use anyhow::{Result, anyhow};

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())
}