import {
    createConnection,
    TextDocuments,
    TextDocument,
    Diagnostic,
    DiagnosticSeverity,
    ProposedFeatures,
    InitializeParams,
    DidChangeConfigurationNotification,
    CompletionItem,
    CompletionItemKind,
    TextDocumentPositionParams
} from 'vscode-languageserver';

// Create a connection for the server. The connection uses Node's IPC as a transport.
// Also include all preview / proposed LSP features.
let connection = createConnection(ProposedFeatures.all);

// Create a simple text document manager. The text document manager
// supports full document sync only
let documents: TextDocuments = new TextDocuments();

let hasConfigurationCapability: boolean = false;
let hasWorkspaceFolderCapability: boolean = false;
let hasDiagnosticRelatedInformationCapability: boolean = false;

connection.onInitialize((params: InitializeParams) => {
    let capabilities = params.capabilities;

    // Does the client support the `workspace/configuration` request?
    // If not, we will fall back using global settings
    hasConfigurationCapability =
        capabilities.workspace && !!capabilities.workspace.configuration;
    hasWorkspaceFolderCapability =
        capabilities.workspace && !!capabilities.workspace.workspaceFolders;
    hasDiagnosticRelatedInformationCapability =
        capabilities.textDocument &&
        capabilities.textDocument.publishDiagnostics &&
        capabilities.textDocument.publishDiagnostics.relatedInformation;

    return {
        capabilities: {
            textDocumentSync: documents.syncKind,
            // Tell the client that the server supports code completion
            completionProvider: {
                resolveProvider: true
        }
    }
    };
});

connection.onInitialized(() => {
    if (hasConfigurationCapability) {
        // Register for all configuration changes.
        connection.client.register(
            DidChangeConfigurationNotification.type,
            undefined
        );
    }
    if (hasWorkspaceFolderCapability) {
        connection.workspace.onDidChangeWorkspaceFolders(_event => {
            connection.console.log('Workspace folder change event received.');
        });
    }
});

// The example settings
interface ExampleSettings {
    maxNumberOfProblems: number;
}

// The global settings, used when the `workspace/configuration` request is not supported by the client.
// Please note that this is not the case when using this server with the client provided in this example
// but could happen with other clients.
const defaultSettings: ExampleSettings = { maxNumberOfProblems: 1000 };
let globalSettings: ExampleSettings = defaultSettings;

// Cache the settings of all open documents
let documentSettings: Map<string, Thenable<ExampleSettings>> = new Map();

connection.onDidChangeConfiguration(change => {
    if (hasConfigurationCapability) {
        // Reset all cached document settings
        documentSettings.clear();
    } else {
        globalSettings = <ExampleSettings>(
            (change.settings.languageServerExample || defaultSettings)
        );
    }

    // Revalidate all open text documents
    documents.all().forEach(validateTextDocument);
});

function getDocumentSettings(resource: string): Thenable<ExampleSettings> {
    if (!hasConfigurationCapability) {
        return Promise.resolve(globalSettings);
    }
    let result = documentSettings.get(resource);
    if (!result) {
        result = connection.workspace.getConfiguration({
            scopeUri: resource,
            section: 'languageServerExample'
        });
        documentSettings.set(resource, result);
    }
    return result;
}

// Only keep settings for open documents
documents.onDidClose(e => {
    documentSettings.delete(e.document.uri);
});

// The content of a text document has changed. This event is emitted
// when the text document first opened or when its content has changed.
documents.onDidChangeContent(change => {
    validateTextDocument(change.document);
});

async function validateTextDocument(textDocument: TextDocument): Promise<void> {
    // In this simple example we get the settings for every validate run.
    let settings = await getDocumentSettings(textDocument.uri);

    // The validator creates diagnostics for all uppercase words length 2 and more
    let text = textDocument.getText();
    let pattern = /\b[A-Z]{2,}\b/g;
    let m: RegExpExecArray;

    let problems = 0;
    let diagnostics: Diagnostic[] = [];
    while ((m = pattern.exec(text)) && problems < settings.maxNumberOfProblems) {
        problems++;
        let diagnostic: Diagnostic = {
            severity: DiagnosticSeverity.Warning,
            range: {
                start: textDocument.positionAt(m.index),
                end: textDocument.positionAt(m.index + m[0].length)
            },
            message: `${m[0]} is all uppercase.`,
            source: 'ex'
        };
        if (hasDiagnosticRelatedInformationCapability) {
            diagnostic.relatedInformation = [
                {
                    location: {
                        uri: textDocument.uri,
                        range: Object.assign({}, diagnostic.range)
                    },
                    message: 'Spelling matters'
                },
                {
                    location: {
                        uri: textDocument.uri,
                        range: Object.assign({}, diagnostic.range)
                    },
                    message: 'Particularly for names'
                }
            ];
        }
        diagnostics.push(diagnostic);
    }

    // Send the computed diagnostics to VSCode.
    connection.sendDiagnostics({ uri: textDocument.uri, diagnostics });
}

connection.onDidChangeWatchedFiles(_change => {
    // Monitored files have change in VSCode
    connection.console.log('We received an file change event');
});

// This handler provides the initial list of the completion items.
connection.onCompletion(
    (_textDocumentPosition: TextDocumentPositionParams): CompletionItem[] => {
    // The pass parameter contains the position of the text document in
    // which code complete got requested. For the example we ignore this
    // info and always provide the same completion items.
    return [
        {
            label: 'TypeScript',
            kind: CompletionItemKind.Text,
            data: 1
        },
        {
            label: 'JavaScript',
            kind: CompletionItemKind.Text,
            data: 2
        }
        ];
    }
);

// This handler resolves additional information for the item selected in
// the completion list.
connection.onCompletionResolve(
    (item: CompletionItem): CompletionItem => {
        if (item.data === 1) {
            item.detail = 'TypeScript details';
            item.documentation = 'TypeScript documentation';
        } else if (item.data === 2) {
            item.detail = 'JavaScript details';
            item.documentation = 'JavaScript documentation';
        }
        return item;
    }
);


/*
connection.onDidOpenTextDocument((params) => {
    // A text document got opened in VSCode.
    // params.uri uniquely identifies the document. For documents store on disk this is a file URI.
    // params.text the initial full content of the document.
    connection.console.log(`${params.textDocument.uri} opened.`);
});
connection.onDidChangeTextDocument((params) => {
    // The content of a text document did change in VSCode.
    // params.uri uniquely identifies the document.
    // params.contentChanges describe the content changes to the document.
    connection.console.log(`${params.textDocument.uri} changed: ${JSON.stringify(params.contentChanges)}`);
});
connection.onDidCloseTextDocument((params) => {
    // A text document got closed in VSCode.
    // params.uri uniquely identifies the document.
    connection.console.log(`${params.textDocument.uri} closed.`);
});
*/

// Make the text document manager listen on the connection
// for open, change and close text document events
documents.listen(connection);

// Listen on the connection
connection.listen();