/**
 * Task #242 (B1) — Capability data-foundation 骨架接口。
 *
 * **本任务**:只接口 + 一个最小实现(`writeRow` 真插表 / `readRows` 真查表),
 * 让 B7 可以平滑加 distill / reuse 路径。
 * **B7**:真把 inner-loop run 蒸馏成 row(parameter-fingerprint / failure-mode / ...)
 * 并在 inner-loop search 步骤复用。
 *
 * 注意:`capability_data_foundation` 表已在 B2 (#255) 建好;本模块直接
 * 复用,不新建 schema。
 */

import { and, desc, eq } from "drizzle-orm";
import {
  db,
  capabilityDataFoundation,
  type CapabilityDataFoundationRow,
  type InsertCapabilityDataFoundationRow,
} from "@workspace/db";
import { newId } from "../../ids.js";

export interface DataFoundationRow {
  id: string;
  capabilityId: string;
  kind: string;
  payload: Record<string, unknown>;
  sourceRunId: string | null;
  createdAt: Date;
}

export interface WriteRowInput {
  capabilityId: string;
  kind: string;
  payload: Record<string, unknown>;
  sourceRunId?: string | null;
}

export interface ReadRowsQuery {
  capabilityId: string;
  kind?: string;
  /** Default 50, max 500. */
  limit?: number;
  /**
   * **Anti-self-loop**: when set, EXCLUDE rows where capabilityId matches
   * the requester (B7 will set this when an inner-loop search step asks
   * for "what other capabilities have learned" without polluting itself).
   */
  excludeSelf?: boolean;
}

function rowToOutput(r: CapabilityDataFoundationRow): DataFoundationRow {
  return {
    id: r.id,
    capabilityId: r.capabilityId,
    kind: r.kind,
    payload: (r.payload ?? {}) as Record<string, unknown>,
    sourceRunId: r.sourceRunId,
    createdAt: r.createdAt,
  };
}

export async function writeRow(input: WriteRowInput): Promise<{ id: string }> {
  if (!input.capabilityId) {
    throw new Error("data-foundation/writeRow: capabilityId required");
  }
  if (!input.kind) {
    throw new Error("data-foundation/writeRow: kind required");
  }
  const id = newId("cdf");
  const row: InsertCapabilityDataFoundationRow = {
    id,
    capabilityId: input.capabilityId,
    kind: input.kind,
    payload: input.payload,
    sourceRunId: input.sourceRunId ?? null,
  };
  await db.insert(capabilityDataFoundation).values(row);
  return { id };
}

export async function readRows(
  query: ReadRowsQuery,
): Promise<DataFoundationRow[]> {
  const limit = Math.min(Math.max(query.limit ?? 50, 1), 500);
  const conds = [];
  if (query.excludeSelf) {
    // 反模式:excludeSelf + capabilityId 同时给:本意是"排除自己读自己的行"
    // 但 capabilityId 是必填,所以这里其实排除其它 capability 的行=空集。
    // 真正的"排除调用方自己"在 B7 inner-loop search 里实现(用 NOT 等),
    // 本骨架只 throw 提示调用方语义不对。
    throw new Error(
      "data-foundation/readRows: excludeSelf is reserved for B7 inner-loop search " +
        "and is not yet implemented; pass capabilityId only to read own rows.",
    );
  }
  if (query.kind) {
    conds.push(
      and(
        eq(capabilityDataFoundation.capabilityId, query.capabilityId),
        eq(capabilityDataFoundation.kind, query.kind),
      ),
    );
  } else {
    conds.push(eq(capabilityDataFoundation.capabilityId, query.capabilityId));
  }
  const rows = await db
    .select()
    .from(capabilityDataFoundation)
    .where(conds[0])
    .orderBy(desc(capabilityDataFoundation.createdAt))
    .limit(limit);
  return rows.map(rowToOutput);
}