#!/usr/bin/env python3
"""
Startup script to handle environment setup and pre-checks.
This script ensures proper directory permissions and environment setup before starting the app.
"""

import os
import sys
import tempfile
from pathlib import Path


def setup_environment():
    """Setup environment variables and directories."""
    
    # Set cache directories to writable locations
    cache_dirs = {
        'SENTENCE_TRANSFORMERS_HOME': ['/tmp/sentence_transformers', '/data/sentence_transformers'],
        'VECTOR_PERSIST_DIR': ['/tmp/vector_db', '/data/vector_db'],
        'HF_HOME': ['/tmp/huggingface', '/data/huggingface'],
        'TRANSFORMERS_CACHE': ['/tmp/transformers', '/data/transformers'],
    }
    
    for env_var, candidates in cache_dirs.items():
        if env_var not in os.environ:
            for candidate in candidates:
                try:
                    Path(candidate).mkdir(parents=True, exist_ok=True)
                    # Test write permission
                    test_file = Path(candidate) / "test_write"
                    test_file.write_text("test")
                    test_file.unlink()
                    os.environ[env_var] = candidate
                    print(f"✅ Set {env_var} to {candidate}")
                    break
                except (OSError, PermissionError):
                    continue
            else:
                # Fallback to system temp
                temp_dir = os.path.join(tempfile.gettempdir(), env_var.lower())
                try:
                    Path(temp_dir).mkdir(parents=True, exist_ok=True)
                    os.environ[env_var] = temp_dir
                    print(f"⚠️ Fallback: Set {env_var} to {temp_dir}")
                except Exception as e:
                    print(f"❌ Could not set {env_var}: {e}")

    # Ensure tokenizer libs don't attempt parallelism post-fork (prevents hangs)
    os.environ.setdefault('TOKENIZERS_PARALLELISM', 'false')
    # Cap thread usage for BLAS backends to avoid CPU thrashing on shared runners
    os.environ.setdefault('OMP_NUM_THREADS', '1')
    os.environ.setdefault('OPENBLAS_NUM_THREADS', '1')
    os.environ.setdefault('MKL_NUM_THREADS', '1')
    os.environ.setdefault('NUMEXPR_NUM_THREADS', '1')


def check_permissions():
    """Check and report on directory permissions."""
    dirs_to_check = [
        os.environ.get('SENTENCE_TRANSFORMERS_HOME', '/tmp/sentence_transformers'),
        os.environ.get('VECTOR_PERSIST_DIR', '/tmp/vector_db'),
        '/tmp',
        '.',
    ]
    
    print("\n📋 Directory Permissions Check:")
    for dir_path in dirs_to_check:
        if not dir_path:
            continue
            
        try:
            path = Path(dir_path)
            if not path.exists():
                path.mkdir(parents=True, exist_ok=True)
            
            # Test write permission
            test_file = path / "test_permissions"
            test_file.write_text("test")
            test_file.unlink()
            
            print(f"✅ {dir_path} - writable")
        except Exception as e:
            print(f"❌ {dir_path} - not writable: {e}")


def main():
    """Main startup routine."""
    print("🚀 Starting CVE Fact Checker setup...")
    
    setup_environment()
    check_permissions()
    
    print("\n🎯 Environment setup complete!")
    print("📍 Key directories:")
    for key in ['SENTENCE_TRANSFORMERS_HOME', 'VECTOR_PERSIST_DIR']:
        print(f"   {key}: {os.environ.get(key, 'Not set')}")
    
    return True


if __name__ == "__main__":
    success = main()
    sys.exit(0 if success else 1)