"""Long-running Agent service: heartbeat + poll Hub jobs + execute pipeline.

startup -> load config -> validate Hub -> validate Firebird -> heartbeat
-> poll job -> claim -> execute -> report result -> back to polling.

No job available: sleep POLL_INTERVAL_SECONDS.
Hub unavailable: retry with simple capped backoff; the Agent stays alive.
Job fails internally (bad Firebird read, classify error, write refused):
the job is reported FAILED with a sanitized error and the Agent keeps polling.
SIGINT/SIGTERM: finish the current job (if any) and stop the loop cleanly.

Written to be runnable as-is today, and easy to later wrap as a Windows
Service (a service wrapper would just call main()); no installer here.
"""
import argparse
import importlib.util
import json
import logging
import logging.handlers
import os
import signal
import sys
import time
from pathlib import Path

AGENT_ROOT = Path(__file__).resolve().parents[1]
PROJECT_ROOT = AGENT_ROOT.parent
sys.path.insert(0, str(AGENT_ROOT / "src"))
sys.path.insert(0, str(PROJECT_ROOT))  # ships central/app engine modules read-only (central.app.*)

from gti_fiscal_agent.client import HubClient  # noqa: E402
from gti_fiscal_agent.firebird_reader import check_connection, read_products  # noqa: E402
from gti_fiscal_agent.pipeline import run_pipeline  # noqa: E402
from gti_fiscal_agent.runner import REFERENCE_SCHEMA_V1, to_hub_product  # noqa: E402
from gti_fiscal_agent.state import AgentState  # noqa: E402

_MAX_BACKOFF_SECONDS = 60

logger = logging.getLogger("gti_fiscal_agent")


def setup_logging(log_path):
    """Rotating local log file. Never logs FB_PASSWORD or AGENT_TOKEN — every
    log call in this module only references non-secret identifiers/counts."""
    logger.setLevel(logging.INFO)
    if logger.handlers:
        return logger
    Path(log_path).parent.mkdir(parents=True, exist_ok=True)
    handler = logging.handlers.RotatingFileHandler(log_path, maxBytes=5_000_000, backupCount=5, encoding="utf-8")
    handler.setFormatter(logging.Formatter("%(asctime)s %(levelname)s %(message)s"))
    logger.addHandler(handler)
    logger.addHandler(logging.StreamHandler())
    return logger


def load_dotenv(path: Path) -> None:
    if not path.exists():
        return
    for line in path.read_text(encoding="utf-8").splitlines():
        line = line.strip()
        if not line or line.startswith("#") or "=" not in line:
            continue
        key, _, value = line.partition("=")
        os.environ.setdefault(key.strip(), value.strip())


def load_executor():
    spec = importlib.util.spec_from_file_location("firebird_write_executor", PROJECT_ROOT / "scripts" / "firebird_write_executor.py")
    module = importlib.util.module_from_spec(spec)
    sys.modules[spec.name] = module
    spec.loader.exec_module(module)
    return module


class Config:
    def __init__(self, env):
        self.hub_url = env.get("GTI_HUB_URL") or env.get("HUB_URL") or "http://localhost:8000"
        self.agent_id = env.get("AGENT_ID", "")
        self.credential_file = env.get("GTI_CREDENTIAL_FILE") or str(Path(os.environ.get("PROGRAMFILES", r"C:\Program Files")) / "GTI" / "FiscalAgent" / "credentials.bin")
        # The permanent token NEVER lives in agent.env: it is decrypted from
        # credentials.bin (DPAPI LocalMachine + SYSTEM/Administrators ACL). An
        # explicit AGENT_TOKEN/AGENT_DEV_TOKEN in env wins (dev override only).
        self.agent_token = self._resolve_agent_token(env)
        self.company_id = env.get("COMPANY_ID", "")
        self.company_uf = env.get("COMPANY_UF", "")
        self.database_path = env["FIREBIRD_DATABASE_PATH"]
        # FISCAL_MODE gates writes technically: DRY_RUN can never write, whatever FIREBIRD_WRITES says. Unset = legacy
        # behaviour (FIREBIRD_WRITES decides). `firebird_writes` below is the EFFECTIVE value used by every write path.
        requested = env.get("FIREBIRD_WRITES", "0") == "1"
        self.fiscal_mode = (env.get("FISCAL_MODE") or ("AUTO_APPLY" if requested else "DRY_RUN")).strip().upper()
        self.requested_writes = requested
        self.firebird_writes = requested and self.fiscal_mode == "AUTO_APPLY"
        self.poll_interval_seconds = float(env.get("POLL_INTERVAL_SECONDS", "5"))
        self.agent_version = env.get("AGENT_VERSION", "1.1.0")
        self.schema_fingerprint = env.get("SCHEMA_FINGERPRINT", REFERENCE_SCHEMA_V1)
        self.state_db = env.get("AGENT_STATE_DB", str(AGENT_ROOT / "agent_state.sqlite"))
        # Pilot write authorization: both must be explicitly set by the installer for
        # a real client database. Left unset, both default to the dev-only values,
        # so a real client path/schema is never silently authorized (see
        # scripts/firebird_write_executor.py's assert_authorized_write_path).
        self.authorized_write_database_path = env.get("AUTHORIZED_WRITE_DATABASE_PATH")
        self.expected_schema_fingerprint = env.get("EXPECTED_SCHEMA_FINGERPRINT", REFERENCE_SCHEMA_V1)
        self.log_path = env.get("AGENT_LOG_PATH", str(AGENT_ROOT / "logs" / "agent.log"))

    @staticmethod
    def _resolve_agent_token(env):
        """DPAPI credential from credentials.bin; explicit AGENT_TOKEN env wins
        (dev override). Fail closed: never log or fabricate a token."""
        from gti_fiscal_agent.credential_store import install_env_from_credentials

        explicit = env.get("AGENT_TOKEN") or env.get("AGENT_DEV_TOKEN") or ""
        if explicit:
            return explicit
        try:
            return install_env_from_credentials(env.get("GTI_CREDENTIAL_FILE") or str(
                Path(os.environ.get("PROGRAMFILES", r"C:\Program Files")) / "GTI" / "FiscalAgent" / "credentials.bin"), env)
        except Exception as exc:  # noqa: BLE001 — fail closed: no token, no heartbeat
            logger.warning("no usable agent credential: %s", exc)
            return ""


class GracefulStop:
    def __init__(self):
        self.stop = False
        signal.signal(signal.SIGINT, self._handle)
        signal.signal(signal.SIGTERM, self._handle)

    def _handle(self, signum, frame):
        self.stop = True


def build_job_coverage(env, client, products, decisions):
    """Company-context-aware coverage over the job's products (read-only). Fails closed when the company context is unresolved."""
    from gti_fiscal_agent.company_context import mask_cnpj, preflight_company_context
    from gti_fiscal_agent.coverage import build_refs, compute_coverage
    from gti_fiscal_agent.firebird_reader import read_evidence
    ctx = preflight_company_context(env)
    if ctx["status"] != "PASS":
        raise RuntimeError("COMPANY_CONTEXT=FAIL: " + "; ".join(ctx.get("reasons") or ["unresolved"]))
    evidence = read_evidence(env, ctx["company_code"])
    refs = build_refs(client.get_json, products, ctx["company_uf"])
    report = compute_coverage(products, decisions, {"uf": ctx["company_uf"], "crt": ctx["company_crt"]}, evidence.get("company_default_csosn"), refs, evidence)
    report["company_context"] = {"COMPANY_CONTEXT_STATUS": "PASS", "classification": ctx["classification"], "company_code": ctx["company_code"], "company_cnpj": ctx["company_cnpj"], "company_uf": ctx["company_uf"],
                                 "company_crt": ctx["company_crt"], "source_of_truth": ctx["source_of_truth"], "confidence": ctx["confidence"], "warnings": ctx["warnings"]}
    return report


def open_write_connection(env, database_path, firebird_writes=True):
    if not firebird_writes:  # technical guarantee: no write-capable connection exists in DRY_RUN / FIREBIRD_WRITES=0
        raise RuntimeError("write connection refused: writes are disabled (FISCAL_MODE=DRY_RUN or FIREBIRD_WRITES=0)")
    import fdb
    return fdb.connect(
        database=database_path,
        user=env["FB_USER"],
        password=env["FB_PASSWORD"],
        fb_library_name=env.get("FIREBIRD_CLIENT_LIBRARY"),
    )


def execute_job(job, config, executor, state, env):
    """Run the pipeline for one claimed job. Never raises for job-domain
    failures (bad Firebird read, classify error) — returns (result_summary, error)."""
    kind = job["kind"]
    payload = job.get("payload") or {}
    try:
        if config.firebird_writes:
            # Layered, per-installation authorization: the path must match this
            # installation's own explicitly configured authorized_write_database_path
            # (defaults to the dev-only constant, so a real client path is refused
            # unless the installer deliberately set it), AND the live schema
            # fingerprint must match what this installation was configured to expect.
            executor.assert_authorized_write_path(config.database_path, authorized_path=config.authorized_write_database_path)
            executor.assert_schema_fingerprint_authorized(config.schema_fingerprint, config.expected_schema_fingerprint)

        codigos = payload.get("codigos") if kind == "REPROCESS_PRODUCTS" else None
        products = read_products(env, codigos=codigos)
        logger.info("job %s: read %d product(s) from Firebird", job.get("job_id"), len(products))

        client = HubClient(config.hub_url, config.agent_token)
        decisions = client.classify_batch([to_hub_product(p) for p in products])

        write_connection = None
        if config.firebird_writes:
            write_connection = open_write_connection(env, config.database_path)
        try:
            summary = run_pipeline(products, decisions, state, config.firebird_writes, write_connection, executor, config.database_path, authorized_path=config.authorized_write_database_path)
        finally:
            if write_connection is not None:
                write_connection.close()

        coverage = build_job_coverage(env, client, products, decisions) if kind == "REPROCESS_ALL" else None
        result_summary = {
            "coverage": coverage,
            "fiscal_mode": getattr(config, "fiscal_mode", None),
            "release_version": env.get("AGENT_VERSION") or "1.1.0",
            "products_processed": summary["processed"],
            "writes_attempted": summary["writes_attempted"],
            "writes_succeeded": summary["writes_succeeded"],
            "writes_failed": summary["writes_failed"],
            "no_ops": summary["no_ops"],
            "firebird_writes_enabled": config.firebird_writes,
            "agent_id": job["agent_id"],
            "schema_fingerprint": config.schema_fingerprint,
        }
        logger.info(
            "job %s finished: processed=%d writes_attempted=%d writes_succeeded=%d writes_failed=%d no_ops=%d",
            job.get("job_id"), summary["processed"], summary["writes_attempted"], summary["writes_succeeded"], summary["writes_failed"], summary["no_ops"],
        )
        if summary["writes_failed"] > 0:
            return result_summary, f"{summary['writes_failed']} write(s) failed guard checks"
        return result_summary, None
    except executor.WriteRefused as error:
        logger.warning("job %s refused: %s", job.get("job_id"), error)
        return None, f"write refused: {error}"
    except Exception as error:  # noqa: BLE001 — job-domain isolation boundary
        logger.warning("job %s failed internally: %s: %s", job.get("job_id"), type(error).__name__, error)
        return None, f"{type(error).__name__}: {error}"


def run(config, env, *, max_iterations=None, stopper=None):
    """`stopper` defaults to a signal-based GracefulStop (SIGINT/SIGTERM), which
    only works from the main thread. A host that manages its own lifecycle
    (e.g. the Windows Service wrapper, which stops the loop via the Service
    Control Manager instead of OS signals) should pass its own stop object —
    anything with a `.stop` boolean attribute — and flip it from any thread."""
    executor = load_executor()
    state = AgentState(config.state_db)
    client = HubClient(config.hub_url, config.agent_token)
    installation_id = state.installation_id() if hasattr(state, "installation_id") else (config.agent_id or "legacy-installation")
    stopper = stopper if stopper is not None else GracefulStop()

    backoff = 1
    was_down = False
    iterations = 0
    last_job_id = None
    while not stopper.stop:
        if max_iterations is not None and iterations >= max_iterations:
            break
        iterations += 1

        try:
            heartbeat_payload = {
                "installation_id": installation_id, "status": "IDLE", "schema_fingerprint": config.schema_fingerprint,
                "agent_version": config.agent_version, "last_job_id": last_job_id, "display_name": env.get("AGENT_DISPLAY_NAME", ""),
                "customer_code": env.get("CUSTOMER_CODE"), "hostname": env.get("AGENT_HOSTNAME") or os.environ.get("COMPUTERNAME"),
                "windows_version": env.get("WINDOWS_VERSION"), "company_code": config.company_id, "company_uf": config.company_uf,
                "database_path": config.database_path, "capabilities": {"heartbeat": True, "jobs": True, "local_logs": True},
                "fiscal_engine_version": env.get("FISCAL_ENGINE_VERSION", config.agent_version), "dataset_versions": {},
            }
            if hasattr(client, "heartbeat_metadata"):
                client.heartbeat_metadata(heartbeat_payload)
            else:
                client.heartbeat("IDLE", schema_fingerprint=config.schema_fingerprint, agent_version=config.agent_version, last_job_id=last_job_id)
            if was_down:
                logger.info("reconnected to Hub after %ss backoff", backoff)
                was_down = False
            backoff = 1
        except Exception as error:
            logger.warning("heartbeat failed, Hub unreachable: %s (retrying in %ss)", error, backoff)
            was_down = True
            time.sleep(backoff)
            backoff = min(backoff * 2, _MAX_BACKOFF_SECONDS)
            continue

        try:
            job = client.next_job()
        except Exception as error:
            logger.warning("poll failed, Hub unreachable: %s (retrying in %ss)", error, backoff)
            was_down = True
            time.sleep(backoff)
            backoff = min(backoff * 2, _MAX_BACKOFF_SECONDS)
            continue

        if job is None:
            time.sleep(config.poll_interval_seconds)
            continue

        last_job_id = job.get("job_id")
        logger.info("job %s received: kind=%s", job.get("job_id"), job["kind"])
        try:
            if hasattr(client, "heartbeat_metadata"):
                client.heartbeat_metadata({"installation_id": installation_id, "status": "BUSY", "schema_fingerprint": config.schema_fingerprint, "agent_version": config.agent_version, "last_job_id": last_job_id})
            else:
                client.heartbeat("BUSY", schema_fingerprint=config.schema_fingerprint, agent_version=config.agent_version, last_job_id=last_job_id)
        except Exception:
            pass  # best-effort; the job itself still proceeds

        result_summary, error = execute_job(job, config, executor, state, env)
        try:
            if error is None:
                client.complete_job(job.get("job_id"), result_summary)
                logger.info("job %s reported COMPLETED", job.get("job_id"))
            else:
                client.fail_job(job.get("job_id"), error)
                logger.warning("job %s reported FAILED: %s", job.get("job_id"), error)
        except Exception as report_error:
            logger.warning("could not report job %s result to Hub: %s", job.get("job_id"), report_error)


def enforce_startup_preflight(env):
    """Full read-only preflight at startup (Hub, auth, Firebird, capabilities, company context, guards). Fail closed."""
    from gti_fiscal_agent.preflight import run_preflight
    report = run_preflight(env, agent_version=env.get("AGENT_VERSION") or "1.1.0")
    logger.info("startup preflight: %s", json.dumps({k: report[k] for k in ("PREFLIGHT", "blockers", "fiscal_mode", "effective_firebird_writes")}, ensure_ascii=False))
    print(json.dumps({"PREFLIGHT": report["PREFLIGHT"], "blockers": report["blockers"]}, ensure_ascii=False))
    if report["PREFLIGHT"] != "PASS":
        logger.error("startup aborted: preflight failed (fail closed): %s", report["blockers"])
        raise SystemExit(2)
    return report


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("--max-iterations", type=int, default=None, help="stop after N poll cycles (used by tests); omit to run forever")
    args = parser.parse_args()

    load_dotenv(Path(os.environ.get("GTI_AGENT_ENV_FILE") or PROJECT_ROOT / ".env"))
    config = Config(os.environ)
    setup_logging(config.log_path)

    logger.info("startup: agent_id=%s company_id=%s agent_version=%s firebird_writes=%s", config.agent_id, config.company_id, config.agent_version, config.firebird_writes)
    hub_ok = HubClient(config.hub_url, config.agent_token).health()
    firebird_ok = check_connection(os.environ)
    logger.info("startup checks: hub_ok=%s firebird_ok=%s", hub_ok, firebird_ok)
    enforce_startup_preflight(os.environ)

    run(config, os.environ, max_iterations=args.max_iterations)
    logger.info("shutdown: stopped cleanly")


if __name__ == "__main__":
    main()