"""
Database Module for User Authentication
========================================
SQLite-based user storage for Pharma K platform.
"""

import sqlite3
import os
from datetime import datetime
from typing import Optional, List, Dict, Any
from pathlib import Path

# Database file location
DB_DIR = Path(__file__).parent.parent / "data"
DB_PATH = DB_DIR / "pharma_k.db"


def get_db_connection() -> sqlite3.Connection:
    """Get database connection, creating tables if needed."""
    # Ensure data directory exists
    DB_DIR.mkdir(parents=True, exist_ok=True)
    
    conn = sqlite3.connect(str(DB_PATH))
    conn.row_factory = sqlite3.Row
    
    # Create tables if not exist
    _init_tables(conn)
    
    return conn


def _init_tables(conn: sqlite3.Connection):
    """Initialize database tables."""
    cursor = conn.cursor()
    
    # Users table
    cursor.execute('''
        CREATE TABLE IF NOT EXISTS users (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            email TEXT UNIQUE NOT NULL,
            password_hash TEXT NOT NULL,
            role TEXT DEFAULT 'user',
            created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
            last_login DATETIME
        )
    ''')
    
    # Admin config table
    cursor.execute('''
        CREATE TABLE IF NOT EXISTS admin_config (
            key TEXT PRIMARY KEY,
            value TEXT NOT NULL,
            updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
        )
    ''')
    
    conn.commit()
    
    # Initialize default admin if not exists
    _init_default_admin(conn)
    
    # Initialize default LLM config
    _init_default_llm_config(conn)


def _init_default_admin(conn: sqlite3.Connection):
    """Create default admin account if not exists."""
    import hashlib
    
    cursor = conn.cursor()
    cursor.execute("SELECT id FROM users WHERE email = 'admin'")
    
    if cursor.fetchone() is None:
        # Use simple hash for admin (bcrypt will be used for regular users)
        password_hash = hashlib.sha256("pharma_admin_2026".encode()).hexdigest()
        
        cursor.execute('''
            INSERT INTO users (email, password_hash, role)
            VALUES (?, ?, 'admin')
        ''', ('admin', password_hash))
        conn.commit()
        print("Default admin account created: admin / pharma_admin_2026")


def _init_default_llm_config(conn: sqlite3.Connection):
    """Initialize default LLM configuration."""
    cursor = conn.cursor()
    
    # Default provider
    cursor.execute('''
        INSERT OR IGNORE INTO admin_config (key, value)
        VALUES ('default_provider', 'kimi')
    ''')
    
    # Default API key (empty - admin needs to set)
    cursor.execute('''
        INSERT OR IGNORE INTO admin_config (key, value)
        VALUES ('default_api_key', '')
    ''')
    
    conn.commit()


# =============================================================================
# User Operations
# =============================================================================

def create_user(email: str, password_hash: str) -> bool:
    """Create a new user account."""
    try:
        conn = get_db_connection()
        cursor = conn.cursor()
        cursor.execute('''
            INSERT INTO users (email, password_hash, role)
            VALUES (?, ?, 'user')
        ''', (email, password_hash))
        conn.commit()
        conn.close()
        return True
    except sqlite3.IntegrityError:
        return False  # Email already exists


def get_user_by_email(email: str) -> Optional[Dict[str, Any]]:
    """Get user by email."""
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM users WHERE email = ?", (email,))
    row = cursor.fetchone()
    conn.close()
    
    if row:
        return dict(row)
    return None


def update_last_login(email: str):
    """Update user's last login time."""
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute('''
        UPDATE users SET last_login = ?
        WHERE email = ?
    ''', (datetime.now().isoformat(), email))
    conn.commit()
    conn.close()


def get_all_users() -> List[Dict[str, Any]]:
    """Get all users (for admin)."""
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute("SELECT id, email, role, created_at, last_login FROM users ORDER BY created_at DESC")
    rows = cursor.fetchall()
    conn.close()
    return [dict(row) for row in rows]


# =============================================================================
# Admin Config Operations
# =============================================================================

def get_admin_config(key: str) -> Optional[str]:
    """Get admin configuration value."""
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute("SELECT value FROM admin_config WHERE key = ?", (key,))
    row = cursor.fetchone()
    conn.close()
    
    if row:
        return row['value']
    return None


def set_admin_config(key: str, value: str):
    """Set admin configuration value."""
    conn = get_db_connection()
    cursor = conn.cursor()
    cursor.execute('''
        INSERT OR REPLACE INTO admin_config (key, value, updated_at)
        VALUES (?, ?, ?)
    ''', (key, value, datetime.now().isoformat()))
    conn.commit()
    conn.close()


def get_default_llm_config() -> Dict[str, str]:
    """Get default LLM configuration."""
    return {
        'provider': get_admin_config('default_provider') or 'kimi',
        'api_key': get_admin_config('default_api_key') or ''
    }


def set_default_llm_config(provider: str, api_key: str):
    """Set default LLM configuration."""
    set_admin_config('default_provider', provider)
    set_admin_config('default_api_key', api_key)