use anyhow::Context as _;
use gpui::{AppContext, WeakEntity};
use lsp::{LanguageServer, LanguageServerName};
use serde_json::Value;

use crate::{LspStore, ProjectSettings};
use settings::Settings;

struct VueServerRequest;
struct TypescriptServerResponse;

impl lsp::notification::Notification for VueServerRequest {
    type Params = Vec<(u64, String, serde_json::Value)>;

    const METHOD: &'static str = "tsserver/request";
}

impl lsp::notification::Notification for TypescriptServerResponse {
    type Params = Vec<(u64, serde_json::Value)>;

    const METHOD: &'static str = "tsserver/response";
}

const VUE_SERVER_NAME: LanguageServerName = LanguageServerName::new_static("vue-language-server");
const VTSLS: LanguageServerName = LanguageServerName::new_static("vtsls");
const TS_LS: LanguageServerName = LanguageServerName::new_static("typescript-language-server");

pub fn register_requests(lsp_store: WeakEntity<LspStore>, language_server: &LanguageServer) {
    let language_server_name = language_server.name();
    if language_server_name != VUE_SERVER_NAME {
        return;
    }

    let vue_server_id = language_server.server_id();
    language_server
        .on_notification::<VueServerRequest, _>({
            move |params, cx| {
                let lsp_store = lsp_store.clone();
                let Ok(Some(vue_server)) = lsp_store.read_with(cx, |this, _| {
                    this.language_server_for_id(vue_server_id)
                }) else {
                    return;
                };

                let requests = params;
                let target_server = match lsp_store.read_with(cx, |this, _| {
                    let language_server_id = this
                        .as_local()
                        .and_then(|local| {
                            local.language_server_ids.iter().find_map(|(seed, v)| {
                                [VTSLS, TS_LS].contains(&seed.name).then_some(v.id)
                            })
                        })
                        .context("Could not find language server")?;

                    this.language_server_for_id(language_server_id)
                        .context("language server not found")
                }) {
                    Ok(Ok(server)) => server,
                    other => {
                        log::warn!(
                            "vue-language-server forwarding skipped: {other:?}. \
                                Returning null tsserver responses"
                        );
                        if !requests.is_empty() {
                            let null_responses = requests
                                .into_iter()
                                .map(|(id, _, _)| (id, Value::Null))
                                .collect::<Vec<_>>();
                            let _ = vue_server
                                .notify::<TypescriptServerResponse>(null_responses);
                        }
                        return;
                    }
                };

                let cx = cx.clone();
                let request_timeout = cx.update(|app|
                    ProjectSettings::get_global(app)
                    .global_lsp_settings
                    .get_request_timeout()
                );

                for (request_id, command, payload) in requests.into_iter() {
                    let target_server = target_server.clone();
                    let vue_server = vue_server.clone();
                    cx.background_spawn(async move {
                        let response = target_server
                            .request::<lsp::request::ExecuteCommand>(
                                lsp::ExecuteCommandParams {
                                    command: "typescript.tsserverRequest".to_owned(),
                                    arguments: vec![Value::String(command), payload],
                                    ..Default::default()
                                }, request_timeout
                            )
                            .await;

                        let response_body = match response {
                            util::ConnectionResult::Result(Ok(result)) => match result {
                                Some(Value::Object(mut map)) => map
                                    .remove("body")
                                    .unwrap_or(Value::Null),
                                Some(_) => Value::Null,
                                None => Value::Null,
                            },
                            util::ConnectionResult::Result(Err(error)) => {
                                log::warn!(
                                    "typescript.tsserverRequest failed: {error:?} for request {request_id}"
                                );
                                Value::Null
                            }
                            other => {
                                log::warn!(
                                    "typescript.tsserverRequest did not return a response: {other:?} for request {request_id}"
                                );
                                Value::Null
                            }
                        };

                        if let Err(err) = vue_server
                            .notify::<TypescriptServerResponse>(vec![(request_id, response_body)])
                        {
                            log::warn!(
                                "Failed to notify vue-language-server of tsserver response: {err:?}"
                            );
                        }
                    })
                    .detach();
                }
            }
        })
        .detach();
}
