import { openSync, readSync, closeSync } from 'node:fs'
import { execFile } from 'node:child_process'
import { promisify } from 'node:util'
import { getClip, getStill, clipVideoPath, stillPath } from '../library'
import { imageDimensions } from '../resolution'
import { resolveSize } from '~/shared/studio2/input.mjs'
const exec = promisify(execFile)

function readImageHeader(path: string, maxBytes = 65536) {
  const fd = openSync(path, 'r')
  try {
    const buf = Buffer.alloc(maxBytes)
    const n = readSync(fd, buf, 0, maxBytes, 0)
    return buf.subarray(0, n)
  } finally {
    closeSync(fd)
  }
}

export async function resolveRequestSize(owner: string, request: any) {
  const video = ['video', 'extend'].includes(request.mode)
  let dimensions: any
  if (video && request.startClipId) {
    const clip = getClip(owner, request.startClipId)
    if (clip.width && clip.height) {
      dimensions = { width: clip.width, height: clip.height }
    } else {
      const result = await exec('ffprobe', ['-v', 'error', '-select_streams', 'v:0', '-show_entries', 'stream=width,height', '-of', 'json', clipVideoPath(owner, request.startClipId)], { windowsHide: true, timeout: 15000 })
      dimensions = JSON.parse(result.stdout).streams?.[0]
    }
  } else {
    const id = request.imageAId || request.identityStillId
    if (id) {
      const still = getStill(owner, id)
      if (still.width && still.height) {
        dimensions = { width: still.width, height: still.height }
      } else {
        // Header only — never read the full archive PNG into memory on Generate click
        dimensions = imageDimensions(readImageHeader(stillPath(owner, id)))
      }
      if (!dimensions) throw new Error('Cannot measure the source still.')
    }
  }
  if (video && request.startClipId && !dimensions?.width) throw new Error('Cannot measure the previous clip.')
  Object.assign(request.settings, resolveSize(request.settings.aspect, dimensions, undefined, request.engine))
}