feat: TypeScript installation wizard with @clack/prompts TUI (#1)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

src/platform/detect.ts

@@ -0,0 +1,44 @@
+import { existsSync } from 'node:fs';
+import { join } from 'node:path';
+import { homedir, platform } from 'node:os';
+
+export type ShellType = 'zsh' | 'bash' | 'fish' | 'powershell' | 'unknown';
+
+export function detectShell(): ShellType {
+  const shell = process.env.SHELL ?? '';
+  if (shell.includes('zsh')) return 'zsh';
+  if (shell.includes('bash')) return 'bash';
+  if (shell.includes('fish')) return 'fish';
+  if (platform() === 'win32') return 'powershell';
+  return 'unknown';
+}
+
+export function getShellProfilePath(): string | null {
+  const home = homedir();
+
+  if (platform() === 'win32') {
+    return join(
+      home,
+      'Documents',
+      'PowerShell',
+      'Microsoft.PowerShell_profile.ps1',
+    );
+  }
+
+  const shell = detectShell();
+  switch (shell) {
+    case 'zsh': {
+      const zdotdir = process.env.ZDOTDIR ?? home;
+      return join(zdotdir, '.zshrc');
+    }
+    case 'bash': {
+      const bashrc = join(home, '.bashrc');
+      if (existsSync(bashrc)) return bashrc;
+      return join(home, '.profile');
+    }
+    case 'fish':
+      return join(home, '.config', 'fish', 'config.fish');
+    default:
+      return join(home, '.profile');
+  }
+}

src/platform/file-ops.ts

@@ -0,0 +1,116 @@
+import {
+  readFileSync,
+  writeFileSync,
+  existsSync,
+  mkdirSync,
+  copyFileSync,
+  renameSync,
+  readdirSync,
+  unlinkSync,
+  cpSync,
+  statSync,
+} from 'node:fs';
+import { dirname, join, relative } from 'node:path';
+
+const MAX_BACKUPS = 3;
+
+/**
+ * Atomic write: write to temp file, then rename.
+ * Creates parent directories as needed.
+ */
+export function atomicWrite(filePath: string, content: string): void {
+  mkdirSync(dirname(filePath), { recursive: true });
+  const tmpPath = `${filePath}.tmp-${process.pid}`;
+  writeFileSync(tmpPath, content, 'utf-8');
+  renameSync(tmpPath, filePath);
+}
+
+/**
+ * Create a backup of a file before overwriting.
+ * Rotates backups to keep at most MAX_BACKUPS.
+ */
+export function backupFile(filePath: string): string | null {
+  if (!existsSync(filePath)) return null;
+  const timestamp = new Date()
+    .toISOString()
+    .replace(/[:.]/g, '')
+    .replace('T', '-')
+    .slice(0, 19);
+  const backupPath = `${filePath}.bak-${timestamp}`;
+  copyFileSync(filePath, backupPath);
+  rotateBackups(filePath);
+  return backupPath;
+}
+
+function rotateBackups(filePath: string): void {
+  const dir = dirname(filePath);
+  const baseName = filePath.split('/').pop()!;
+  const prefix = `${baseName}.bak-`;
+
+  try {
+    const backups = readdirSync(dir)
+      .filter((f) => f.startsWith(prefix))
+      .sort()
+      .reverse();
+
+    for (let i = MAX_BACKUPS; i < backups.length; i++) {
+      unlinkSync(join(dir, backups[i]));
+    }
+  } catch {
+    // Non-fatal: backup rotation failure doesn't block writes
+  }
+}
+
+/**
+ * Sync a source directory to a target, with optional preserve paths.
+ * Replaces the rsync/cp logic from install.sh.
+ */
+export function syncDirectory(
+  source: string,
+  target: string,
+  options: { preserve?: string[]; excludeGit?: boolean } = {},
+): void {
+  const preserveSet = new Set(options.preserve ?? []);
+
+  // Collect files from source
+  function copyRecursive(src: string, dest: string, relBase: string): void {
+    if (!existsSync(src)) return;
+
+    const stat = statSync(src);
+    if (stat.isDirectory()) {
+      const relPath = relative(relBase, src);
+
+      // Skip .git
+      if (options.excludeGit && relPath === '.git') return;
+
+      // Skip preserved paths at top level
+      if (preserveSet.has(relPath) && existsSync(dest)) return;
+
+      mkdirSync(dest, { recursive: true });
+      for (const entry of readdirSync(src)) {
+        copyRecursive(join(src, entry), join(dest, entry), relBase);
+      }
+    } else {
+      const relPath = relative(relBase, src);
+
+      // Skip preserved files at top level
+      if (preserveSet.has(relPath) && existsSync(dest)) return;
+
+      mkdirSync(dirname(dest), { recursive: true });
+      copyFileSync(src, dest);
+    }
+  }
+
+  copyRecursive(source, target, source);
+}
+
+/**
+ * Safely read a file, returning null if it doesn't exist.
+ */
+export function safeReadFile(filePath: string): string | null {
+  try {
+    return readFileSync(filePath, 'utf-8');
+  } catch {
+    return null;
+  }
+}