import type { Model } from "@earendil-works/pi-ai";
import {
  remoteIdentityMatches,
  supportsRemoteCompaction,
  type RemoteModelIdentity,
  type ResponseItem,
} from "./remote-compaction.ts";

export type JsonRecord = Record<string, unknown>;

export interface ActiveRemoteReplay {
  checkpointId: string;
  identity: RemoteModelIdentity;
  explicitHistory: ResponseItem[];
}

export function isJsonRecord(value: unknown): value is JsonRecord {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

function clone<T>(value: T): T {
  return JSON.parse(JSON.stringify(value)) as T;
}

export function rewriteProviderPayload(params: {
  payload: JsonRecord;
  model: Model<any>;
  active: ActiveRemoteReplay;
}): JsonRecord | undefined {
  if (!Array.isArray(params.payload.input)) return undefined;
  if (!supportsRemoteCompaction(params.model)) return undefined;
  if (!remoteIdentityMatches(params.active.identity, params.model)) return undefined;

  const next: JsonRecord = {
    ...params.payload,
    input: clone(params.active.explicitHistory),
    store: false,
  };
  delete next.messages;
  delete next.previous_response_id;
  return next;
}

export function extractRequestShape(payload: unknown): {
  reasoning?: Record<string, unknown>;
  text?: Record<string, unknown>;
} | undefined {
  if (!isJsonRecord(payload)) return undefined;
  const reasoning = isJsonRecord(payload.reasoning) ? clone(payload.reasoning) : undefined;
  const text = isJsonRecord(payload.text) ? clone(payload.text) : undefined;
  return { reasoning, text };
}