#!/bin/bash

# Exit on error
set -e

# Function to print error messages
error() {
    echo -e "\e[31mERROR:\e[0m $1" >&2
    exit 1
}

# Function to print success messages
success() {
    echo -e "\e[32mSUCCESS:\e[0m $1"
}

# Function to print info messages
info() {
    echo -e "\e[34mINFO:\e[0m $1"
}

# Function to check if a command exists
check_command() {
    if ! command -v "$1" &> /dev/null; then
        error "Required command '$1' not found. Please install it first."
    fi
}

# Function to compare version numbers
version_compare() {
    if [[ "$1" == "$2" ]]; then
        echo 0
        return
    fi
    local IFS=.
    local i ver1=($1) ver2=($2)
    # Fill empty positions in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++)); do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++)); do
        # Fill empty positions in ver2 with zeros
        if [[ -z ${ver2[i]} ]]; then
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]})); then
            echo 1
            return
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]})); then
            echo -1
            return
        fi
    done
    echo 0
}

# Check for required system commands
check_command python3
check_command pip3

# Check Python version
PYTHON_VERSION=$(python3 -c 'import sys; print(".".join(map(str, sys.version_info[:2])))')
MIN_VERSION="3.8"
if [ $(version_compare "$PYTHON_VERSION" "$MIN_VERSION") -lt 0 ]; then
    error "Python version must be $MIN_VERSION or higher (found $PYTHON_VERSION)"
fi
success "Python version check passed (found $PYTHON_VERSION)"

# Function to install packages on Fedora
install_fedora_deps() {
    info "Installing Fedora dependencies..."
    # Check which packages need to be installed
    local packages=()
    local check_packages=(
        "python3-devel"
        "gcc"
        "python3-pip"
        "python3-setuptools"
        "python3-numpy"
        "python3-opencv"
        "python3-flask"
        "python3-gunicorn"
        "bc"
        "lsof"
    )

    for pkg in "${check_packages[@]}"; do
        if ! rpm -q "$pkg" &>/dev/null; then
            packages+=("$pkg")
        fi
    done

    # Only run dnf if there are packages to install
    if [ ${#packages[@]} -gt 0 ]; then
        info "Installing missing packages: ${packages[*]}"
        sudo dnf install -y "${packages[@]}" || error "Failed to install required packages"
    else
        info "All required system packages are already installed"
    fi
}

# Function to install packages on Ubuntu/Debian
install_ubuntu_deps() {
    info "Installing Ubuntu/Debian dependencies..."
    sudo apt-get update || error "Failed to update package lists"
    sudo apt-get install -y \
        python3-dev \
        python3-pip \
        python3-venv \
        python3-numpy \
        python3-opencv \
        python3-flask \
        python3-gunicorn \
        bc \
        lsof \
        || error "Failed to install required packages"
}

# Check and install system dependencies based on distribution
install_system_deps() {
    if [ -f /etc/os-release ]; then
        . /etc/os-release
        case $ID in
            fedora)
                install_fedora_deps
                ;;
            ubuntu|debian)
                install_ubuntu_deps
                ;;
            *)
                info "Unknown distribution. Please ensure you have the following packages installed:"
                echo "- Python development package (python3-devel/python3-dev)"
                echo "- GCC compiler"
                echo "- Python pip"
                echo "- Python venv"
                echo "- Python numpy"
                echo "- Python OpenCV"
                echo "- Python Flask"
                echo "- Python Gunicorn"
                echo "- bc"
                echo "- lsof"
                ;;
        esac
    fi
}

# Install system dependencies
install_system_deps

# Create and activate virtual environment
if [ ! -d "venv" ]; then
    info "Creating virtual environment..."
    # Create venv with system packages to use system numpy and opencv
    python3 -m venv venv --system-site-packages || error "Failed to create virtual environment"
    success "Virtual environment created successfully"
fi

# Ensure virtual environment is activated
if [ -z "$VIRTUAL_ENV" ]; then
    info "Activating virtual environment..."
    source venv/bin/activate || error "Failed to activate virtual environment"
fi

# Upgrade pip to latest version
info "Upgrading pip..."
python3 -m pip install --upgrade pip setuptools wheel || error "Failed to upgrade pip and setuptools"

# Create or update requirements.txt with compatible package versions
if [ ! -f "requirements.txt" ]; then
    info "Creating requirements.txt..."
    cat > requirements.txt << EOF
# Web framework and extensions
Flask>=3.0.0
Flask-Cors>=4.0.0
Werkzeug>=3.0.0
gunicorn>=21.2.0

# Core dependencies
opencv-python-headless>=4.8.0

# Flask dependencies
click>=8.1.7
itsdangerous>=2.1.2
Jinja2>=3.1.2
MarkupSafe>=2.1.3
EOF
    success "Created requirements.txt"
fi

# Install requirements with better error handling
info "Installing/updating requirements..."
# First ensure pip is up to date
pip install --upgrade pip

# Install packages with specific options for better compatibility
PYTHONWARNINGS="ignore" pip install \
    --no-cache-dir \
    --prefer-binary \
    --only-binary :all: \
    -r requirements.txt || error "Failed to install requirements"

success "Requirements installed successfully"

# Create necessary directories
info "Creating required directories..."
mkdir -p logs || error "Failed to create logs directory"
success "Created required directories"

# Function to check if port is available
check_port() {
    if lsof -Pi :5000 -sTCP:LISTEN -t >/dev/null ; then
        error "Port 5000 is already in use. Please stop the other process first."
    fi
}

# Check if port is available
check_port

# Start Gunicorn with modern settings
info "Starting server with Gunicorn..."
exec gunicorn web_server:app \
    --bind 0.0.0.0:5000 \
    --workers $(nproc) \
    --worker-class gthread \
    --threads 2 \
    --timeout 120 \
    --access-logfile logs/access.log \
    --error-logfile logs/error.log \
    --capture-output \
    --log-level info \
    --reload \
    --max-requests 1000 \
    --max-requests-jitter 50 \
    || error "Failed to start Gunicorn server"