use std::collections::HashSet;

use anyhow::{Result, anyhow};
use rand::prelude::*;

const SBOX: [u8; 256] = [
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
];

const INV_SBOX: [u8; 256] = [
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d,
];

const RCON: [[u8; 4]; 10] = [
    [0x01, 0x00, 0x00, 0x00],
    [0x02, 0x00, 0x00, 0x00],
    [0x04, 0x00, 0x00, 0x00],
    [0x08, 0x00, 0x00, 0x00],
    [0x10, 0x00, 0x00, 0x00],
    [0x20, 0x00, 0x00, 0x00],
    [0x40, 0x00, 0x00, 0x00],
    [0x80, 0x00, 0x00, 0x00],
    [0x1b, 0x00, 0x00, 0x00],
    [0x36, 0x00, 0x00, 0x00],
];

pub fn add_round_key(block: &[u8; 16], round_key: &[u8; 16]) -> [u8; 16] {
    std::array::from_fn(|i| block[i] ^ round_key[i])
}

pub fn sub_bytes(block: &[u8; 16]) -> [u8; 16] {
    std::array::from_fn(|i| SBOX[block[i] as usize])
}

pub fn inv_sub_bytes(block: &[u8; 16]) -> [u8; 16] {
    std::array::from_fn(|i| INV_SBOX[block[i] as usize])
}

pub fn shift_rows(block: &[u8; 16]) -> [u8; 16] {
    let mut result = [0u8; 16];
    // Row 0 (no shift)
    result[0] = block[0];
    result[4] = block[4];
    result[8] = block[8];
    result[12] = block[12];
    // Row 1 (shift left by 1)
    result[1] = block[5];
    result[5] = block[9];
    result[9] = block[13];
    result[13] = block[1];
    // Row 2 (shift left by 2)
    result[2] = block[10];
    result[6] = block[14];
    result[10] = block[2];
    result[14] = block[6];
    // Row 3 (shift left by 3)
    result[3] = block[15];
    result[7] = block[3];
    result[11] = block[7];
    result[15] = block[11];
    result
}

pub fn inv_shift_rows(block: &[u8; 16]) -> [u8; 16] {
    let mut result = [0u8; 16];
    // Row 0 (no shift)
    result[0] = block[0];
    result[4] = block[4];
    result[8] = block[8];
    result[12] = block[12];
    // Row 1 (shift right by 1, equivalent to shift left by 3)
    result[1] = block[13];
    result[5] = block[1];
    result[9] = block[5];
    result[13] = block[9];
    // Row 2 (shift right by 2, equivalent to shift left by 2)
    result[2] = block[10];
    result[6] = block[14];
    result[10] = block[2];
    result[14] = block[6];
    // Row 3 (shift right by 3, equivalent to shift left by 1)
    result[3] = block[7];
    result[7] = block[11];
    result[11] = block[15];
    result[15] = block[3];
    result
}

fn gf_mul_01(a: u8) -> u8 {
    a
}

fn gf_mul_02(a: u8) -> u8 {
    if a & 0x80 != 0 {
        (a << 1) ^ 0x1b
    } else {
        a << 1
    }
}

fn gf_mul_03(a: u8) -> u8 {
    gf_mul_02(a) ^ a
}

fn gf_mul_0e(a: u8) -> u8 {
    gf_mul_02(gf_mul_02(gf_mul_02(a))) ^ gf_mul_04(a) ^ gf_mul_02(a)
}

fn gf_mul_0b(a: u8) -> u8 {
    gf_mul_08(a) ^ gf_mul_02(a) ^ a
}

fn gf_mul_0d(a: u8) -> u8 {
    gf_mul_08(a) ^ gf_mul_04(a) ^ a
}

fn gf_mul_09(a: u8) -> u8 {
    gf_mul_08(a) ^ a
}

fn gf_mul_04(a: u8) -> u8 {
    gf_mul_02(gf_mul_02(a))
}

fn gf_mul_08(a: u8) -> u8 {
    gf_mul_02(gf_mul_04(a))
}

pub fn mix_columns(block: &[u8; 16]) -> [u8; 16] {
    // [02 03 01 01]
    // [01 02 03 01]
    // [01 01 02 03]
    // [03 01 01 02]
    let mut result = [0u8; 16];
    for i in 0..4 {
        let col = [
            block[i * 4],
            block[i * 4 + 1],
            block[i * 4 + 2],
            block[i * 4 + 3],
        ];
        result[i * 4] =
            gf_mul_02(col[0]) ^ gf_mul_03(col[1]) ^ gf_mul_01(col[2]) ^ gf_mul_01(col[3]);
        result[i * 4 + 1] =
            gf_mul_01(col[0]) ^ gf_mul_02(col[1]) ^ gf_mul_03(col[2]) ^ gf_mul_01(col[3]);
        result[i * 4 + 2] =
            gf_mul_01(col[0]) ^ gf_mul_01(col[1]) ^ gf_mul_02(col[2]) ^ gf_mul_03(col[3]);
        result[i * 4 + 3] =
            gf_mul_03(col[0]) ^ gf_mul_01(col[1]) ^ gf_mul_01(col[2]) ^ gf_mul_02(col[3]);
    }
    result
}

pub fn inv_mix_columns(block: &[u8; 16]) -> [u8; 16] {
    // [0E 0B 0D 09]
    // [09 0E 0B 0D]
    // [0D 09 0E 0B]
    // [0B 0D 09 0E]
    let mut result = [0u8; 16];
    for i in 0..4 {
        let col = [
            block[i * 4],
            block[i * 4 + 1],
            block[i * 4 + 2],
            block[i * 4 + 3],
        ];
        result[i * 4] =
            gf_mul_0e(col[0]) ^ gf_mul_0b(col[1]) ^ gf_mul_0d(col[2]) ^ gf_mul_09(col[3]);
        result[i * 4 + 1] =
            gf_mul_09(col[0]) ^ gf_mul_0e(col[1]) ^ gf_mul_0b(col[2]) ^ gf_mul_0d(col[3]);
        result[i * 4 + 2] =
            gf_mul_0d(col[0]) ^ gf_mul_09(col[1]) ^ gf_mul_0e(col[2]) ^ gf_mul_0b(col[3]);
        result[i * 4 + 3] =
            gf_mul_0b(col[0]) ^ gf_mul_0d(col[1]) ^ gf_mul_09(col[2]) ^ gf_mul_0e(col[3]);
    }
    result
}

pub fn expand_key(key: &[u8; 16]) -> [[u8; 16]; 11] {
    let mut round_key: [[u8; 16]; 11] = [[0u8; 16]; 11];
    round_key[0] = *key;

    for round in 1..round_key.len() {
        let prev_key = round_key[round - 1];
        let mut new_key = [0u8; 16];

        // 对前一轮密钥的最后4字节进行g变换
        let g_result = g_func(prev_key[12..16].try_into().unwrap(), round - 1);

        // 新密钥的每4字节都要与前面的4字节异或
        for i in 0..4 {
            new_key[i] = prev_key[i] ^ g_result[i];
        }

        for i in 4..8 {
            new_key[i] = prev_key[i] ^ new_key[i - 4];
        }

        for i in 8..12 {
            new_key[i] = prev_key[i] ^ new_key[i - 4];
        }

        for i in 12..16 {
            new_key[i] = prev_key[i] ^ new_key[i - 4];
        }

        round_key[round] = new_key;
    }

    round_key
}

fn rot_word(word: [u8; 4]) -> [u8; 4] {
    [word[1], word[2], word[3], word[0]]
}

fn xor_rcon(word: [u8; 4], round: usize) -> [u8; 4] {
    let mut result = word;
    result[0] ^= RCON[round][0]; // 只对第一个字节进行Rcon异或
    result
}

fn sub_word(word: [u8; 4]) -> [u8; 4] {
    [
        SBOX[word[0] as usize],
        SBOX[word[1] as usize],
        SBOX[word[2] as usize],
        SBOX[word[3] as usize],
    ]
}

fn g_func(word: [u8; 4], round: usize) -> [u8; 4] {
    let mut result = rot_word(word);
    result = sub_word(result);
    result = xor_rcon(result, round);
    result
}

pub fn aes_ecb_enc(input: &[u8], key: &[u8; 16]) -> Result<Vec<u8>> {
    if !input.len().is_multiple_of(16) {
        return Err(anyhow!("Invalid input length"));
    }
    let mut cipher: Vec<u8> = Vec::new();
    let round_keys = expand_key(key);
    for i in 0..(input.len() / 16) {
        let mut block: [u8; 16] = input[(i * 16)..(i * 16 + 16)].try_into()?;
        block = add_round_key(&block, &round_keys[0]);
        for round_key in round_keys.iter().take(10).skip(1) {
            block = sub_bytes(&block);
            block = shift_rows(&block);
            block = mix_columns(&block);
            block = add_round_key(&block, round_key);
        }
        block = sub_bytes(&block);
        block = shift_rows(&block);
        block = add_round_key(&block, &round_keys[10]);
        cipher.extend(block);
    }

    Ok(cipher)
}

pub fn aes_ecb_dec(input: &[u8], key: &[u8; 16]) -> Result<Vec<u8>> {
    if !input.len().is_multiple_of(16) {
        return Err(anyhow!("Invalid input length"));
    }

    let mut plaintext: Vec<u8> = Vec::new();
    let round_keys = expand_key(key);

    for i in 0..(input.len() / 16) {
        let mut block: [u8; 16] = input[(i * 16)..(i * 16 + 16)].try_into()?;
        block = add_round_key(&block, &round_keys[10]);
        block = inv_shift_rows(&block);
        block = inv_sub_bytes(&block);
        for j in 0..9 {
            block = add_round_key(&block, &round_keys[9 - j]);
            block = inv_mix_columns(&block);
            block = inv_shift_rows(&block);
            block = inv_sub_bytes(&block);
        }
        block = add_round_key(&block, &round_keys[0]);
        plaintext.extend(block);
    }

    Ok(plaintext)
}

pub fn aes_cbc_enc(input: &[u8], key: &[u8; 16], iv: &[u8; 16]) -> Result<Vec<u8>> {
    if !input.len().is_multiple_of(16) {
        return Err(anyhow!("Invalid input length"));
    }
    let mut cipher: Vec<u8> = Vec::new();
    let round_keys = expand_key(key);
    let mut prev_block = *iv;
    for i in 0..(input.len() / 16) {
        let mut block: [u8; 16] = input[(i * 16)..(i * 16 + 16)].try_into()?;
        block = block
            .iter()
            .zip(prev_block.iter())
            .map(|(b, iv)| b ^ iv)
            .collect::<Vec<u8>>()
            .try_into()
            .unwrap();
        block = add_round_key(&block, &round_keys[0]);
        for round_key in round_keys.iter().take(10).skip(1) {
            block = sub_bytes(&block);
            block = shift_rows(&block);
            block = mix_columns(&block);
            block = add_round_key(&block, round_key);
        }
        block = sub_bytes(&block);
        block = shift_rows(&block);
        block = add_round_key(&block, &round_keys[10]);
        cipher.extend(block);
        prev_block = block;
    }

    Ok(cipher)
}

pub fn aes_cbc_dec(input: &[u8], key: &[u8; 16], iv: &[u8; 16]) -> Result<Vec<u8>> {
    if !input.len().is_multiple_of(16) {
        return Err(anyhow!("Invalid input length"));
    }

    let mut plaintext: Vec<u8> = Vec::new();
    let round_keys = expand_key(key);
    let mut prev_block = *iv;
    for i in 0..(input.len() / 16) {
        let mut block: [u8; 16] = input[(i * 16)..(i * 16 + 16)].try_into()?;
        block = add_round_key(&block, &round_keys[10]);
        block = inv_shift_rows(&block);
        block = inv_sub_bytes(&block);
        for j in 0..9 {
            block = add_round_key(&block, &round_keys[9 - j]);
            block = inv_mix_columns(&block);
            block = inv_shift_rows(&block);
            block = inv_sub_bytes(&block);
        }
        block = add_round_key(&block, &round_keys[0]);
        block = block
            .iter()
            .zip(prev_block.iter())
            .map(|(b, iv)| b ^ iv)
            .collect::<Vec<u8>>()
            .try_into()
            .unwrap();
        plaintext.extend(block);
        prev_block = input[(i * 16)..(i * 16 + 16)].try_into()?;
    }

    Ok(plaintext)
}

pub fn pkcs7_padding(data: &mut Vec<u8>, block_size: usize) {
    if block_size == 0 {
        panic!("Block size must be greater than zero");
    }
    if block_size > 255 {
        panic!("Block size must be less than or equal to 255");
    }
    let mut padding_length = block_size - (data.len() % block_size);
    if padding_length == 0 {
        padding_length = block_size;
    }
    data.extend(vec![padding_length as u8; padding_length]);
}

pub fn pkcs7_unpadding(input: &[u8]) -> Result<Vec<u8>> {
    if input.is_empty() {
        return Err(anyhow!("Input cannot be empty"));
    }
    let padding_length = *input.last().unwrap();
    if padding_length == 0 || padding_length > input.len() as u8 {
        return Err(anyhow!("Invalid PKCS#7 padding"));
    }
    for &byte in input.iter().rev().take(padding_length as usize) {
        if byte != padding_length {
            return Err(anyhow!("Invalid PKCS#7 padding"));
        }
    }
    Ok(input[..input.len() - padding_length as usize].to_vec())
}

pub fn is_ecb(cipher: &[u8]) -> bool {
    // Check if the input is a valid ECB encrypted data
    let mut seen_blocks = HashSet::new();
    for chunk in cipher.chunks(16) {
        if seen_blocks.contains(chunk) {
            return true; // Duplicate block found, indicating ECB mode
        }
        seen_blocks.insert(chunk);
    }

    false
}

pub fn is_valid_english(input_str: &str, ratio: Option<f32>) -> bool {
    let ratio = ratio.unwrap_or(0.6);
    let mut total_chars = 0;
    let mut alphabet_chars = 0;
    let mut prev_char = None;
    for c in input_str.chars() {
        // 检查连续空格
        if c == ' ' && prev_char == Some(' ') {
            return false;
        }

        // 检查是否为可打印字符
        if !(c.is_ascii_lowercase()
            || c.is_ascii_uppercase()
            || c.is_ascii_digit()
            || " .,!?;:'\"-()".contains(c))
        {
            return false;
        }

        // 检查是否为换行符
        if c == '\n' {
            return false;
        }
        total_chars += 1;
        if c.is_alphabetic() {
            alphabet_chars += 1;
        }
        prev_char = Some(c);
    }
    // 字符占文本的比例
    let alphabet_ratio = alphabet_chars as f32 / total_chars as f32;
    if alphabet_ratio < ratio {
        return false;
    }

    true
}

pub fn xor_with_key(input: &[u8], key: &[u8]) -> Result<Vec<u8>> {
    if key.is_empty() {
        return Err(anyhow!("empty key"));
    }
    Ok(input
        .iter()
        .zip(key.iter().cycle())
        .map(|(&a, &b)| a ^ b)
        .collect())
}

pub fn gen_random_key() -> [u8; 16] {
    let mut rng = rand::rng();
    let mut key = [0u8; 16];
    rng.fill(&mut key);
    key
}

pub fn aes_ctr_enc(input: &[u8], key: &[u8; 16], nonce: u64) -> Result<Vec<u8>> {
    let mut key_stream = Vec::new();
    for round in 0..=(input.len() / 16) as u64 {
        let input: Vec<u8> = nonce
            .to_le_bytes()
            .into_iter()
            .chain(round.to_le_bytes())
            .collect();
        let stream_block = aes_ecb_enc(&input, key)?;
        key_stream.extend(stream_block);
    }
    let output: Vec<u8> = input.iter().zip(key_stream).map(|(&a, b)| a ^ b).collect();

    Ok(output)
}

pub fn aes_ctr_dec(input: &[u8], key: &[u8; 16], nonce: u64) -> Result<Vec<u8>> {
    aes_ctr_enc(input, key, nonce)
}

pub struct MT19937 {
    mt: [u32; 624],
    index: usize,
}

impl MT19937 {
    pub fn new(seed: u32) -> Self {
        let mut mt = [0; 624];
        mt[0] = seed;
        for i in 1..624 {
            mt[i] = 0x6c078965u32
                .wrapping_mul(mt[i - 1] ^ (mt[i - 1] >> 30))
                .wrapping_add(i as u32)
        }
        let index = 0;
        MT19937 { mt, index }
    }

    pub fn extract_number(&mut self) -> u32 {
        if self.index == 0 {
            self.generate_numbers();
        }
        let mut result = self.mt[self.index];

        result ^= result >> 11;
        result ^= (result << 7) & 0x9d2c5680;
        result ^= (result << 15) & 0xefc60000;
        result ^= result >> 18;
        self.index = (self.index + 1) % 624;

        result
    }

    fn generate_numbers(&mut self) {
        for i in 0..624 {
            let y: u32 = (self.mt[i] & 0x80000000) + (self.mt[(i + 1) % 624] & 0x7fffffff);
            self.mt[i] = self.mt[(i + 397) % 624] ^ (y >> 1);
            if !y.is_multiple_of(2) {
                self.mt[i] ^= 0x9908b0df;
            }
        }
    }
}

pub fn sha1(input: &[u8]) -> [u8; 20] {
    let mut h0 = 0x67452301u32;
    let mut h1 = 0xEFCDAB89u32;
    let mut h2 = 0x98BADCFEu32;
    let mut h3 = 0x10325476u32;
    let mut h4 = 0xC3D2E1F0u32;

    let message_bits_len = input.len() * 8;
    let mut buffer = input.to_vec();
    buffer.push(0x80u8);

    while (buffer.len() % 64) != 56 {
        buffer.push(0x00u8);
    }

    buffer.extend_from_slice(&(message_bits_len as u64).to_be_bytes());

    for chunk in buffer.chunks(64) {
        let mut extend_buf = [0u32; 80];
        for i in 0..16 {
            let bytes: [u8; 4] = chunk[4 * i..4 * i + 4].try_into().unwrap();
            extend_buf[i] = u32::from_be_bytes(bytes);
        }
        for i in 16..80 {
            extend_buf[i] =
                (extend_buf[i - 3] ^ extend_buf[i - 8] ^ extend_buf[i - 14] ^ extend_buf[i - 16])
                    .rotate_left(1);
        }
        let mut a = h0;
        let mut b = h1;
        let mut c = h2;
        let mut d = h3;
        let mut e = h4;
        for (i, &w_i) in extend_buf.iter().enumerate() {
            let f = match i {
                0..20 => (b & c) | (!b & d),
                20..40 => b ^ c ^ d,
                40..60 => (b & c) | (b & d) | (c & d),
                60..80 => b ^ c ^ d,
                _ => panic!("Invalid round: {}", i),
            };
            let k = match i {
                0..20 => 0x5A827999,
                20..40 => 0x6ED9EBA1,
                40..60 => 0x8F1BBCDC,
                60..80 => 0xCA62C1D6,
                _ => panic!("Invalid round: {}", i),
            };
            let temp = a
                .rotate_left(5)
                .wrapping_add(f)
                .wrapping_add(e)
                .wrapping_add(w_i)
                .wrapping_add(k);

            e = d;
            d = c;
            c = b.rotate_left(30);
            b = a;
            a = temp;
        }
        h0 = h0.wrapping_add(a);
        h1 = h1.wrapping_add(b);
        h2 = h2.wrapping_add(c);
        h3 = h3.wrapping_add(d);
        h4 = h4.wrapping_add(e);
    }

    let mut digest = [0u8; 20];

    digest[0..4].copy_from_slice(&h0.to_be_bytes());
    digest[4..8].copy_from_slice(&h1.to_be_bytes());
    digest[8..12].copy_from_slice(&h2.to_be_bytes());
    digest[12..16].copy_from_slice(&h3.to_be_bytes());
    digest[16..20].copy_from_slice(&h4.to_be_bytes());

    digest
}