pi-lsp/cli.ts

#!/usr/bin/env -S npx tsx
import * as path from "node:path";
import { startClientForFile } from "./src/client.ts";
import { isLspCommand, listCommands, runCommand } from "./src/commands.ts";
import { pickServer } from "./src/root.ts";
import {
  daemonDiagnostics,
  daemonRequest,
  daemonShutdown,
  daemonStatus,
} from "./src/daemonClient.ts";
import { socketPath } from "./src/daemonProtocol.ts";

// Usage
function usage(): never {
  process.stderr.write(
    `Usage:\n` +
      `  cli.ts <file> <lsp_command> <req_data_json> [--no-daemon]\n` +
      `  cli.ts daemon <status|stop>\n` +
      `\n` +
      `Commands: ${listCommands().join(", ")}\n` +
      `\n` +
      `By default requests are routed through the long-lived pi-lsp\n` +
      `daemon (autospawned). Pass --no-daemon for a one-shot in-process\n` +
      `client (useful for debugging).\n` +
      `\n` +
      `Example:\n` +
      `  cli.ts backend/api/server.go hover '{"position":{"line":223,"character":22}}'\n`,
  );
  process.exit(2);
}

// Daemon Subcommand - `daemon status` / `daemon stop`. Start is implicit:
// any LSP request autospawns the daemon if it isn't running.
async function daemonSubcommand(action: string | undefined): Promise<void> {
  switch (action) {
    case "status": {
      const result = await daemonStatus();
      process.stdout.write(JSON.stringify(result, null, 2) + "\n");
      return;
    }
    case "stop": {
      try {
        const result = await daemonShutdown();
        process.stdout.write(JSON.stringify(result, null, 2) + "\n");
      } catch (err) {
        // Already-stopped daemons surface as connect errors; treat as no-op.
        process.stderr.write(
          `daemon not running (${(err as Error).message})\n`,
        );
      }
      return;
    }
    default:
      process.stderr.write(
        `Usage: cli.ts daemon <status|stop>\nSocket: ${socketPath()}\n`,
      );
      process.exit(2);
  }
}

// Run In-Process - The legacy one-shot path: spawn the LSP server here,
// run the command, dispose, exit. Kept for `--no-daemon` debugging.
async function runInProcess(
  fileArg: string,
  cmdArg: string,
  params: Record<string, unknown>,
): Promise<void> {
  if (!isLspCommand(cmdArg)) {
    process.stderr.write(
      `Unknown command "${cmdArg}". Known: ${listCommands().join(", ")}\n`,
    );
    process.exit(2);
  }
  const filePath = path.resolve(fileArg);
  const server = pickServer(filePath);
  const { client, uri } = await startClientForFile(server, filePath);
  try {
    const result = await runCommand(cmdArg, client, uri, params);
    process.stdout.write(JSON.stringify(result, null, 2) + "\n");
  } finally {
    // Fire-And-Forget Shutdown - With `gopls -remote=auto` (and similar)
    // the spawned process is a thin client to a background daemon; a
    // graceful shutdown can hang the parent. Kick it off but don't wait.
    void client.dispose();
  }
}

// Run Via Daemon - The default path. Hover/definition/references/completion/
// documentSymbol map to specific LSP method strings; diagnostics uses a
// dedicated op since it's notification-driven.
async function runViaDaemon(
  fileArg: string,
  cmdArg: string,
  params: Record<string, unknown>,
): Promise<void> {
  const methodMap: Record<string, string> = {
    hover: "textDocument/hover",
    definition: "textDocument/definition",
    references: "textDocument/references",
    completion: "textDocument/completion",
    documentSymbol: "textDocument/documentSymbol",
  };
  const filePath = path.resolve(fileArg);
  let result: unknown;
  if (cmdArg === "diagnostics") {
    result = await daemonDiagnostics(filePath);
  } else if (cmdArg in methodMap) {
    // References Default - Match commands.ts: include declaration unless
    // caller explicitly overrode `context`.
    if (cmdArg === "references" && !("context" in params)) {
      params.context = { includeDeclaration: true };
    }
    result = await daemonRequest(filePath, methodMap[cmdArg], params);
  } else {
    process.stderr.write(
      `Unknown command "${cmdArg}". Known: ${listCommands().join(", ")}\n`,
    );
    process.exit(2);
  }
  process.stdout.write(JSON.stringify(result, null, 2) + "\n");
}

async function main() {
  const argv = process.argv.slice(2);

  // Daemon Subcommand - First arg is the literal word "daemon".
  if (argv[0] === "daemon") {
    await daemonSubcommand(argv[1]);
    return;
  }

  // Parse Flags - Pull out --no-daemon; positional args are unchanged.
  const noDaemon = argv.includes("--no-daemon");
  const positional = argv.filter((a) => a !== "--no-daemon");
  const [fileArg, cmdArg, jsonArg] = positional;
  if (!fileArg || !cmdArg || jsonArg === undefined) usage();

  // Parse Request JSON
  let params: Record<string, unknown>;
  try {
    params = jsonArg.trim() === "" ? {} : JSON.parse(jsonArg);
  } catch (err) {
    process.stderr.write(
      `Invalid JSON for req_data_json: ${(err as Error).message}\n`,
    );
    process.exit(2);
  }

  if (noDaemon) {
    await runInProcess(fileArg, cmdArg, params);
  } else {
    await runViaDaemon(fileArg, cmdArg, params);
  }
}

main()
  .then(() => {
    // Hard Exit - Any lingering handles (sockets, LSP stdio, daemon stubs)
    // would keep the event loop alive. For a short-lived CLI we just exit.
    process.exit(0);
  })
  .catch((err) => {
    process.stderr.write(`${(err as Error).stack ?? err}\n`);
    process.exit(1);
  });