use actix_web::{
    HttpRequest, HttpResponse,
    web::{self, Bytes},
};
use futures_util::stream;

use crate::consts;

fn mix_u32s(seed: impl Iterator<Item = u32>) -> u32 {
    // from wyhash32, according to GPT, should just have a nice bit distribution anyways
    const U32_BIT_MIXING_CONSTANT: u32 = 0x7feb_352d;
    const U32_SELF_BIT_MIXING: u32 = 0x846c_a68b;

    let mut random = seed.fold(0_u32, |acc, e| {
        // mix bits
        acc.wrapping_add(e.wrapping_mul(U32_BIT_MIXING_CONSTANT))
    });

    // GPT's suggestion for a nicer distribution, like 8 cpu instructions so whatever
    random ^= random >> 16;
    random = random.wrapping_mul(U32_SELF_BIT_MIXING);
    random ^= random >> 15;

    random
}

pub async fn not_found(req: HttpRequest) -> HttpResponse {
    let seed = req.path().as_bytes();
    let random = mix_u32s(seed.iter().copied().map(u32::from));

    let res = consts::ERROR_ASCII_ARTS[random as usize % consts::ERROR_ASCII_ARTS.len()];

    let method = req.method().as_str();
    let url = req.path();

    HttpResponse::NotFound()
        .content_type("text/plain; charset=utf-8")
        .streaming(stream::iter([
            Ok::<_, !>(web::Bytes::from(format!(
                "> {method} '{url}'\n404 NOT FOUND\nLet's all love lain\n\n"
            ))),
            Ok(Bytes::from_static(res.as_bytes())),
        ]))
    // .body(format!(
    //     "> {method} '{url}'\n404 NOT FOUND\nLet's all love lain\n\n{res}"
    // ))
}