use crate::syntax_tokens::semantic_tokens;
use crate::utils::UriUtils;
use crate::workspace::{Workspace, start_workspace_thread};
use std::sync::Arc;
use tokio::sync::RwLock;
use tower_lsp_server::jsonrpc::Result;
use tower_lsp_server::ls_types::request::{GotoDeclarationParams, GotoDeclarationResponse};
use tower_lsp_server::{Client, LspService, Server};
use tower_lsp_server::{LanguageServer, ls_types::*};

mod syntax_tokens;
mod utils;
mod workspace;

struct Backend {
	client: Client,
	workspaces: RwLock<Vec<Arc<Workspace>>>,
}

impl LanguageServer for Backend {
	async fn initialize(&self, params: InitializeParams) -> Result<InitializeResult> {
		let mut workspaces = self.workspaces.write().await;
		for workspace in workspaces.drain(..) {
			workspace.close().await;
		}

		for folder in params.workspace_folders.iter().flatten() {
			workspaces
				.push(start_workspace_thread(folder.uri.clone(), self.client.clone()).unwrap());
		}

		Ok(InitializeResult {
			capabilities: ServerCapabilities {
				hover_provider: Some(HoverProviderCapability::Simple(true)),
				definition_provider: Some(OneOf::Left(true)),
				declaration_provider: Some(DeclarationCapability::Simple(true)),
				text_document_sync: Some(TextDocumentSyncCapability::Options(
					TextDocumentSyncOptions {
						save: Some(TextDocumentSyncSaveOptions::SaveOptions(SaveOptions {
							include_text: Some(false),
						})),
						change: Some(TextDocumentSyncKind::INCREMENTAL),
						..Default::default()
					},
				)),
				semantic_tokens_provider: Some(
					SemanticTokensServerCapabilities::SemanticTokensOptions(
						SemanticTokensOptions {
							legend: SemanticTokensLegend {
								token_types: semantic_tokens::TOKENS.to_vec(),
								token_modifiers: vec![],
							},
							full: Some(SemanticTokensFullOptions::Bool(true)),
							range: Some(false),
							..Default::default()
						},
					),
				),
				..Default::default()
			},
			..Default::default()
		})
	}

	async fn initialized(&self, _: InitializedParams) {
		self.client
			.log_message(MessageType::INFO, "server initialized!")
			.await;
	}

	async fn hover(&self, params: HoverParams) -> Result<Option<Hover>> {
		if let Some(w) = self
			.find_workspace(&params.text_document_position_params.text_document.uri)
			.await
		{
			return Ok(w.hover(params).await);
		}
		Ok(None)
	}

	async fn goto_declaration(
		&self,
		params: GotoDeclarationParams,
	) -> Result<Option<GotoDeclarationResponse>> {
		if let Some(w) = self
			.find_workspace(&params.text_document_position_params.text_document.uri)
			.await
		{
			return Ok(w.go_to_declaration(params).await);
		}
		Ok(None)
	}

	async fn goto_definition(
		&self,
		params: GotoDeclarationParams,
	) -> Result<Option<GotoDeclarationResponse>> {
		if let Some(w) = self
			.find_workspace(&params.text_document_position_params.text_document.uri)
			.await
		{
			return Ok(w.go_to_declaration(params).await);
		}
		Ok(None)
	}

	async fn did_change(&self, params: DidChangeTextDocumentParams) {
		if let Some(w) = self.find_workspace(&params.text_document.uri).await {
			w.file_changed(params).await;
		}
	}

	async fn did_save(&self, params: DidSaveTextDocumentParams) {
		if let Some(w) = self.find_workspace(&params.text_document.uri).await {
			w.reload().await;
		}
	}

	async fn semantic_tokens_full(
		&self,
		params: SemanticTokensParams,
	) -> Result<Option<SemanticTokensResult>> {
		if let Some(w) = self.find_workspace(&params.text_document.uri).await {
			return Ok(w.semantic_tokens(params).await);
		}
		Ok(None)
	}

	async fn shutdown(&self) -> Result<()> {
		let mut workspaces = self.workspaces.write().await;
		for workspace in workspaces.drain(..) {
			workspace.close().await;
		}
		Ok(())
	}
}

impl Backend {
	pub async fn find_workspace(&self, file: &Uri) -> Option<Arc<Workspace>> {
		let workspaces = self.workspaces.read().await;
		let path = file.strip_header();
		workspaces
			.iter()
			.find(|w| path.starts_with(&w.base))
			.cloned()
	}
}

#[tokio::main]
async fn main() {
	let stdin = tokio::io::stdin();
	let stdout = tokio::io::stdout();

	let (service, socket) = LspService::new(|client| Backend {
		client,
		workspaces: RwLock::default(),
	});
	Server::new(stdin, stdout, socket).serve(service).await;
}