"""The scheduler: one tick moves every ready task one step forward.

A tick is deliberately boring. It finds the tasks that are *waiting for a turn*
(``STAGE_ROLE`` names an actor and the stage is not terminal), keeps the ones
whose dependencies have completed and whose organization can still pay, picks a
free employee of the stage's role, runs exactly one turn, and applies the
verdict. Everything after ``WORK_REPORT`` is a gate, and everything after the
pipeline is a platform merge — the AI never runs git (PLAN-v2 D6).

Two properties matter more than throughput:

* **Idempotence under a lost race.** The stage moves through the optimistic
  ``advance`` from ``engine/state.py``. Two workers ticking the same task both
  try; exactly one wins and the other sees a ``ConflictError`` and moves on.
  That is why the caps below are *selection* caps: several worker processes may
  each run a tick, and the compare-and-set keeps them honest.
* **No infinite loops.** A task is sent back only by incrementing its cycle, and
  a task at ``max_cycles`` goes to the manager's error turn instead of grinding
  forever.
"""

from __future__ import annotations

from collections.abc import Awaitable, Callable
from dataclasses import dataclass, field

from app.application.engine.gates import GateOutcome, GateRunner
from app.application.engine.manager import ManagerOutcome, ManagerTurns, _pick_granted_model
from app.application.engine.protocol import Tag, TagName
from app.application.engine.runner import TurnRequest, TurnRunner
from app.application.engine.state import advance, park_dependents
from app.application.ports.delivery_hooks import DeliveryHooks, NullDeliveryHooks
from app.application.ports.memory import MemoryPort, NullMemory, TaskOutcome
from app.application.ports.repo_workspace import RepoWorkspacePort, WorktreeRef
from app.application.ports.sandbox_provider import SandboxProviderPort
from app.core.config import settings
from app.core.errors import ConflictError
from app.domain.base import utcnow
from app.domain.workforce.engine import (
    MAX_TRANSIENT_RETRIES,
    ErrorKind,
    GateName,
    is_transient,
)
from app.domain.workforce.models import Employee, RoleKey, Run, RunStatus, Task, TaskStatus
from app.domain.workforce.pipeline import (
    Outcome,
    Stage,
    TaskPipelineState,
    coarse_status,
    next_stage,
    requires_worktree,
)
from app.infrastructure.repositories.billing import CreditWalletRepository
from app.infrastructure.repositories.engine import (
    EmployeeProfileRepository,
    EngineTurnRepository,
    GateResultRepository,
    PipelineStateRepository,
    StaleStageError,
    TaskSpendRepository,
)
from app.infrastructure.repositories.workforce import (
    EmployeeRepository,
    RunRepository,
    TaskRepository,
)

#: Stages that wait for an AI turn. ``merge_request`` is not here: it is git,
#: and git is the platform's job, not a model's.
TURN_STAGES: tuple[Stage, ...] = (
    Stage.PENDING_MANAGER_REVIEW,
    Stage.PENDING_ANALYSIS,
    Stage.PENDING_IMPLEMENTATION,
    Stage.PENDING_REVIEW,
    Stage.PENDING_TEST,
    Stage.PENDING_FINAL_REVIEW,
    Stage.ERROR_REVIEW,
)
#: The stage the platform executes itself.
MERGE_STAGES: tuple[Stage, ...] = (Stage.MERGE_REQUEST,)

#: The commit author's e-mail. The platform owns git, so the platform owns the
#: address; the *name* is the employee's, which is what a reviewer reads.
ENGINE_COMMIT_EMAIL = "platform@smart-org.local"

#: Persian reason shown when work pauses because the money ran out.
BUDGET_PAUSED_MESSAGE = "اعتبار سازمان برای ادامهٔ کار کافی نیست؛ کار موقتاً متوقف شد."

#: The stage a turn has to be at for each manager mode.
_MANAGER_STAGES: frozenset[Stage] = frozenset(
    {Stage.PENDING_MANAGER_REVIEW, Stage.PENDING_FINAL_REVIEW, Stage.ERROR_REVIEW}
)


@dataclass(slots=True)
class TickReport:
    """What one tick did. The worker logs it; the tests read it."""

    selected: int = 0
    acted: int = 0
    skipped: int = 0
    failed: int = 0
    merged: int = 0
    paused: int = 0
    decisions: dict[str, int] = field(default_factory=dict)
    notes: list[str] = field(default_factory=list)

    def note(self, text: str) -> None:
        self.notes.append(text)

    def count(self, key: str) -> None:
        self.decisions[key] = self.decisions.get(key, 0) + 1


class Scheduler:
    """Runs one turn for every ready task. One instance per session."""

    def __init__(
        self,
        *,
        states: PipelineStateRepository,
        tasks: TaskRepository,
        employees: EmployeeRepository,
        profiles: EmployeeProfileRepository,
        runs: RunRepository,
        turns: EngineTurnRepository,
        gates: GateResultRepository,
        manager: ManagerTurns,
        runner: TurnRunner,
        gate_runner: GateRunner,
        repo_workspace: RepoWorkspacePort,
        sandbox: SandboxProviderPort | None = None,
        memory: MemoryPort | None = None,
        delivery: DeliveryHooks | None = None,
        wallets: CreditWalletRepository | None = None,
        spend: TaskSpendRepository | None = None,
        sandbox_session_for: Callable[[Task], Awaitable[str]] | None = None,
    ) -> None:
        self.states = states
        self.tasks = tasks
        self.employees = employees
        self.profiles = profiles
        self.runs = runs
        self.turns = turns
        self.gates = gates
        self.manager = manager
        self.runner = runner
        self.gate_runner = gate_runner
        self.repo_workspace = repo_workspace
        self.sandbox = sandbox
        self.memory = memory or NullMemory()
        self.delivery = delivery or NullDeliveryHooks()
        self.wallets = wallets
        self.spend = spend
        self.sandbox_session_for = sandbox_session_for

    # ------------------------------------------------------------------ #
    # the tick                                                           #
    # ------------------------------------------------------------------ #

    async def tick(self, *, limit: int = 50) -> TickReport:
        """Move every ready task one step. A failure never aborts the tick."""
        report = TickReport()
        turn_states = await self.states.list_at_stages(TURN_STAGES, limit=limit)
        merge_states = await self.states.list_at_stages(MERGE_STAGES, limit=limit)

        selected = self._select(turn_states)
        report.selected = len(selected)
        for state in selected:
            await self._guarded(self._step, state, report)

        for state in self._select(merge_states):
            await self._guarded(self._merge_step, state, report)
        return report

    async def _guarded(self, step, state: TaskPipelineState, report: TickReport) -> None:
        """One task must never stop the tick: catch, record, continue."""
        try:
            await step(state, report)
        except ConflictError:
            # Another worker moved this task first; that is a normal outcome.
            report.skipped += 1
            report.note(f"task {state.task_id}: موتور دیگری زودتر حرکت کرد")
        except Exception as exc:  # noqa: BLE001 - the tick keeps going
            report.failed += 1
            report.note(f"task {state.task_id}: {type(exc).__name__}: {exc}")

    def _select(self, states: list[TaskPipelineState]) -> list[TaskPipelineState]:
        """Apply the caps: per organization first, then globally."""
        per_org: dict[str, int] = {}
        chosen: list[TaskPipelineState] = []
        for state in states:
            count = per_org.get(state.organization_id, 0)
            if count >= settings.engine_max_turns_per_org:
                continue
            if len(chosen) >= settings.engine_max_concurrent_turns:
                break
            per_org[state.organization_id] = count + 1
            chosen.append(state)
        return chosen

    async def _step(self, state: TaskPipelineState, report: TickReport) -> None:
        task = await self.tasks.get(state.task_id)
        if task is None or task.status in (
            TaskStatus.DONE,
            TaskStatus.FAILED,
            TaskStatus.CANCELLED,
        ):
            report.skipped += 1
            return

        reason = await self._budget_reason(task)
        if reason is not None:
            await self._pause(state, task, reason)
            report.paused += 1
            return

        if not await self._dependencies_done(state):
            report.skipped += 1
            report.note(f"task {task.id}: وابستگی‌ها هنوز تمام نشده‌اند")
            return

        actor = state.actor()
        if actor is None:
            report.skipped += 1
            return
        employee = await self._employee_for(state, actor.role)
        if employee is None:
            report.skipped += 1
            report.note(f"task {task.id}: کارمند آزادی برای نقش {actor.role.value} نیست")
            return

        await self.profiles.set_busy(employee_id=employee.id, task_id=task.id)
        try:
            if state.stage in _MANAGER_STAGES:
                await self._manager_step(state, task, employee, report)
            else:
                await self._work_step(state, task, employee, report)
        finally:
            await self.profiles.set_busy(employee_id=employee.id, task_id=None)

    # ------------------------------------------------------------------ #
    # manager stages                                                     #
    # ------------------------------------------------------------------ #

    async def _manager_step(
        self, state: TaskPipelineState, task: Task, employee: Employee, report: TickReport
    ) -> None:
        run = await self._open_run(task, employee)
        try:
            if state.stage is Stage.PENDING_MANAGER_REVIEW:
                outcome = await self.manager.triage(task=task, run_id=run.id, employee=employee)
            elif state.stage is Stage.PENDING_FINAL_REVIEW:
                outcome = await self.manager.final_review(
                    task=task,
                    run_id=run.id,
                    employee=employee,
                    spec=await self._last_reply(task.id, RoleKey.PLANNER),
                    diff_text=(await self._diff_for(task, state))[0],
                    test_output=await self._gate_detail(task.id, str(GateName.TESTS)),
                    gate_summary=await self._gate_summary(task.id),
                )
            else:
                outcome = await self.manager.error_review(
                    task=task,
                    run_id=run.id,
                    employee=employee,
                    error_summary=await self._error_context(task),
                )
        except Exception as exc:  # noqa: BLE001 - one task must not stop the tick
            await self._close_run(run, ok=False, error=str(exc))
            report.failed += 1
            report.note(f"task {task.id}: {type(exc).__name__}: {exc}")
            return
        await self._close_run(run, ok=outcome.acted, error="" if outcome.acted else outcome.message)
        await self._settle(state, task, outcome, report)

    async def _settle(
        self,
        state: TaskPipelineState,
        task: Task,
        outcome: ManagerOutcome,
        report: TickReport,
    ) -> None:
        """Turn a manager verdict into a tick result (or a failure)."""
        report.count(outcome.decision or "idle")
        if outcome.acted:
            report.acted += 1
            if outcome.stage in (Stage.CANCELLED, Stage.FAILED):
                await park_dependents(self.states, task_id=task.id)
            return
        if outcome.error_kind:
            await self._retry_or_fail(state, task, outcome.message, outcome.error_kind)
            report.failed += 1
            return
        report.skipped += 1
        report.note(f"task {task.id}: تصمیمی گرفته نشد ({outcome.message[:120]})")

    # ------------------------------------------------------------------ #
    # work stages (planner / developer / reviewer / tester)              #
    # ------------------------------------------------------------------ #

    async def _work_step(
        self, state: TaskPipelineState, task: Task, employee: Employee, report: TickReport
    ) -> None:
        actor = state.actor()
        if actor is None:  # pragma: no cover - _step checked this
            report.skipped += 1
            return
        worktree = await self._worktree_for(task, state)
        run = await self._open_run(task, employee)
        request = TurnRequest(
            organization_id=task.organization_id,
            task=task,
            role=actor.role,
            mode=actor.mode,
            stage=state.stage,
            run_id=run.id,
            employee=employee,
            model_id=await self.manager._model_id_for(employee, task.organization_id),
            sandbox_root=worktree.sandbox_path if worktree else "/workspace",
            session_external_id=await self._sandbox_session(task),
            extra_context=await self._work_context(task, state),
            user_id=task.created_by_user_id,
        )
        result = await self.runner.run_turn(request)
        if not result.ok:
            await self._close_run(run, ok=False, error=result.error)
            await self._retry_or_fail(state, task, result.error, result.error_kind)
            report.failed += 1
            return
        await self._close_run(run, ok=True)
        await self._apply_work_outcome(state, task, employee, result.tags, report, worktree)

    async def _apply_work_outcome(
        self,
        state: TaskPipelineState,
        task: Task,
        employee: Employee,
        tags: tuple[Tag, ...],
        report: TickReport,
        worktree: WorktreeRef | None,
    ) -> None:
        names = {tag.name.value for tag in tags}
        if state.stage is Stage.PENDING_ANALYSIS:
            # The planner's plan *is* the deliverable for analysis_only.
            await self._advance_or_complete(state, task)
        elif state.stage is Stage.PENDING_IMPLEMENTATION:
            await self._after_implementation(state, task, employee, report, worktree)
            return
        elif state.stage is Stage.PENDING_REVIEW:
            if "REVIEW_CHANGES" in names:
                await self._send_back(state, task, "بازبین اصلاحاتی خواست.")
                report.failed += 1
                return
            await self._advance_or_complete(state, task)
        elif state.stage is Stage.PENDING_TEST:
            await self._after_tester(state, task, tags, report)
            return
        else:  # pragma: no cover - TURN_STAGES has no other work stage
            report.skipped += 1
            report.note(f"task {task.id}: مرحلهٔ ناشناخته {state.stage.value}")
            return
        report.acted += 1

    # -- the gate chain ---------------------------------------------------- #

    async def _after_implementation(
        self,
        state: TaskPipelineState,
        task: Task,
        employee: Employee,
        report: TickReport,
        worktree: WorktreeRef | None,
    ) -> None:
        if worktree is None:
            await self._fail_task(
                state, task, "درخت کاری برای این کار ساخته نشد.", ErrorKind.MODEL
            )
            report.failed += 1
            return
        diff = await self.repo_workspace.diff(worktree=worktree)
        code_task = GateRunner.code_task(state.kind)

        guard = await self.gate_runner.diff_guard(task=task, diff=diff, code_task=code_task)
        if not guard.ok:
            await self._send_back(state, task, guard.detail)
            report.failed += 1
            return
        await self._save_branch(state, worktree)

        progress, new_hash, same_count = await self.gate_runner.no_progress(
            task=task,
            previous_hash=state.last_diff_hash,
            same_count=state.same_diff_count,
            diff_text=diff.text,
        )
        await self._patch(state, last_diff_hash=new_hash, same_diff_count=same_count)
        if not progress.ok:
            await self._send_back(state, task, progress.detail)
            report.failed += 1
            return

        if code_task and self.sandbox is not None:
            tests = await self.gate_runner.tests(
                task=task,
                sandbox=self.sandbox,
                session_external_id=await self._sandbox_session(task),
            )
            if not tests.ok:
                await self._escalate_after_repeated_red(task, employee)
                await self._send_back(state, task, tests.detail)
                report.failed += 1
                return
        await self._advance_or_complete(state, task)
        report.acted += 1

    async def _after_tester(
        self,
        state: TaskPipelineState,
        task: Task,
        tags: tuple[Tag, ...],
        report: TickReport,
    ) -> None:
        names = {tag.name.value for tag in tags}
        if TagName.TEST_FAIL.value in names:
            await self._send_back(state, task, "آزمون‌گر شکست تست‌ها را گزارش کرد.")
            report.failed += 1
            return
        waiver = next(
            (tag for tag in tags if tag.name is TagName.TEST_PASS), None
        )
        reason = waiver.attr("waive", "").strip() if waiver is not None else ""
        gate = await self.gate_runner.green(task=task, waived=bool(reason), waiver_reason=reason)
        if not gate.ok:
            await self._send_back(state, task, gate.detail)
            report.failed += 1
            return
        if reason:
            await self._patch(state, waiver_reason=reason)
        await self._advance_or_complete(state, task)
        report.acted += 1

    # ------------------------------------------------------------------ #
    # merge (git is the platform's)                                      #
    # ------------------------------------------------------------------ #

    async def _merge_step(self, state: TaskPipelineState, report: TickReport) -> None:
        task = await self.tasks.get(state.task_id)
        if task is None or task.status in (
            TaskStatus.DONE,
            TaskStatus.FAILED,
            TaskStatus.CANCELLED,
        ):
            report.skipped += 1
            return
        worktree = await self._worktree_for(task, state)
        if worktree is None:
            await self._fail_task(state, task, "درخت کاری برای ادغام وجود ندارد.", ErrorKind.MODEL)
            report.failed += 1
            return
        employee = await self._task_employee(task)
        author = f"{employee.name if employee else 'موتور'} <{ENGINE_COMMIT_EMAIL}>"
        sha = await self.repo_workspace.commit(
            worktree=worktree, message=f"task/{task.id}: {task.title}", author=author
        )
        if sha is None:
            await self._fail_task(state, task, "هیچ تغییری برای ثبت وجود ندارد.", ErrorKind.MODEL)
            report.failed += 1
            return

        synced = await self.repo_workspace.sync_with_base(worktree=worktree)
        if not synced.ok:
            await self._merge_conflict(state, task, synced.conflict_files, report)
            return
        if synced.base_changed and self.sandbox is not None:
            tests = await self.gate_runner.tests(
                task=task,
                sandbox=self.sandbox,
                session_external_id=await self._sandbox_session(task),
            )
            if not tests.ok:
                await self._send_back(state, task, tests.detail)
                report.failed += 1
                return

        merged = await self.repo_workspace.merge_into(
            project_id=task.project_id or "", branch=worktree.branch, target="dev"
        )
        if not merged.ok:
            await self._merge_conflict(state, task, merged.conflict_files, report)
            return
        pushed = await self.repo_workspace.push(project_id=task.project_id or "", branch="dev")
        if not pushed.ok:
            await self._fail_task(
                state, task, f"فرستادن شاخه ناموفق بود: {pushed.message}", ErrorKind.NETWORK
            )
            report.failed += 1
            return

        final_sha = pushed.sha or merged.sha or sha
        await self._move(state, task, Stage.COMPLETED)
        await self.repo_workspace.remove_worktree(worktree=worktree)
        if task.project_id:
            await self.delivery.on_branch_pushed(
                organization_id=task.organization_id,
                project_id=task.project_id,
                branch="dev",
                sha=final_sha,
                source="engine",
            )
        await self._remember_outcome(task, state, final_sha)
        report.merged += 1
        report.acted += 1

    async def _merge_conflict(
        self,
        state: TaskPipelineState,
        task: Task,
        files: list[str],
        report: TickReport,
    ) -> None:
        detail = "تعارض ادغام در: " + ", ".join(files or ["نامشخص"])
        await self.gate_runner.record(
            task=task,
            outcome=GateOutcome(gate=GateName.DIFF_GUARD, ok=False, detail=detail),
        )
        attempts = state.retry_count + 1
        if attempts >= settings.engine_max_merge_conflicts:
            await self._fail_task(
                state, task, "تعارض ادغام پس از چند تلاش برطرف نشد.", ErrorKind.PROTOCOL
            )
            report.failed += 1
            return
        await self._patch(state, retry_count=attempts)
        await self._send_back(state, task, detail)
        report.failed += 1

    # ------------------------------------------------------------------ #
    # moving a task                                                      #
    # ------------------------------------------------------------------ #

    async def _advance_or_complete(self, state: TaskPipelineState, task: Task) -> None:
        await self._move(state, task, next_stage(state.pipeline, state.stage, Outcome.OK))

    async def _send_back(self, state: TaskPipelineState, task: Task, detail: str) -> None:
        """Cycle once and return to the developer, or ask the manager."""
        cycles = state.cycle + 1
        await self._patch(state, cycle=cycles)
        if cycles >= state.max_cycles:
            await self._move(state, task, Stage.ERROR_REVIEW)
            return
        await self._move(state, task, Stage.PENDING_IMPLEMENTATION)

    async def _move(self, state: TaskPipelineState, task: Task, target: Stage) -> None:
        if target is state.stage:
            return
        await advance(self.states, task_id=task.id, expected_from=state.stage, to=target)
        await self.tasks.set_status(task.id, coarse_status(target))
        if target in (Stage.FAILED, Stage.CANCELLED):
            # A dead task keeps no worktree behind it, and its dependents must
            # not wait for work that will never finish (agybot bug M1).
            await self._release_worktree(task, state)
            await park_dependents(self.states, task_id=task.id)

    async def _release_worktree(self, task: Task, state: TaskPipelineState) -> None:
        worktree = await self._worktree_for(task, state)
        if worktree is not None:
            await self.repo_workspace.remove_worktree(worktree=worktree)

    async def _patch(self, state: TaskPipelineState, **fields: object) -> None:
        try:
            updated = await self.states.patch(
                task_id=state.task_id, expected_version=state.version, **fields
            )
        except StaleStageError:
            # Another worker moved the row first; the next tick sees the truth.
            return
        # Keep the caller's snapshot current so a second patch in the same step
        # locks against the version this write produced, not the one before it.
        state.version = updated.version

    # ------------------------------------------------------------------ #
    # budget                                                             #
    # ------------------------------------------------------------------ #

    async def _pause(self, state: TaskPipelineState, task: Task, reason: str) -> None:
        await self._move(state, task, Stage.PAUSED)
        await self._post_note(task, reason)

    async def _budget_reason(self, task: Task) -> str | None:
        if self.wallets is not None:
            wallet = await self.wallets.get_for_org(task.organization_id)
            # No wallet means no budget was ever set: a fresh org must not be
            # frozen out of its first task.
            if wallet is not None and wallet.balance <= 0:
                return BUDGET_PAUSED_MESSAGE
        if self.spend is not None and settings.engine_max_task_credits > 0:
            used = await self.spend.spend_for_task(task.id)
            if used >= settings.engine_max_task_credits:
                return "سقف اعتبار این کار پر شده است؛ کار متوقف شد."
        return None

    async def _retry_or_fail(
        self, state: TaskPipelineState, task: Task, message: str, kind: str
    ) -> None:
        """A transient failure gets two more tries; then the manager decides."""
        if not is_transient(kind):
            await self._fail_task(state, task, message, ErrorKind(kind))
            return
        attempts = state.retry_count + 1
        if attempts > MAX_TRANSIENT_RETRIES:
            await self._fail_task(state, task, message, ErrorKind.UNAVAILABLE)
            return
        await self._patch(state, retry_count=attempts)

    async def _fail_task(
        self, state: TaskPipelineState, task: Task, reason: str, kind: ErrorKind
    ) -> None:
        if state.stage is Stage.ERROR_REVIEW:
            # The error turn tried and could not act: the task is failed.
            await self._move(state, task, Stage.FAILED)
        else:
            await self._move(state, task, Stage.ERROR_REVIEW)
        await self._post_note(task, reason)

    # ------------------------------------------------------------------ #
    # small helpers                                                      #
    # ------------------------------------------------------------------ #

    async def _open_run(self, task: Task, employee: Employee) -> Run:
        return await self.runs.create(
            Run(
                task_id=task.id,
                employee_id=employee.id,
                status=RunStatus.RUNNING,
                started_at=utcnow(),
            )
        )

    async def _close_run(self, run: Run, *, ok: bool, error: str = "") -> None:
        await self.runs.set_status(
            run.id,
            RunStatus.COMPLETED if ok else RunStatus.FAILED,
            error=error or None,
            finished_at=utcnow(),
        )

    async def _dependencies_done(self, state: TaskPipelineState) -> bool:
        for dependency in state.depends_on:
            other = await self.states.get(dependency)
            if other is None:
                continue
            if other.stage is not Stage.COMPLETED:
                return False
        return True

    async def _employee_for(self, state: TaskPipelineState, role: RoleKey) -> Employee | None:
        roster = [
            e
            for e in await self.employees.list_for_org(state.organization_id, limit=200)
            if e.is_available and e.role_key is role
        ]
        free: list[tuple[int, Employee]] = []
        for employee in roster:
            profile = await self.profiles.get(employee.id)
            if profile is None or profile.busy_task_id is not None:
                continue
            free.append((await self.tasks.count_open_for_employee(employee.id), employee))
        if not free:
            return None
        free.sort(key=lambda pair: pair[0])
        return free[0][1]

    async def _task_employee(self, task: Task) -> Employee | None:
        if not task.assigned_employee_id:
            return None
        return await self.employees.get_for_org(task.organization_id, task.assigned_employee_id)

    async def _worktree_for(self, task: Task, state: TaskPipelineState) -> WorktreeRef | None:
        if not requires_worktree(state.pipeline) or not task.project_id:
            return None
        return await self.repo_workspace.create_task_worktree(
            project_id=task.project_id, task_id=task.id, base="dev"
        )

    async def _save_branch(self, state: TaskPipelineState, worktree: WorktreeRef) -> None:
        if state.branch != worktree.branch:
            await self._patch(state, branch=worktree.branch)

    async def _sandbox_session(self, task: Task) -> str:
        if self.sandbox_session_for is None:
            return ""
        return await self.sandbox_session_for(task)

    async def _diff_for(self, task: Task, state: TaskPipelineState) -> tuple[str, list[str]]:
        worktree = await self._worktree_for(task, state)
        if worktree is None:
            return "", []
        diff = await self.repo_workspace.diff(worktree=worktree)
        return diff.text, list(diff.changed_files)

    async def _last_reply(self, task_id: str, role: RoleKey) -> str:
        turns = await self.turns.list_for_task(task_id)
        for turn in reversed(turns):
            if turn.role is role and turn.ok:
                return turn.reply_excerpt
        return ""

    async def _gate_detail(self, task_id: str, gate: str) -> str:
        row = await self.gates.latest_for(task_id, gate)
        return row.detail if row else ""

    async def _gate_summary(self, task_id: str) -> str:
        rows = await self.gates.list_for_task(task_id, limit=40)
        if not rows:
            return ""
        return "\n".join(
            f"{row.gate.value}: {'سبز' if row.ok else 'قرمز'}" for row in rows[-6:]
        )

    async def _work_context(self, task: Task, state: TaskPipelineState) -> str:
        parts: list[str] = []
        spec = await self._last_reply(task.id, RoleKey.PLANNER)
        if state.stage in (
            Stage.PENDING_IMPLEMENTATION,
            Stage.PENDING_REVIEW,
            Stage.PENDING_TEST,
        ) and spec:
            parts.append("برنامهٔ اجرا:\n" + spec)
        if state.stage is Stage.PENDING_IMPLEMENTATION:
            review = await self._last_reply(task.id, RoleKey.REVIEWER)
            if review:
                parts.append("نظر بازبین:\n" + review)
            tests = await self._gate_detail(task.id, str(GateName.TESTS))
            if tests:
                parts.append("آخرین نتیجهٔ تست:\n" + tests)
        elif state.stage is Stage.PENDING_REVIEW:
            diff_text, files = await self._diff_for(task, state)
            parts.append("فایل‌های تغییریافته: " + ", ".join(files))
            parts.append("تفاوت:\n" + diff_text[:8000])
        return "\n\n".join(p for p in parts if p)

    async def _error_context(self, task: Task) -> str:
        tests = await self._gate_detail(task.id, str(GateName.TESTS))
        return tests or "کار به بازبینی خطا رسید."

    async def _escalate_after_repeated_red(self, task: Task, employee: Employee) -> None:
        """A second red run: move the developer onto the strongest granted model.

        One escalation only. A model that is already the strongest, or an org
        with nothing stronger granted, is left alone — the cycle guard is what
        eventually stops the loop.
        """
        rows = await self.gates.list_for_task(task.id, limit=40)
        reds = sum(1 for row in rows if row.gate is GateName.TESTS and not row.ok)
        if reds < 2:
            return
        granted = await self.manager.grants.granted_models(organization_id=task.organization_id)
        strong = _pick_granted_model(granted, "strong", fallback=False)
        if not strong:
            return
        profile = await self.profiles.get(employee.id)
        if profile is None or profile.ai_model_id == strong:
            return
        await self.profiles.set_model(employee_id=employee.id, ai_model_id=strong)

    async def _post_note(self, task: Task, content: str) -> None:
        if not content:
            return
        await self.manager._post_system_message(
            organization_id=task.organization_id,
            project_id=task.project_id,
            content=content,
        )

    async def _remember_outcome(self, task: Task, state: TaskPipelineState, sha: str) -> None:
        try:
            await self.memory.on_task_finished(
                organization_id=task.organization_id,
                task=TaskOutcome(
                    task_id=task.id,
                    title=task.title,
                    status="completed",
                    summary=f"شاخهٔ dev با شناسهٔ {sha[:12]} به‌روزرسانی شد.",
                    cycles=state.cycle,
                ),
            )
        except Exception:  # noqa: BLE001 - memory must never fail a task
            return


__all__ = [
    "BUDGET_PAUSED_MESSAGE",
    "ENGINE_COMMIT_EMAIL",
    "MERGE_STAGES",
    "TURN_STAGES",
    "Scheduler",
    "TickReport",
]