#!/bin/bash

################################################################################
# Video Optimizer - Deployment Script
################################################################################
# This script deploys the backend application to /opt/video-optimizer-back
# Run this script AFTER copying files to /opt/video-optimizer-back
#
# Usage:
#   sudo bash deploy.sh [--initial]
#
# Options:
#   --initial    First-time deployment (creates venv, installs dependencies)
#                On subsequent runs without this flag, script will:
#                - Update code
#                - Restart the systemd service
################################################################################

set -e  # Exit on any error

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Configuration
APP_DIR="/opt/video-optimizer-back"
VENV_DIR="$APP_DIR/venv"
BACKEND_DIR="$APP_DIR/backend"
SERVICE_NAME="video-optimizer-backend"
APP_USER="www-data"
APP_GROUP="www-data"

# Check if running as root
if [ "$EUID" -ne 0 ]; then
    echo -e "${RED}ERROR: This script must be run as root (use sudo)${NC}"
    exit 1
fi

# Check if initial deployment flag is set
INITIAL_DEPLOY=false
if [ "$1" == "--initial" ]; then
    INITIAL_DEPLOY=true
fi

################################################################################
# Functions
################################################################################

print_header() {
    echo ""
    echo -e "${BLUE}========================================${NC}"
    echo -e "${BLUE}$1${NC}"
    echo -e "${BLUE}========================================${NC}"
    echo ""
}

print_success() {
    echo -e "${GREEN}✓ $1${NC}"
}

print_error() {
    echo -e "${RED}✗ $1${NC}"
}

print_warning() {
    echo -e "${YELLOW}⚠ $1${NC}"
}

print_info() {
    echo -e "${BLUE}ℹ $1${NC}"
}

################################################################################
# Main Deployment
################################################################################

print_header "Video Optimizer - Backend Deployment"

# Check if app directory exists
if [ ! -d "$APP_DIR" ]; then
    print_error "Application directory not found: $APP_DIR"
    print_info "Please copy application files to $APP_DIR first"
    exit 1
fi

print_success "Application directory found: $APP_DIR"

# Change to app directory
cd "$APP_DIR"

################################################################################
# Initial Setup (only on first deployment)
################################################################################

if [ "$INITIAL_DEPLOY" = true ]; then
    print_header "Initial Deployment Setup"

    # Check if Python 3 is installed
    if ! command -v python3 &> /dev/null; then
        print_error "Python 3 is not installed"
        print_info "Install with: sudo apt-get install python3 python3-venv python3-pip"
        exit 1
    fi
    print_success "Python 3 found: $(python3 --version)"

    # Check if FFmpeg is installed
    if ! command -v ffmpeg &> /dev/null; then
        print_warning "FFmpeg is not installed - video conversion will not work!"
        print_info "Install with: sudo apt-get install ffmpeg"
        read -p "Continue anyway? (y/n) " -n 1 -r
        echo
        if [[ ! $REPLY =~ ^[Yy]$ ]]; then
            exit 1
        fi
    else
        print_success "FFmpeg found: $(ffmpeg -version | head -n1)"
    fi

    # Create virtual environment
    print_info "Creating Python virtual environment..."
    if [ -d "$VENV_DIR" ]; then
        print_warning "Virtual environment already exists, removing old one..."
        rm -rf "$VENV_DIR"
    fi
    python3 -m venv "$VENV_DIR"
    print_success "Virtual environment created"

    # Activate virtual environment and install dependencies
    print_info "Installing Python dependencies..."
    source "$VENV_DIR/bin/activate"
    pip install --upgrade pip
    pip install -r "$BACKEND_DIR/requirements.txt"
    deactivate
    print_success "Dependencies installed"

    # Check if .env file exists
    if [ ! -f "$APP_DIR/.env" ]; then
        print_error ".env file not found!"
        print_info "Please create $APP_DIR/.env from .env.example"
        print_info "Required settings:"
        print_info "  - FLASK_ENV=production"
        print_info "  - AZURE_CLIENT_ID=<your-client-id>"
        print_info "  - AZURE_TENANT_ID=<your-tenant-id>"
        print_info "  - REDIRECT_URI=https://ai-sandbox.oliver.solutions/video-optimizer"
        print_info "  - FRONTEND_URL=https://ai-sandbox.oliver.solutions/video-optimizer"
        print_info "  - SECRET_KEY=<generate-random-key>"
        exit 1
    fi
    print_success ".env file found"

else
    print_header "Updating Existing Deployment"

    # Check if venv exists
    if [ ! -d "$VENV_DIR" ]; then
        print_error "Virtual environment not found!"
        print_info "Run with --initial flag for first-time setup: sudo bash deploy.sh --initial"
        exit 1
    fi
    print_success "Virtual environment found"

    # Update dependencies (in case requirements.txt changed)
    print_info "Updating Python dependencies..."
    source "$VENV_DIR/bin/activate"
    pip install --upgrade pip
    pip install -r "$BACKEND_DIR/requirements.txt"
    deactivate
    print_success "Dependencies updated"
fi

################################################################################
# Create Required Directories
################################################################################

print_info "Creating required directories..."
mkdir -p "$BACKEND_DIR/uploads"
mkdir -p "$BACKEND_DIR/outputs"
mkdir -p "$BACKEND_DIR/logs"
mkdir -p "$BACKEND_DIR/logs/conversions"
print_success "Directories created"

################################################################################
# Set Permissions
################################################################################

print_info "Setting file permissions..."

# Set ownership to www-data for entire app directory
chown -R $APP_USER:$APP_GROUP "$APP_DIR"

# Ensure www-data can write to working directories
chmod -R 755 "$APP_DIR"
chmod -R 775 "$BACKEND_DIR/uploads"
chmod -R 775 "$BACKEND_DIR/outputs"
chmod -R 775 "$BACKEND_DIR/logs"

# Protect .env file (readable only by owner)
if [ -f "$APP_DIR/.env" ]; then
    chmod 600 "$APP_DIR/.env"
    chown $APP_USER:$APP_GROUP "$APP_DIR/.env"
fi

print_success "Permissions set"

################################################################################
# Service Management
################################################################################

print_header "Service Management"

# Check if service is running
if systemctl is-active --quiet $SERVICE_NAME; then
    print_info "Stopping $SERVICE_NAME service..."
    systemctl stop $SERVICE_NAME
    print_success "Service stopped"
fi

# Reload systemd daemon
print_info "Reloading systemd daemon..."
systemctl daemon-reload
print_success "Systemd daemon reloaded"

# Enable service (if not already enabled)
if ! systemctl is-enabled --quiet $SERVICE_NAME; then
    print_info "Enabling $SERVICE_NAME service..."
    systemctl enable $SERVICE_NAME
    print_success "Service enabled"
else
    print_success "Service already enabled"
fi

# Start service
print_info "Starting $SERVICE_NAME service..."
systemctl start $SERVICE_NAME
sleep 2

# Check if service started successfully
if systemctl is-active --quiet $SERVICE_NAME; then
    print_success "Service started successfully"
else
    print_error "Service failed to start!"
    print_info "Check logs with: sudo journalctl -u $SERVICE_NAME -n 50 --no-pager"
    exit 1
fi

################################################################################
# Verification
################################################################################

print_header "Deployment Verification"

# Check service status
print_info "Service status:"
systemctl status $SERVICE_NAME --no-pager -l | head -n 10

# Test health endpoint
print_info "Testing health endpoint..."
sleep 3
if curl -f http://localhost:5000/api/health > /dev/null 2>&1; then
    print_success "Backend API is responding"
else
    print_warning "Backend API is not responding (may still be starting up)"
    print_info "Check logs with: sudo journalctl -u $SERVICE_NAME -f"
fi

################################################################################
# Summary
################################################################################

print_header "Deployment Complete!"

echo -e "Backend Service: ${GREEN}Running${NC}"
echo -e "Service Name: $SERVICE_NAME"
echo -e "Application Dir: $APP_DIR"
echo ""
echo "Useful Commands:"
echo "  View logs:       sudo journalctl -u $SERVICE_NAME -f"
echo "  Restart service: sudo systemctl restart $SERVICE_NAME"
echo "  Stop service:    sudo systemctl stop $SERVICE_NAME"
echo "  Service status:  sudo systemctl status $SERVICE_NAME"
echo ""
echo "Next Steps:"
echo "  1. Copy frontend files to /var/www/html/video-optimizer"
echo "  2. Configure Apache (see DEPLOYMENT.md)"
echo "  3. Test application: https://ai-sandbox.oliver.solutions/video-optimizer"
echo ""