import * as cp from 'child_process';
import * as path from 'path';
import * as vscode from 'vscode';
import {
  LanguageClient,
  LanguageClientOptions,
  ServerOptions,
  TransportKind,
} from 'vscode-languageclient/node';

let client: LanguageClient | undefined;
let outputChannel: vscode.OutputChannel;

export function activate(context: vscode.ExtensionContext): void {
  outputChannel = vscode.window.createOutputChannel('PgTidy');
  context.subscriptions.push(outputChannel);

  // Commands are always registered so they work even when the LSP is disabled.
  context.subscriptions.push(
    vscode.commands.registerCommand('pgtidy.showVersion', cmdShowVersion),
    vscode.commands.registerCommand('pgtidy.showConfig', cmdShowConfig),
    vscode.commands.registerCommand('pgtidy.formatDocument', cmdFormatDocument),
  );

  const cfg = vscode.workspace.getConfiguration('pgtidy');
  if (!cfg.get<boolean>('enable', true)) {
    return;
  }

  const bin = cfg.get<string>('path', 'pgtidy');

  const serverOptions: ServerOptions = {
    command: bin,
    args: ['lsp'],
    transport: TransportKind.stdio,
  };

  const clientOptions: LanguageClientOptions = {
    documentSelector: [{ scheme: 'file', language: 'sql' }],
    synchronize: {
      fileEvents: vscode.workspace.createFileSystemWatcher('**/*.{sql,pgsql}'),
    },
  };

  client = new LanguageClient('pgtidy', 'PgTidy', serverOptions, clientOptions);
  context.subscriptions.push(client);
  client.start();
}

export function deactivate(): Thenable<void> | undefined {
  return client?.stop();
}

function binary(): string {
  return vscode.workspace.getConfiguration('pgtidy').get<string>('path', 'pgtidy');
}

function contextDir(): string | undefined {
  const folders = vscode.workspace.workspaceFolders;
  if (folders && folders.length > 0) {
    return folders[0].uri.fsPath;
  }
  const doc = vscode.window.activeTextEditor?.document;
  if (doc && !doc.isUntitled) {
    return path.dirname(doc.uri.fsPath);
  }
  return undefined;
}

function cmdShowVersion(): void {
  cp.execFile(binary(), ['version'], (err, stdout, stderr) => {
    if (err) {
      vscode.window.showErrorMessage(`PgTidy: ${stderr.trim() || err.message}`);
      return;
    }
    vscode.window.showInformationMessage(stdout.trim());
  });
}

function cmdShowConfig(): void {
  const cwd = contextDir();
  cp.execFile(binary(), ['config'], { cwd }, (err, stdout, stderr) => {
    if (err) {
      vscode.window.showErrorMessage(`PgTidy: ${stderr.trim() || err.message}`);
      return;
    }
    outputChannel.clear();
    outputChannel.appendLine('PgTidy — effective configuration');
    if (cwd) {
      outputChannel.appendLine(`(resolved from: ${cwd})`);
    }
    outputChannel.appendLine('');
    outputChannel.append(stdout);
    outputChannel.show(true);
  });
}

async function cmdFormatDocument(): Promise<void> {
  const editor = vscode.window.activeTextEditor;
  if (!editor) {
    vscode.window.showWarningMessage('PgTidy: no active editor');
    return;
  }
  await vscode.commands.executeCommand('editor.action.formatDocument');
}