/**
 * Recovery export functions for replicated atproto account data.
 *
 * Provides CAR file export (for repo import to a new PDS) and blob
 * export for disaster recovery scenarios.
 */

import { BlockMap, blocksToCarFile } from "@atproto/repo";
import { CID } from "@atproto/lex-data";
import type { SyncStorage } from "./sync-storage.js";
import type { BlockStore } from "../ipfs.js";

/**
 * Assemble a CAR v1 file from all replicated blocks for a DID.
 *
 * Uses @atproto/repo's blocksToCarFile which produces spec-compliant
 * CAR v1 with the commit root as the single root CID.
 *
 * Returns null if the DID has no sync state or root CID.
 */
export async function exportRepoAsCar(
	did: string,
	syncStorage: SyncStorage,
	blockStore: BlockStore,
): Promise<{ car: Uint8Array; rootCid: string; blockCount: number } | null> {
	const state = syncStorage.getState(did);
	if (!state?.rootCid) return null;

	const blockCids = syncStorage.getBlockCids(did);
	const blocks = new BlockMap();
	let blockCount = 0;

	for (const cidStr of blockCids) {
		const bytes = await blockStore.getBlock(cidStr);
		if (bytes) {
			blocks.set(CID.parse(cidStr), bytes);
			blockCount++;
		}
	}

	if (blockCount === 0) return null;

	const root = CID.parse(state.rootCid);
	const car = await blocksToCarFile(root, blocks);

	return { car, rootCid: state.rootCid, blockCount };
}

/**
 * Export all blob bytes for a DID.
 *
 * Returns an array of { cid, bytes } for every tracked blob CID
 * that has data in the blockstore. Blobs without data are skipped.
 */
export async function exportBlobs(
	did: string,
	syncStorage: SyncStorage,
	blockStore: BlockStore,
): Promise<Array<{ cid: string; bytes: Uint8Array }>> {
	const blobCids = syncStorage.getBlobCids(did);
	const results: Array<{ cid: string; bytes: Uint8Array }> = [];

	for (const cid of blobCids) {
		const bytes = await blockStore.getBlock(cid);
		if (bytes) {
			results.push({ cid, bytes });
		}
	}

	return results;
}