import { ATTACHMENTS_RUNTIME_DESCRIPTION } from "../../prompts/prompts.js";
import type { Attachment } from "../../utils/attachment-utils.js";
import type { SandboxRuntimeProvider } from "./SandboxRuntimeProvider.js";

/**
 * Attachments Runtime Provider
 *
 * OPTIONAL provider that provides file access APIs to sandboxed code.
 * Only needed when attachments are present.
 * Attachments are read-only snapshot data - no messaging needed.
 */
export class AttachmentsRuntimeProvider implements SandboxRuntimeProvider {
  constructor(private attachments: Attachment[]) {}

  getData(): Record<string, any> {
    const attachmentsData = this.attachments.map((a) => ({
      id: a.id,
      fileName: a.fileName,
      mimeType: a.mimeType,
      size: a.size,
      content: a.content,
      extractedText: a.extractedText,
    }));

    return { attachments: attachmentsData };
  }

  getRuntime(): (sandboxId: string) => void {
    // This function will be stringified, so no external references!
    // These functions read directly from window.attachments
    // Works both online AND offline (no messaging needed!)
    return (_sandboxId: string) => {
      (window as any).listAttachments = () =>
        ((window as any).attachments || []).map((a: any) => ({
          id: a.id,
          fileName: a.fileName,
          mimeType: a.mimeType,
          size: a.size,
        }));

      (window as any).readTextAttachment = (attachmentId: string) => {
        const a = ((window as any).attachments || []).find(
          (x: any) => x.id === attachmentId,
        );
        if (!a) throw new Error(`Attachment not found: ${attachmentId}`);
        if (a.extractedText) return a.extractedText;
        try {
          return atob(a.content);
        } catch {
          throw new Error(`Failed to decode text content for: ${attachmentId}`);
        }
      };

      (window as any).readBinaryAttachment = (attachmentId: string) => {
        const a = ((window as any).attachments || []).find(
          (x: any) => x.id === attachmentId,
        );
        if (!a) throw new Error(`Attachment not found: ${attachmentId}`);
        const bin = atob(a.content);
        const bytes = new Uint8Array(bin.length);
        for (let i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i);
        return bytes;
      };
    };
  }

  getDescription(): string {
    return ATTACHMENTS_RUNTIME_DESCRIPTION;
  }
}