#!/bin/bash

# Setup script for V4L2 loopback virtual camera
# Used for testing camera simulation on Linux systems

set -e

echo "==============================================="
echo "V4L2 Loopback Virtual Camera Setup"
echo "==============================================="

# Check if running on Linux
if [[ "$OSTYPE" != "linux-gnu"* ]]; then
    echo "Error: This script only works on Linux systems"
    echo "For macOS, consider using OBS Virtual Camera or similar"
    exit 1
fi

# Check for root privileges
if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root (use sudo)"
   exit 1
fi

# Function to check if a command exists
command_exists() {
    command -v "$1" >/dev/null 2>&1
}

# Install v4l2loopback if not present
install_v4l2loopback() {
    echo "Installing v4l2loopback..."
    
    if command_exists apt-get; then
        # Debian/Ubuntu
        apt-get update
        apt-get install -y v4l2loopback-dkms v4l2loopback-utils v4l-utils ffmpeg
    elif command_exists yum; then
        # RHEL/CentOS/Fedora
        yum install -y kmod-v4l2loopback v4l-utils ffmpeg
    elif command_exists pacman; then
        # Arch Linux
        pacman -S --noconfirm v4l2loopback-dkms v4l-utils ffmpeg
    else
        echo "Error: Unsupported package manager"
        echo "Please install v4l2loopback manually"
        exit 1
    fi
}

# Check if v4l2loopback module is available
if ! modinfo v4l2loopback >/dev/null 2>&1; then
    echo "v4l2loopback not found. Installing..."
    install_v4l2loopback
fi

# Check if FFmpeg is installed
if ! command_exists ffmpeg; then
    echo "FFmpeg not found. Installing..."
    if command_exists apt-get; then
        apt-get install -y ffmpeg
    elif command_exists yum; then
        yum install -y ffmpeg
    elif command_exists pacman; then
        pacman -S --noconfirm ffmpeg
    fi
fi

# Remove existing v4l2loopback module if loaded
if lsmod | grep -q v4l2loopback; then
    echo "Removing existing v4l2loopback module..."
    modprobe -r v4l2loopback
fi

# Load v4l2loopback module with specific parameters
echo "Loading v4l2loopback module..."
modprobe v4l2loopback \
    devices=2 \
    video_nr=10,11 \
    card_label="Meteor Cam 1","Meteor Cam 2" \
    exclusive_caps=1

# Verify devices were created
echo ""
echo "Checking virtual devices..."
if [[ -e /dev/video10 ]] && [[ -e /dev/video11 ]]; then
    echo "✅ Virtual cameras created successfully:"
    echo "   - /dev/video10 (Meteor Cam 1)"
    echo "   - /dev/video11 (Meteor Cam 2)"
else
    echo "❌ Failed to create virtual cameras"
    exit 1
fi

# Set permissions for non-root access
chmod 666 /dev/video10 /dev/video11

# List all video devices
echo ""
echo "Available video devices:"
v4l2-ctl --list-devices

# Show device capabilities
echo ""
echo "Virtual camera capabilities:"
v4l2-ctl -d /dev/video10 --all | head -20

# Create test video if it doesn't exist
TEST_VIDEO_DIR="/tmp/meteor_test_videos"
TEST_VIDEO="$TEST_VIDEO_DIR/meteor_test.mp4"

if [[ ! -f "$TEST_VIDEO" ]]; then
    echo ""
    echo "Creating test video..."
    mkdir -p "$TEST_VIDEO_DIR"
    
    # Generate a test video with synthetic meteor events
    ffmpeg -f lavfi -i testsrc2=size=1280x720:rate=30 \
           -f lavfi -i sine=frequency=1000:duration=10 \
           -t 10 \
           -vf "drawtext=text='Meteor Test Video':fontsize=30:fontcolor=white:x=(w-text_w)/2:y=50" \
           -c:v libx264 -preset fast \
           -y "$TEST_VIDEO" 2>/dev/null
    
    echo "✅ Test video created: $TEST_VIDEO"
fi

# Function to stream video to virtual camera
stream_to_camera() {
    local video_file=$1
    local device=$2
    local label=$3
    
    echo ""
    echo "Starting stream to $device ($label)..."
    echo "Command: ffmpeg -re -i \"$video_file\" -f v4l2 -pix_fmt yuv420p \"$device\""
    echo ""
    echo "Press Ctrl+C to stop the stream"
    
    # Stream video to virtual camera (loop infinitely)
    ffmpeg -re -stream_loop -1 -i "$video_file" \
           -f v4l2 \
           -pix_fmt yuv420p \
           -vf "scale=1280:720,drawtext=text='$label - %{localtime}':fontsize=20:fontcolor=white:x=10:y=10" \
           "$device" 2>/dev/null &
    
    local pid=$!
    echo "Stream PID: $pid"
    
    # Save PID for cleanup
    echo $pid > "/tmp/meteor_cam_stream_$(basename $device).pid"
    
    return 0
}

# Function to stop all streams
stop_streams() {
    echo ""
    echo "Stopping all streams..."
    
    for pidfile in /tmp/meteor_cam_stream_*.pid; do
        if [[ -f "$pidfile" ]]; then
            pid=$(cat "$pidfile")
            if kill -0 "$pid" 2>/dev/null; then
                kill "$pid"
                echo "Stopped stream PID: $pid"
            fi
            rm "$pidfile"
        fi
    done
}

# Parse command line arguments
ACTION=${1:-help}

case "$ACTION" in
    start)
        VIDEO_FILE=${2:-$TEST_VIDEO}
        DEVICE=${3:-/dev/video10}
        
        if [[ ! -f "$VIDEO_FILE" ]]; then
            echo "Error: Video file not found: $VIDEO_FILE"
            exit 1
        fi
        
        stream_to_camera "$VIDEO_FILE" "$DEVICE" "Meteor Cam"
        ;;
    
    start-all)
        VIDEO_FILE=${2:-$TEST_VIDEO}
        
        if [[ ! -f "$VIDEO_FILE" ]]; then
            echo "Error: Video file not found: $VIDEO_FILE"
            exit 1
        fi
        
        stream_to_camera "$VIDEO_FILE" "/dev/video10" "Meteor Cam 1"
        stream_to_camera "$VIDEO_FILE" "/dev/video11" "Meteor Cam 2"
        
        echo ""
        echo "Both virtual cameras are now streaming"
        echo "You can test them with:"
        echo "  cargo run -- --camera-source v4l2:/dev/video10"
        echo "  cargo run -- --camera-source v4l2:/dev/video11"
        ;;
    
    stop)
        stop_streams
        ;;
    
    status)
        echo "Virtual camera status:"
        echo ""
        
        if lsmod | grep -q v4l2loopback; then
            echo "✅ v4l2loopback module loaded"
        else
            echo "❌ v4l2loopback module not loaded"
        fi
        
        echo ""
        echo "Active streams:"
        for pidfile in /tmp/meteor_cam_stream_*.pid; do
            if [[ -f "$pidfile" ]]; then
                pid=$(cat "$pidfile")
                if kill -0 "$pid" 2>/dev/null; then
                    device=$(basename "$pidfile" .pid | sed 's/meteor_cam_stream_//')
                    echo "  - Stream to /dev/$device (PID: $pid)"
                fi
            fi
        done
        ;;
    
    unload)
        stop_streams
        echo "Unloading v4l2loopback module..."
        modprobe -r v4l2loopback
        echo "✅ Module unloaded"
        ;;
    
    help|*)
        echo ""
        echo "Usage: $0 [command] [options]"
        echo ""
        echo "Commands:"
        echo "  start [video_file] [device]  - Start streaming to a virtual camera"
        echo "                                  Default: $TEST_VIDEO to /dev/video10"
        echo "  start-all [video_file]        - Start streaming to all virtual cameras"
        echo "  stop                          - Stop all active streams"
        echo "  status                        - Show virtual camera status"
        echo "  unload                        - Stop streams and unload module"
        echo "  help                          - Show this help message"
        echo ""
        echo "Examples:"
        echo "  $0 start                      # Start with test video"
        echo "  $0 start meteor.mp4           # Use custom video"
        echo "  $0 start meteor.mp4 /dev/video11  # Specific device"
        echo "  $0 start-all meteor.mp4       # Stream to all devices"
        echo "  $0 stop                       # Stop all streams"
        echo ""
        echo "Test with meteor edge client:"
        echo "  cargo run -- --camera-source v4l2:/dev/video10"
        ;;
esac

echo ""
echo "==============================================="