#!/usr/bin/env python3
"""
Timelapse Device Agent (Pi4 + DSLR)
- Provision device claim
- Poll approval
- Persist API key
- Send heartbeat loop
"""

import os
import time
import json
import socket
import platform
import uuid
from pathlib import Path
from datetime import datetime

import requests

# ── Config ──────────────────────────────────────────────────
SERVER_URL = os.environ.get('TL_SERVER_URL', 'http://localhost:3001')
DEVICE_NAME = os.environ.get('TL_DEVICE_NAME', socket.gethostname())
SERIAL_NO = os.environ.get('TL_SERIAL_NO', f'PI4-{socket.gethostname()}')
CONFIG_DIR = Path(os.environ.get('TL_CONFIG_DIR', '/boot/timelapse'))
CONFIG_FILE = CONFIG_DIR / 'agent.json'
API_KEY_FILE = CONFIG_DIR / 'agent.key'
HEARTBEAT_INTERVAL = int(os.environ.get('TL_HEARTBEAT_INTERVAL', '30'))
POLL_INTERVAL = int(os.environ.get('TL_CLAIM_POLL_INTERVAL', '10'))


def now_str() -> str:
    return datetime.now().strftime('%H:%M:%S')


def log(msg: str):
    print(f"[{now_str()}] {msg}", flush=True)


def get_device_uuid() -> str:
    # Stable UUID per machine
    machine_id = Path('/etc/machine-id')
    if machine_id.exists():
        return machine_id.read_text().strip()
    return str(uuid.getnode())


def ensure_config_dir():
    CONFIG_DIR.mkdir(parents=True, exist_ok=True)


def load_config() -> dict:
    if not CONFIG_FILE.exists():
        return {}
    try:
        return json.loads(CONFIG_FILE.read_text())
    except Exception:
        return {}


def save_config(cfg: dict):
    ensure_config_dir()
    CONFIG_FILE.write_text(json.dumps(cfg, indent=2))


def save_api_key(key: str):
    ensure_config_dir()
    API_KEY_FILE.write_text(key)
    os.chmod(API_KEY_FILE, 0o600)


def load_api_key() -> str | None:
    if not API_KEY_FILE.exists():
        return None
    return API_KEY_FILE.read_text().strip()


def claim_device(device_uuid: str) -> dict:
    url = f"{SERVER_URL}/v1/devices/claim"
    payload = {
        'deviceUuid': device_uuid,
        'deviceName': DEVICE_NAME,
        'serialNo': SERIAL_NO,
    }
    r = requests.post(url, json=payload, timeout=10)
    r.raise_for_status()
    return r.json()


def poll_claim_status(claim_code: str) -> dict:
    url = f"{SERVER_URL}/v1/devices/claim/{claim_code}/status"
    r = requests.get(url, timeout=10)
    r.raise_for_status()
    return r.json()


def gather_metrics() -> dict:
    temp_c = None
    battery = None

    try:
        p = Path('/sys/class/thermal/thermal_zone0/temp')
        if p.exists():
            temp_c = round(int(p.read_text().strip()) / 1000, 1)
    except Exception:
        pass

    try:
        statvfs = os.statvfs('/')
        free_gb = int((statvfs.f_bavail * statvfs.f_frsize) / (1024**3))
    except Exception:
        free_gb = 50

    return {
        'tempC': temp_c,
        'batteryPct': battery,
        'storageFreeGb': free_gb,
        'capturesToday': 0,
        'lastCaptureAt': datetime.utcnow().isoformat(),
        'networkStatus': 'online',
    }


def send_heartbeat(device_id: str, api_key: str):
    url = f"{SERVER_URL}/v1/devices/{device_id}/heartbeat"
    headers = {
        'Content-Type': 'application/json',
        'X-API-Key': api_key,
    }
    payload = {
        'deviceId': device_id,
        'status': 'online',
        'firmwareVersion': 'agent-0.1.0',
        **gather_metrics(),
    }

    r = requests.post(url, json=payload, headers=headers, timeout=10)
    if r.ok:
        data = r.json()
        log(f"heartbeat ok | pendingCommands={data.get('pendingCommands', 0)}")
    else:
        log(f"heartbeat failed {r.status_code}: {r.text[:120]}")


def provision_if_needed() -> tuple[str, str]:
    cfg = load_config()
    api_key = load_api_key()

    if cfg.get('deviceId') and api_key:
        return cfg['deviceId'], api_key

    device_uuid = cfg.get('deviceUuid') or get_device_uuid()
    cfg['deviceUuid'] = device_uuid
    save_config(cfg)

    claim = claim_device(device_uuid)

    claim_code = claim.get('claimCode', '')
    status = claim.get('status', 'pending')

    if status == 'approved' and claim.get('deviceId') and claim.get('apiKey'):
        cfg['deviceId'] = claim['deviceId']
        save_config(cfg)
        save_api_key(claim['apiKey'])
        return cfg['deviceId'], claim['apiKey']

    if not claim_code:
        raise RuntimeError('Claim failed: empty claim code')

    log('=================================================')
    log('DEVICE WAITING FOR APPROVAL')
    log(f' Claim code: {claim_code}')
    log(f' Device UUID: {device_uuid}')
    log(f' Device name: {DEVICE_NAME}')
    log(' Approve in dashboard before continuing...')
    log('=================================================')

    while True:
        s = poll_claim_status(claim_code)
        st = s.get('status')
        if st == 'approved' and s.get('apiKey') and s.get('deviceId'):
            cfg['deviceId'] = s['deviceId']
            save_config(cfg)
            save_api_key(s['apiKey'])
            log(f"Approved! deviceId={s['deviceId']}")
            return s['deviceId'], s['apiKey']

        if st in ('rejected', 'expired'):
            raise RuntimeError(f'Claim {st}. Please rerun setup.')

        time.sleep(POLL_INTERVAL)


def main():
    log('Timelapse Device Agent starting...')
    device_id, api_key = provision_if_needed()
    log(f'Provisioned as deviceId={device_id}')

    while True:
        try:
            send_heartbeat(device_id, api_key)
        except Exception as e:
            log(f'heartbeat error: {e}')
        time.sleep(HEARTBEAT_INTERVAL)


if __name__ == '__main__':
    main()