#!/usr/bin/env python3
"""
Script to generate fake telemetry data for Cassandra
Generates approximately 1GB of data
"""

from cassandra.cluster import Cluster
import random
from datetime import datetime, timedelta
import uuid
import sys

# Database connection details
DB_HOST = "10.0.21.51"
DB_PORT = "9042"
KEYSPACE = "telemetry"
TABLE_NAME = "device_metrics"

# Data generation settings
import os
TARGET_ROWS = int(os.getenv("GEN_ROWS", "5000"))  # light, configurable via GEN_ROWS
BATCH_SIZE = min(5000, max(500, TARGET_ROWS))

# Sample data
METRIC_TYPES = ["temperature", "humidity", "pressure", "voltage", "current"]
DEVICE_PREFIX = "device-"

def generate_fake_device_metric():
    """Generate a single fake device metric"""
    device_id = f"{DEVICE_PREFIX}{random.randint(1, 50000)}"
    
    # Random timestamp within the last year
    days_ago = random.randint(0, 365)
    metric_ts = datetime.now() - timedelta(days=days_ago, hours=random.randint(0, 23), 
                                           minutes=random.randint(0, 59))
    
    metric_type = random.choice(METRIC_TYPES)
    metric_value = round(random.uniform(0.0, 100.0), 4)
    
    # Generate a long payload field
    payload = "X" * 200
    
    return (device_id, metric_ts, metric_type, metric_value, payload)

def main():
    print(f"Connecting to Cassandra at {DB_HOST}:{DB_PORT}...")
    
    cluster = Cluster([DB_HOST], port=DB_PORT)
    session = cluster.connect()
    
    print(f"Generating {TARGET_ROWS} device metrics...")
    print(f"Batch size: {BATCH_SIZE}")
    
    total_generated = 0
    batch = []
    
    for i in range(TARGET_ROWS):
        batch.append(generate_fake_device_metric())
        
        if len(batch) >= BATCH_SIZE:
            session.execute(
                f"""
                INSERT INTO {KEYSPACE}.{TABLE_NAME} (device_id, metric_ts, metric_type, metric_value, payload)
                VALUES (%s, %s, %s, %s, %s)
                """,
                batch
            )
            total_generated += len(batch)
            batch = []
            
            if total_generated % 100000 == 0:
                print(f"Generated {total_generated} rows...")
    
    # Insert remaining rows
    if batch:
        session.execute(
            f"""
            INSERT INTO {KEYSPACE}.{TABLE_NAME} (device_id, metric_ts, metric_type, metric_value, payload)
            VALUES (%s, %s, %s, %s, %s)
            """,
            batch
        )
        total_generated += len(batch)
    
    session.shutdown()
    cluster.shutdown()
    
    print(f"Completed! Generated {total_generated} device metrics.")

if __name__ == "__main__":
    main()