import { FileExtensionRegex } from "../const"

/**
 * https://github.com/nostr-protocol/nips/blob/master/94.md impl
 */
export class Nip94 {
  static parse(tags: Array<Array<string>>) {
    return readNip94Tags(tags)
  }
}

export interface Nip94Tags {
  url?: string
  mimeType?: string
  hash?: string
  originalHash?: string
  size?: number
  dimensions?: [number, number]
  magnet?: string
  blurHash?: string
  thumb?: string
  image?: Array<string>
  summary?: string
  alt?: string
  fallback?: Array<string>
  duration?: number
  bitrate?: number
}

/**
 * Read NIP-94 tags from event tags
 */
export function readNip94Tags(tags: Array<Array<string>>) {
  const res: Nip94Tags = {}
  for (const tx of tags) {
    const [k, v] = tx as [string, string | undefined]
    if (v === undefined) continue
    switch (k) {
      case "url": {
        // if URL already set, treat next url as fallback
        if (res.url) {
          res.fallback ??= []
          res.fallback.push(v)
        } else {
          res.url = v
        }
        break
      }
      case "m": {
        res.mimeType = v
        break
      }
      case "x": {
        res.hash = v
        break
      }
      case "ox": {
        res.originalHash = v
        break
      }
      case "size": {
        res.size = Number(v)
        break
      }
      case "dim": {
        res.dimensions = v.split("x").map(Number) as [number, number]
        break
      }
      case "magnet": {
        res.magnet = v
        break
      }
      case "blurhash": {
        res.blurHash = v
        break
      }
      case "thumb": {
        res.thumb = v
        break
      }
      case "image": {
        res.image ??= []
        res.image.push(v)
        break
      }
      case "summary": {
        res.summary = v
        break
      }
      case "alt": {
        res.alt = v
        break
      }
      case "fallback": {
        res.fallback ??= []
        res.fallback.push(v)
        break
      }
      case "duration": {
        res.duration = Number(v)
        break
      }
      case "bitrate": {
        res.bitrate = Number(v)
        break
      }
    }
  }
  return res
}

export function addExtensionToNip94Url(meta: Nip94Tags) {
  if (!meta.url?.match(FileExtensionRegex) && meta.mimeType) {
    switch (meta.mimeType) {
      case "image/webp": {
        return `${meta.url}.webp`
      }
      case "image/jpeg":
      case "image/jpg": {
        return `${meta.url}.jpg`
      }
      case "video/mp4": {
        return `${meta.url}.mp4`
      }
    }
  }
  return meta.url
}