#!/usr/bin/env python3
"""Test pool payload decoding with the new MQTT message format"""

import json
import struct
from typing import Optional

PAYLOAD_SIZE = 15
MAGIC1 = 0x42
MAGIC2 = 0x99


def crc8_xor(data: bytes) -> int:
    """Simple XOR checksum used by the pool payload."""
    c = 0
    for b in data:
        c ^= b
    return c


def decode_pool_payload(candidate_bytes: bytes, expected_seq: Optional[int] = None):
    """Scan a byte stream for a plausible pool payload.

    Slides a 15-byte window, validates with CRC, version/nodeId, and range checks,
    and scores candidates. Returns the best decoded dict or None.
    """
    # Drop leading preamble (0xAA) if present
    while candidate_bytes.startswith(b"\xaa"):
        candidate_bytes = candidate_bytes[1:]

    best = None
    best_score = -1

    for offset in range(0, len(candidate_bytes) - PAYLOAD_SIZE + 1):
        chunk = candidate_bytes[offset:offset + PAYLOAD_SIZE]
        try:
            magic1, magic2, version, nodeId, seq, t_ds10, t_bme10, hum10, pres1, crc_received = struct.unpack(
                '<BBBBHhhHHB', chunk
            )
        except struct.error:
            continue

        crc_calculated = crc8_xor(chunk[:-1])
        if crc_calculated != crc_received:
            continue

        if version != 1 or nodeId != 1:
            continue

        # Plausibility checks (unit scaled)
        if not (-300 <= t_ds10 <= 600):  # -30.0 to 60.0°C
            continue
        if not (-300 <= t_bme10 <= 600):
            continue
        if not (0 <= hum10 <= 1000):  # 0.0–100.0%
            continue
        if not (8000 <= pres1 <= 11000):  # 800.0–1100.0 hPa
            continue

        score = 0
        if magic1 == MAGIC1 and magic2 == MAGIC2:
            score += 2
        if expected_seq is not None and seq == expected_seq:
            score += 1
        # CRC already validated; reward shorter offset to prefer first valid
        score -= offset * 0.001

        if score > best_score:
            best_score = score
            best = {
                "offset": offset,
                "magic_ok": magic1 == MAGIC1 and magic2 == MAGIC2,
                "version": version,
                "nodeId": nodeId,
                "sequence": seq,
                "t_ds_c": t_ds10 / 10.0,
                "t_bme_c": t_bme10 / 10.0,
                "humidity": hum10 / 10.0,
                "pressure_hpa": pres1 / 10.0,
                "crc_valid": True,
            }

    return best


# Test with the actual MQTT message
mqtt_message = {
    "time": "2025-12-27T13:26:47",
    "model": "pool",
    "count": 1,
    "num_rows": 1,
    "rows": [
        {
            "len": 143,
            "data": "429901013400a801f6002b0294272a000000"
        }
    ],
    "codes": ["{143}429901013400a801f6002b0294272a000000"]
}

print("Testing pool payload decode with new MQTT format:")
print(f"MQTT message: {json.dumps(mqtt_message, indent=2)}")
print()

hex_data = mqtt_message['rows'][0]['data']
print(f"Hex data from rows[0]['data']: {hex_data}")
print(f"Hex data length: {len(hex_data)} chars ({len(hex_data)//2} bytes)")

# Strip 'aaaaaa' prefix if present
if hex_data.startswith('aaaaaa'):
    hex_data = hex_data[6:]
    print(f"Stripped 'aaaaaa' prefix, remaining: {hex_data}")

byte_data = bytes.fromhex(hex_data)
print(f"Byte data: {byte_data.hex()}")
print()

# Decode with sliding window
decoded = decode_pool_payload(byte_data)

if decoded:
    print("✓ Payload decoded successfully!")
    print(json.dumps(decoded, indent=2))
    
    print()
    print("Generated sensor messages:")
    
    bme_msg = {
        'time': mqtt_message['time'],
        'model': 'pool',
        'id': decoded['nodeId'] * 10 + 1,
        'battery_ok': 1,
        'temperature_C': decoded['t_bme_c'],
        'humidity': decoded['humidity'],
        'pressure_rel': decoded['pressure_hpa'],
        'mic': 'CRC'
    }
    
    ds_msg = {
        'time': mqtt_message['time'],
        'model': 'pool',
        'id': decoded['nodeId'] * 10 + 2,
        'battery_ok': 1,
        'temperature_C': decoded['t_ds_c'],
        'mic': 'CRC'
    }
    
    print("BME280 message:")
    print(json.dumps(bme_msg, indent=2))
    print()
    print("DS18B20 message:")
    print(json.dumps(ds_msg, indent=2))
else:
    print("✗ Failed to decode payload!")