import { and, desc, eq, inArray, isNull, ne, sql } from "drizzle-orm";
import {
  heartbeatRuns,
  issues,
  dotAgentBindings,
  dotRunnerAssignments,
  museAgentBindings,
  museRunnerAssignments,
  issueRecoveryActions,
  issueThreadInteractions,
  nativeRunFinalizations,
  type Db,
} from "@paperclipai/db";
import type { ExecutionProjection } from "@paperclipai/shared";
import { EXECUTION_CONTROL_DEADLINE_MS } from "./execution-control-deadline.js";
import { executionFailureRetryCount } from "./execution-recovery-attempt.js";
import { retryIdempotentDatabaseOperation } from "../database-retry.js";
import { workspaceRecoveryDisplay } from "./workspace-recovery-receipt.js";
import { readTaskDrain } from "./task-admission.js";
import { getStartupRecoveryState } from "../startup-recovery-state.js";
import { hasPendingRunCleanup } from "./execution-blocker.js";
const MAX_PREDECESSOR_CLEANUP_CHECKS = 16;
const text = (v: unknown) => (typeof v === "string" ? v : null);
const executionRunColumns = {
  id: heartbeatRuns.id,
  agentId: heartbeatRuns.agentId,
  driverKind: heartbeatRuns.driverKind,
  errorCode: heartbeatRuns.errorCode,
  executionControlDeadlineAt: heartbeatRuns.executionControlDeadlineAt,
  finishedAt: heartbeatRuns.finishedAt,
  lastOutputAt: heartbeatRuns.lastOutputAt,
  lastUsefulActionAt: heartbeatRuns.lastUsefulActionAt,
  nativeIssueId: heartbeatRuns.nativeIssueId,
  nextAction: heartbeatRuns.nextAction,
  processPid: heartbeatRuns.processPid,
  retryOfRunId: heartbeatRuns.retryOfRunId,
  runtimeMode: heartbeatRuns.runtimeMode,
  scheduledRetryAt: heartbeatRuns.scheduledRetryAt,
  scheduledRetryAttempt: heartbeatRuns.scheduledRetryAttempt,
  scheduledRetryReason: heartbeatRuns.scheduledRetryReason,
  startedAt: heartbeatRuns.startedAt,
  status: heartbeatRuns.status,
  contextSnapshot: sql<Record<string, unknown>>`jsonb_build_object(
    'issueId', ${heartbeatRuns.contextSnapshot}->'issueId',
    'wakeReason', ${heartbeatRuns.contextSnapshot}->'wakeReason',
    'failureRetriesBeforeAiConnectionWait', ${heartbeatRuns.contextSnapshot}->'failureRetriesBeforeAiConnectionWait',
    'failureRetriesBeforeWorkspaceWait', ${heartbeatRuns.contextSnapshot}->'failureRetriesBeforeWorkspaceWait')`,
};
type Run = Pick<typeof heartbeatRuns.$inferSelect, keyof typeof executionRunColumns>;
type Coordinator = typeof nativeRunFinalizations.$inferSelect;
type WaitingExternalProvider = "muse" | "openai_dot";
type Recovery = Pick<
  typeof issueRecoveryActions.$inferSelect,
  "cause" | "nextAction"
> &
  Partial<
    Pick<typeof issueRecoveryActions.$inferSelect, "status" | "evidence">
  >;

/** Batched reads; list consumers do not perform per-task polling. */
export async function executionProjectionsForRuns(
  db: Db,
  companyId: string,
  runIds: string[],
  now = new Date(),
  options: { retryDatabaseReads?: boolean } = {},
) {
  const projections = new Map<string, ExecutionProjection>();
  if (!runIds.length) return projections;
  // Opt in only with a pooled Db outside a transaction. Issue enrichment also
  // calls this helper with a transaction, whose failed reads must not replay.
  const read = <T>(query: () => Promise<T>) => options.retryDatabaseReads
    ? retryIdempotentDatabaseOperation(query)
    : query();
  const runs = await read(async () => db
    .select(executionRunColumns)
    .from(heartbeatRuns)
    .where(
      and(
        eq(heartbeatRuns.companyId, companyId),
        inArray(heartbeatRuns.id, runIds),
      ),
    ));
  const coordinators = await read(async () => db
    .select()
    .from(nativeRunFinalizations)
    .where(
      and(
        eq(nativeRunFinalizations.companyId, companyId),
        inArray(nativeRunFinalizations.runId, runIds),
      ),
    ));
  const issueIds = [
    ...new Set(
      runs
        .map((run) => run.nativeIssueId ?? text(run.contextSnapshot?.issueId))
        .filter((id): id is string => !!id),
    ),
  ];
  const pending = issueIds.length
    ? await read(async () => db
        .select({
          issueId: issueThreadInteractions.issueId,
          kind: issueThreadInteractions.kind,
        })
        .from(issueThreadInteractions)
        .where(
          and(
            eq(issueThreadInteractions.companyId, companyId),
            inArray(issueThreadInteractions.issueId, issueIds),
            eq(issueThreadInteractions.status, "pending"),
          ),
        ))
    : [];
  const recovery = issueIds.length
    ? await read(async () => db
        .select({
          issueId: issueRecoveryActions.sourceIssueId,
          cause: issueRecoveryActions.cause,
          nextAction: issueRecoveryActions.nextAction,
          evidence: issueRecoveryActions.evidence,
          status: issueRecoveryActions.status,
        })
        .from(issueRecoveryActions)
        .where(
          and(
            eq(issueRecoveryActions.companyId, companyId),
            inArray(issueRecoveryActions.sourceIssueId, issueIds),
            inArray(issueRecoveryActions.status, [
              "active",
              "escalated",
              "resolved",
            ]),
          ),
        )
        .orderBy(desc(issueRecoveryActions.updatedAt)))
    : [];
  // A live controller is not evidence that an external agent accepted work.
  // Read each provider journal once for the batch, never once per task.
  const waitingByRun = new Map<string, WaitingExternalProvider>();
  const externalRunIds = (driverKind: string) => runs
    .filter(run => run.status === "running" && run.runtimeMode === "native" && run.driverKind === driverKind)
    .map(run => run.id);
  const museRunIds = externalRunIds("muse_external");
  if (museRunIds.length) {
    const offered = await read(async () => db
      .select({ runId: museRunnerAssignments.runId })
      .from(museRunnerAssignments)
      .innerJoin(museAgentBindings, and(
        eq(museAgentBindings.id, museRunnerAssignments.bindingId),
        eq(museAgentBindings.companyId, museRunnerAssignments.companyId),
        eq(museAgentBindings.agentId, museRunnerAssignments.agentId),
        eq(museAgentBindings.generation, museRunnerAssignments.bindingGeneration),
        isNull(museAgentBindings.revokedAt),
      ))
      .where(and(
        eq(museRunnerAssignments.companyId, companyId),
        inArray(museRunnerAssignments.runId, museRunIds),
        inArray(museRunnerAssignments.status, ["offered", "claimed"]),
        isNull(museRunnerAssignments.nativeAcceptedAt),
      )));
    for (const row of offered) waitingByRun.set(row.runId, "muse");
  }
  const dotRunIds = externalRunIds("openai_dot_mcp");
  if (dotRunIds.length) {
    const offered = await read(async () => db
      .select({ runId: dotRunnerAssignments.runId })
      .from(dotRunnerAssignments)
      .innerJoin(dotAgentBindings, and(
        eq(dotAgentBindings.id, dotRunnerAssignments.bindingId),
        eq(dotAgentBindings.companyId, dotRunnerAssignments.companyId),
        eq(dotAgentBindings.agentId, dotRunnerAssignments.agentId),
        eq(dotAgentBindings.generation, dotRunnerAssignments.bindingGeneration),
        isNull(dotAgentBindings.revokedAt),
      ))
      .where(and(
        eq(dotRunnerAssignments.companyId, companyId),
        inArray(dotRunnerAssignments.runId, dotRunIds),
        eq(dotRunnerAssignments.status, "offered"),
        isNull(dotRunnerAssignments.acceptedAt),
      )));
    for (const row of offered) waitingByRun.set(row.runId, "openai_dot");
  }
  // A queued turn cannot start while its predecessor's cleanup is pending
  // (for example a stopped run whose runner has not released yet). Name that
  // wait instead of an unexplained "Queued". The predecessors are the ones
  // admission checks: the task's execution owner, the run this one retries,
  // and the agent's latest settled run on the same task, whose in-process
  // executor the claim also waits for. Pending uses admission's own predicate.
  const settlingPredecessorKeys = new Set<string>();
  const queuedRuns = runs.filter(run => run.status === "queued");
  const issueIdOf = (run: Run) => run.nativeIssueId ?? text(run.contextSnapshot?.issueId);
  const queuedIssueIds = [...new Set(queuedRuns.map(issueIdOf).filter((id): id is string => !!id))];
  if (queuedIssueIds.length) {
    const issueKey = sql<string>`coalesce(${heartbeatRuns.nativeIssueId}::text, ${heartbeatRuns.contextSnapshot}->>'issueId')`;
    // Two set-based reads for the whole batch, then one bounded, parallel
    // admission check per distinct predecessor.
    const [owners, latestSettled] = await Promise.all([
      read(async () => db
        .select({ id: issues.id, executionRunId: issues.executionRunId })
        .from(issues)
        .where(and(eq(issues.companyId, companyId), inArray(issues.id, queuedIssueIds)))),
      read(async () => db
        .selectDistinctOn([heartbeatRuns.agentId, issueKey], { id: heartbeatRuns.id, agentId: heartbeatRuns.agentId, issueId: issueKey })
        .from(heartbeatRuns)
        .where(and(
          eq(heartbeatRuns.companyId, companyId),
          inArray(heartbeatRuns.agentId, [...new Set(queuedRuns.map(run => run.agentId))]),
          inArray(issueKey, queuedIssueIds),
          inArray(heartbeatRuns.status, ["succeeded", "failed", "cancelled", "timed_out"]),
        ))
        .orderBy(heartbeatRuns.agentId, issueKey, desc(heartbeatRuns.createdAt))),
    ]);
    const ownerByIssue = new Map(owners.map(row => [row.id, row.executionRunId]));
    const latestByAgentIssue = new Map(latestSettled.map(row => [`${row.agentId}:${row.issueId}`, row.id]));
    const candidatesByRun = new Map<string, string[]>();
    for (const run of queuedRuns) {
      const issueId = issueIdOf(run);
      if (!issueId) continue;
      candidatesByRun.set(run.id, [...new Set([ownerByIssue.get(issueId), run.retryOfRunId,
        latestByAgentIssue.get(`${run.agentId}:${issueId}`)].filter((id): id is string => !!id && id !== run.id))]);
    }
    const distinct = [...new Set([...candidatesByRun.values()].flat())];
    // A label is not worth an unbounded fan-out on large list reads.
    if (distinct.length <= MAX_PREDECESSOR_CLEANUP_CHECKS) {
      const pendingIds = new Set((await Promise.all(distinct.map(async id =>
        (await read(() => hasPendingRunCleanup(db, companyId, id))) ? id : null))).filter((id): id is string => !!id));
      for (const [runId, candidates] of candidatesByRun)
        if (candidates.some(id => pendingIds.has(id))) settlingPredecessorKeys.add(runId);
    }
  }
  const coordinatorByRun = new Map(coordinators.map((row) => [row.runId, row]));
  for (const run of runs) {
    const issueId = run.nativeIssueId ?? text(run.contextSnapshot?.issueId);
    const matching = recovery.filter(
      (row) =>
        row.issueId === issueId &&
        (row.status !== "resolved" || row.evidence.executionReconciliation || row.evidence.automaticRecovery) &&
        (row.evidence.runId === run.id || row.evidence.sourceRunId === run.id),
    );
    const action =
      matching.find((row) => row.status !== "resolved") ?? matching[0];
    projections.set(
      run.id,
      projectExecution(
        run,
        coordinatorByRun.get(run.id),
        pending.filter((row) => row.issueId === issueId),
        action,
        now,
        waitingByRun.get(run.id),
        settlingPredecessorKeys.has(run.id),
      ),
    );
  }
  return projections;
}
export async function executionProjectionForRun(
  db: Db,
  companyId: string,
  runId: string,
  now = new Date(),
): Promise<ExecutionProjection | null> {
  return (
    (await executionProjectionsForRuns(db, companyId, [runId], now)).get(
      runId,
    ) ?? null
  );
}
export function projectExecution(
  run: Run,
  coordinator: Coordinator | undefined,
  pending: Array<{ kind: string }>,
  recoveryAction: Recovery | undefined,
  now = new Date(),
  waitingForProvider?: WaitingExternalProvider,
  waitingForPredecessor = false,
): ExecutionProjection {
  const detail = coordinator?.failureDetail ?? {};
  const successorRunId = text(detail.successorRunId);
  const projection: ExecutionProjection = {
    // A live run is always stoppable by the board (POST /heartbeat-runs/:id/cancel);
    // a failed native run is stoppable only while its retry is still pending.
    canStop: run.status === "running" || run.status === "queued" || (
      run.runtimeMode === "native" && run.status === "failed" && run.driverKind !== "grok_bot_mcp" && !!run.nativeIssueId
      && coordinator?.runId === run.id && coordinator.issueId === run.nativeIssueId && coordinator.resultId === null
      && coordinator.phase === "retryable_failure"),
    phase: "queued",
    label: "Queued",
    cause: run.errorCode ?? coordinator?.failureCode ?? null,
    lastConfirmedActivityAt:
      (
        run.lastUsefulActionAt ??
        run.lastOutputAt ??
        run.startedAt
      )?.toISOString() ?? null,
    retryAt:
      (coordinator?.nextAttemptAt ?? run.scheduledRetryAt)?.toISOString() ??
      null,
    attempt: coordinator?.attempt ?? executionFailureRetryCount(run) + 1,
    maxAttempts: 3,
    recoveryOwner: null,
    nextAction: text(detail.nextAction) ?? run.nextAction,
    permittedActions: ["inspect_run"],
    predecessorRunId: run.retryOfRunId,
    successorRunId,
  };
  const set = (phase: ExecutionProjection["phase"], label: string) =>
    Object.assign(projection, { phase, label });
  if (recoveryAction?.status === "resolved" && recoveryAction.evidence?.automaticRecovery) {
    projection.cause = recoveryAction.cause;
    projection.nextAction = workspaceRecoveryDisplay(recoveryAction.evidence, run.id)?.message
      ?? recoveryAction.nextAction;
    const continuation = recoveryAction.evidence.explicitUserContinuation as
      { previousRunId?: unknown; runId?: unknown } | undefined;
    const explicitSuccessor = text(continuation?.runId);
    if (continuation?.previousRunId === run.id && explicitSuccessor && explicitSuccessor !== run.id) {
      // The admission transaction already recorded the user's successor. Keep
      // the old failure diagnostic without making it hold the newer attempt.
      projection.successorRunId = explicitSuccessor;
      projection.nextAction = null;
      return set("completed", "Continued in another run");
    }
    // Diagnostic projection only: no user decision or replay affordance.
    return set("recovery_needed", "Stopped");
  }
  if (
    recoveryAction?.status === "resolved" &&
    recoveryAction.evidence?.executionReconciliation
  ) {
    if (recoveryAction.evidence.continuationDelivery === "invalidated") {
      projection.cause = "continuation_ownership_changed";
      projection.nextAction =
        "The task was closed or reassigned before delivery. Inspect the current task owner and status.";
      return set("failed", "Continuation cancelled");
    }
    const deliveredRunId = text(recoveryAction.evidence.continuationRunId);
    projection.successorRunId = deliveredRunId;
    projection.cause = null;
    projection.nextAction = deliveredRunId
      ? null
      : "The previous execution is reconciled. Its continuation is queued for delivery.";
    return set(
      deliveredRunId ? "completed" : "queued",
      deliveredRunId ? "Continued in another run" : "Continuation queued",
    );
  }
  if (
    (run.status === "running" &&
      (run.executionControlDeadlineAt || coordinator?.controlDeadlineAt)) ||
    [
      "result_persisted",
      "ready_for_assessment",
      "arbitrating",
      "workspace_pending",
    ].includes(coordinator?.phase ?? "")
  )
    return set("finishing", "Finishing");
  if (successorRunId) return set("completed", "Continued in another run");
  if (run.status === "scheduled_retry" && run.scheduledRetryReason === "ai_connection_busy") {
    projection.nextAction = "Waiting for the AI subscription's current execution to finish; the scheduled check will revalidate access.";
    return set("retry_scheduled", "Waiting for AI subscription");
  }
  if (run.status === "scheduled_retry" && run.scheduledRetryReason === "ai_connection_pool_wait"
      && run.contextSnapshot?.wakeReason === "provider_limit_retry") {
    const resetAt = run.scheduledRetryAt ? new Date(run.scheduledRetryAt).toISOString() : "its reported reset";
    projection.nextAction = `Waiting for the agent's provider usage limit to reset; the work starts at ${resetAt}. To continue sooner, restore the provider allowance or change the agent's AI connection, then start a manual run.`;
    return set("retry_scheduled", "Waiting for usage limit reset");
  }
  if (run.status === "scheduled_retry" && run.scheduledRetryReason === "workspace_busy") {
    projection.nextAction = "Waiting for the live workspace holder to finish; the scheduled check will revalidate ownership.";
    return set("retry_scheduled", "Waiting for workspace");
  }
  // Cleanup can fail before a finalization coordinator exists. The missing
  // row must not turn a quarantined native session into an ordinary Retry.
  const cleanupQuarantined = run.runtimeMode === "native" &&
    ["failed", "timed_out"].includes(run.status) &&
    run.errorCode === "native_session_cleanup_quarantined";
  if (!cleanupQuarantined && (
    coordinator?.phase === "retryable_failure" ||
    run.status === "scheduled_retry"
  )) {
    projection.recoveryOwner = "agent";
    return set(
      projection.retryAt && new Date(projection.retryAt) > now
        ? "retry_scheduled"
        : "reconnecting",
      projection.retryAt && new Date(projection.retryAt) > now
        ? "Retry scheduled"
        : "Reconnecting",
    );
  }
  if (coordinator?.phase === "terminal_failure" || recoveryAction || cleanupQuarantined) {
    if (
      !cleanupQuarantined &&
      coordinator?.failureCode === "native_provider_terminal_failed" &&
      !detail.replacementDenied &&
      run.finishedAt &&
      now.getTime() - run.finishedAt.getTime() < EXECUTION_CONTROL_DEADLINE_MS
    ) {
      projection.recoveryOwner = "agent";
      projection.nextAction =
        "Checking that the previous provider stopped and its action outcomes are known before continuing.";
      return set("reconnecting", "Checking recovery");
    }
    projection.recoveryOwner = "board";
    projection.cause =
      recoveryAction?.cause ??
      text(detail.replacementDenied) ??
      projection.cause;
    projection.nextAction = recoveryAction?.nextAction ?? projection.nextAction;
    if (cleanupQuarantined && !projection.nextAction) {
      projection.nextAction = "Verify the stopped session and its saved work before starting a new attempt.";
    }
    projection.permittedActions.push("inspect_recovery");
    return set("recovery_needed", "Recovery needed");
  }
  if (run.status === "succeeded") {
    if (pending.length)
      return set(
        pending.some((row) => row.kind === "connection_intent")
          ? "waiting_for_access"
          : "waiting_for_answer",
        pending.some((row) => row.kind === "connection_intent")
          ? "Waiting for access"
          : "Waiting for answer",
      );
    return set("completed", "Completed");
  }
  if (["failed", "cancelled", "timed_out", "interrupted"].includes(run.status))
    return set("failed", run.status === "cancelled" ? "Cancelled" : "Failed");
  if (run.status === "running") {
    const leaseConfirmed =
      coordinator?.phase === "observed" &&
      coordinator.leaseExpiresAt &&
      coordinator.leaseExpiresAt > now;
    let processConfirmed = false;
    if (run.runtimeMode === "legacy" && run.processPid) {
      try {
        process.kill(run.processPid, 0);
        processConfirmed = true;
      } catch {
        /* No execution confirmation. */
      }
    }
    if (leaseConfirmed && waitingForProvider) {
      projection.nextAction = "The assignment is offered. Waiting for the external agent to accept it.";
      return set("waiting_for_provider", `Waiting for ${waitingForProvider === "muse" ? "Muse" : "Dot"}`);
    }
    return leaseConfirmed || processConfirmed
      ? set("working", "Working")
      : set("reconnecting", "Confirming execution");
  }
  if (run.status === "queued" && !run.startedAt && readTaskDrain(now)) {
    projection.cause = "task_drain";
    projection.nextAction = "This turn will start automatically when maintenance finishes.";
    return set("queued", "Waiting for maintenance");
  }
  // Process-local, like the drain: while this server starts, recovers, or
  // shuts down, its full queued-run pass has not run (or no longer runs).
  const serverPhase = getStartupRecoveryState().phase;
  if (run.status === "queued" && serverPhase !== "ready") {
    projection.cause = "server_restarting";
    projection.nextAction = serverPhase === "draining"
      ? "The server is restarting for an update. This turn starts automatically on the replacement server."
      : "The server restarted and is finishing recovery. This turn starts automatically when recovery completes.";
    return set("queued", "Waiting for server restart");
  }
  if (run.status === "queued" && waitingForPredecessor) {
    projection.cause = "previous_run_settling";
    projection.nextAction = "The previous run on this task is still releasing its runner. This turn starts automatically when it settles.";
    return set("queued", "Waiting for previous run to stop");
  }
  return projection;
}