import {
  buildCsvDownloadItem,
  buildPngDownloadItem,
  type DownloadItem,
} from '../actions/download'
import type { PieWidgetData } from './types'

/**
 * Download menu items for the Pie widget. Always includes a CSV item with
 * `series, name, value` columns (one row per slice; series labels come from
 * `seriesNames` if provided, else `series_<n>`). When `getCaptureEl` is
 * supplied, prepends a PNG item that rasterises the captured element via
 * `html2canvas`.
 */
export function createPieDownloadConfig(args: {
  filename: string
  getData: () => PieWidgetData
  seriesNames?: readonly string[]
  getCaptureEl?: () => HTMLElement | null
  pngPixelRatio?: number
  pngBackgroundColor?: string | null
}): DownloadItem[] {
  const items: DownloadItem[] = []
  if (args.getCaptureEl) {
    items.push(
      buildPngDownloadItem({
        filename: args.filename,
        getCaptureEl: args.getCaptureEl,
        pixelRatio: args.pngPixelRatio,
        backgroundColor: args.pngBackgroundColor,
      }),
    )
  }
  items.push(
    buildCsvDownloadItem({
      filename: args.filename,
      getRows: () => {
        const data = args.getData()
        const rows: unknown[][] = [['series', 'name', 'value']]
        for (const [i, series] of data.entries()) {
          const seriesName = args.seriesNames?.[i] ?? `series_${i + 1}`
          for (const slice of series) {
            rows.push([seriesName, slice.name, slice.value])
          }
        }
        return rows
      },
    }),
  )
  return items
}