import { loadEnv } from "../../config/env.js";
import type { S3Client, S3Config } from "@factory/storage";
import { S3Client as StorageClient } from "@factory/storage";
import { m } from "@factory/observability";

/**
 * TASK-0101 — S3 client factory (consolidated on `@factory/storage`).
 *
 * The previous `s3-presign.ts` (a local SigV4 signer + single-bucket
 * config) is DELETED: presigning now lives in `packages/storage`
 * (query-string SigV4, `presignPut`/`presignGet`) and bucket config comes
 * from the spec env pair `S3_BUCKET_FILES` / `S3_BUCKET_THUMBS`
 * (`S3_BUCKET` remains a legacy alias for the files bucket — AGENTS.md 6).
 *
 * Decision record: the API talks to the storage layer ONLY through
 * `@factory/storage` (client + presign + keys + mime) — no second SigV4
 * implementation in the app tree.
 */

export type FilesS3 = Pick<
  S3Client,
  | "headObject"
  | "readPrefix"
  | "getObject"
  | "deleteObject"
  | "listObjects"
  | "putObject"
>;

/** Config for the uploaded-objects bucket (files). */
export function filesBucketConfig(env = loadEnv()): S3Config {
  return {
    endpoint: env.S3_ENDPOINT.replace(/\/+$/, ""),
    region: env.S3_REGION,
    bucket: env.S3_BUCKET_FILES || env.S3_BUCKET,
    accessKeyId: env.S3_ACCESS_KEY,
    secretAccessKey: env.S3_SECRET_KEY,
    forcePathStyle: true,
  };
}

/** Config for the thumbnails bucket. */
export function thumbsBucketConfig(env = loadEnv()): S3Config {
  return {
    endpoint: env.S3_ENDPOINT.replace(/\/+$/, ""),
    region: env.S3_REGION,
    bucket: env.S3_BUCKET_THUMBS,
    accessKeyId: env.S3_ACCESS_KEY,
    secretAccessKey: env.S3_SECRET_KEY,
    forcePathStyle: true,
  };
}

/** Signed-URL lifetime (seconds) — spec default 900. */
export function signExpirySeconds(env = loadEnv()): number {
  return env.S3_SIGN_EXPIRY_SECONDS;
}

/**
 * TASK-0135: the spec's storage metrics (`storage_ops_total` /
 * `storage_op_duration_seconds`, op = put|get|delete|head|list).
 *
 * Central, not per-call-site: `@factory/storage`'s S3Client already invokes an
 * `onRequest` observability hook around EVERY actual S3 REST request (the
 * hook is called once BEFORE and once AFTER the fetch — only the call with a
 * numeric `durationMs` is a completion). We map the S3 REST verb to the spec's
 * op label (a path-style LIST has no key → `list`; GET/PUT/DELETE/HEAD on a
 * key → get/put/delete/head) and record once per completion. No-op when OTel
 * is disabled (the instruments are no-op). Presigning (`presignPut`/`presignGet`)
 * is local URL construction — it performs no S3 request, so it is NOT counted
 * as an op (recorded decision).
 */
function storageMetricsHook(info: {
  method: string;
  url: string;
  status?: number;
  ok?: boolean;
  durationMs?: number;
}): void {
  if (info.durationMs === undefined) return; // the pre-request call — no duration yet
  const u = new URL(info.url);
  // LIST is a bucket-level GET carrying `list-type=2` (see S3Client.listObjects)
  // — a plain GET on a key is an object download (get), even though object
  // keys contain slashes. PUT/DELETE/HEAD are unambiguous.
  const op =
    info.method === "PUT"
      ? "put"
      : info.method === "DELETE"
        ? "delete"
        : info.method === "HEAD"
          ? "head"
          : u.searchParams.has("list-type")
            ? "list"
            : "get";
  m.storage.op({ op }, info.durationMs / 1000);
}

/** A fresh files-bucket client per call is cheap (stateless); DI-friendly. */
export function makeFilesClient(env = loadEnv()): S3Client {
  return new StorageClient({ config: filesBucketConfig(env), onRequest: storageMetricsHook });
}

/** A fresh thumbs-bucket client. */
export function makeThumbsClient(env = loadEnv()): S3Client {
  return new StorageClient({ config: thumbsBucketConfig(env), onRequest: storageMetricsHook });
}

/**
 * Delete every object under `prefix` (list-then-delete, paginated past the
 * 1000-key cap). Best-effort per key (a per-key delete failure does not abort
 * the sweep — the orphan sweeper backstops any leak). Returns the number of
 * keys deleted.
 *
 * TASK-0104: `File.thumbnailKey` records ONE artifact (the 480 variant), but a
 * file can own SEVERAL thumbnail objects (160/480/1280 for an image, a first-
 * page/frame for pdf/video, under `thumbs/{ws}/{fileId}/{size}/…`). Purge must
 * remove the WHOLE set (spec §3 "…+ thumbnails + DB rows"), not just the single
 * recorded key — otherwise the other variants become orphans.
 */
export async function deletePrefix(s3: S3Client, prefix: string): Promise<number> {
  let deleted = 0;
  let token: string | undefined;
  for (;;) {
    const page = await s3.listObjects(prefix, 1000, token);
    for (const key of page.keys) {
      await s3.deleteObject(key).catch(() => undefined);
      deleted += 1;
    }
    if (!page.truncated || !page.nextToken) break;
    token = page.nextToken;
  }
  return deleted;
}