#!/usr/bin/env node

import { access } from "node:fs/promises";
import { dirname, join, resolve } from "node:path";
import { fileURLToPath } from "node:url";

// Route production MCP before importing Incur. Incur owns registration helpers
// such as `mcp add`, while the MCP runtime serves the tool catalog over stdio
// or, with `--http`, over streamable HTTP.
const args = process.argv.slice(2);
const { default: packageJson } = await import("../package.json", {
  with: { type: "json" },
});
process.env.REA_PACKAGE_VERSION = packageJson.version;
const isMcpEntry = args[0] === "--mcp" || args[0] === "mcp";
const isMcpMode = isMcpEntry && args.length === 1;
const isMcpDoctorMode = args[0] === "mcp" && args[1] === "doctor";
// Only flags may follow the entry: `mcp add --http` stays Incur's `mcp add`,
// while `mcp -h --http` reaches the HTTP entry's own help.
const isMcpHttpMode =
  isMcpEntry &&
  (args[1]?.startsWith("-") ?? false) &&
  args.slice(1).includes("--http");
/** Exit status of a writer terminated by SIGPIPE (128 + 13). */
const SIGPIPE_EXIT_STATUS = 141;
// Set once the reader of CLI output has closed the pipe.
let stdoutClosed = false;
const packageRoot = resolve(dirname(fileURLToPath(import.meta.url)), "..");

// Windows home lookup throws for an empty USERPROFILE. Dependencies resolve
// home during import, before REA's own resolver can apply its account fallback.
if (process.platform === "win32" && process.env.USERPROFILE === "") {
  delete process.env.USERPROFILE;
}

// Playwright's registry assumes one of its three desktop host platforms when
// it chooses the browser cache directory. Termux reports `android`, although
// its Node runtime and filesystem are POSIX-compatible. Keep the cache path
// explicit so REA can start on Termux. Browser launch still requires a
// caller-supplied Android-compatible Chromium executable.
if (
  process.platform === "android" &&
  process.env.PLAYWRIGHT_BROWSERS_PATH === undefined
) {
  const cacheRoot =
    process.env.XDG_CACHE_HOME ?? join(process.env.HOME ?? ".", ".cache");
  process.env.PLAYWRIGHT_BROWSERS_PATH = join(cacheRoot, "ms-playwright");
}

const runtimeFiles =
  isMcpMode || isMcpHttpMode
    ? ["dist/mcp/main.js"]
    : isMcpDoctorMode
      ? ["dist/mcp/main.js", "dist/cli-runtime/mcpDoctor.js"]
      : [
          "dist/cli-runtime/cli.js",
          "dist/cli-runtime/cliOutput.js",
          "dist/cli-runtime/cliResultOutput.js",
        ];

if (!(await compiledRuntimeExists(runtimeFiles))) {
  process.stderr.write(
    `REA's compiled runtime is missing. Run \`npm ci && npm run build:cached\` in ${packageRoot} to install dependencies and build REA, then restart it. If this is an installed package, reinstall rea-agents.\n`,
  );
  process.exitCode = 1;
} else if (isMcpMode) {
  const { runEntrypoint } = await import("../dist/mcp/main.js");
  await runEntrypoint();
} else if (isMcpHttpMode) {
  const { runMcpHttpEntrypoint } = await import("../dist/mcp/main.js");
  await runMcpHttpEntrypoint(args.slice(1));
} else if (isMcpDoctorMode) {
  guardClosedStdout();
  const { runProductionMcpDoctorCli } =
    await import("../dist/cli-runtime/mcpDoctor.js");
  const result = await runProductionMcpDoctorCli(args.slice(2), {
    dispatcherPath: fileURLToPath(import.meta.url),
    packageRoot,
  });
  writeStdout(result.output);
  process.exitCode = result.exitCode;
} else {
  const { cliConfigurationError, closeCliJavaScriptResources, createCli } =
    await import("../dist/cli-runtime/cli.js");
  const { createCliResultOutput } =
    await import("../dist/cli-runtime/cliResultOutput.js");
  const {
    normalizeCliArguments,
    renderCliOutputArgumentError,
    renderEmptyFilteredCliOutput,
    validateCliOutputArguments,
  } = await import("../dist/cli-runtime/cliOutput.js");
  guardClosedStdout();
  const cliArgs = normalizeCliArguments(args);
  const outputArguments = validateCliOutputArguments(cliArgs);
  const configurationError = cliConfigurationError(process.env);
  let dispatchFailure;
  // Incur can exit from the callback below before this function returns.
  // That callback owns the status, including a closed-pipe exit of 141.
  let exiting = false;
  try {
    // Doctor is the readiness report for this failure. Other commands still stop
    // here so they do not run with an unusable log level.
    if (configurationError !== undefined && !isDoctorCommand(cliArgs)) {
      process.stderr.write(`${configurationError}\n`);
      process.exitCode = 1;
    } else if (!outputArguments.ok) {
      writeStdout(renderCliOutputArgumentError(outputArguments));
      process.exitCode = 1;
    } else {
      let wroteOutput = false;
      const resultOutput = createCliResultOutput(cliArgs, process.stdout);
      try {
        await createCli(process.env, resultOutput).serve(cliArgs, {
          stdout: (output) => {
            if (resultOutput?.handled) {
              if (resultOutput.failed && !stdoutClosed)
                process.stderr.write(output);
              return;
            }
            if (output.length > 0) wroteOutput = true;
            writeStdout(output);
          },
          // A command failure caused by the closed pipe keeps the pipe's status.
          // Worker shutdown is shared with the dispatch finally below. A failed
          // shutdown is reported here because this callback is what exits.
          exit: (code) => {
            exiting = true;
            const status = stdoutClosed ? SIGPIPE_EXIT_STATUS : code;
            void Promise.resolve()
              .then(() => closeCliJavaScriptResources())
              .then(
                () => {
                  process.exit(status);
                },
                (cleanup) => {
                  process.stderr.write(
                    `Failed to close the JavaScript analysis worker: ${cleanupFailureText(cleanup)}\n`,
                  );
                  process.exit(
                    stdoutClosed
                      ? SIGPIPE_EXIT_STATUS
                      : status === 0
                        ? 1
                        : status,
                  );
                },
              );
          },
        });
      } catch (cause) {
        if (wroteOutput) throw cause;
        const recovered = await resultOutput
          ?.recoverFormattingFailure(cause)
          .catch((writeFailure) => {
            // Recovery writes outside Incur's command boundary. A reader that
            // declined this document keeps the same quiet SIGPIPE outcome.
            if (!stdoutClosed) throw writeFailure;
            return true;
          });
        if (!recovered) throw cause;
        process.exitCode = stdoutClosed ? SIGPIPE_EXIT_STATUS : 1;
      }
      if (!wroteOutput && !resultOutput?.handled)
        writeStdout(renderEmptyFilteredCliOutput(cliArgs) ?? "");
    }
  } catch (cause) {
    dispatchFailure = cause;
  } finally {
    // Serve and output rendering can throw after a worker is parked. Stop it
    // on that path too, and keep the dispatch failure when both fail.
    try {
      await closeCliJavaScriptResources();
    } catch (cleanup) {
      // The exit callback reports this same shared failure and then exits.
      if (!exiting) {
        dispatchFailure =
          dispatchFailure === undefined
            ? cleanup
            : new AggregateError(
                [dispatchFailure, cleanup],
                "CLI dispatch failed and the JavaScript analysis worker remained owned",
              );
      }
    }
  }
  if (!exiting && dispatchFailure !== undefined) throw dispatchFailure;
}

/** True when the first positional command is `doctor`, after global output flags. */
function isDoctorCommand(arguments_) {
  const valuedFlags = new Set([
    "--format",
    "--filter-output",
    "--token-limit",
    "--token-offset",
  ]);
  for (let index = 0; index < arguments_.length; index += 1) {
    const argument = arguments_[index];
    if (argument === "--") return arguments_[index + 1] === "doctor";
    if (valuedFlags.has(argument)) {
      index += 1;
      continue;
    }
    if (argument.startsWith("-")) continue;
    return argument === "doctor";
  }
  return false;
}

/**
 * A reader that closes the pipe early, as `rea ... | head` does, has declined
 * the rest of the output. Stop writing without reporting a failure, and exit
 * with the status a SIGPIPE-terminated writer reports. MCP stdio keeps its own
 * client lifecycle.
 */
function cleanupFailureText(cleanup) {
  if (cleanup instanceof Error) return cleanup.stack ?? cleanup.message;
  return String(cleanup);
}

function guardClosedStdout() {
  process.stdout.on("error", (cause) => {
    if (cause?.code === "EPIPE") {
      stdoutClosed = true;
      process.exitCode = SIGPIPE_EXIT_STATUS;
      return;
    }
    // Other failures stay unhandled unless a pending JSON write reports them.
    if (process.stdout.listenerCount("error") === 1) throw cause;
  });
}

function writeStdout(output) {
  if (!stdoutClosed) process.stdout.write(output);
}

async function compiledRuntimeExists(paths) {
  for (const path of paths) {
    try {
      await access(resolve(packageRoot, path));
    } catch (cause) {
      if (isMissing(cause)) return false;
      throw cause;
    }
  }
  return true;
}

function isMissing(cause) {
  return (
    typeof cause === "object" &&
    cause !== null &&
    "code" in cause &&
    cause.code === "ENOENT"
  );
}