// 复刻后端 yuxi/utils/subagent_thread_utils.py 的 make_child_thread_id：
// child_thread_id = "subagent_" + sha256("{parent}:{slug}:{tool_call_id}")[:55]
// 子智能体由 graph.ainvoke 独立调用，流式事件不带 tool_call_id，前端据此自行推算 child_thread_id。
const PREFIX = 'subagent_'
const DIGEST_LENGTH = 64 - PREFIX.length

const SHA256_K = [
  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
  0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
  0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
  0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
  0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
  0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
  0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
  0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
]

const rightRotate = (value, shift) => ((value >>> shift) | (value << (32 - shift))) >>> 0

const bytesToHex = (bytes) =>
  Array.from(bytes)
    .map((byte) => byte.toString(16).padStart(2, '0'))
    .join('')

const sha256Hex = (bytes) => {
  const paddedLength = Math.ceil((bytes.length + 9) / 64) * 64
  const padded = new Uint8Array(paddedLength)
  padded.set(bytes)
  padded[bytes.length] = 0x80

  const view = new DataView(padded.buffer)
  const bitLength = bytes.length * 8
  view.setUint32(paddedLength - 8, Math.floor(bitLength / 0x100000000))
  view.setUint32(paddedLength - 4, bitLength >>> 0)

  const words = new Uint32Array(64)
  const hash = [
    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
  ]

  for (let offset = 0; offset < paddedLength; offset += 64) {
    for (let index = 0; index < 16; index += 1) {
      words[index] = view.getUint32(offset + index * 4)
    }
    for (let index = 16; index < 64; index += 1) {
      const s0 =
        rightRotate(words[index - 15], 7) ^
        rightRotate(words[index - 15], 18) ^
        (words[index - 15] >>> 3)
      const s1 =
        rightRotate(words[index - 2], 17) ^
        rightRotate(words[index - 2], 19) ^
        (words[index - 2] >>> 10)
      words[index] = (words[index - 16] + s0 + words[index - 7] + s1) >>> 0
    }

    let [a, b, c, d, e, f, g, h] = hash
    for (let index = 0; index < 64; index += 1) {
      const s1 = rightRotate(e, 6) ^ rightRotate(e, 11) ^ rightRotate(e, 25)
      const ch = (e & f) ^ (~e & g)
      const temp1 = (h + s1 + ch + SHA256_K[index] + words[index]) >>> 0
      const s0 = rightRotate(a, 2) ^ rightRotate(a, 13) ^ rightRotate(a, 22)
      const maj = (a & b) ^ (a & c) ^ (b & c)
      const temp2 = (s0 + maj) >>> 0

      h = g
      g = f
      f = e
      e = (d + temp1) >>> 0
      d = c
      c = b
      b = a
      a = (temp1 + temp2) >>> 0
    }

    hash[0] = (hash[0] + a) >>> 0
    hash[1] = (hash[1] + b) >>> 0
    hash[2] = (hash[2] + c) >>> 0
    hash[3] = (hash[3] + d) >>> 0
    hash[4] = (hash[4] + e) >>> 0
    hash[5] = (hash[5] + f) >>> 0
    hash[6] = (hash[6] + g) >>> 0
    hash[7] = (hash[7] + h) >>> 0
  }

  return hash.map((word) => word.toString(16).padStart(8, '0')).join('')
}

const digestSha256Hex = async (bytes) => {
  const subtle = globalThis.crypto?.subtle
  if (typeof subtle?.digest === 'function') {
    const buffer = await subtle.digest('SHA-256', bytes)
    return bytesToHex(new Uint8Array(buffer))
  }
  return sha256Hex(bytes)
}

export async function makeChildThreadId(parentThreadId, agentSlug, toolCallId) {
  if (!parentThreadId || !agentSlug || !toolCallId) return ''
  const data = new TextEncoder().encode(`${parentThreadId}:${agentSlug}:${toolCallId}`)
  const hex = await digestSha256Hex(data)
  return `${PREFIX}${hex.slice(0, DIGEST_LENGTH)}`
}