import "server-only";

import os from "node:os";
import path from "node:path";
import { promises as fs } from "node:fs";

const PSD_LOCAL_CACHE_ROOT = path.join(
  process.env.AGENT_PSD_LOCAL_CACHE_DIR || os.tmpdir(),
  "agent-psd-cache"
);

function sanitizePathSegment(value: string, fallback: string) {
  const normalized = String(value || "")
    .trim()
    .replace(/[^a-zA-Z0-9_-]/g, "-")
    .replace(/-+/g, "-")
    .replace(/^-+|-+$/g, "");

  return normalized || fallback;
}

function normalizeTemplateExtension(fileName: string) {
  const normalized = String(fileName || "").trim().toLowerCase();
  if (normalized.endsWith(".psb")) {
    return "psb";
  }
  return "psd";
}

function toBuffer(value: ArrayBuffer | Buffer) {
  if (Buffer.isBuffer(value)) {
    return value;
  }

  return Buffer.from(value);
}

export function resolveAgentPsdLocalCachePath(params: {
  templateId: string;
  fileName?: string | null;
}) {
  const templateId = sanitizePathSegment(params.templateId, "template");
  const extension = normalizeTemplateExtension(String(params.fileName || ""));
  return path.join(PSD_LOCAL_CACHE_ROOT, `${templateId}.${extension}`);
}

export async function cacheAgentPsdSourceLocally(params: {
  templateId: string;
  fileName?: string | null;
  buffer: ArrayBuffer | Buffer;
}) {
  const localFilePath = resolveAgentPsdLocalCachePath({
    templateId: params.templateId,
    fileName: params.fileName,
  });
  await fs.mkdir(path.dirname(localFilePath), { recursive: true });
  await fs.writeFile(localFilePath, toBuffer(params.buffer));
  return localFilePath;
}

export async function readAgentPsdSourceFromLocalCache(params: {
  templateId: string;
  fileName?: string | null;
}) {
  return fs.readFile(
    resolveAgentPsdLocalCachePath({
      templateId: params.templateId,
      fileName: params.fileName,
    })
  );
}

export async function hasAgentPsdLocalCache(params: {
  templateId: string;
  fileName?: string | null;
}) {
  try {
    await fs.access(
      resolveAgentPsdLocalCachePath({
        templateId: params.templateId,
        fileName: params.fileName,
      })
    );
    return true;
  } catch {
    return false;
  }
}

export async function deleteAgentPsdLocalCache(params: {
  templateId: string;
  fileName?: string | null;
}) {
  const localFilePath = resolveAgentPsdLocalCachePath({
    templateId: params.templateId,
    fileName: params.fileName,
  });
  await fs.rm(localFilePath, { force: true });
}