// Request + RequestBuilder — mirrors NPE Request.java.
//
// PARITY: add_header silently overwrites instead of appending, per NPE
// Request.java:215-221. Callers depend on this. append_header is our
// own clean addition for callers we control.

use std::collections::BTreeMap;

use crate::localization::Localization;

pub type Headers = BTreeMap<String, Vec<String>>;

#[derive(Clone, Debug, Eq, PartialEq)]
pub enum Method {
    Get,
    Head,
    Post,
    Put,
    Delete,
}

impl Method {
    pub fn as_str(&self) -> &'static str {
        match self {
            Method::Get => "GET",
            Method::Head => "HEAD",
            Method::Post => "POST",
            Method::Put => "PUT",
            Method::Delete => "DELETE",
        }
    }
}

#[derive(Clone, Debug)]
pub struct Request {
    method: Method,
    url: String,
    headers: Headers,
    body: Option<Vec<u8>>,
    localization: Option<Localization>,
    automatic_localization_header: bool,
}

impl Request {
    pub fn get(url: impl Into<String>) -> RequestBuilder {
        RequestBuilder::new(Method::Get, url)
    }

    pub fn head(url: impl Into<String>) -> RequestBuilder {
        RequestBuilder::new(Method::Head, url)
    }

    pub fn post(url: impl Into<String>, body: Vec<u8>) -> RequestBuilder {
        RequestBuilder::new(Method::Post, url).body(Some(body))
    }

    pub fn method(&self) -> &Method {
        &self.method
    }

    pub fn url(&self) -> &str {
        &self.url
    }

    pub fn headers(&self) -> &Headers {
        &self.headers
    }

    pub fn body(&self) -> Option<&[u8]> {
        self.body.as_deref()
    }

    pub fn localization(&self) -> Option<&Localization> {
        self.localization.as_ref()
    }

    pub fn automatic_localization_header(&self) -> bool {
        self.automatic_localization_header
    }
}

#[derive(Clone, Debug)]
pub struct RequestBuilder {
    method: Method,
    url: String,
    headers: Headers,
    body: Option<Vec<u8>>,
    localization: Option<Localization>,
    automatic_localization_header: bool,
}

impl RequestBuilder {
    pub fn new(method: Method, url: impl Into<String>) -> Self {
        Self {
            method,
            url: url.into(),
            headers: BTreeMap::new(),
            body: None,
            localization: None,
            automatic_localization_header: true,
        }
    }

    /// PARITY with NPE Request.Builder.addHeader: silently overwrites any
    /// existing values for `name`. Callers downstream of NPE-derived code
    /// depend on this. For new code prefer [`Self::append_header`].
    pub fn add_header(mut self, name: impl Into<String>, value: impl Into<String>) -> Self {
        let key = lowercase(name.into());
        self.headers.insert(key, vec![value.into()]);
        self
    }

    /// Appends a value to `name`, creating the entry if absent. This is the
    /// behavior NPE's addHeader was intended to have. Use freely in our own
    /// code; avoid when porting NPE call sites that rely on overwrite.
    pub fn append_header(mut self, name: impl Into<String>, value: impl Into<String>) -> Self {
        let key = lowercase(name.into());
        self.headers.entry(key).or_default().push(value.into());
        self
    }

    pub fn headers(mut self, headers: Headers) -> Self {
        self.headers = headers
            .into_iter()
            .map(|(k, v)| (lowercase(k), v))
            .collect();
        self
    }

    pub fn body(mut self, body: Option<Vec<u8>>) -> Self {
        self.body = body;
        self
    }

    pub fn localization(mut self, localization: Option<Localization>) -> Self {
        self.localization = localization;
        self
    }

    pub fn automatic_localization_header(mut self, on: bool) -> Self {
        self.automatic_localization_header = on;
        self
    }

    pub fn build(self) -> Request {
        Request {
            method: self.method,
            url: self.url,
            headers: self.headers,
            body: self.body,
            localization: self.localization,
            automatic_localization_header: self.automatic_localization_header,
        }
    }
}

fn lowercase(s: String) -> String {
    s.to_ascii_lowercase()
}

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

    #[test]
    fn add_header_overwrites_parity() {
        let r = Request::get("https://x")
            .add_header("X-Foo", "first")
            .add_header("X-Foo", "second")
            .build();
        assert_eq!(r.headers().get("x-foo"), Some(&vec!["second".into()]));
    }

    #[test]
    fn append_header_accumulates() {
        let r = Request::get("https://x")
            .append_header("X-Foo", "first")
            .append_header("X-Foo", "second")
            .build();
        assert_eq!(
            r.headers().get("x-foo"),
            Some(&vec!["first".into(), "second".into()])
        );
    }

    #[test]
    fn headers_keys_lowercased() {
        let r = Request::get("https://x").add_header("Content-Type", "text/plain").build();
        assert!(r.headers().contains_key("content-type"));
        assert!(!r.headers().contains_key("Content-Type"));
    }
}