//! Provides convenience traits and functions to build HTTP responses.

use std::{
    convert::TryInto,
    fmt::Display,
    time::{Duration, SystemTime},
};

use crate::http::{self, header, response::Builder, HeaderMap, StatusCode};

/// Adds convenience methods to [`Builder`].
pub trait SputnikBuilder {
    /// Sets the Content-Type.
    fn content_type(self, mime: mime::Mime) -> Builder;

    /// Appends the Set-Cookie header.
    fn set_cookie(self, cookie: Cookie) -> Builder;
}

#[derive(Default, Debug)]
pub struct Cookie {
    pub name: String,
    pub value: String,
    pub expires: Option<SystemTime>,
    pub max_age: Option<Duration>,
    pub domain: Option<String>,
    pub path: Option<String>,
    pub secure: Option<bool>,
    pub http_only: Option<bool>,
    pub same_site: Option<SameSite>,
}

impl Display for Cookie {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}={}", self.name, self.value)?;
        if let Some(true) = self.http_only {
            write!(f, "; HttpOnly")?;
        }
        if let Some(same_site) = &self.same_site {
            write!(f, "; SameSite={}", same_site)?;

            if same_site == &SameSite::None && self.secure.is_none() {
                write!(f, "; Secure")?;
            }
        }
        if let Some(true) = self.secure {
            write!(f, "; Secure")?;
        }
        if let Some(path) = &self.path {
            write!(f, "; Path={}", path)?;
        }
        if let Some(domain) = &self.domain {
            write!(f, "; Domain={}", domain)?;
        }
        if let Some(max_age) = &self.max_age {
            write!(f, "; Max-Age={}", max_age.as_secs())?;
        }
        if let Some(time) = self.expires {
            write!(f, "; Expires={}", httpdate::fmt_http_date(time))?;
        }

        Ok(())
    }
}

#[derive(Debug, PartialEq)]
pub enum SameSite {
    Strict,
    Lax,
    None,
}

impl Display for SameSite {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            SameSite::Strict => write!(f, "Strict"),
            SameSite::Lax => write!(f, "Lax"),
            SameSite::None => write!(f, "None"),
        }
    }
}

/// Creates a new builder with a given Location header and status code.
pub fn redirect(location: &str, code: StatusCode) -> Builder {
    Builder::new()
        .status(code)
        .header(header::LOCATION, location)
}

impl SputnikBuilder for Builder {
    fn content_type(mut self, mime: mime::Mime) -> Self {
        self.headers_mut().map(|h| h.content_type(mime));
        self
    }

    fn set_cookie(mut self, cookie: Cookie) -> Builder {
        self.headers_mut().map(|h| h.set_cookie(cookie));
        self
    }
}

/// Constructs an expired cookie to delete a cookie.
pub fn delete_cookie(name: &str) -> Cookie {
    Cookie {
        name: name.into(),
        max_age: Some(Duration::from_secs(0)),
        expires: Some(SystemTime::now() - Duration::from_secs(60 * 60 * 24)),
        ..Default::default()
    }
}

/// Adds convenience methods to [`HeaderMap`].
pub trait SputnikHeaders {
    /// Sets the Content-Type.
    fn content_type(&mut self, mime: mime::Mime);

    /// Appends a Set-Cookie header.
    fn set_cookie(&mut self, cookie: Cookie);
}

impl SputnikHeaders for HeaderMap {
    fn content_type(&mut self, mime: mime::Mime) {
        self.insert(header::CONTENT_TYPE, mime.to_string().try_into().unwrap());
    }

    fn set_cookie(&mut self, cookie: Cookie) {
        self.append(header::SET_COOKIE, cookie.to_string().try_into().unwrap());
    }
}

/// Adds a convenience method to consume a [`Builder`] with an empty body.
pub trait EmptyBuilder<B> {
    /// Consume the builder with an empty body.
    fn empty(self) -> http::Result<http::response::Response<B>>;
}

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

    #[test]
    fn test_set_cookie() {
        let mut map = HeaderMap::new();
        map.set_cookie(Cookie {
            name: "some".into(),
            value: "cookie".into(),
            ..Default::default()
        });
        map.set_cookie(Cookie {
            name: "some".into(),
            value: "cookie".into(),
            ..Default::default()
        });
        assert_eq!(map.len(), 2);
    }

    #[test]
    fn test_content_type() {
        let mut map = HeaderMap::new();
        map.content_type(mime::TEXT_PLAIN);
        map.content_type(mime::TEXT_HTML);
        assert_eq!(map.len(), 1);
        assert_eq!(map.get(header::CONTENT_TYPE).unwrap(), "text/html");
    }
}