import { dirname } from "node:path";
import type { DB, Kysely } from "@umt/db";
import { sql } from "@umt/db";

// 运维一次性子命令(备份/恢复脚本调用):映射清单导出、恢复后打开只读对账。
// 映射清单是"路径不携带完整身份"前提下的关键资产(需求 §8.5):数据库之外再留一份可读 JSON,
// 用于人工核对与恢复演练的行数校验;不含任何密钥(secret 表只随 pg_dump 走,主密钥永不入备份)。

/** 各表导出的关键列 */
export const MAPPING_TABLES = {
  library_root: ["id", "name", "media_kind", "local_path", "management_mode", "enabled", "sentinel_file"],
  path_mapping: [
    "id",
    "view_kind",
    "downloader_instance_id",
    "media_server_instance_id",
    "library_root_id",
    "remote_prefix",
    "local_prefix",
    "priority",
    "enabled",
  ],
  media_entity: ["id", "kind", "title", "original_title", "year", "status", "merged_into_id", "updated_at"],
  external_identity: [
    "id",
    "media_entity_id",
    "content_unit_id",
    "provider",
    "entity_type",
    "external_id",
    "status",
    "evidence_level",
    "locked",
    "revision",
  ],
  path_binding: [
    "id",
    "media_entity_id",
    "content_unit_id",
    "season_number",
    "binding_kind",
    "library_root_id",
    "relative_path",
    "template_version",
    "status",
    "superseded_by_id",
  ],
  asset_location: [
    "id",
    "media_asset_id",
    "location_kind",
    "library_root_id",
    "downloader_instance_id",
    "relative_path",
    "status",
    "is_primary",
    "size_bytes",
    "inode",
    "device",
    "mtime",
  ],
  acquisition_slot: [
    "id",
    "media_entity_id",
    "content_unit_id",
    "subscription_id",
    "policy_revision_id",
    "name",
    "status",
    "current_asset_id",
    "revision",
  ],
  organization_record: [
    "id",
    "media_entity_id",
    "content_unit_id",
    "download_task_id",
    "source_downloader_instance_id",
    "source_path",
    "target_library_root_id",
    "target_path",
    "action",
    "status",
    "plan_fingerprint",
    "finished_at",
  ],
} as const satisfies Partial<Record<keyof DB, readonly string[]>>;

export type MappingTable = keyof typeof MAPPING_TABLES;

export interface MappingExport {
  format: "umt-mappings/1";
  exportedAt: string;
  appVersion: string;
  counts: Record<MappingTable, number>;
  tables: Record<MappingTable, Record<string, unknown>[]>;
}

/** 按主键顺序导出映射清单 */
export async function exportMappings(db: Kysely<DB>, appVersion: string): Promise<MappingExport> {
  const counts = {} as Record<MappingTable, number>;
  const tables = {} as Record<MappingTable, Record<string, unknown>[]>;
  for (const [table, cols] of Object.entries(MAPPING_TABLES) as [MappingTable, readonly string[]][]) {
    const { rows } = await sql<
      Record<string, unknown>
    >`select ${sql.join(cols.map((c) => sql.ref(c)))} from ${sql.table(table)} order by id`.execute(db);
    tables[table] = rows;
    counts[table] = rows.length;
  }
  return { format: "umt-mappings/1", exportedAt: new Date().toISOString(), appVersion, counts, tables };
}

/** 写 JSON(先写临时文件再改名,避免半截文件) */
export async function writeMappingExport(path: string, data: MappingExport): Promise<void> {
  await Deno.mkdir(dirname(path), { recursive: true });
  const tmp = `${path}.partial`;
  await Deno.writeTextFile(tmp, `${JSON.stringify(data, null, 2)}\n`);
  await Deno.rename(tmp, path);
}

/** 两份清单逐表比行数,返回不一致的表 */
export function diffCounts(
  expected: Record<string, number>,
  actual: Record<string, number>,
): Array<{ table: string; expected: number; actual: number }> {
  const out: Array<{ table: string; expected: number; actual: number }> = [];
  for (const table of new Set([...Object.keys(expected), ...Object.keys(actual)])) {
    const e = expected[table] ?? -1;
    const a = actual[table] ?? -1;
    if (e !== a) out.push({ table, expected: e, actual: a });
  }
  return out;
}

/** 打开 automation.readOnlyReconcile(保留该分组其它字段)并写审计 */
export async function enableReadOnlyReconcile(db: Kysely<DB>, reason: string): Promise<void> {
  await db.transaction().execute(async (trx) => {
    await sql`insert into settings (key, value, updated_at)
      values ('automation', ${JSON.stringify({ readOnlyReconcile: true })}::jsonb, now())
      on conflict (key) do update set value = settings.value || excluded.value, updated_at = now()`.execute(trx);
    await trx
      .insertInto("audit_event")
      .values({
        actor_type: "system",
        actor_id: "restore",
        action: "ops.read_only_reconcile_on",
        target_type: "settings",
        target_id: "automation",
        payload: JSON.stringify({ reason }),
      })
      .execute();
  });
}