use anyhow::Result;
use async_trait::async_trait;
use gpui::AsyncApp;
use language::{
    LspAdapter, LspAdapterDelegate, LspInstaller, Toolchain, language_settings::AllLanguageSettings,
};
use lsp::{LanguageServerBinary, LanguageServerName, Uri};
use node_runtime::{NodeRuntime, VersionStrategy};
use project::lsp_store::language_server_settings;
use semver::Version;
use serde_json::Value;
use settings::{Settings, SettingsLocation};
use std::{
    ffi::OsString,
    future::Future,
    path::{Path, PathBuf},
    sync::Arc,
};
use util::{ResultExt, maybe, merge_json_value_into, rel_path::RelPath};

const SERVER_PATH: &str = "node_modules/yaml-language-server/bin/yaml-language-server";

fn server_binary_arguments(server_path: &Path) -> Vec<OsString> {
    vec![server_path.into(), "--stdio".into()]
}

pub struct YamlLspAdapter {
    node: NodeRuntime,
}

impl YamlLspAdapter {
    const SERVER_NAME: LanguageServerName = LanguageServerName::new_static("yaml-language-server");
    const PACKAGE_NAME: &str = "yaml-language-server";
    pub fn new(node: NodeRuntime) -> Self {
        YamlLspAdapter { node }
    }
}

impl LspInstaller for YamlLspAdapter {
    type BinaryVersion = Version;

    async fn fetch_latest_server_version(
        &self,
        _: &dyn LspAdapterDelegate,
        _: bool,
        _: &mut AsyncApp,
    ) -> Result<Self::BinaryVersion> {
        self.node
            .npm_package_latest_version("yaml-language-server")
            .await
    }

    async fn check_if_user_installed(
        &self,
        delegate: &dyn LspAdapterDelegate,
        _: Option<Toolchain>,
        _: &AsyncApp,
    ) -> Option<LanguageServerBinary> {
        let path = delegate.which(Self::SERVER_NAME.as_ref()).await?;
        let env = delegate.shell_env().await;

        Some(LanguageServerBinary {
            path,
            env: Some(env),
            arguments: vec!["--stdio".into()],
        })
    }

    fn fetch_server_binary(
        &self,
        latest_version: Self::BinaryVersion,
        container_dir: PathBuf,
        _: &Arc<dyn LspAdapterDelegate>,
    ) -> impl Send + Future<Output = Result<LanguageServerBinary>> + use<> {
        let node = self.node.clone();

        async move {
            let server_path = container_dir.join(SERVER_PATH);
            let latest_version = latest_version.to_string();

            node.npm_install_packages(
                &container_dir,
                &[(Self::PACKAGE_NAME, latest_version.as_str())],
            )
            .await?;

            Ok(LanguageServerBinary {
                path: node.binary_path().await?,
                env: None,
                arguments: server_binary_arguments(&server_path),
            })
        }
    }

    fn check_if_version_installed(
        &self,
        version: &Self::BinaryVersion,
        container_dir: &PathBuf,
        _: &Arc<dyn LspAdapterDelegate>,
    ) -> impl Send + Future<Output = Option<LanguageServerBinary>> + use<> {
        let node = self.node.clone();
        let version = version.clone();
        let container_dir = container_dir.clone();

        async move {
            let server_path = container_dir.join(SERVER_PATH);

            let should_install_language_server = node
                .should_install_npm_package(
                    Self::PACKAGE_NAME,
                    &server_path,
                    &container_dir,
                    VersionStrategy::Latest(&version),
                )
                .await;

            if should_install_language_server {
                None
            } else {
                Some(LanguageServerBinary {
                    path: node.binary_path().await.ok()?,
                    env: None,
                    arguments: server_binary_arguments(&server_path),
                })
            }
        }
    }

    async fn cached_server_binary(
        &self,
        container_dir: PathBuf,
        _: &dyn LspAdapterDelegate,
    ) -> Option<LanguageServerBinary> {
        get_cached_server_binary(container_dir, &self.node).await
    }
}

#[async_trait(?Send)]
impl LspAdapter for YamlLspAdapter {
    fn name(&self) -> LanguageServerName {
        Self::SERVER_NAME
    }

    async fn workspace_configuration(
        self: Arc<Self>,
        delegate: &Arc<dyn LspAdapterDelegate>,
        _: Option<Toolchain>,
        _: Option<Uri>,
        cx: &mut AsyncApp,
    ) -> Result<Value> {
        let location = SettingsLocation {
            worktree_id: delegate.worktree_id(),
            path: RelPath::empty(),
        };

        let tab_size = cx.update(|cx| {
            AllLanguageSettings::get(Some(location), cx)
                .language(Some(location), Some(&"YAML".into()), cx)
                .tab_size
        });

        let mut options = serde_json::json!({
            "[yaml]": {"editor.tabSize": tab_size},
            "yaml": {"format": {"enable": true}}
        });

        let project_options = cx.update(|cx| {
            language_server_settings(delegate.as_ref(), &Self::SERVER_NAME, cx)
                .and_then(|s| worktree_root(delegate, s.settings.clone()))
        });
        if let Some(override_options) = project_options {
            merge_json_value_into(override_options, &mut options);
        }
        Ok(options)
    }
}

fn worktree_root(delegate: &Arc<dyn LspAdapterDelegate>, settings: Option<Value>) -> Option<Value> {
    let Some(Value::Object(mut settings_map)) = settings else {
        return settings;
    };

    let Some(Value::Object(yaml_config)) = settings_map.get_mut("yaml") else {
        return Some(Value::Object(settings_map));
    };

    let Some(Value::Object(schemas)) = yaml_config.remove("schemas") else {
        return Some(Value::Object(settings_map));
    };

    let schemas = schemas
        .into_iter()
        .map(|(url, v)| {
            if !url.starts_with(".") && !url.starts_with("~") {
                (url, v)
            } else {
                let resolved_url = delegate
                    .resolve_relative_path(url.into())
                    .to_string_lossy()
                    .into_owned();
                (resolved_url, v)
            }
        })
        .collect::<serde_json::Map<String, Value>>();

    yaml_config.insert("schemas".into(), Value::Object(schemas));
    Some(Value::Object(settings_map))
}

async fn get_cached_server_binary(
    container_dir: PathBuf,
    node: &NodeRuntime,
) -> Option<LanguageServerBinary> {
    maybe!(async {
        let server_path = container_dir.join(SERVER_PATH);
        anyhow::ensure!(
            server_path.exists(),
            "missing executable in directory {server_path:?}"
        );
        Ok(LanguageServerBinary {
            path: node.binary_path().await?,
            env: None,
            arguments: server_binary_arguments(&server_path),
        })
    })
    .await
    .log_err()
}
