import { and, asc, desc, eq, inArray, sql } from "drizzle-orm";
import {
  agentWakeupRequests,
  heartbeatRuns,
  heartbeatRunEvents,
  issueComments,
  issueThreadInteractions,
  issues,
  runIdentityContexts,
  type Db,
} from "@paperclipai/db";
import { conflict, forbidden } from "../errors.js";
import { isUuidLike } from "@paperclipai/shared";
import { queuedCommentIdsFromRunContext, queuedCommentIdsFromWakePayload } from "./issue-queued-comment-queue.js";

/** Resolve an explicit click from persisted receipts, never caller context or message authors. */
export async function explicitOperatorRunIdentity(
  executor: Pick<Db, "select">,
  run: Pick<typeof heartbeatRuns.$inferSelect, "id" | "companyId" | "agentId" | "contextSnapshot" | "wakeupRequestId">,
) {
  const [request] = run.wakeupRequestId ? await executor.select().from(agentWakeupRequests).where(and(
    eq(agentWakeupRequests.id, run.wakeupRequestId), eq(agentWakeupRequests.companyId, run.companyId),
    eq(agentWakeupRequests.agentId, run.agentId), eq(agentWakeupRequests.runId, run.id),
  )) : [];
  if (request?.payload?.manualUserWake === true) {
    if (request.requestedByActorType !== "user" || !request.requestedByActorId) {
      throw forbidden("Manual wake requires an authenticated user");
    }
    return { actorId: request.requestedByActorId, cause: "manual_user_wake" };
  }
  const prefix = "queued-comment-interrupt:";
  if (!request?.idempotencyKey?.startsWith(prefix)) return null;
  const queueId = request.idempotencyKey.slice(prefix.length);
  // The key only locates a candidate. The consumed queue, actor, run, company,
  // agent, task, and delivered messages must all independently agree.
  if (!isUuidLike(queueId)) {
    throw forbidden("Queued-message interrupt authority is unavailable");
  }
  const [receipt] = await executor.select().from(agentWakeupRequests).where(and(
    eq(agentWakeupRequests.id, queueId), eq(agentWakeupRequests.companyId, run.companyId),
    eq(agentWakeupRequests.agentId, run.agentId), eq(agentWakeupRequests.runId, run.id),
    eq(agentWakeupRequests.status, "coalesced"),
  ));
  const marker = receipt?.payload?.queuedCommentInterrupt;
  const actorId = marker && typeof marker === "object" && "actorId" in marker ? marker.actorId : null;
  const ids = queuedCommentIdsFromWakePayload(receipt?.payload);
  const deliveredIds = queuedCommentIdsFromRunContext(run.contextSnapshot);
  if (typeof actorId !== "string" || !actorId || !ids.length ||
      receipt?.payload?.issueId !== run.contextSnapshot?.issueId ||
      !ids.every(id => deliveredIds.includes(id)) ||
      request.requestedByActorType !== "user" || request.requestedByActorId !== actorId) {
    throw forbidden("Queued-message interrupt authority is unavailable");
  }
  return { actorId, cause: "queued_comment_interrupt" };
}

export type RunIdentityContext = typeof runIdentityContexts.$inferSelect;
type Executor = Pick<Db, "select" | "insert" | "update">;

/**
 * Lock the task before the run, matching task mutation ordering. Identity
 * operations do not change parent keys: NO KEY UPDATE still serializes writers
 * and steering, while allowing audit inserts to check their foreign keys.
 * FOR UPDATE can deadlock with an append that holds KEY SHARE on the run and
 * then checks the task while identity capture holds the task and waits on the run.
 */
async function lockIdentityTask(
  executor: Pick<Db, "select">,
  companyId: string,
  runId: string,
) {
  const [run] = await executor
    .select({
      context: heartbeatRuns.contextSnapshot,
      issueId: heartbeatRuns.nativeIssueId,
    })
    .from(heartbeatRuns)
    .where(
      and(eq(heartbeatRuns.id, runId), eq(heartbeatRuns.companyId, companyId)),
    );
  const issueId = run?.context?.issueId ?? run?.context?.taskId ?? run?.issueId;
  if (
    issueId !== undefined &&
    issueId !== null &&
    (typeof issueId !== "string" || !isUuidLike(issueId))
  ) {
    throw forbidden("Run task identity is invalid");
  }
  if (typeof issueId === "string")
    await executor
      .select({ id: issues.id })
      .from(issues)
      .where(and(eq(issues.id, issueId), eq(issues.companyId, companyId)))
      .for("no key update");
}

async function append(
  executor: Executor,
  input: {
    companyId: string;
    runId: string;
    responsibleUserId: string | null;
    messageId?: string | null;
    parentContextId?: string | null;
    cause: string;
    correlationId: string;
    status?: "accepted" | "pending";
  },
) {
  const [existing] = await executor
    .select()
    .from(runIdentityContexts)
    .where(
      and(
        eq(runIdentityContexts.runId, input.runId),
        eq(runIdentityContexts.correlationId, input.correlationId),
      ),
    );
  if (existing) return existing;
  const [last] = await executor
    .select()
    .from(runIdentityContexts)
    .where(eq(runIdentityContexts.runId, input.runId))
    .orderBy(desc(runIdentityContexts.revision))
    .limit(1);
  const [created] = await executor
    .insert(runIdentityContexts)
    .values({
      ...input,
      revision: (last?.revision ?? 0) + 1,
      acceptedAt: input.status === "pending" ? null : new Date(),
    })
    .returning();
  if (!created) throw new Error("Failed to persist run identity");
  if (created.status === "accepted") await activate(executor, created);
  return created;
}

async function activate(executor: Executor, context: RunIdentityContext) {
  const [run] = await executor
    .update(heartbeatRuns)
    .set({
      responsibleUserId: context.responsibleUserId,
      activeIdentityContextId: context.id,
      updatedAt: new Date(),
    })
    .where(
      and(
        eq(heartbeatRuns.id, context.runId),
        eq(heartbeatRuns.companyId, context.companyId),
      ),
    )
    .returning();
  const issueId = run?.contextSnapshot?.issueId ?? run?.contextSnapshot?.taskId;
  if (typeof issueId === "string")
    await executor
      .update(issues)
      .set({ continuationIdentityContextId: context.id })
      .where(
        and(eq(issues.id, issueId), eq(issues.companyId, context.companyId)),
      );
}

/** Called only for newly dispatched runs. Historical rows are never backfilled. */
export async function initializeRunIdentity(
  db: Db,
  input: {
    companyId: string;
    runId: string;
    responsibleUserId: string | null;
    messageIds?: string[];
    issueId?: string | null;
    interactionId?: string | null;
    parentRunId?: string | null;
    parentContextId?: string | null;
    cause: string;
  },
) {
  return db.transaction(async (tx) => {
    await lockIdentityTask(tx, input.companyId, input.runId);
    const [run] = await tx
      .select()
      .from(heartbeatRuns)
      .where(
        and(
          eq(heartbeatRuns.id, input.runId),
          eq(heartbeatRuns.companyId, input.companyId),
        ),
      )
      .for("no key update");
    if (!run) throw forbidden("Run identity does not belong to this company");
    if (run.activeIdentityContextId) {
      const [current] = await tx
        .select()
        .from(runIdentityContexts)
        .where(eq(runIdentityContexts.id, run.activeIdentityContextId));
      return current!;
    }
    const operatorIdentity = await explicitOperatorRunIdentity(tx, run);
    const [parent] = input.parentRunId
      ? await tx
          .select()
          .from(heartbeatRuns)
          .where(
            and(
              eq(heartbeatRuns.id, input.parentRunId),
              eq(heartbeatRuns.companyId, input.companyId),
            ),
          )
      : [];
    const [interaction] =
      input.interactionId && input.issueId
        ? await tx
            .select()
            .from(issueThreadInteractions)
            .where(
              and(
                eq(issueThreadInteractions.id, input.interactionId),
                eq(issueThreadInteractions.companyId, input.companyId),
                eq(issueThreadInteractions.issueId, input.issueId),
              ),
            )
        : [];
    const parentId = operatorIdentity ? null : (
      interaction?.sourceIdentityContextId ?? input.parentContextId ?? parent?.activeIdentityContextId
    );
    const [origin] = parentId
      ? await tx
          .select()
          .from(runIdentityContexts)
          .where(
            and(
              eq(runIdentityContexts.id, parentId),
              eq(runIdentityContexts.companyId, input.companyId),
              eq(runIdentityContexts.status, "accepted"),
            ),
          )
      : [];
    if (parentId && !origin)
      throw forbidden("Originating execution identity is unavailable");
    let current = await append(tx, {
      companyId: input.companyId,
      runId: input.runId,
      responsibleUserId: operatorIdentity?.actorId ?? (origin ? origin.responsibleUserId : input.responsibleUserId),
      parentContextId: origin?.id ?? null,
      cause:
        operatorIdentity ? operatorIdentity.cause : origin?.cause === "company_default" ? "company_default" : input.cause,
      correlationId: "dispatch",
    });
    const ids = [...new Set(input.messageIds ?? [])];
    const comments =
      ids.length && input.issueId
        ? await tx
            .select()
            .from(issueComments)
            .where(
              and(
                eq(issueComments.companyId, input.companyId),
                eq(issueComments.issueId, input.issueId),
                inArray(issueComments.id, ids),
              ),
            )
        : [];
    for (const id of ids) {
      const comment = comments.find((c) => c.id === id);
      if (!comment?.authorUserId) continue;
      current = await append(tx, {
        companyId: input.companyId,
        runId: input.runId,
        responsibleUserId: operatorIdentity?.actorId ?? comment.authorUserId,
        messageId: id,
        parentContextId: current.id,
        cause: operatorIdentity?.cause ?? "instruction",
        correlationId: `message:${id}`,
      });
    }
    return current;
  });
}

/** Caller holds the task and run row locks, in that order. Reserve before delivery so acquisitions cannot guess. */
export async function prepareSteeredIdentity(
  executor: Executor,
  input: {
    companyId: string;
    runId: string;
    messageId: string;
    issueId: string;
    source?: "comment" | "interaction";
  },
) {
  const [run] = await executor
    .select()
    .from(heartbeatRuns)
    .where(
      and(
        eq(heartbeatRuns.id, input.runId),
        eq(heartbeatRuns.companyId, input.companyId),
      ),
    );
  const [comment] = input.source === "interaction" ? [] : await executor
    .select()
    .from(issueComments)
    .where(
      and(
        eq(issueComments.id, input.messageId),
        eq(issueComments.companyId, input.companyId),
        eq(issueComments.issueId, input.issueId),
      ),
    );
  const [interaction] = input.source === "interaction" ? await executor.select().from(issueThreadInteractions).where(and(
    eq(issueThreadInteractions.id, input.messageId),
    eq(issueThreadInteractions.companyId, input.companyId),
    eq(issueThreadInteractions.issueId, input.issueId),
    inArray(issueThreadInteractions.status, ["accepted", "answered", "rejected"]),
  )) : [];
  const responsibleUserId = interaction?.resolvedByUserId ?? comment?.authorUserId;
  if (!run || !responsibleUserId)
    throw forbidden("Steering requires an authenticated message author");
  if (
    run.status !== "running" ||
    (run.contextSnapshot?.issueId !== input.issueId &&
      run.contextSnapshot?.taskId !== input.issueId)
  ) {
    throw conflict("Steering targets a different or inactive execution");
  }
  return append(executor, {
    companyId: input.companyId,
    runId: input.runId,
    responsibleUserId,
    messageId: input.messageId,
    parentContextId: run.activeIdentityContextId,
    cause: "steering",
    correlationId: `${input.source === "interaction" ? "interaction" : "message"}:${input.messageId}`,
    status: "pending",
  });
}

export async function reserveSteeredIdentity(
  db: Db,
  input: Parameters<typeof prepareSteeredIdentity>[1],
) {
  return db.transaction(async (tx) => {
    await lockIdentityTask(tx, input.companyId, input.runId);
    const [run] = await tx
      .select()
      .from(heartbeatRuns)
      .where(
        and(
          eq(heartbeatRuns.id, input.runId),
          eq(heartbeatRuns.companyId, input.companyId),
        ),
      )
      .for("no key update");
    // Processes started before the broker rollout keep their original environment.
    if (!run?.activeIdentityContextId) return null;
    const [pending] = await tx
      .select()
      .from(runIdentityContexts)
      .where(
        and(
          eq(runIdentityContexts.runId, run.id),
          eq(runIdentityContexts.status, "pending"),
        ),
      )
      .limit(1);
    if (pending && pending.messageId !== input.messageId) {
      if (await storedSteeringAcknowledgement(tx, pending))
        await acceptSteeredIdentity(tx, pending);
      else
        throw conflict(
          "A prior steering acknowledgement must be reconciled first",
        );
    }
    const [existing] = await tx
      .select()
      .from(runIdentityContexts)
      .where(
        and(
          eq(runIdentityContexts.runId, run.id),
          eq(runIdentityContexts.messageId, input.messageId),
          eq(runIdentityContexts.status, "accepted"),
        ),
      );
    if (existing) return existing;
    const context = await prepareSteeredIdentity(tx, input);
    if (context.status === "rejected") {
      await tx
        .update(runIdentityContexts)
        .set({ status: "pending" })
        .where(eq(runIdentityContexts.id, context.id));
      return { ...context, status: "pending" };
    }
    return context;
  });
}

export async function rejectSteeredIdentity(
  db: Db,
  context: RunIdentityContext,
) {
  await db
    .update(runIdentityContexts)
    .set({ status: "rejected" })
    .where(
      and(
        eq(runIdentityContexts.id, context.id),
        eq(runIdentityContexts.status, "pending"),
      ),
    );
}

export async function acceptSteeredIdentity(
  executor: Executor,
  context: RunIdentityContext,
) {
  // A replay must not reactivate a historical identity after later instructions.
  const [accepted] = await executor
    .update(runIdentityContexts)
    .set({ status: "accepted", acceptedAt: new Date() })
    .where(
      and(
        eq(runIdentityContexts.id, context.id),
        eq(runIdentityContexts.status, "pending"),
      ),
    )
    .returning();
  if (accepted) await activate(executor, accepted);
}

export async function captureRunIdentity(
  db: Db,
  input: { companyId: string; runId: string; agentId: string },
) {
  // Lock acquisition serializes with steering delivery and its durable acknowledgement.
  return db.transaction(async (tx) => {
    await lockIdentityTask(tx, input.companyId, input.runId);
    const [run] = await tx
      .select()
      .from(heartbeatRuns)
      .where(
        and(
          eq(heartbeatRuns.id, input.runId),
          eq(heartbeatRuns.companyId, input.companyId),
          eq(heartbeatRuns.agentId, input.agentId),
        ),
      )
      .for("no key update");
    if (!run || run.status !== "running")
      throw forbidden(
        "Credential acquisition requires this agent's active run",
      );
    const [pending] = await tx
      .select()
      .from(runIdentityContexts)
      .where(
        and(
          eq(runIdentityContexts.runId, run.id),
          eq(runIdentityContexts.status, "pending"),
        ),
      )
      .limit(1);
    if (pending) {
      const acknowledgement = await storedSteeringAcknowledgement(tx, pending);
      if (!acknowledgement)
        throw conflict(
          "Message acceptance is being reconciled; retry credential acquisition",
        );
      await acceptSteeredIdentity(tx, pending);
      run.activeIdentityContextId = pending.id;
      run.responsibleUserId = pending.responsibleUserId;
    }
    const [context] = run.activeIdentityContextId
      ? await tx
          .select()
          .from(runIdentityContexts)
          .where(
            and(
              eq(runIdentityContexts.id, run.activeIdentityContextId),
              eq(runIdentityContexts.runId, run.id),
            ),
          )
      : [];
    return { run, context: context ?? null };
  });
}

export async function listRunIdentityContexts(
  db: Db,
  companyId: string,
  runId: string,
) {
  return db
    .select()
    .from(runIdentityContexts)
    .where(
      and(
        eq(runIdentityContexts.companyId, companyId),
        eq(runIdentityContexts.runId, runId),
      ),
    )
    .orderBy(asc(runIdentityContexts.revision));
}

/** Late native acknowledgements settle reservations even when the HTTP caller timed out. */
export async function reconcileSteeredIdentity(
  db: Db,
  context: RunIdentityContext,
) {
  await db.transaction(async (tx) => {
    await lockIdentityTask(tx, context.companyId, context.runId);
    const [run] = await tx
      .select()
      .from(heartbeatRuns)
      .where(
        and(
          eq(heartbeatRuns.id, context.runId),
          eq(heartbeatRuns.companyId, context.companyId),
        ),
      )
      .for("no key update");
    if (!run) return;
    await acceptSteeredIdentity(tx, context);
  });
}

/** Only events validated and persisted by the native control-plane transport count. */
export async function storedSteeringAcknowledgement(
  executor: Pick<Db, "select">,
  context: Pick<RunIdentityContext, "companyId" | "runId" | "messageId">,
) {
  if (!context.messageId) return null;
  const [receipt] = await executor
    .select({ payload: heartbeatRunEvents.payload })
    .from(heartbeatRunEvents)
    .where(
      and(
        eq(heartbeatRunEvents.companyId, context.companyId),
        eq(heartbeatRunEvents.runId, context.runId),
        eq(heartbeatRunEvents.eventType, "item.completed"),
        sql`${heartbeatRunEvents.sourceEventId} is not null`,
        sql`${heartbeatRunEvents.payload}->'prpEvent'->'payload'->>'kind' = 'steering_acknowledgement'`,
        sql`${heartbeatRunEvents.payload}->'prpEvent'->>'itemId' like ${`%:steer:${context.messageId}`}`,
      ),
    )
    .limit(1);
  const event = receipt?.payload?.prpEvent as { turnId?: string } | undefined;
  return typeof event?.turnId === "string" ? { turnId: event.turnId } : null;
}