import * as fs from 'fs/promises'
import * as path from 'path'
import ora from 'ora'
import { getCliClient } from '../cli-client.js'
import { resolveAsset, type RefsReader } from '../refs.js'
import { previewResult } from '../output.js'

export interface PreviewCommandOptions {
  unapproved?: boolean
  out?: string
  baseUrl?: string
}

export async function resolvePreviewRef(
  client: RefsReader,
  ref: string,
  includeUnapproved: boolean,
): Promise<{ name: string; version: string; previewUrl: string }> {
  const asset = await resolveAsset(client, ref, { includeUnapproved })
  if (!asset.previewUrl) {
    throw new Error(`Asset "${ref}" has no preview image`)
  }

  return { name: asset.name, version: asset.version, previewUrl: asset.previewUrl }
}

export async function previewCommand(ref: string, opts: PreviewCommandOptions): Promise<void> {
  const spinner = ora({
    text: `Resolving preview for ${ref}`,
    isEnabled: Boolean(process.stderr.isTTY),
    isSilent: !process.stderr.isTTY,
  }).start()

  try {
    const { client } = await getCliClient({ baseUrl: opts.baseUrl })
    const preview = await resolvePreviewRef(client.asset, ref, opts.unapproved ?? false)

    spinner.text = `Downloading preview for ${preview.name}@${preview.version}`
    const response = await fetch(preview.previewUrl)
    if (!response.ok) {
      throw new Error(`Failed to download preview (${response.status}) from ${preview.previewUrl}`)
    }
    const bytes = new Uint8Array(await response.arrayBuffer())
    const out = path.resolve(opts.out ?? `${preview.name}-preview.webp`)

    await fs.mkdir(path.dirname(out), { recursive: true })
    await fs.writeFile(out, bytes)

    spinner.stop()
    console.log(previewResult(preview.name, preview.version, out))
  } catch (err) {
    spinner.stop()
    throw err
  }
}