export {}
declare const self: {
  onmessage: ((e: MessageEvent) => void) | null
  postMessage: (message: unknown) => void
}

self.onmessage = async (e: MessageEvent) => {
  const file = e.data.file as File
  try {
    // Read entire file into ArrayBuffer (with progress reporting)
    const CHUNK_READ_SIZE = 16 * 1024 * 1024 // 16MB chunks for progress reporting
    const buffer = new ArrayBuffer(file.size)
    const view = new Uint8Array(buffer)
    let offset = 0

    while (offset < file.size) {
      const end = Math.min(offset + CHUNK_READ_SIZE, file.size)
      const slice = file.slice(offset, end)
      const chunkBuffer = await slice.arrayBuffer()
      view.set(new Uint8Array(chunkBuffer), offset)
      offset = end
      self.postMessage({ progress: offset / file.size })
    }

    // Compute SHA256 on entire buffer at once
    const hashBuffer = await crypto.subtle.digest('SHA-256', buffer)
    const hashArray = Array.from(new Uint8Array(hashBuffer))
    const sha256 = hashArray.map(b => b.toString(16).padStart(2, '0')).join('')

    self.postMessage({ sha256, progress: 1 })
  } catch (error) {
    self.postMessage({ error: error instanceof Error ? error.message : 'SHA256 computation failed' })
  }
}