import { format, parseISO } from "date-fns"
import type { AssetResponse } from "./types"

export interface DateGroup {
  date: string
  label: string
  assets: AssetResponse[]
}

export function getPhotoDate(asset: AssetResponse): Date {
  const dto = asset.metadata?.DateTimeOriginal as string | undefined
  if (dto) {
    const parsed = new Date(dto.replace(" ", "T"))
    if (!isNaN(parsed.getTime())) return parsed
  }
  return parseISO(asset.created_at)
}

export function groupByDate(assets: AssetResponse[]): DateGroup[] {
  const map = new Map<string, AssetResponse[]>()

  for (const asset of assets) {
    const d = getPhotoDate(asset)
    const key = format(d, "yyyy-MM-dd")
    const group = map.get(key)
    if (group) group.push(asset)
    else map.set(key, [asset])
  }

  return Array.from(map.entries()).map(([date, assets]) => ({
    date,
    label: format(parseISO(date), "MMMM d, yyyy"),
    assets,
  }))
}