// ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========

import { toHex } from './hex.ts'

export async function sha256(bytes: Uint8Array): Promise<Uint8Array> {
  const digest = await crypto.subtle.digest('SHA-256', bytes as BufferSource)
  return new Uint8Array(digest)
}

export async function sha256Hex(bytes: Uint8Array): Promise<string> {
  return toHex(await sha256(bytes))
}

async function subtleHex(algo: AlgorithmIdentifier, bytes: Uint8Array): Promise<string> {
  const digest = await crypto.subtle.digest(algo, bytes as BufferSource)
  return toHex(new Uint8Array(digest))
}

export async function sha1Hex(bytes: Uint8Array): Promise<string> {
  return subtleHex('SHA-1', bytes)
}

export async function sha384Hex(bytes: Uint8Array): Promise<string> {
  return subtleHex('SHA-384', bytes)
}

export async function sha512Hex(bytes: Uint8Array): Promise<string> {
  return subtleHex('SHA-512', bytes)
}

const S = [
  7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14,
  20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6,
  10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21,
]

const K = [
  0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
  0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
  0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
  0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
  0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
  0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
  0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
  0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,
]

function rotl(x: number, n: number): number {
  return ((x << n) | (x >>> (32 - n))) >>> 0
}

export function md5(bytes: Uint8Array): Uint8Array {
  const len = bytes.byteLength
  const bitLen = len * 8
  const padLen = (len % 64 < 56 ? 56 : 120) - (len % 64)
  const total = len + padLen + 8
  const buf = new Uint8Array(total)
  buf.set(bytes)
  buf[len] = 0x80
  const view = new DataView(buf.buffer)
  view.setUint32(total - 8, bitLen >>> 0, true)
  view.setUint32(total - 4, Math.floor(bitLen / 0x100000000) >>> 0, true)

  let a0 = 0x67452301
  let b0 = 0xefcdab89
  let c0 = 0x98badcfe
  let d0 = 0x10325476

  const M = new Uint32Array(16)
  for (let off = 0; off < total; off += 64) {
    for (let j = 0; j < 16; j++) M[j] = view.getUint32(off + j * 4, true)
    let A = a0
    let B = b0
    let C = c0
    let D = d0
    for (let i = 0; i < 64; i++) {
      let F: number
      let g: number
      if (i < 16) {
        F = (B & C) | (~B & D)
        g = i
      } else if (i < 32) {
        F = (D & B) | (~D & C)
        g = (5 * i + 1) % 16
      } else if (i < 48) {
        F = B ^ C ^ D
        g = (3 * i + 5) % 16
      } else {
        F = C ^ (B | ~D)
        g = (7 * i) % 16
      }
      F = (F + A + (K[i] ?? 0) + (M[g] ?? 0)) >>> 0
      A = D
      D = C
      C = B
      B = (B + rotl(F, S[i] ?? 0)) >>> 0
    }
    a0 = (a0 + A) >>> 0
    b0 = (b0 + B) >>> 0
    c0 = (c0 + C) >>> 0
    d0 = (d0 + D) >>> 0
  }

  const out = new Uint8Array(16)
  const outView = new DataView(out.buffer)
  outView.setUint32(0, a0, true)
  outView.setUint32(4, b0, true)
  outView.setUint32(8, c0, true)
  outView.setUint32(12, d0, true)
  return out
}

export function md5Hex(bytes: Uint8Array): string {
  return toHex(md5(bytes))
}
