use common::ron_api;
use gloo::net::http::{Request, RequestBuilder};
use serde::{de::DeserializeOwned, Serialize};
use thiserror::Error;

use crate::toast::{self, Level};

#[derive(Error, Debug)]
pub enum Error {
    #[error("Gloo error: {0}")]
    Gloo(#[from] gloo::net::Error),

    #[error("RON Spanned error: {0}")]
    Ron(#[from] ron::error::SpannedError),

    #[error("HTTP error: {0}")]
    Http(String),

    #[error("Unknown error: {0}")]
    Other(String),
}

type Result<T> = std::result::Result<T, Error>;

const CONTENT_TYPE: &str = "Content-Type";
const CONTENT_TYPE_RON: &str = "application/ron";

async fn req_with_body<T, U>(
    api_name: &str,
    body: U,
    method_fn: fn(&str) -> RequestBuilder,
) -> Result<T>
where
    T: DeserializeOwned,
    U: Serialize,
{
    let url = format!("/ron-api/{}", api_name);
    let request_builder = method_fn(&url).header(CONTENT_TYPE, CONTENT_TYPE_RON);
    send_req(request_builder.body(ron_api::to_string(body))?).await
}

async fn req_with_params<T, U>(
    api_name: &str,
    params: U,
    method_fn: fn(&str) -> RequestBuilder,
) -> Result<T>
where
    T: DeserializeOwned,
    U: Serialize,
{
    let mut url = format!("/ron-api/{}?", api_name);
    serde_html_form::ser::push_to_string(&mut url, params).unwrap();
    let request_builder = method_fn(&url).header(CONTENT_TYPE, CONTENT_TYPE_RON);
    send_req(request_builder.build()?).await
}

async fn send_req<T>(request: Request) -> Result<T>
where
    T: DeserializeOwned,
{
    match request.send().await {
        Err(error) => {
            toast::show_message(Level::Info, &format!("Internal server error: {}", error));
            Err(Error::Gloo(error))
        }
        Ok(response) => {
            if !response.ok() {
                toast::show_message(
                    Level::Info,
                    &format!("HTTP error: {}", response.status_text()),
                );
                Err(Error::Http(response.status_text()))
            } else {
                let mut r = response.binary().await?;
                // An empty response is considered to be an unit value.
                if r.is_empty() {
                    r = b"()".to_vec();
                }
                Ok(ron::de::from_bytes::<T>(&r)?)
            }
        }
    }
}

pub async fn put<T, U>(api_name: &str, body: U) -> Result<T>
where
    T: DeserializeOwned,
    U: Serialize,
{
    req_with_body(api_name, body, Request::put).await
}

pub async fn post<T, U>(api_name: &str, body: U) -> Result<T>
where
    T: DeserializeOwned,
    U: Serialize,
{
    req_with_body(api_name, body, Request::post).await
}

pub async fn delete<T, U>(api_name: &str, body: U) -> Result<T>
where
    T: DeserializeOwned,
    U: Serialize,
{
    req_with_body(api_name, body, Request::delete).await
}

pub async fn get<T, U>(api_name: &str, params: U) -> Result<T>
where
    T: DeserializeOwned,
    U: Serialize,
{
    req_with_params(api_name, params, Request::get).await
}