import os
import sqlite3
import time
import json
from datetime import datetime
from app.config import DB_PATH, CACHE_EXPIRY_HOURS

# Initialize SQLite database
def init_db():
    global DB_PATH

    # Try to use the mounted volume first
    db_path = '/db/cache.db'
    db_dir = os.path.dirname(db_path)

    # Check if directory exists and is writable
    dir_writable = False
    if os.path.exists(db_dir):
        try:
            test_file = os.path.join(db_dir, '.write_test')
            with open(test_file, 'w') as f:
                f.write('test')
            os.remove(test_file)
            dir_writable = True
        except (IOError, PermissionError):
            print(f"Directory {db_dir} exists but is not writable")
            dir_writable = False

    # If directory doesn't exist or isn't writable, try to create it
    if not os.path.exists(db_dir) or not dir_writable:
        try:
            os.makedirs(db_dir, exist_ok=True)
            # Test if we can write to the directory
            test_file = os.path.join(db_dir, '.write_test')
            with open(test_file, 'w') as f:
                f.write('test')
            os.remove(test_file)
            print(f"Created directory: {db_dir}")
            dir_writable = True
        except Exception as e:
            print(f"Warning: Could not create or write to directory {db_dir}: {e}")
            # Fallback to using a local database file
            db_path = 'cache.db'
            print(f"Using local database file: {db_path}")

    try:
        conn = sqlite3.connect(db_path)
        cursor = conn.cursor()
        cursor.execute('''
        CREATE TABLE IF NOT EXISTS cache (
            url TEXT,
            route TEXT,
            data TEXT,
            timestamp INTEGER,
            PRIMARY KEY (url, route)
        )
        ''')
        conn.commit()
        conn.close()
        print(f"Database initialized at {db_path}")
        # Update the global DB_PATH
        DB_PATH = db_path
    except sqlite3.OperationalError as e:
        print(f"Error initializing database at {db_path}: {e}")
        # Fallback to using a local database file if the mounted volume has permission issues
        db_path = 'cache.db'
        print(f"Falling back to local database file: {db_path}")
        try:
            conn = sqlite3.connect(db_path)
            cursor = conn.cursor()
            cursor.execute('''
            CREATE TABLE IF NOT EXISTS cache (
                url TEXT,
                route TEXT,
                data TEXT,
                timestamp INTEGER,
                PRIMARY KEY (url, route)
            )
            ''')
            conn.commit()
            conn.close()
            print(f"Local database initialized at {db_path}")
            # Update the global DB_PATH
            DB_PATH = db_path
        except sqlite3.OperationalError as e2:
            print(f"Error initializing local database: {e2}")
            raise

# Get cached data if it exists and is not older than the expiry time
def get_cached_data(url, route):
    conn = sqlite3.connect(DB_PATH)
    cursor = conn.cursor()
    cache_expiry = int(time.time()) - (CACHE_EXPIRY_HOURS * 60 * 60)  # Convert hours to seconds
    cursor.execute(
        "SELECT data FROM cache WHERE url = ? AND route = ? AND timestamp > ?",
        (url, route, cache_expiry)
    )
    result = cursor.fetchone()
    conn.close()

    if result:
        print(f"Cache hit for {url} on route {route}")
        return json.loads(result[0])
    return None

# Save data to cache
def save_to_cache(url, route, data):
    conn = sqlite3.connect(DB_PATH)
    cursor = conn.cursor()
    timestamp = int(time.time())

    # Convert data to JSON string
    data_json = json.dumps(data)

    cursor.execute(
        "INSERT OR REPLACE INTO cache (url, route, data, timestamp) VALUES (?, ?, ?, ?)",
        (url, route, data_json, timestamp)
    )
    conn.commit()
    conn.close()
    print(f"Saved to cache: {url} on route {route}")

# Function to clean up old cache entries
def cleanup_old_cache_entries():
    try:
        print(f"Running scheduled cache cleanup (entries older than {CACHE_EXPIRY_HOURS} hours)")
        conn = sqlite3.connect(DB_PATH)
        cursor = conn.cursor()

        # Calculate the timestamp for entries older than the expiry time
        expiry_timestamp = int(time.time()) - (CACHE_EXPIRY_HOURS * 60 * 60)

        # Get count of entries to be deleted
        cursor.execute("SELECT COUNT(*) FROM cache WHERE timestamp < ?", (expiry_timestamp,))
        count = cursor.fetchone()[0]

        # Delete old entries
        cursor.execute("DELETE FROM cache WHERE timestamp < ?", (expiry_timestamp,))
        conn.commit()
        conn.close()

        print(f"Cache cleanup completed: {count} entries removed")
    except Exception as e:
        print(f"Error during cache cleanup: {e}")