import { invoke } from '@tauri-apps/api/core';
import { listen } from '@tauri-apps/api/event';
import { BaseExtension, events } from '@janhq/core';

export enum Settings {
  hfToken = 'hf-token',
}

interface DownloadItem {
  url: string
  save_path: string
}

type DownloadEvent = {
  transferred: number
  total: number
}

export default class DownloadManager extends BaseExtension {
  hfToken?: string

  async onLoad() {
    this.registerSettings(SETTINGS)
    this.hfToken = await this.getSetting<string>(Settings.hfToken, undefined)
  }

  async onUnload() { }

  async downloadFile(
    url: string,
    savePath: string,
    taskId: string,
    onProgress?: (transferred: number, total: number) => void
  ) {
    return await this.downloadFiles(
      [{ url, save_path: savePath }],
      taskId,
      onProgress
    )
  }

  async downloadFiles(
    items: DownloadItem[],
    taskId: string,
    onProgress?: (transferred: number, total: number) => void
  ) {
    // relay tauri events to onProgress callback
    const unlisten = await listen<DownloadEvent>(`download-${taskId}`, (event) => {
      if (onProgress) {
        let payload = event.payload
        onProgress(payload.transferred, payload.total)
      }
    })

    try {
      await invoke<void>(
        "download_files",
        { items, taskId, headers: this._getHeaders() },
      )
    } catch (error) {
      console.error("Error downloading task", taskId, error)
      throw error
    } finally {
      unlisten()
    }
  }

  async cancelDownload(taskId: string) {
    try {
      await invoke<void>("cancel_download_task", { taskId })
    } catch (error) {
      console.error("Error cancelling download:", error)
      throw error
    }
  }

  _getHeaders() {
    return {
      ...(this.hfToken && { Authorization: `Bearer ${this.hfToken}` })
    }
  }
}