#!/usr/bin/env python3
"""
GAKR AI Chatbot - Startup Script
Handles environment setup and server startup
"""

import os
import sys
import subprocess
import argparse
import socket
from pathlib import Path

def configure_output_encoding():
    """Avoid UnicodeEncodeError on non-UTF terminal encodings."""
    try:
        if hasattr(sys.stdout, "reconfigure"):
            sys.stdout.reconfigure(encoding="utf-8", errors="replace")
        if hasattr(sys.stderr, "reconfigure"):
            sys.stderr.reconfigure(encoding="utf-8", errors="replace")
    except Exception:
        pass

def print_banner():
    """Print startup banner"""
    print("""
    +--------------------------------------------------------------+
    |                                                              |
    |                GAKR AI Chatbot Platform                      |
    |                                                              |
    |         Powered by NVIDIA API + Web Search                   |
    |                                                              |
    +--------------------------------------------------------------+
    """)

def check_python_version():
    """Check if Python version is compatible"""
    if sys.version_info < (3, 8):
        print("❌ Error: Python 3.8 or higher is required")
        print(f"   Current version: {sys.version_info.major}.{sys.version_info.minor}")
        return False
    print(f"✅ Python {sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}")
    return True

def check_dependencies():
    """Check if required dependencies are installed"""
    backend_dir = Path(__file__).parent / "backend"
    req_file = backend_dir / "requirements.txt"
    
    if not req_file.exists():
        print("⚠️  requirements.txt not found")
        return False
    
    print("📦 Checking dependencies...")
    
    # Try to import key modules
    try:
        import fastapi
        print("   ✓ FastAPI")
    except ImportError:
        print("   ✗ FastAPI (not installed)")
        return False
    
    try:
        import httpx
        print("   ✓ httpx")
    except ImportError:
        print("   ✗ httpx (not installed)")
        return False

    try:
        import PyPDF2
        print("   ✓ PyPDF2")
    except ImportError:
        print("   ✗ PyPDF2 (not installed)")
        return False

    try:
        import docx  # noqa: F401
        print("   ✓ python-docx")
    except ImportError:
        print("   ✗ python-docx (not installed)")
        return False

    try:
        from PIL import Image  # noqa: F401
        print("   ✓ Pillow")
    except ImportError:
        print("   ✗ Pillow (not installed)")
        return False

    try:
        import openpyxl  # noqa: F401
        print("   ✓ openpyxl")
    except ImportError:
        print("   ✗ openpyxl (not installed)")
        return False

    try:
        import xlrd  # noqa: F401
        print("   ✓ xlrd")
    except ImportError:
        print("   ⚠️ xlrd (not installed, legacy .xls parsing disabled)")

    try:
        import pytesseract
        try:
            pytesseract.get_tesseract_version()
            print("   ✓ pytesseract + Tesseract OCR")
        except Exception:
            print("   ⚠️ pytesseract installed, but Tesseract OCR binary not detected")
    except ImportError:
        print("   ⚠️ pytesseract (not installed, image OCR disabled)")
    except Exception as e:
        print(f"   ⚠️ pytesseract unavailable ({type(e).__name__}: {e})")
        print("      Image OCR disabled; server will continue without OCR.")

    return True

def setup_directories():
    """Create necessary directories"""
    base_dir = Path(__file__).parent
    
    dirs = [
        base_dir / "data",
        base_dir / "data" / "uploads"
    ]
    
    for d in dirs:
        d.mkdir(parents=True, exist_ok=True)
    
    print("✅ Directories initialized")

def is_port_available(host, port):
    """Check whether a TCP port is available for binding"""
    bind_host = host if host and host != "0.0.0.0" else "0.0.0.0"
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        try:
            sock.bind((bind_host, int(port)))
            return True
        except OSError:
            return False

def find_available_port(host, start_port, max_tries=50):
    """Find first available port starting from start_port"""
    port = int(start_port)
    for _ in range(max_tries):
        if is_port_available(host, port):
            return port
        port += 1
    return None

def start_server(host, port, reload):
    """Start the FastAPI server"""
    backend_dir = Path(__file__).parent / "backend"

    requested_port = int(port)
    selected_port = find_available_port(host, requested_port)
    if selected_port is None:
        print(f"\n❌ No available port found from {requested_port} to {requested_port + 49}")
        print("   Stop existing server processes or pass a different --port value.")
        return 1

    if selected_port != requested_port:
        print(f"\n⚠️  Port {requested_port} is already in use. Switching to port {selected_port}.")
        port = selected_port

    print(f"\n🚀 Starting server on http://{host}:{port}")
    print("   Press Ctrl+C to stop\n")
    
    cmd = [
        sys.executable, "-m", "uvicorn",
        "main:app",
        "--host", host,
        "--port", str(port),
    ]
    
    if reload:
        cmd.append("--reload")
    
    try:
        result = subprocess.run(cmd, cwd=backend_dir)
        return result.returncode
    except KeyboardInterrupt:
        print("\n\n👋 Server stopped")
        return 0

def main():
    configure_output_encoding()

    parser = argparse.ArgumentParser(description="GAKR AI Chatbot Server")
    default_port = int(os.getenv("PORT", "7860"))
    parser.add_argument("--host", default="0.0.0.0", help="Host to bind (default: 0.0.0.0)")
    parser.add_argument("--port", type=int, default=default_port, help=f"Port to run on (default: {default_port})")
    parser.add_argument("--reload", action="store_true", help="Enable auto-reload for development")
    parser.add_argument("--skip-checks", action="store_true", help="Skip dependency checks")
    
    args = parser.parse_args()
    
    print_banner()
    
    # Check Python version
    if not check_python_version():
        sys.exit(1)
    
    # Setup directories
    setup_directories()
    
    # Check dependencies
    if not args.skip_checks:
        if not check_dependencies():
            print("\n❌ Please install dependencies first:")
            print("   pip install -r backend/requirements.txt")
            sys.exit(1)
    
    # Start server
    exit_code = start_server(args.host, args.port, args.reload)
    if exit_code != 0:
        sys.exit(exit_code)

if __name__ == "__main__":
    main()