<?php
declare(strict_types = 1);

namespace LanguageServer;

use LanguageServer\Server\TextDocument;
use LanguageServer\Protocol\{
    ServerCapabilities,
    ClientCapabilities,
    TextDocumentSyncKind,
    Message,
    MessageType,
    InitializeResult
};
use AdvancedJsonRpc\{Dispatcher, ResponseError, Response as ResponseBody, Request as RequestBody};
use Sabre\Event\Loop;

class LanguageServer extends \AdvancedJsonRpc\Dispatcher
{
    /**
     * Handles textDocument/* method calls
     *
     * @var Server\TextDocument
     */
    public $textDocument;

    /**
     * Handles workspace/* method calls
     *
     * @var Server\Workspace
     */
    public $workspace;

    public $telemetry;
    public $window;
    public $completionItem;
    public $codeLens;

    private $protocolReader;
    private $protocolWriter;
    private $client;

    private $project;

    public function __construct(ProtocolReader $reader, ProtocolWriter $writer)
    {
        parent::__construct($this, '/');
        $this->protocolReader = $reader;
        $this->protocolReader->onMessage(function (Message $msg) {
            $err = null;
            $result = null;
            try {
                // Invoke the method handler to get a result
                $result = $this->dispatch($msg->body);
            } catch (ResponseError $e) {
                // If a ResponseError is thrown, send it back in the Response (result will be null)
                $err = $e;
            } catch (Throwable $e) {
                // If an unexpected error occured, send back an INTERNAL_ERROR error response (result will be null)
                $err = new ResponseError(
                    $e->getMessage(),
                    $e->getCode() === 0 ? ErrorCode::INTERNAL_ERROR : $e->getCode(),
                    null,
                    $e
                );
            }
            // Only send a Response for a Request
            // Notifications do not send Responses
            if (RequestBody::isRequest($msg->body)) {
                $this->protocolWriter->write(new Message(new ResponseBody($msg->body->id, $result, $err)));
            }
        });
        $this->protocolWriter = $writer;
        $this->client = new LanguageClient($writer);

        $this->project = new Project($this->client);

        $this->textDocument = new Server\TextDocument($this->project, $this->client);
        $this->workspace = new Server\Workspace($this->project, $this->client);
    }

    /**
     * The initialize request is sent as the first request from the client to the server.
     *
     * @param int $processId The process Id of the parent process that started the server.
     * @param ClientCapabilities $capabilities The capabilities provided by the client (editor)
     * @param string|null $rootPath The rootPath of the workspace. Is null if no folder is open.
     * @return InitializeResult
     */
    public function initialize(int $processId, ClientCapabilities $capabilities, string $rootPath = null): InitializeResult
    {
        // start building project index
        if ($rootPath) {
            $this->indexProject($rootPath);
        }

        $serverCapabilities = new ServerCapabilities();
        // Ask the client to return always full documents (because we need to rebuild the AST from scratch)
        $serverCapabilities->textDocumentSync = TextDocumentSyncKind::FULL;
        // Support "Find all symbols"
        $serverCapabilities->documentSymbolProvider = true;
        // Support "Find all symbols in workspace"
        $serverCapabilities->workspaceSymbolProvider = true;
        // Support "Format Code"
        $serverCapabilities->documentFormattingProvider = true;
        // Support "Go to definition"
        $serverCapabilities->definitionProvider = true;

        return new InitializeResult($serverCapabilities);
    }

    /**
     * The shutdown request is sent from the client to the server. It asks the server to shut down, but to not exit
     * (otherwise the response might not be delivered correctly to the client). There is a separate exit notification that
     * asks the server to exit.
     *
     * @return void
     */
    public function shutdown()
    {

    }

    /**
     * A notification to ask the server to exit its process.
     *
     * @return void
     */
    public function exit()
    {
        exit(0);
    }

    /**
     * Parses workspace files, one at a time.
     *
     * @param string $rootPath The rootPath of the workspace.
     * @return void
     */
    private function indexProject(string $rootPath)
    {
        $fileList = findFilesRecursive($rootPath, '/^.+\.php$/i');
        $numTotalFiles = count($fileList);

        $startTime = microtime(true);
        $fileNum = 0;

        $processFile = function() use (&$fileList, &$fileNum, &$processFile, $rootPath, $numTotalFiles, $startTime) {
            if ($fileNum < $numTotalFiles) {
                $file = $fileList[$fileNum];
                $uri = pathToUri($file);
                $fileNum++;
                $shortName = substr($file, strlen($rootPath) + 1);
                $this->client->window->logMessage(MessageType::INFO, "Parsing file $fileNum/$numTotalFiles: $shortName.");

                $this->project->getDocument($uri)->updateContent(file_get_contents($file));

                Loop\setTimeout($processFile, 0);
            } else {
                $duration = (int)(microtime(true) - $startTime);
                $mem = (int)(memory_get_usage(true) / (1024 * 1024));
                $this->client->window->logMessage(MessageType::INFO, "All PHP files parsed in $duration seconds. $mem MiB allocated.");
            }
        };

        Loop\setTimeout($processFile, 0);
    }
}