"use client";

// Media (attachment) helpers over the be-crm data door (crm.media.*). The browser transfers bytes
// DIRECTLY to IIOS storage via the signed URLs — be-crm only mints them. Used by Messenger + Mail.

import { useCallback } from "react";
import { useAppShell } from "@abe-kap/appshell-sdk/react";

export interface UploadedAttachment { contentRef: string; mimeType: string; sizeBytes: number; filename: string }

export const MAX_ATTACHMENT_BYTES = 26 * 1024 * 1024; // matches IIOS's cap

export function isImage(mime?: string | null): boolean {
  return !!mime && mime.startsWith("image/");
}

// Some types (notably .md) have no OS-registered MIME, so the browser reports an empty file.type.
// Fall back to the extension for the text types IIOS allows, else a generic binary.
const EXT_MIME: Record<string, string> = {
  md: "text/markdown", markdown: "text/markdown",
  html: "text/html", htm: "text/html",
  txt: "text/plain", csv: "text/csv",
};
function mimeForFile(file: File): string {
  if (file.type) return file.type;
  const ext = file.name.toLowerCase().split(".").pop() ?? "";
  return EXT_MIME[ext] ?? "application/octet-stream";
}

/** Upload a File → { contentRef, mimeType, sizeBytes, filename }. Throws on oversize / failure. */
export function useUploadAttachment() {
  const { sdk } = useAppShell();
  return useCallback(async (file: File): Promise<UploadedAttachment> => {
    if (file.size > MAX_ATTACHMENT_BYTES) throw new Error("File is too large (max 25 MB).");
    const mime = mimeForFile(file);
    const { objectKey, uploadUrl } = (await sdk.command("crm.media.presignUpload", { mime, sizeBytes: file.size })) as { objectKey: string; uploadUrl: string };
    const res = await fetch(uploadUrl, { method: "PUT", body: file });
    if (!res.ok) throw new Error(`Upload failed (${res.status}).`);
    return { contentRef: objectKey, mimeType: mime, sizeBytes: file.size, filename: file.name };
  }, [sdk]);
}

/** Mint a short-lived signed URL to display/download an attachment by its contentRef. */
export function useDownloadUrl() {
  const { sdk } = useAppShell();
  return useCallback(async (contentRef: string, mime?: string): Promise<string> => {
    const { url } = (await sdk.command("crm.media.presignDownload", { contentRef, ...(mime ? { mime } : {}) })) as { url: string };
    return url;
  }, [sdk]);
}