'''
Script to get air-quality values from the AMS CCS811 sensor and write to database.
/usr/bin/python3 /var/www/nebuleair_pro_4g/CCS811/write_data.py

CCS811 is a MOX gas sensor: eCO2 (equivalent CO2 in ppm, derived from VOCs) and
TVOC (Total VOC in ppb). TVOC is the primary measurement of interest.

I2C, library adafruit-circuitpython-ccs811. Address from config_table
(key CCS811_address, e.g. "0x5A" / "0x5B"), default 0x5A.
'''

import sqlite3
import sys
import time

DB_PATH = "/var/www/nebuleair_pro_4g/sqlite/sensors.db"
DEFAULT_ADDRESS = 0x5A
DATA_READY_RETRIES = 30
DATA_READY_DELAY = 0.2  # seconds


def get_config(cursor, key, default):
    cursor.execute("SELECT value FROM config_table WHERE key = ?", (key,))
    row = cursor.fetchone()
    return row[0] if row else default


def main():
    conn = sqlite3.connect(DB_PATH)
    cursor = conn.cursor()

    # Self-heal: ensure the table exists even if create_db.py was skipped during OTA.
    # Duplicates the canonical schema from sqlite/create_db.py — keep them in sync.
    cursor.execute("""
        CREATE TABLE IF NOT EXISTS data_CCS811 (
            timestamp TEXT,
            eCO2 INTEGER,
            TVOC INTEGER
        )
    """)
    conn.commit()

    addr_str = get_config(cursor, "CCS811_address", "0x5A")
    try:
        address = int(str(addr_str), 16)
    except ValueError:
        address = DEFAULT_ADDRESS

    try:
        import board
        import busio
        import adafruit_ccs811
    except Exception as e:
        print(f"CCS811: library import failed: {e}")
        conn.close()
        sys.exit(1)

    try:
        i2c = busio.I2C(board.SCL, board.SDA)
        ccs811 = adafruit_ccs811.CCS811(i2c, address=address)
    except Exception as e:
        print(f"CCS811: cannot init at {hex(address)}: {e}")
        conn.close()
        sys.exit(1)

    try:
        ready = False
        for _ in range(DATA_READY_RETRIES):
            if ccs811.data_ready:
                ready = True
                break
            time.sleep(DATA_READY_DELAY)

        if not ready:
            print("CCS811: data not ready (warming up?), skipping.")
            return

        eco2 = int(ccs811.eco2)
        tvoc = int(ccs811.tvoc)

        cursor.execute("SELECT last_updated FROM timestamp_table LIMIT 1")
        row = cursor.fetchone()
        rtc_time_str = row[0]

        cursor.execute(
            "INSERT INTO data_CCS811 (timestamp, eCO2, TVOC) VALUES (?, ?, ?)",
            (rtc_time_str, eco2, tvoc),
        )
        conn.commit()
        print(f"eCO2: {eco2} ppm, TVOC: {tvoc} ppb (saved at {rtc_time_str})")
    except Exception as e:
        print(f"CCS811 error: {e}")
    finally:
        conn.close()


if __name__ == "__main__":
    main()