure
INSTALL_DIR="$HOME/esim-provisioning"
mkdir -p "$INSTALL_DIR"/{server/core_adapters,portal/{css,js,assets},scripts,tests,data}

# Copy server code (assumes script run from repo root)
SCRIPT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
cp -r "$SCRIPT_DIR/server" "$INSTALL_DIR/"
cp -r "$SCRIPT_DIR/portal" "$INSTALL_DIR/"
cp -r "$SCRIPT_DIR/scripts" "$INSTALL_DIR/"
cp "$SCRIPT_DIR/config.yaml.example" "$INSTALL_DIR/config.yaml"

# Configure for Android (port 8080, data path in home)
sed -i 's|port: 5000|port: 8080|' "$INSTALL_DIR/config.yaml"
sed -i "s|/opt/esim-provisioning/data|$INSTALL_DIR/data|" "$INSTALL_DIR/config.yaml"

# Configure nginx for Android (port 8080 as reverse proxy target)
cat > "$PREFIX/etc/nginx/nginx.conf" << 'EOF'
worker_processes 1;
events { worker_connections 64; }
http {
    server {
        listen 8080 default_server;
        server_name _;
        location /activate {
            alias /data/data/com.termux/files/home/esim-provisioning/portal/;
            index index.html;
        }
        location /css/ { alias /data/data/com.termux/files/home/esim-provisioning/portal/css/; }
        location /js/ { alias /data/data/com.termux/files/home/esim-provisioning/portal/js/; }
        location /api/ { proxy_pass http://127.0.0.1:5000; }
        location / { return 302 http://192.168.43.1:8080/activate; }
    }
}
EOF

# Initialize database
cd "$INSTALL_DIR"
CONFIG_PATH=config.yaml python scripts/init_db.py

# Create start script
cat > "$INSTALL_DIR/start.sh" << 'STARTEOF'
#!/data/data/com.termux/files/usr/bin/bash
cd ~/esim-provisioning
echo "Starting eSIM provisioning server..."
nginx
CONFIG_PATH=config.yaml python -m server.app &
echo "Server started. Access at http://192.168.43.1:8080/activate"
echo "To stop: pkill nginx && pkill python"
STARTEOF
chmod +x "$INSTALL_DIR/start.sh"

# Termux:Boot integration (auto-start on reboot)
mkdir -p "$HOME/.termux/boot"
cp "$INSTALL_DIR/start.sh" "$HOME/.termux/boot/esim-provisioning.sh"

echo ""
echo "=== Setup Complete ==="
echo ""
echo "Next steps:"
echo "1. Enable WiFi Hotspot in Android Settings"
echo "   - SSID: Emergency-5G (or any name)"
echo "   - No password"
echo "2. Run: ~/esim-provisioning/start.sh"
echo "3. Users connect to hotspot and visit http://192.168.43.1:8080/activate"
echo ""
echo "Note: Install Termux:Boot app for auto-start on reboot"
```

---

## `android/README.md`

### Prerequisites
- Android 9+
- Termux app (from F-Droid, NOT Play Store)
- Optional: Termux:Boot (for auto-start)
- 5G-capable device with pre-provisioned SIM for gNB backhaul

### Installation
```bash
# In Termux:
cd /path/to/esim-provisioning
bash android/termux_setup.sh
```

### Starting the Server
```bash
~/esim-provisioning/start.sh
```

### WiFi Hotspot Setup
1. Android Settings → Network → Hotspot
2. Set name to `Emergency-5G` (optional, any name works)
3. Remove password (open network)
4. Enable hotspot

### Captive Portal Limitation
Android's captive portal detection requires DNS manipulation. Without root, clients must navigate manually to `http://192.168.43.1:8080/activate`. With root + Termux, dnsmasq can be used for full DNS hijacking.

### Known Android Hotspot IPs
- Most Android: `192.168.43.1`
- Samsung: `192.168.0.1` or `192.168.43.1`
- Pixel: `192.168.43.1`

Update `config.yaml` and nginx config with your device's hotspot IP.

---

## Verification
```bash
# On Android in Termux:
~/esim-provisioning/start.sh
curl http://127.0.0.1:5000/api/status
curl http://127.0.0.1:8080/activate  # through nginx
```