#!/bin/bash
# audio-stack-start — initialize the full low-latency audio environment
# Run with: sudo audio-stack-start
# Then JACK runs as the 'pi' user (or current user if not root)

set -e

echo ""
echo "╔══════════════════════════════════════════╗"
echo "║   Audio Stack Initialization             ║"
echo "╚══════════════════════════════════════════╝"
echo ""

# ── 1. CPU Governor ──────────────────────────────────
echo "1/6 Setting CPU governor → performance..."
for cpu in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do
    if [ -f "$cpu" ]; then
        echo performance > "$cpu" 2>/dev/null || true
    fi
done
echo "   Done."

# ── 2. IRQ Priorities ────────────────────────────────
echo "2/6 Configuring IRQ priorities..."
if command -v rtirq > /dev/null 2>&1; then
    if systemctl is-active --quiet rtirq 2>/dev/null; then
        systemctl restart rtirq 2>/dev/null || true
    else
        systemctl start rtirq 2>/dev/null || true
    fi
    echo "   rtirq started."
else
    echo "   rtirq not installed. Run: sudo apt install rtirq-init"
fi

# ── 3. PAM Limits Check ──────────────────────────────
echo "3/6 Checking PAM limits..."
CURRENT_RTPRIO=$(ulimit -r 2>/dev/null || echo "unknown")
CURRENT_MEMLOCK=$(ulimit -l 2>/dev/null || echo "unknown")
echo "   rtprio: $CURRENT_RTPRIO (need 99)"
echo "   memlock: $CURRENT_MEMLOCK (need unlimited)"

# ── 4. USB Audio Driver ──────────────────────────────
echo "4/6 Configuring USB audio driver..."
if lsmod 2>/dev/null | grep -q snd_usb_audio; then
    modprobe -r snd-usb-audio 2>/dev/null || true
    sleep 1
fi
modprobe snd-usb-audio nrpacks=1 2>/dev/null || true
echo "   snd-usb-audio loaded with nrpacks=1"

# ── 5. USB Audio Detection ───────────────────────────
echo "5/6 Checking USB audio device..."
sleep 1
if aplay -l 2>/dev/null | grep -qi usb; then
    echo "   USB audio interface detected:"
    aplay -l 2>/dev/null | grep -i usb | head -3 | sed 's/^/     /'
else
    echo "   WARNING: No USB audio interface found!"
    echo "   Check: lsusb | grep -i audio"
fi

# ── 6. Start JACK ────────────────────────────────────
echo "6/6 Starting JACK2..."
if pgrep -x jackd > /dev/null; then
    echo "   JACK is already running. PID: $(pgrep -x jackd)"
else
    if [ "$EUID" -eq 0 ] && id pi >/dev/null 2>&1; then
        # Running as root, drop to pi user
        sudo -u pi jackd -P70 -t2000 -d alsa -d hw:USB -r48000 -p128 -n3 -S > /tmp/jackd.log 2>&1 &
        echo "   JACK launched as user 'pi' (PID: $!)"
    else
        jackd -P70 -t2000 -d alsa -d hw:USB -r48000 -p128 -n3 -S > /tmp/jackd.log 2>&1 &
        echo "   JACK launched (PID: $!)"
    fi
    sleep 2
fi

# ── Final status ─────────────────────────────────────
echo ""
echo "╔══════════════════════════════════════════╗"
echo "║   Audio Stack Ready                       ║"
echo "╚══════════════════════════════════════════╝"
echo ""
echo "  Check ports:    jack_lsp -c system"
echo "  Test latency:   jack_delay -O system:playback_1 -I system:capture_1"
echo "  Auto-route:     jack-route-default"
echo "  Stop stack:     audio-stack-stop"
echo "  Xrun monitor:   jack_cpu_load"
echo ""