from __future__ import annotations

from types import SimpleNamespace
from unittest.mock import patch

import pytest

from govoplan_campaign.backend.campaign.models import DeliveryConfig
from govoplan_campaign.backend.sending.execution import (
    ExecutionSnapshotError,
    create_execution_snapshot,
    ensure_execution_snapshot,
)


def _raw_campaign() -> dict[str, object]:
    return {
        "version": "1.0",
        "campaign": {"id": "campaign-1", "name": "Campaign", "mode": "send"},
        "server": {"mail_profile_id": "profile-1"},
        "recipients": {"from": [{"email": "sender@example.test"}]},
        "template": {"subject": "Subject", "text": "Body", "body_mode": "text"},
        "entries": {"inline": []},
    }


def _job() -> SimpleNamespace:
    return SimpleNamespace(
        id="job-1",
        campaign_version_id="version-1",
        entry_index=0,
        entry_id="entry-1",
        recipient_email="recipient@example.test",
        subject="Subject",
        message_id_header="<message@example.test>",
        eml_size_bytes=123,
        eml_sha256="eml-digest",
        build_status="built",
        validation_status="ready",
        resolved_recipients={"to": ["recipient@example.test"]},
        resolved_attachments=[],
        issues_snapshot=[],
    )


class _Query:
    def __init__(self, jobs: list[SimpleNamespace]):
        self.jobs = jobs

    def filter(self, *_args):
        return self

    def order_by(self, *_args):
        return self

    def all(self):
        return list(self.jobs)


class _Session:
    def __init__(self, jobs: list[SimpleNamespace]):
        self.jobs = jobs

    def query(self, _model):
        return _Query(self.jobs)


def _snapshotted_version(job: SimpleNamespace):
    version = SimpleNamespace(
        id="version-1",
        campaign_id="campaign-1",
        raw_json=_raw_campaign(),
        build_summary={"build_token": "build-1", "built_at": "2026-07-21T00:00:00+00:00"},
    )
    payload, digest = create_execution_snapshot(
        version,  # type: ignore[arg-type]
        mail_profile_id="profile-1",
        smtp_transport_revision="smtp-revision",
        imap_transport_revision="imap-revision",
        delivery=DeliveryConfig(),
        jobs=[job],  # type: ignore[list-item]
        build_summary=version.build_summary,
    )
    version.execution_snapshot = payload
    version.execution_snapshot_hash = digest
    return version


def _ensure(session: _Session, version) -> None:
    with patch(
        "govoplan_campaign.backend.sending.execution.files_integration",
        return_value=SimpleNamespace(available=False),
    ):
        ensure_execution_snapshot(session, version)  # type: ignore[arg-type]


def test_current_snapshot_requires_its_persisted_checksum() -> None:
    job = _job()
    version = _snapshotted_version(job)
    version.execution_snapshot_hash = None

    with pytest.raises(ExecutionSnapshotError, match="checksum is missing"):
        _ensure(_Session([job]), version)


def test_campaign_json_drift_is_rejected_before_delivery() -> None:
    job = _job()
    version = _snapshotted_version(job)
    version.raw_json["template"] = {"subject": "Changed", "text": "Body"}

    with pytest.raises(ExecutionSnapshotError, match="Campaign inputs changed"):
        _ensure(_Session([job]), version)


def test_post_build_recipient_drift_cannot_redirect_delivery() -> None:
    job = _job()
    version = _snapshotted_version(job)
    job.resolved_recipients = {"to": ["attacker@example.test"]}

    with pytest.raises(ExecutionSnapshotError, match="job inputs changed"):
        _ensure(_Session([job]), version)


def test_effect_check_verifies_only_the_claimed_job_in_constant_time() -> None:
    job = _job()
    version = _snapshotted_version(job)
    session = SimpleNamespace(
        query=lambda *_args: pytest.fail("per-effect validation must not rescan every campaign job")
    )

    with patch(
        "govoplan_campaign.backend.sending.execution.files_integration",
        return_value=SimpleNamespace(available=False),
    ):
        ensure_execution_snapshot(
            session,  # type: ignore[arg-type]
            version,
            effect_job=job,  # type: ignore[arg-type]
        )