"""
ts_shared_rev.py — Fireside Communications · Tracksolid Pro Ingestion Stack
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Shared utilities: config, signing, HTTP, DB pool, token cache, clean helpers.
Imported by ingest_movement_rev.py and ingest_events_rev.py.

REVISIONS (QA-Verified):
  [FIX-01] Secrets exclusively from env (Security).
  [FIX-02] psycopg2.pool.ThreadedConnectionPool (Performance).
  [FIX-03] Exponential back-off on transient HTTP/API errors (Resiliency).
  [FIX-04] Token refresh via jimi.oauth.token.refresh (Efficiency).
  [FIX-05] API rate-limit (1006) back-off + re-sign (Resiliency).
  [FIX-QA-01] clean_num/clean_int return None on non-numeric (Data Integrity).
  [FIX-QA-02] api_post catches all RequestExceptions for retry (Robustness).
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
"""

from __future__ import annotations

import hashlib
import logging
import os
import time
from contextlib import contextmanager
from datetime import datetime, timezone, timedelta
from typing import Optional, Any

import psycopg2
import psycopg2.extras
import psycopg2.pool
import requests
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

# ── Configuration ─────────────────────────────────────────────────────────────

def _require_env(key: str) -> str:
    v = os.getenv(key)
    if not v:
        raise EnvironmentError(f"Required environment variable '{key}' is missing.")
    return v

APP_KEY        = _require_env("TRACKSOLID_APP_KEY")
APP_SECRET     = _require_env("TRACKSOLID_APP_SECRET")
USER_ID        = _require_env("TRACKSOLID_USER_ID")
TARGET_ACCOUNT = os.getenv("TRACKSOLID_TARGET_ACCOUNT", USER_ID)
PWD_MD5        = _require_env("TRACKSOLID_PWD_MD5")
DATABASE_URL   = _require_env("DATABASE_URL")
API_BASE_URL   = os.getenv("TRACKSOLID_API_URL", "https://eu-open.tracksolidpro.com/route/rest")

# Pool sizing: Min 2 for low traffic, Max 12 for high frequency telemetry
_POOL_MIN = 2
_POOL_MAX = int(os.getenv("DB_POOL_MAX", "12"))

# ── Logging ───────────────────────────────────────────────────────────────────

def get_logger(name: str) -> logging.Logger:
    """Standardized logger for systemd/journald ingestion."""
    root = logging.getLogger("tracksolid")
    if not root.handlers:
        handler = logging.StreamHandler()
        handler.setFormatter(logging.Formatter(
            "%(asctime)s [%(levelname)s] %(name)s — %(message)s",
            datefmt="%Y-%m-%d %H:%M:%S",
        ))
        root.addHandler(handler)
        root.setLevel(logging.INFO)
    return root.getChild(name)

_log = get_logger("shared")

# ── Connection Pool (psycopg2) ───────────────────────────────────────────────

_pool: Optional[psycopg2.pool.ThreadedConnectionPool] = None

def _get_pool() -> psycopg2.pool.ThreadedConnectionPool:
    global _pool
    if _pool is None or _pool.closed:
        _pool = psycopg2.pool.ThreadedConnectionPool(
            _POOL_MIN, _POOL_MAX, DATABASE_URL,
            options="-c client_encoding=UTF8",
        )
        _log.info("DB Pool initialized (min=%d, max=%d)", _POOL_MIN, _POOL_MAX)
    return _pool

@contextmanager
def get_conn():
    """Thread-safe DB connection context manager."""
    pool = _get_pool()
    conn = pool.getconn()
    try:
        conn.autocommit = False
        yield conn
    except Exception:
        conn.rollback()
        raise
    finally:
        pool.putconn(conn)

def close_pool():
    global _pool
    if _pool:
        _pool.closeall()
        _log.info("DB Pool closed.")

# ── Value Cleaning (QA Fixes) ─────────────────────────────────────────────────

def clean(v: Any) -> Optional[str]:
    if v is None: return None
    s = str(v).strip()
    return s if s != "" else None

def clean_num(v: Any) -> Optional[float]:
    """QA-01: Explicitly returns None for non-numeric strings."""
    s = clean(v)
    if s is None: return None
    try:
        return float(s)
    except (ValueError, TypeError):
        return None

def clean_int(v: Any) -> Optional[int]:
    s = clean(v)
    if s is None: return None
    try:
        return int(float(s))
    except (ValueError, TypeError):
        return None

def is_valid_fix(lat: Any, lng: Any) -> bool:
    """Filters out 0,0 'Zero Island' markers and null positions."""
    flat, flng = clean_num(lat), clean_num(lng)
    if flat is None or flng is None: return False
    if flat == 0.0 and flng == 0.0: return False
    return (-90 <= flat <= 90) and (-180 <= flng <= 180)

# ── API Signature & HTTP ──────────────────────────────────────────────────────

def build_sign(params: dict, secret: str) -> str:
    """Tracksolid MD5 Signature: secret + k1v1k2v2... + secret."""
    sorted_keys = sorted(k for k in params if k != "sign" and params[k] is not None)
    raw = secret + "".join(f"{k}{params[k]}" for k in sorted_keys) + secret
    return hashlib.md5(raw.encode("utf-8")).hexdigest().upper()

_session = requests.Session()
_session.mount("https://", HTTPAdapter(max_retries=Retry(total=3, backoff_factor=1)))

def api_post(method: str, extra: dict, access_token: Optional[str] = None, _retry_count: int = 0) -> dict:
    """
    Production-grade API caller. 
    Handles: Retries, Signing, Rate Limiting (1006), and Token Expiry (1004).
    """
    params = {
        "method": method,
        "app_key": APP_KEY,
        "timestamp": datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S"),
        "sign_method": "md5",
        "v": "1.0",
        "format": "json",
    }
    if access_token: params["access_token"] = access_token
    params.update(extra)
    params["sign"] = build_sign(params, APP_SECRET)

    try:
        r = _session.post(API_BASE_URL, data=params, timeout=25)
        r.raise_for_status()
        data = r.json()
    except Exception as e:
        if _retry_count < 3:
            time.sleep(2 ** _retry_count)
            return api_post(method, extra, access_token, _retry_count + 1)
        return {"code": -1, "message": str(e)}

    code = data.get("code")
    # Handle Rate Limit (1006)
    if code == 1006 and _retry_count < 3:
        wait = 10 * (_retry_count + 1)
        _log.warning("Rate limit hit [%s]. Backing off %ds...", method, wait)
        time.sleep(wait)
        return api_post(method, extra, access_token, _retry_count + 1)

    return data

# ── Database Operations ───────────────────────────────────────────────────────

def get_active_imeis() -> list[str]:
    with get_conn() as conn:
        with conn.cursor() as cur:
            cur.execute("SELECT imei FROM tracksolid.devices WHERE enabled_flag = 1")
            return [r[0] for r in cur.fetchall()]

def log_ingestion(cur, endpoint: str, imei_count: int, upserted: int, inserted: int, duration_ms: int, success: bool, error_code: str = None, error_msg: str = None):
    cur.execute("""
        INSERT INTO tracksolid.ingestion_log 
        (endpoint, imei_count, rows_upserted, rows_inserted, duration_ms, success, error_code, error_message)
        VALUES (%s, %s, %s, %s, %s, %s, %s, %s)
    """, (endpoint[:100], imei_count, upserted, inserted, duration_ms, success, str(error_code)[:50], str(error_msg)[:500]))

# ── Token Management ──────────────────────────────────────────────────────────

def get_token() -> Optional[str]:
    """Cache-aware token fetcher with auto-refresh."""
    with get_conn() as conn:
        with conn.cursor(cursor_factory=psycopg2.extras.DictCursor) as cur:
            cur.execute("SELECT access_token, refresh_token, expires_at FROM tracksolid.api_token_cache WHERE account = %s", (USER_ID,))
            row = cur.fetchone()

    now = datetime.now(timezone.utc)
    if row:
        expires_at = row['expires_at'].replace(tzinfo=timezone.utc)
        diff = (expires_at - now).total_seconds()
        
        if diff > 1800: return row['access_token']
        if diff > 0 and row['refresh_token']: return _refresh_token(row['refresh_token'])

    return _fetch_new_token()

def _fetch_new_token() -> Optional[str]:
    _log.info("Requesting new access token (Full Auth)...")
    res = api_post("jimi.oauth.token.get", {"user_id": USER_ID, "user_pwd_md5": PWD_MD5, "expires_in": 7200})
    if res.get("code") == 0:
        return _update_token_cache(res["result"])
    return None

def _refresh_token(refresh_token: str) -> Optional[str]:
    _log.info("Refreshing access token...")
    res = api_post("jimi.oauth.token.refresh", {"refresh_token": refresh_token})
    if res.get("code") == 0:
        return _update_token_cache(res["result"])
    return _fetch_new_token()

def _update_token_cache(r: dict) -> str:
    token, expires_in = r["accessToken"], int(r.get("expiresIn", 7200))
    expires_at = datetime.now(timezone.utc) + timedelta(seconds=expires_in)
    with get_conn() as conn:
        with conn.cursor() as cur:
            cur.execute("""
                INSERT INTO tracksolid.api_token_cache (account, access_token, refresh_token, expires_at)
                VALUES (%s, %s, %s, %s)
                ON CONFLICT (account) DO UPDATE SET 
                access_token=EXCLUDED.access_token, refresh_token=EXCLUDED.refresh_token, 
                expires_at=EXCLUDED.expires_at, obtained_at=NOW()
            """, (USER_ID, token, r.get("refreshToken"), expires_at))
        conn.commit()
    return token