use std::net::SocketAddr;

use axum::http::HeaderMap;

use crate::consts;

pub fn get_ip_and_user_agent(headers: &HeaderMap, remote_address: SocketAddr) -> (String, String) {
    let ip = match headers.get(consts::REVERSE_PROXY_IP_HTTP_FIELD) {
        Some(v) => v.to_str().unwrap_or_default().to_string(),
        None => remote_address.to_string(),
    };

    let user_agent = headers
        .get(axum::http::header::USER_AGENT)
        .map(|v| v.to_str().unwrap_or_default())
        .unwrap_or_default()
        .to_string();

    (ip, user_agent)
}

pub fn get_url_from_host(host: &str) -> String {
    let port: Option<u16> = 'p: {
        let split_port: Vec<&str> = host.split(':').collect();
        if split_port.len() == 2 {
            if let Ok(p) = split_port[1].parse::<u16>() {
                break 'p Some(p);
            }
        }
        None
    };
    format!(
        "http{}://{}",
        if port.is_some() && port.unwrap() != 443 {
            ""
        } else {
            "s"
        },
        host
    )
}

pub fn substitute(str: &str, pattern: &str, replacements: &[&str]) -> String {
    let mut result = String::with_capacity(
        (str.len() + replacements.iter().map(|s| s.len()).sum::<usize>())
            .saturating_sub(pattern.len() * replacements.len()),
    );

    let mut i = 0;
    for s in str.split(pattern) {
        result.push_str(s);
        if i < replacements.len() {
            result.push_str(replacements[i]);
        }
        i += 1;
    }

    if i == 1 {
        return str.to_string();
    }

    result
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_substitute() {
        assert_eq!(substitute("", "", &[]), "");
        assert_eq!(substitute("", "", &[""]), "");
        assert_eq!(substitute("", "{}", &["a"]), "");
        assert_eq!(substitute("a", "{}", &["b"]), "a");
        assert_eq!(substitute("a{}", "{}", &["b"]), "ab");
        assert_eq!(substitute("{}c", "{}", &["b"]), "bc");
        assert_eq!(substitute("a{}c", "{}", &["b"]), "abc");
        assert_eq!(substitute("{}b{}", "{}", &["a", "c"]), "abc");
        assert_eq!(substitute("{}{}{}", "{}", &["a", "bc", "def"]), "abcdef");
        assert_eq!(substitute("{}{}{}", "{}", &["a"]), "a");
    }
}