import { mkdtempSync, writeFileSync, readFileSync, rmSync } from 'node:fs'
import { join } from 'node:path'
import { tmpdir } from 'node:os'
import { runFfmpeg } from '../ffmpeg'
import { imageDimensions } from '../resolution'
export async function fitStill(data: Buffer, width: number, height: number) {
  const dir=mkdtempSync(join(tmpdir(),'studio2-fit-'))
  try {
    const input=join(dir,'source'),output=join(dir,'fitted.png')
    writeFileSync(input,data)
    await runFfmpeg(['-y','-i',input,'-vf',`scale=${width}:${height}:force_original_aspect_ratio=decrease,pad=${width}:${height}:(ow-iw)/2:(oh-ih)/2:color=black,setsar=1`,'-frames:v','1',output])
    return readFileSync(output)
  } finally { rmSync(dir,{recursive:true,force:true}) }
}
/** Only skip the scale+pad when the still already matches the job canvas pixel-for-pixel.
 * A same-aspect-but-larger still (e.g. a 4032x2268 phone photo against a 1344x768 canvas)
 * still needs fitting: MiniMaxH3AddGuide expects an image sized to the job's own latent,
 * not merely the same aspect ratio. Unreadable dimensions always fit (safe default). */
export function needsFit(data: Buffer, width: number, height: number) {
  const size = imageDimensions(data)
  if (!size?.width || !size?.height) return true
  return !(size.width === width && size.height === height)
}