//! Deterministic native HTTP fixture for curl comparisons.
use std::{
    collections::BTreeMap,
    io::{BufRead, BufReader, Read, Write},
    net::TcpListener,
};
fn main() {
    let ready = std::env::args().nth(1).expect("readiness path");
    let listener = TcpListener::bind("127.0.0.1:0").unwrap();
    std::fs::write(ready, listener.local_addr().unwrap().port().to_string()).unwrap();
    for stream in listener.incoming() {
        let mut stream = stream.unwrap();
        let mut read = BufReader::new(stream.try_clone().unwrap());
        let mut first = String::new();
        read.read_line(&mut first).unwrap();
        let words: Vec<_> = first.split_whitespace().collect();
        if words.len() < 2 {
            continue;
        }
        let method = words[0];
        let path = words[1];
        let mut headers: BTreeMap<String, Vec<String>> = BTreeMap::new();
        let mut length = 0;
        loop {
            let mut line = String::new();
            read.read_line(&mut line).unwrap();
            if line == "\r\n" || line.is_empty() {
                break;
            }
            let (name, value) = line.split_once(':').unwrap();
            let name = name.to_ascii_lowercase();
            let value = value.trim();
            if name == "content-length" {
                length = value.parse().unwrap();
            }
            if [
                "accept",
                "content-type",
                "authorization",
                "user-agent",
                "x-test",
            ]
            .contains(&name.as_str())
            {
                headers.entry(name).or_default().push(value.into());
            }
        }
        let mut body = vec![0; length];
        read.read_exact(&mut body).unwrap();
        let echo = serde_json::json!({"method":method,"path":path,"body":String::from_utf8_lossy(&body),"headers":headers}).to_string();
        let (status, reason, response, extra) = match path {
            "/plain" => (200, "OK", "hello\n".into(), "".into()),
            "/404" => (404, "Not Found", "missing\n".into(), "".into()),
            "/redirect" => (
                302,
                "Found",
                "redirect\n".into(),
                "location: /echo\r\n".into(),
            ),
            "/303" => (
                303,
                "See Other",
                "redirect\n".into(),
                "location: /echo\r\n".into(),
            ),
            "/307" => (
                307,
                "Temporary Redirect",
                "redirect\n".into(),
                "location: /echo\r\n".into(),
            ),
            "/loop" => (
                302,
                "Found",
                "redirect\n".into(),
                "location: /loop\r\n".into(),
            ),
            "/slow" => {
                std::thread::sleep(std::time::Duration::from_millis(100));
                (200, "OK", "slow\n".into(), "".into())
            }
            _ => (200, "OK", echo, "".into()),
        };
        let response: String = response;
        let extra: String = extra;
        let _ = write!(
            stream,
            "HTTP/1.1 {status} {reason}\r\ncontent-type: text/plain\r\ncontent-length: {}\r\n{extra}\r\n{}",
            response.len(),
            if method == "HEAD" { "" } else { &response }
        );
    }
}