# coding=utf-8
"""
@Time   :2026/6/24
@Author :tao.chen
"""
import os
import secrets
import time
import uuid
from datetime import datetime

from common.config import settings
from common.logging import logger
from common.sql_guard import validate_pyspark_code
from spark_executor.core.connection_store import store as conn_store
from spark_executor.core.job_store import JobStore
from spark_executor.core.log_parser import parse_spark_submit_output
from spark_executor.core.pending_store import store as pending_store
from spark_executor.core.spark_submit import (
    SparkSubmitError,
    build_spark_submit_command,
    run_spark_submit,
)
from spark_executor.models import Job, PendingSubmission, SubmitResult


def _script_path_error(path: str) -> ValueError:
    """Instructive error for an invalid script_path. The MCP client receives
    this via the ValueError -> 400 exception handler in server.py."""
    return ValueError(
        f"script_path does not exist or is not a file: {path!r}. "
        f"Two ways to fix this:\n"
        f"  1. (Recommended) Call write_job_file(code=...) first to write "
        f"the PySpark source to disk, then pass the returned script_path.\n"
        f"  2. If the file already exists on the host, mount it into the "
        f"container (e.g. -v /host/path:/app/scripts:ro in docker run) and "
        f"pass the in-container path here."
    )


def _check_script_path(script_path: str) -> None:
    """Verify script_path points at an existing regular file. Raises ValueError
    (-> 400 via the FastAPI exception handler) with an instructive message."""
    if not script_path or not os.path.isfile(script_path):
        raise _script_path_error(script_path)


def _sql_guard_error(offenses: list[str]) -> ValueError:
    """Instructive 400 error when the script's SQL fails the safety policy."""
    return ValueError(
        f"Script SQL violates the safety policy. "
        f"Only SELECT and INSERT statements are allowed. "
        f"Found forbidden statement(s): {offenses}. "
        f"Edit the script and try again. (If the code was generated via "
        f"write_job_file, the generator should have caught this — check "
        f"for f-string-based SQL injection where the static analysis can't "
        f"see the runtime value.)"
    )


def _new_pending_id() -> str:
    return "p_" + secrets.token_hex(6)


def prepare_submit_job(
    *,
    connection: str,
    script_path: str,
    queue: str = "default",
    executor_memory: str = "2G",
    executor_cores: int = 2,
    num_executors: int = 2,
    app_name: str,
    extra_args: dict[str, str] | None = None,
) -> dict[str, object]:
    """Snapshot connection params and persist a PendingSubmission. Does NOT submit."""
    logger.debug(
        f"prepare_submit_job enter connection={connection} script_path={script_path} "
        f"queue={queue} executor_memory={executor_memory} executor_cores={executor_cores} "
        f"num_executors={num_executors} app_name={app_name}"
    )
    # Order of checks matters for the error the agent sees:
    #   1. Unknown connection  -> 404 (KeyError -> 404 in server.py)
    #   2. Missing script file -> 400 (ValueError -> 400)
    #   3. SQL policy violation -> 400 (ValueError -> 400)
    # Connection is checked first because it is a more fundamental problem
    # (the agent is asking about a cluster that doesn't exist), and the
    # agent shouldn't have to fix the script path only to learn the
    # connection name is wrong.
    conn = conn_store.get(connection)
    if conn is None:
        raise KeyError(f"Unknown connection: {connection}")
    # Fail fast: a non-existent path is the most common agent mistake (it
    # generated the code in its own context but forgot to call
    # write_job_file first, or its path refers to the host filesystem
    # which is invisible inside the container). Better to surface this with
    # a 400 + clear remediation than to let spark-submit fail later with
    # an opaque FileNotFoundError -> 500.
    _check_script_path(script_path)
    # SQL safety: re-validate the script even though write_job_file
    # already guards its own output. Catches files written by other means
    # (host volume mounts, manual edits).
    with open(script_path, encoding="utf-8") as f:
        script_body = f.read()
    offenses = validate_pyspark_code(script_body)
    if offenses:
        logger.warning(
            f"prepare_submit_job rejected: SQL policy violation(s) in "
            f"{script_path}: {offenses}"
        )
        raise _sql_guard_error(offenses)

    pending_id = _new_pending_id()
    pending = PendingSubmission(
        pending_id=pending_id,
        app_name=app_name,
        connection=connection,
        master=conn.master,
        deploy_mode=conn.deploy_mode,
        yarn_rm_url=conn.yarn_rm_url,
        script_path=script_path,
        queue=queue,
        executor_memory=executor_memory,
        executor_cores=executor_cores,
        num_executors=num_executors,
        spark_conf=dict(conn.spark_conf),
        extra_args=dict(extra_args or {}),
        created_at=datetime.utcnow(),
        status="PENDING",
    )
    pending_store.save(pending)
    logger.info(
        f"prepare_submit_job ok pending_id={pending_id} connection={connection} "
        f"master={conn.master} script_path={script_path}"
    )
    return {
        "pending_id": pending_id,
        "status": "PENDING",
        "parameters": pending.model_dump(),
    }


# Module-level job store singleton; replaced in tests.
job_store: JobStore = JobStore()


def confirm_submit_job(*, pending_id: str) -> SubmitResult:
    """Actually invoke spark-submit for a previously-prepared PendingSubmission."""
    logger.debug(f"confirm_submit_job enter pending_id={pending_id}")
    pending = pending_store.get(pending_id)
    if pending is None:
        raise KeyError(f"Unknown pending_id: {pending_id}")

    if pending.status == "SUBMITTED":
        logger.info(
            f"confirm_submit_job idempotent pending_id={pending_id} "
            f"job_id={pending.job_id} application_id={pending.application_id}"
        )
        return SubmitResult(
            job_id=pending.job_id,
            application_id=pending.application_id,
            tracking_url=pending.tracking_url,
        )
    if pending.status == "CANCELLED":
        raise ValueError(f"pending_id {pending_id} is CANCELLED, cannot confirm")
    if pending.status == "FAILED":
        pending.status = "PENDING"
        pending.error = None
        pending_store.save(pending)
        logger.info(f"confirm_submit_job reset pending_id={pending_id} from FAILED to PENDING")
    if pending.status != "PENDING":
        raise ValueError(
            f"pending_id {pending_id} is in status {pending.status!r}, not PENDING"
        )

    # Defense in depth: re-verify the script still exists. A user could
    # delete the file between prepare and confirm (or an external cleanup
    # job could remove it). 400 via the ValueError -> 400 handler.
    _check_script_path(pending.script_path)

    cmd = build_spark_submit_command(
        master=pending.master,
        deploy_mode=pending.deploy_mode,
        script_path=pending.script_path,
        queue=pending.queue,
        executor_memory=pending.executor_memory,
        executor_cores=pending.executor_cores,
        num_executors=pending.num_executors,
        spark_conf=pending.spark_conf,
        extra_args=pending.extra_args,
    )
    logger.info(
        f"confirm_submit_job start pending_id={pending_id} "
        f"application_target={pending.master} script_path={pending.script_path}"
    )

    last_error: SparkSubmitError | None = None
    max_attempts = settings.confirm_max_retries + 1
    for attempt in range(1, max_attempts + 1):
        try:
            result = run_spark_submit(cmd)
        except SparkSubmitError as exc:
            last_error = exc
            logger.warning(
                f"confirm_submit_job attempt {attempt}/{max_attempts} failed "
                f"pending_id={pending_id} err={exc}"
            )
            if attempt < max_attempts:
                time.sleep(settings.confirm_retry_delay_seconds)
            continue
        except Exception:
            # Unexpected failure (not a spark-submit error): fail fast without retry.
            logger.exception(
                f"confirm_submit_job unexpected error pending_id={pending_id}"
            )
            raise

        application_id, tracking_url = parse_spark_submit_output(result.stderr)
        job_id = uuid.uuid4().hex[:12]

        # Persist pending as SUBMITTED before creating the in-memory Job so a
        # job_store failure cannot leave the record as PENDING while the YARN
        # app is already running.
        pending.status = "SUBMITTED"
        pending.job_id = job_id
        pending.application_id = application_id
        pending.tracking_url = tracking_url
        pending_store.save(pending)

        job_store.put(
            Job(
                job_id=job_id,
                application_id=application_id,
                script_path=pending.script_path,
                queue=pending.queue,
                submit_time=datetime.utcnow(),
                connection=pending.connection,
                yarn_rm_url=pending.yarn_rm_url,
            )
        )

        logger.info(
            f"confirm_submit_job ok pending_id={pending_id} job_id={job_id} "
            f"application_id={application_id}"
        )
        return SubmitResult(
            job_id=job_id,
            application_id=application_id,
            tracking_url=tracking_url,
        )

    # Exhausted all retries.
    assert last_error is not None
    pending.status = "FAILED"
    pending.error = str(last_error)
    pending_store.save(pending)
    logger.error(
        f"confirm_submit_job failed pending_id={pending_id} after {max_attempts} attempts "
        f"err={last_error}"
    )
    raise last_error


def list_pending_jobs() -> list[dict[str, object]]:
    logger.debug("list_pending_jobs enter")
    return [p.model_dump() for p in pending_store.list_all()]


def get_pending_job(pending_id: str) -> dict[str, object]:
    logger.debug(f"get_pending_job enter pending_id={pending_id}")
    p = pending_store.get(pending_id)
    if p is None:
        raise KeyError(f"Unknown pending_id: {pending_id}")
    return p.model_dump()


def cancel_pending_job(pending_id: str) -> dict[str, str]:
    logger.debug(f"cancel_pending_job enter pending_id={pending_id}")
    p = pending_store.get(pending_id)
    if p is None:
        raise KeyError(f"Unknown pending_id: {pending_id}")
    if p.status in ("SUBMITTED", "FAILED"):
        raise ValueError(
            f"pending_id {pending_id} is in status {p.status!r} and cannot be cancelled"
        )
    p.status = "CANCELLED"
    pending_store.save(p)
    logger.info(f"cancel_pending_job ok pending_id={pending_id}")
    return {"pending_id": pending_id, "status": "CANCELLED"}


def update_pending_job(
    *,
    pending_id: str,
    script_path: str | None = None,
    queue: str | None = None,
    executor_memory: str | None = None,
    executor_cores: int | None = None,
    num_executors: int | None = None,
    app_name: str | None = None,
    extra_args: dict[str, str] | None = None,
) -> dict[str, object]:
    logger.debug(f"update_pending_job enter pending_id={pending_id}")
    pending = pending_store.get(pending_id)
    if pending is None:
        raise KeyError(f"Unknown pending_id: {pending_id}")
    if pending.status != "PENDING":
        raise ValueError(
            f"pending_id {pending_id} is in status {pending.status!r}; "
            f"only PENDING submissions can be updated"
        )

    if script_path is not None:
        _check_script_path(script_path)
        with open(script_path, encoding="utf-8") as f:
            script_body = f.read()
        offenses = validate_pyspark_code(script_body)
        if offenses:
            logger.warning(
                f"update_pending_job rejected: SQL policy violation(s) in "
                f"{script_path}: {offenses}"
            )
            raise _sql_guard_error(offenses)
        pending.script_path = script_path

    if queue is not None:
        pending.queue = queue
    if executor_memory is not None:
        pending.executor_memory = executor_memory
    if executor_cores is not None:
        pending.executor_cores = executor_cores
    if num_executors is not None:
        pending.num_executors = num_executors
    if app_name is not None:
        pending.app_name = app_name
    if extra_args is not None:
        pending.extra_args = dict(extra_args)

    pending_store.save(pending)
    logger.info(f"update_pending_job ok pending_id={pending_id}")
    return {"pending_id": pending_id, "status": pending.status, "parameters": pending.model_dump()}