"""Campaign runner — the side-effect shell around the pure scheduler.

Given a campaign and a clock position (real elapsed seconds), it asks
``campaign_scheduler.decide_schedule`` what is due, then durably claims each
plan occurrence before reusing the existing single-run execution path
(``EvalEngine.run`` with an ``existing_run``). Child-Run identities are the
primary idempotency authority; the legacy campaign summary remains a fallback
for pre-identity Runs created before this migration.

This module also hosts the durable scheduler loop: a thin async shell that,
tick by tick, maps real wall-clock elapsed time (since the campaign's persisted
``started_at``) to a window offset and calls ``advance_campaign``. All authority
lives in the DB (window start, spawned progress, status), so the loop can be
torn down and rebuilt on restart without losing or duplicating work.
"""

import asyncio
import logging
from dataclasses import dataclass, field
from typing import Optional

from sqlmodel import Session

from agenteval.evaluation.analysis import enqueue_campaign_analysis, resolve_analysis_model
from agenteval.evaluation.campaign_lifecycle import complete_campaign
from agenteval.evaluation.campaign_lifecycle import start_campaign as start_campaign_lifecycle
from agenteval.evaluation.campaign_scheduler import (
    TickAction,
    clock_offset,
    decide_schedule,
    decide_tick,
    elapsed_seconds,
    resolve_finalize,
)
from agenteval.evaluation.engine import EvalEngine
from agenteval.models import (
    Campaign,
    CampaignStatus,
    CampaignSummary,
    EvalRun,
    RunStatus,
    RunTrigger,
    SchedulerState,
)
from agenteval.storage.db import get_session, utc_now
from agenteval.storage.repository import (
    CampaignRepository,
    CampaignRunClaimStatus,
    RunRepository,
    ScenarioRepository,
    TargetRepository,
)
from agenteval.task_registry import TaskRegistry

# Real wall-clock seconds between scheduler ticks. time_scale compresses the
# *window*, not the tick cadence — production 24h campaigns still tick slowly.
DEFAULT_TICK_SECONDS = 1.0

_logger = logging.getLogger("agenteval")

# Live loop tasks + cooperative cancel events, keyed by campaign id. Authority
# is the DB; this registry only holds the in-process handles for the loop.
campaign_registry = TaskRegistry()


@dataclass
class AdvanceResult:
    """Outcome of advancing a campaign's clock once."""

    spawned_run_ids: list[str] = field(default_factory=list)
    finished: bool = False


@dataclass
class CampaignRecoveryResult:
    """Outcome of reconciling child Runs left by a previous process."""

    resumed_run_ids: list[str] = field(default_factory=list)
    failed_run_ids: list[str] = field(default_factory=list)


def _spawned_indices(campaign: Campaign, session: Optional[Session] = None) -> set[int]:
    """Return plan entries completed by durable identities or legacy progress.

    Once any durable occurrence exists for an entry, identities replace the
    legacy summary for that entry. This repairs summaries written by older
    runners after only part of a multi-occurrence entry was claimed.
    """
    legacy = set(campaign.summary.scheduler.spawned_indices) if campaign.summary else set()
    if not campaign.id or session is None:
        return legacy

    occurrences: dict[int, set[int]] = {}
    for run in RunRepository(session).list_by_campaign(campaign.id):
        if run.campaign_plan_index is None or run.campaign_occurrence_index is None:
            continue
        occurrences.setdefault(run.campaign_plan_index, set()).add(run.campaign_occurrence_index)

    return {
        plan_index
        for plan_index, entry in enumerate(campaign.plan)
        if (
            plan_index in occurrences
            and set(range(entry.count)).issubset(occurrences[plan_index])
        )
        or (plan_index not in occurrences and plan_index in legacy)
    }


def current_window_offset(campaign: Campaign) -> float:
    """The campaign's live window position (seconds), clamped to the window.

    RUNNING campaigns derive it from the persisted ``started_at`` and
    ``time_scale``; not-yet-started campaigns report 0.
    """
    if campaign.started_at is None:
        return 0.0
    offset = clock_offset(
        elapsed_seconds=elapsed_seconds(now=utc_now(), started_at=campaign.started_at),
        time_scale=campaign.time_scale,
    )
    return min(offset, float(campaign.window_seconds))


def campaign_progress(campaign: Campaign, runs: list[EvalRun]) -> dict:
    """Live progress of a campaign, derived from its child Runs.

    ``completed_runs`` counts only COMPLETED child Runs; failures stay out of
    this field (pass_rate semantics are ADR-0002's concern, not this counter).
    """
    return {
        "current_offset_seconds": current_window_offset(campaign),
        "spawned_runs": len(runs),
        "completed_runs": sum(1 for r in runs if r.status == RunStatus.COMPLETED),
    }


async def _spawn_child_run(
    campaign: Campaign,
    scenario_id: str,
    *,
    plan_index: int,
    occurrence_index: int,
    session: Session,
) -> Optional[str]:
    """Claim one occurrence and drive its pending Run through the engine.

    A rejected claim means the Campaign stopped being runnable between the
    scheduler decision and this write; callers must stop spawning. An existing
    pending Run is resumed, while an existing running/completed/failed Run is
    returned without replaying external messages.
    """
    scenario = ScenarioRepository(session).get(scenario_id)
    if not scenario:
        raise ValueError(f"campaign scenario missing: {scenario_id}")

    claim = RunRepository(session).claim_campaign_run(
        campaign_id=campaign.id or "",
        scenario_id=scenario_id,
        scenario_version=scenario.version or 1,
        plan_index=plan_index,
        occurrence_index=occurrence_index,
    )
    if claim.status in (CampaignRunClaimStatus.NOT_FOUND, CampaignRunClaimStatus.CONFLICT):
        return None
    run = claim.run
    if run is None:
        raise RuntimeError(f"Campaign child claim returned no Run: {claim.status.value}")

    if run.status is RunStatus.PENDING:
        target = TargetRepository(session).get(campaign.target_id)
        if not target:
            raise ValueError(f"campaign target missing: {campaign.target_id}")
        engine = EvalEngine(target=target, scenario=scenario, triggered_by=RunTrigger.CAMPAIGN)
        await engine.run(existing_run=run)
    return run.id or ""


async def advance_campaign(
    *,
    campaign_id: str,
    elapsed_seconds: float,
    session: Session,
    cancel_event: Optional[asyncio.Event] = None,
) -> Optional[AdvanceResult]:
    """Advance the campaign clock to ``elapsed_seconds`` and spawn due Runs.

    ``elapsed_seconds`` is real wall-clock time since the window started; it is
    mapped to a window offset via ``time_scale``. A due entry whose spawning
    raises is recorded but remains due until every occurrence has a durable
    child-Run identity. Returns ``None`` if the campaign does not exist.
    """
    repo = CampaignRepository(session)
    campaign = repo.get(campaign_id)
    if not campaign:
        return None

    offset = clock_offset(elapsed_seconds=elapsed_seconds, time_scale=campaign.time_scale)
    spawned = _spawned_indices(campaign, session)
    decision = decide_schedule(
        plan=campaign.plan,
        window_seconds=campaign.window_seconds,
        clock_offset_seconds=offset,
        spawned_indices=spawned,
    )

    result = AdvanceResult(finished=decision.finished)
    errors: list[dict] = list(campaign.summary.scheduler.errors) if campaign.summary else []
    for due in decision.due:
        # Cancellation stops further spawning; runs already in flight finish.
        if cancel_event is not None and cancel_event.is_set():
            break
        claim_rejected = False
        try:
            for occurrence_index in range(due.entry.count):
                run_id = await _spawn_child_run(
                    campaign,
                    due.entry.scenario_id,
                    plan_index=due.index,
                    occurrence_index=occurrence_index,
                    session=session,
                )
                if run_id is None:
                    claim_rejected = True
                    break
                result.spawned_run_ids.append(run_id)
        except Exception as exc:  # one entry failing must not wedge the campaign
            errors.append({"entry_index": due.index, "error": str(exc)})
            _logger.warning("活动 %s 计划条目 %d 派生失败（跳过）: %s", campaign_id, due.index, exc)
        if claim_rejected:
            break
        spawned = _spawned_indices(campaign, session)
        # Persist progress per entry: a failure partway through a multi-entry
        # advance must never lose which entries already spawned, since restart
        # recovery reads this back from the DB. Mutate the existing summary so
        # any unknown top-level keys survive the read-modify-write.
        summary = campaign.summary or CampaignSummary()
        summary.scheduler = SchedulerState(spawned_indices=sorted(spawned), errors=errors)
        campaign.summary = summary
        repo.save_scheduler_state(campaign_id, summary)

    return result


def _auto_start_analysis(campaign: Campaign, session: Session) -> None:
    """Enqueue 智能分析 when a 正式线 campaign completes.

    Accelerated campaigns, an unresolvable analysis model, and any enqueue
    failure all skip silently — the analysis is an enhancement and must never
    block or break campaign completion.
    """
    if campaign.time_scale != 1 or not campaign.id:
        return
    try:
        if resolve_analysis_model(campaign, session) is None:
            return
        enqueue_campaign_analysis(campaign.id, triggered_by="auto")
    except Exception as exc:
        _logger.warning("活动 %s 自动分析触发失败（已跳过）: %s", campaign.id, exc)


async def reconcile_campaign_child_runs(
    campaign_id: str,
    session: Session,
    *,
    cancel_event: Optional[asyncio.Event] = None,
) -> Optional[CampaignRecoveryResult]:
    """Resume safe pending claims and fail running Runs without replaying.

    A pending claim has not crossed the Engine's send seam and can be resumed.
    A running Run may already have reached the target, so recovery records an
    explicit interruption instead of executing it again.
    """
    campaign = CampaignRepository(session).get(campaign_id)
    if campaign is None:
        return None
    if campaign.status is not CampaignStatus.RUNNING:
        return CampaignRecoveryResult()

    run_repo = RunRepository(session)
    result = CampaignRecoveryResult(
        failed_run_ids=run_repo.mark_campaign_running_interrupted(campaign_id)
    )
    for run in run_repo.list_pending_campaign_children(campaign_id):
        if cancel_event is not None and cancel_event.is_set():
            break
        plan_index = run.campaign_plan_index
        occurrence_index = run.campaign_occurrence_index
        valid_identity = (
            plan_index is not None
            and occurrence_index is not None
            and 0 <= plan_index < len(campaign.plan)
            and 0 <= occurrence_index < campaign.plan[plan_index].count
            and run.scenario_id == campaign.plan[plan_index].scenario_id
        )
        if not valid_identity:
            failed = run_repo.mark_pending_campaign_child_interrupted(run.id or "")
            if failed and failed.id:
                result.failed_run_ids.append(failed.id)
            continue

        try:
            resumed_id = await _spawn_child_run(
                campaign,
                run.scenario_id,
                plan_index=plan_index,
                occurrence_index=occurrence_index,
                session=session,
            )
            if resumed_id is None:
                break
            result.resumed_run_ids.append(resumed_id)
        except Exception as exc:
            fresh = run_repo.get(run.id or "")
            if fresh is not None and fresh.status is RunStatus.PENDING:
                failed = run_repo.mark_pending_campaign_child_interrupted(run.id or "")
                if failed and failed.id:
                    result.failed_run_ids.append(failed.id)
            elif fresh is not None and fresh.status is RunStatus.FAILED and fresh.id:
                result.failed_run_ids.append(fresh.id)
            _logger.warning("活动 %s 子运行 %s 恢复失败: %s", campaign_id, run.id, exc)

    return result


# ── durable scheduler loop ──────────────────────────────────────────────────


async def run_campaign_loop(
    campaign_id: str, cancel: asyncio.Event, *, tick_seconds: float = DEFAULT_TICK_SECONDS
) -> None:
    """Drive one campaign to completion, ticking on real wall-clock time.

    The loop holds no authority and no decision logic: every tick it reloads the
    campaign, asks the pure ``decide_tick`` what to do, and only performs I/O.
    It exits when the window finishes, the campaign leaves RUNNING (e.g. it was
    cancelled), or the cooperative cancel event fires.
    """
    session = get_session()
    try:
        await reconcile_campaign_child_runs(campaign_id, session, cancel_event=cancel)
        while not cancel.is_set():
            repo = CampaignRepository(session)
            campaign = repo.get(campaign_id)
            if not campaign:
                return

            now = utc_now()
            decision = decide_tick(
                now=now,
                started_at=campaign.started_at,
                status=campaign.status,
                window_seconds=campaign.window_seconds,
                time_scale=campaign.time_scale,
                plan=campaign.plan,
                spawned_indices=_spawned_indices(campaign, session),
            )
            if decision.action is TickAction.STOP:
                return

            elapsed = elapsed_seconds(now=now, started_at=campaign.started_at)
            await advance_campaign(
                campaign_id=campaign_id,
                elapsed_seconds=elapsed,
                session=session,
                cancel_event=cancel,
            )

            if decision.action is TickAction.COMPLETE:
                current = repo.get(campaign_id)
                # The lifecycle CAS is the authoritative cancel-race guard.
                if current and resolve_finalize(current.status) is TickAction.COMPLETE:
                    try:
                        completed = complete_campaign(campaign_id=campaign_id, session=session)
                    except Exception as exc:
                        _logger.warning("活动 %s 完成迁移失败: %s", campaign_id, exc)
                    else:
                        _auto_start_analysis(completed, session)
                        return

            try:
                await asyncio.wait_for(cancel.wait(), timeout=tick_seconds)
            except asyncio.TimeoutError:
                pass
    except Exception as exc:  # a crashing loop must not take down the app
        _logger.warning("活动调度循环 %s 异常退出: %s", campaign_id, exc)
    finally:
        session.close()


def start_campaign(campaign_id: str, session: Session, *, tick_seconds: float = DEFAULT_TICK_SECONDS) -> Optional[asyncio.Task]:
    """Move a campaign into RUNNING (stamping ``started_at`` on first start) and
    launch its loop. Reused for both create-then-start and restart recovery:
    a PLANNED campaign gets a fresh ``started_at``; an already-RUNNING one keeps
    its original window start so recovery resumes at the correct offset.
    """
    campaign = CampaignRepository(session).get(campaign_id)
    if not campaign or campaign.status in (CampaignStatus.COMPLETED, CampaignStatus.CANCELLED, CampaignStatus.FAILED):
        return None

    started = start_campaign_lifecycle(session, campaign_id)
    if started is None:
        return None

    return campaign_registry.launch(
        campaign_id,
        lambda cancel: run_campaign_loop(campaign_id, cancel, tick_seconds=tick_seconds),
    )


def request_cancel(campaign_id: str) -> None:
    """Signal the loop (if live) to stop spawning and exit promptly."""
    campaign_registry.cancel(campaign_id)


def resume_running_campaigns(session: Session, *, tick_seconds: float = DEFAULT_TICK_SECONDS) -> int:
    """On startup, relaunch a loop for every campaign left in RUNNING."""
    resumed = 0
    for campaign in CampaignRepository(session).list_all():
        if campaign.status == CampaignStatus.RUNNING and campaign.id:
            start_campaign(campaign.id, session, tick_seconds=tick_seconds)
            resumed += 1
    return resumed


async def shutdown_all() -> None:
    """Gracefully stop all live loops (Web app shutdown)."""
    await campaign_registry.shutdown_all()