import {
  S3Client,
  PutObjectCommand,
  GetObjectCommand,
  ListObjectsV2Command,
  DeleteObjectCommand,
} from "npm:@aws-sdk/client-s3@3";
import { mkdir, readFile, writeFile } from "node:fs/promises";
import { dirname, join } from "node:path";
import { config, DATA_DIR } from "./config.ts";

/**
 * Almacenamiento de archivos (Fase 4c): expedientes cifrados, PDFs de
 * gafetes, logos. Antes vivían en el volumen local (panel-data) -- un
 * volumen local no se comparte entre réplicas ni microservicios, así que
 * es el mismo cuello de botella que motivó salir de SQLite, solo que en
 * otra capa. El contenido YA viene cifrado con AES-GCM (docs_crypto.ts)
 * antes de llegar aquí -- el bucket nunca ve texto plano.
 *
 * Backend real: S3-compatible (Cloudflare R2). Si no hay credenciales S3
 * (dev local), cae a disco bajo DATA_DIR. En staging/producción el volumen
 * local no escala: hay que configurar S3_*.
 */

let client: S3Client | null = null;

export function s3Configured(): boolean {
  return !!(config.s3Endpoint && config.s3Bucket && config.s3AccessKeyId && config.s3SecretAccessKey);
}

export type StoragePing = {
  configured: boolean;
  ok: boolean;
  backend: "s3" | "local";
  error?: string;
};

function s3Err(e: unknown): string {
  if (e && typeof e === "object") {
    const o = e as {
      name?: string;
      message?: string;
      Code?: string;
      $metadata?: { httpStatusCode?: number };
    };
    return [o.name, o.Code, o.$metadata?.httpStatusCode, o.message].filter(Boolean).join(": ");
  }
  return String(e);
}

/**
 * R2: HeadBucket suele dar 403 con token de Account API acotado al bucket.
 * ListObjectsV2 (o un put/get sonda) es lo que realmente usamos en runtime.
 */
export async function pingStorage(): Promise<StoragePing> {
  if (!s3Configured()) {
    try {
      await mkdir(join(DATA_DIR, "local-objects"), { recursive: true });
      return { configured: false, ok: true, backend: "local" };
    } catch (e) {
      return { configured: false, ok: false, backend: "local", error: s3Err(e) };
    }
  }
  try {
    await getClient().send(
      new ListObjectsV2Command({ Bucket: config.s3Bucket, MaxKeys: 1 }),
    );
    return { configured: true, ok: true, backend: "s3" };
  } catch (listErr) {
    try {
      await probeStorageReadWrite();
      return { configured: true, ok: true, backend: "s3" };
    } catch (writeErr) {
      const error = `list=${s3Err(listErr)}; write=${s3Err(writeErr)}`;
      console.error(
        "[storage] ping failed",
        error,
        "endpoint=",
        config.s3Endpoint,
        "bucket=",
        config.s3Bucket,
        "region=",
        config.s3Region,
      );
      return { configured: true, ok: false, backend: "s3", error };
    }
  }
}

/** Put + get + delete de un objeto sonda. No dejar basura en el bucket. */
export async function probeStorageReadWrite(): Promise<void> {
  const key = `_panels/connectivity-probe-${crypto.randomUUID()}`;
  const payload = new TextEncoder().encode("panels-connectivity-probe");
  await putObject(key, payload);
  const got = await getObject(key);
  if (new TextDecoder().decode(got) !== "panels-connectivity-probe") {
    throw new Error("El objeto sonda no coincide con lo escrito");
  }
  if (s3Configured()) {
    await getClient().send(new DeleteObjectCommand({ Bucket: config.s3Bucket, Key: key }));
  }
}

function getClient(): S3Client {
  if (!client) {
    client = new S3Client({
      endpoint: config.s3Endpoint,
      region: config.s3Region || "auto",
      forcePathStyle: true,
      // R2 no implementa los checksums CRC32 que el SDK v3 manda por defecto.
      requestChecksumCalculation: "WHEN_REQUIRED",
      responseChecksumValidation: "WHEN_REQUIRED",
      credentials: {
        accessKeyId: config.s3AccessKeyId,
        secretAccessKey: config.s3SecretAccessKey,
      },
    });
  }
  return client;
}

async function streamToUint8Array(body: unknown): Promise<Uint8Array> {
  const chunks: Uint8Array[] = [];
  // deno-lint-ignore no-explicit-any
  for await (const chunk of body as any) {
    chunks.push(chunk instanceof Uint8Array ? chunk : new Uint8Array(chunk));
  }
  const total = chunks.reduce((n, c) => n + c.length, 0);
  const out = new Uint8Array(total);
  let offset = 0;
  for (const c of chunks) {
    out.set(c, offset);
    offset += c.length;
  }
  return out;
}

export async function putObject(key: string, bytes: Uint8Array): Promise<void> {
  if (s3Configured()) {
    await getClient().send(
      new PutObjectCommand({ Bucket: config.s3Bucket, Key: key, Body: bytes }),
    );
    return;
  }
  const path = join(DATA_DIR, "local-objects", key);
  await mkdir(dirname(path), { recursive: true });
  await writeFile(path, bytes);
}

export async function getObject(key: string): Promise<Uint8Array> {
  if (s3Configured()) {
    const res = await getClient().send(
      new GetObjectCommand({ Bucket: config.s3Bucket, Key: key }),
    );
    return await streamToUint8Array(res.Body);
  }
  const path = join(DATA_DIR, "local-objects", key);
  return await readFile(path);
}

export async function deleteObject(key: string): Promise<void> {
  if (s3Configured()) {
    await getClient().send(
      new DeleteObjectCommand({ Bucket: config.s3Bucket, Key: key }),
    );
    return;
  }
  const path = join(DATA_DIR, "local-objects", key);
  try {
    const { unlink } = await import("node:fs/promises");
    await unlink(path);
  } catch (e) {
    if ((e as NodeJS.ErrnoException)?.code !== "ENOENT") throw e;
  }
}

// --- Convenciones de key por dominio (equivalentes a los antiguos
// workerDir/projectDir/companyDir + Deno.readFile/writeFile) ---
export function workerDocKey(workerId: number, storageName: string): string {
  return `expedientes/${workerId}/${storageName}`;
}
export function projectDocKey(projectId: number, storageName: string): string {
  return `proyectos/${projectId}/${storageName}`;
}
export function companyDocKey(companyId: number, storageName: string): string {
  return `empresas/${companyId}/${storageName}`;
}
export function badgeJobPdfKey(jobId: number): string {
  return `pdfs/gafetes-${jobId}.pdf`;
}
export function loanReceiptPdfKey(loanId: number, weekId: number): string {
  return `pdfs/prestamo-${loanId}-semana-${weekId}.pdf`;
}
export function expenseDocKey(expenseId: number, storageName: string): string {
  return `expenses/${expenseId}/${storageName}`;
}
export function projectLogoKey(projectId: number, side: "left" | "right", ext: string): string {
  return `logos/${projectId}-${side}.${ext}`;
}