"""Celery entrypoints for delivering persisted human input forms.

The generic form-delivery task must stay independent from email availability so
non-email providers can run even when mail is not configured. The legacy email
task keeps its historical mail and feature gates for callers that still need
email-only semantics. The generic task only checks email availability after
loading persisted delivery contexts and only when an email context is present.
"""

import logging
import time
from collections.abc import Sequence

import click
from celery import shared_task
from sqlalchemy.orm import Session, sessionmaker

from core.app.layers.pause_state_persist_layer import WorkflowResumptionContext
from core.workflow.human_input_adapter import DeliveryMethodType
from extensions.ext_database import db
from extensions.ext_mail import mail
from graphon.runtime import RuntimeState, VariablePool
from models.human_input import HumanInputForm
from repositories.factory import DifyAPIRepositoryFactory
from services.feature_service import FeatureService
from services.human_input_form_delivery_provider import (
    HumanInputFormDeliveryContext,
    HumanInputFormDeliveryDispatcher,
    HumanInputFormDeliveryProviderRegistry,
)

logger = logging.getLogger(__name__)

FORM_DELIVERY_METHOD_TYPES = (DeliveryMethodType.EMAIL, DeliveryMethodType.IM)


def _has_email_context(contexts: Sequence[HumanInputFormDeliveryContext]) -> bool:
    return any(context.delivery_method_type == DeliveryMethodType.EMAIL for context in contexts)


def _load_variable_pool(workflow_run_id: str | None) -> VariablePool | None:
    if not workflow_run_id:
        return None

    session_factory = sessionmaker(bind=db.engine, expire_on_commit=False)
    workflow_run_repo = DifyAPIRepositoryFactory.create_api_workflow_run_repository(session_factory)
    pause_entity = workflow_run_repo.get_workflow_pause(workflow_run_id)
    if pause_entity is None:
        logger.info("No pause state found for workflow run %s", workflow_run_id)
        return None

    try:
        resumption_context = WorkflowResumptionContext.loads(pause_entity.get_state().decode())
    except Exception:
        logger.exception("Failed to load resumption context for workflow run %s", workflow_run_id)
        return None

    graph_runtime_state = RuntimeState.from_snapshot(resumption_context.serialized_graph_runtime_state)
    return graph_runtime_state.variable_pool


def _open_session(session_factory: sessionmaker | Session | None):
    if session_factory is None:
        return Session(db.engine)
    if isinstance(session_factory, Session):
        return session_factory
    return session_factory()


def _filter_unavailable_email_contexts(
    *,
    contexts: Sequence[HumanInputFormDeliveryContext],
    tenant_id: str,
    form_id: str,
) -> tuple[HumanInputFormDeliveryContext, ...]:
    contexts_tuple = tuple(contexts)
    if not _has_email_context(contexts_tuple):
        return contexts_tuple

    email_delivery_enabled = False
    if mail.is_inited():
        try:
            features = FeatureService.get_features(tenant_id, exclude_vector_space=True)
            email_delivery_enabled = features.human_input_email_delivery_enabled
        except Exception:
            logger.exception(
                "Failed to check human input email delivery availability; skipping email contexts, "
                "tenant=%s, form_id=%s",
                tenant_id,
                form_id,
            )

    if email_delivery_enabled:
        return contexts_tuple

    return tuple(context for context in contexts_tuple if context.delivery_method_type != DeliveryMethodType.EMAIL)


def _is_email_delivery_enabled(*, tenant_id: str, form_id: str) -> bool:
    features = FeatureService.get_features(tenant_id, exclude_vector_space=True)
    email_delivery_enabled = features.human_input_email_delivery_enabled
    if not email_delivery_enabled:
        logger.info(
            "Human input email delivery is not available for tenant=%s, form_id=%s",
            tenant_id,
            form_id,
        )
    return email_delivery_enabled


def _load_and_dispatch_form_delivery(
    *,
    form_id: str,
    node_title: str | None,
    session_factory,
    delivery_method_types: Sequence[DeliveryMethodType] | None,
    require_mail_inited: bool,
    require_email_feature: bool,
    filter_unavailable_email: bool,
    log_label: str,
) -> None:
    if require_mail_inited and not mail.is_inited():
        return

    logger.info(click.style(f"Start human input {log_label} delivery for form {form_id}", fg="green"))
    start_at = time.perf_counter()

    try:
        with _open_session(session_factory) as session:
            form = session.get(HumanInputForm, form_id)
            if form is None:
                logger.warning("Human input form not found, form_id=%s", form_id)
                return

            if require_email_feature and not _is_email_delivery_enabled(tenant_id=form.tenant_id, form_id=form_id):
                return

            variable_pool = _load_variable_pool(form.workflow_run_id)
            registry = HumanInputFormDeliveryProviderRegistry.default(mail_client=mail)
            dispatcher = HumanInputFormDeliveryDispatcher(registry=registry)
            contexts = dispatcher.load_form_contexts(
                session=session,
                form=form,
                variable_pool=variable_pool,
                delivery_method_types=delivery_method_types,
            )

        if filter_unavailable_email:
            contexts = _filter_unavailable_email_contexts(
                contexts=contexts,
                tenant_id=form.tenant_id,
                form_id=form_id,
            )
        dispatcher.dispatch_contexts(contexts)

        end_at = time.perf_counter()
        logger.info(
            click.style(
                f"Human input {log_label} delivery succeeded for form {form_id}: latency: {end_at - start_at}",
                fg="green",
            )
        )
    except Exception:
        logger.exception(
            "Dispatch human input %s delivery failed, form_id=%s, node_title=%s",
            log_label,
            form_id,
            node_title,
        )


@shared_task(queue="mail")
def dispatch_human_input_form_delivery_task(form_id: str, node_title: str | None = None, session_factory=None):
    _load_and_dispatch_form_delivery(
        form_id=form_id,
        node_title=node_title,
        session_factory=session_factory,
        delivery_method_types=FORM_DELIVERY_METHOD_TYPES,
        require_mail_inited=False,
        require_email_feature=False,
        filter_unavailable_email=True,
        log_label="form",
    )


@shared_task(queue="mail")
def dispatch_human_input_email_task(form_id: str, node_title: str | None = None, session_factory=None):
    _load_and_dispatch_form_delivery(
        form_id=form_id,
        node_title=node_title,
        session_factory=session_factory,
        delivery_method_types=(DeliveryMethodType.EMAIL,),
        require_mail_inited=True,
        require_email_feature=True,
        filter_unavailable_email=False,
        log_label="email",
    )