import {
  PoorlyFormattedDidError,
  UnsupportedDidWebPathError,
} from '../errors.js'
import { DidCache } from '../types.js'
import { BaseResolver } from './base-resolver.js'
import { timed } from './util.js'

export const DOC_PATH = '/.well-known/did.json'

export class DidWebResolver extends BaseResolver {
  constructor(
    public timeout: number,
    public cache?: DidCache,
  ) {
    super(cache)
  }

  async resolveNoCheck(did: string): Promise<unknown> {
    const parsedId = did.split(':').slice(2).join(':')
    const parts = parsedId.split(':').map(decodeURIComponent)
    let path: string
    if (parts.length < 1) {
      throw new PoorlyFormattedDidError(did)
    } else if (parts.length === 1) {
      path = parts[0] + DOC_PATH
    } else {
      // how we *would* resolve a did:web with path, if atproto supported it
      //path = parts.join('/') + '/did.json'
      throw new UnsupportedDidWebPathError(did)
    }

    const url = new URL(`https://${path}`)
    if (url.hostname === 'localhost') {
      url.protocol = 'http'
    }

    return timed(this.timeout, async (signal) => {
      const res = await fetch(url, {
        signal,
        redirect: 'error',
        headers: { accept: 'application/did+ld+json,application/json' },
      })

      // Positively not found, versus due to e.g. network error
      if (!res.ok) return null

      return res.json()
    })
  }
}