/**
 * Regression tests for issue #208 — "Plain shell PTY exits with code 1 after
 * successful tmux creation in Docker".
 *
 * The shell-mode pane command used to be the literal string `$SHELL`. It ends up
 * inside the `bash -c "…"` argument of the respawn-pane line, which execSync runs
 * through `/bin/sh -c`, so it was expanded by the SERVER process's shell against
 * the SERVER process's env. Containers (and system-level systemd units) do not set
 * SHELL, so it expanded to nothing and the pane command ended in a dangling `&&`:
 *
 *   bash: -c: line 1: syntax error: unexpected end of file
 *
 * These tests pin the resolver's guarantees and assert that a shell launch command
 * survives the outer `sh -c` layer with an unset SHELL.
 */

import { describe, it, expect, beforeEach, afterEach } from 'vitest';
import { execFileSync } from 'node:child_process';
import { buildSpawnCommand } from '../src/tmux-manager.js';
import { resolveLocalShell } from '../src/utils/shell-resolver.js';

describe('resolveLocalShell', () => {
  const originalShell = process.env.SHELL;

  afterEach(() => {
    if (originalShell === undefined) delete process.env.SHELL;
    else process.env.SHELL = originalShell;
  });

  it('returns an absolute executable path when SHELL is unset (container case)', () => {
    delete process.env.SHELL;
    const shell = resolveLocalShell();
    expect(shell).not.toBe('');
    expect(shell.startsWith('/')).toBe(true);
    // Proves the resolved path is really launchable, not just a plausible string.
    expect(execFileSync(shell, ['-c', 'echo ok'], { encoding: 'utf8' }).trim()).toBe('ok');
  });

  it('returns an absolute executable path when SHELL is empty or whitespace', () => {
    for (const value of ['', '   ']) {
      process.env.SHELL = value;
      const shell = resolveLocalShell();
      expect(shell.startsWith('/')).toBe(true);
      expect(execFileSync(shell, ['-c', 'echo ok'], { encoding: 'utf8' }).trim()).toBe('ok');
    }
  });

  it('honors a valid $SHELL', () => {
    process.env.SHELL = '/bin/sh';
    expect(resolveLocalShell()).toBe('/bin/sh');
  });

  it('ignores a $SHELL that does not exist', () => {
    process.env.SHELL = '/nonexistent/shell-that-is-not-here';
    const shell = resolveLocalShell();
    expect(shell).not.toBe('/nonexistent/shell-that-is-not-here');
    expect(shell.startsWith('/')).toBe(true);
  });

  it('ignores a relative $SHELL (never emits a bare word into the launch command)', () => {
    process.env.SHELL = 'bash';
    expect(resolveLocalShell().startsWith('/')).toBe(true);
  });

  it('ignores nologin-style stubs that would exit instantly', () => {
    process.env.SHELL = '/usr/sbin/nologin';
    expect(resolveLocalShell()).not.toContain('nologin');
    process.env.SHELL = '/bin/false';
    expect(resolveLocalShell()).not.toBe('/bin/false');
  });
});

describe('shell-mode spawn command (issue #208)', () => {
  const originalShell = process.env.SHELL;

  beforeEach(() => {
    delete process.env.SHELL;
  });

  afterEach(() => {
    if (originalShell === undefined) delete process.env.SHELL;
    else process.env.SHELL = originalShell;
  });

  it('never emits an unexpanded $SHELL into the pane command', () => {
    const cmd = buildSpawnCommand({ mode: 'shell', sessionId: 'abc123de-0000-0000-0000-000000000000' });
    expect(cmd).not.toContain('$SHELL');
    expect(cmd.trim()).not.toBe('');
  });

  it('produces a launch command that parses after the outer sh -c expansion layer', () => {
    const cmd = buildSpawnCommand({ mode: 'shell', sessionId: 'abc123de-0000-0000-0000-000000000000' });
    // Mirrors tmux-manager: `… bash -c ${JSON.stringify(launchCmd)}` handed to `sh -c`.
    const launchCmd = `cd ${JSON.stringify('/tmp')} && export CODEMAN_MUX=1 && ${cmd}`;
    const outer = `bash -n -c ${JSON.stringify(launchCmd)}`;

    // `bash -n` parses without executing: exits 0 on the fix, 2 with the dangling `&&`.
    const result = execFileSync('/bin/sh', ['-c', `${outer}; echo "rc=$?"`], { encoding: 'utf8' });
    expect(result).toContain('rc=0');
    expect(result).not.toContain('unexpected end of file');
  });
});