use actix_web::http::header::{CACHE_CONTROL, CONTENT_TYPE};
use actix_web::{HttpRequest, HttpResponse};

pub struct Asset {
    pub path: &'static str,
    pub content_type: &'static str,
    pub bytes: &'static [u8],
}

include!(concat!(env!("OUT_DIR"), "/assets.rs"));

pub fn count() -> usize {
    ASSETS.len()
}

/// 非 SPA 的首段路径：这些前缀只服务于接口，拼错时给 JSON 404，
/// 避免把已移除的旧路径回落到 index.html 变成 200。
const API_PREFIXES: [&str; 2] = ["api", "auth"];

pub async fn serve(request: HttpRequest) -> HttpResponse {
    let raw = request.path().trim_start_matches('/');
    let path = if raw.is_empty() { "index.html" } else { raw };

    let looks_like_api = 'inline_looks_like_api: {
        if path.starts_with(".well-known/") {
            break 'inline_looks_like_api true;
        }
        let first = path.split('/').next().unwrap_or_default();
        API_PREFIXES.contains(&first)
    };
    if looks_like_api {
        return api_not_found();
    }

    if lookup(path).is_none()
        && path
            .rsplit('/')
            .next()
            .and_then(|name| name.rsplit_once('.'))
            .is_some_and(|(_, ext)| {
                !ext.is_empty() && ext.len() <= 5 && ext.chars().all(|c| c.is_ascii_alphanumeric())
            })
    {
        return api_not_found();
    }

    match lookup(path).or_else(|| lookup("index.html")) {
        Some(asset) => {
            let cache_control = if asset.path.starts_with("assets/") {
                "public, max-age=31536000, immutable"
            } else {
                "no-cache"
            };

            HttpResponse::Ok()
                .insert_header((CONTENT_TYPE, asset.content_type))
                .insert_header((CACHE_CONTROL, cache_control))
                .body(asset.bytes)
        }
        None => HttpResponse::ServiceUnavailable()
            .insert_header((CONTENT_TYPE, "text/plain; charset=utf-8"))
            .body(
                "view/dist has no build output; run `just identity-web-build` and rebuild kenapi\n",
            ),
    }
}

fn lookup(path: &str) -> Option<&'static Asset> {
    ASSETS.iter().find(|asset| asset.path == path)
}

fn api_not_found() -> HttpResponse {
    HttpResponse::NotFound().json(
        export::rest::AppResponseData::<export::rest::NoData>::err(404, "unknown api route")
            .with_error_code("not_found"),
    )
}