Initial commit

README.md

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+# Sigil
+
+Minimal dotfile symlink manager with per-package Lua config.
+
+## Install (dev)
+
+```
+go run . <command>
+```
+
+## Commands
+
+- `sigil apply` - apply symlinks from `~/.dotfiles`
+- `sigil add <path>` - add an existing file or folder
+
+## Repo layout
+
+```
+~/.dotfiles/
+  nvim/
+    config.lua
+    files/
+      init.lua
+```
+
+## `config.lua`
+
+```lua
+return {
+  target = {
+    linux = "~/.config/nvim",
+    macos = "~/Library/Application Support/nvim",
+    default = "~/.config/nvim",
+  },
+}
+```
+
+## Notes
+
+- Uses `SIGIL_REPO` env var to override the repo path.
+- Conflicts are detected (existing non-symlink files will stop apply).

go.mod

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+module sigil
+
+go 1.25.7
+
+require github.com/yuin/gopher-lua v1.1.1

go.sum

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+github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
+github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=

main.go

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+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	lua "github.com/yuin/gopher-lua"
+)
+
+const (
+	configFileName = "config.lua"
+	filesDirName   = "files"
+)
+
+type packageConfig struct {
+	targets map[string]string
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		usage()
+		os.Exit(1)
+	}
+
+	var err error
+	switch os.Args[1] {
+	case "apply":
+		err = applyCmd()
+	case "add":
+		err = addCmd(os.Args[2:])
+	case "help", "-h", "--help":
+		usage()
+		return
+	default:
+		err = fmt.Errorf("unknown command %q", os.Args[1])
+	}
+
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "sigil:", err)
+		os.Exit(1)
+	}
+}
+
+func usage() {
+	fmt.Println("sigil: minimal dotfile symlink manager")
+	fmt.Println("usage:")
+	fmt.Println("  sigil apply")
+	fmt.Println("  sigil add <path>")
+}
+
+func applyCmd() error {
+	repo, err := repoPath()
+	if err != nil {
+		return err
+	}
+
+	entries, err := os.ReadDir(repo)
+	if err != nil {
+		return err
+	}
+
+	for _, entry := range entries {
+		if !entry.IsDir() || strings.HasPrefix(entry.Name(), ".") {
+			continue
+		}
+
+		pkgDir := filepath.Join(repo, entry.Name())
+		configPath := filepath.Join(pkgDir, configFileName)
+		if _, err := os.Stat(configPath); err != nil {
+			if errors.Is(err, os.ErrNotExist) {
+				continue
+			}
+			return err
+		}
+
+		cfg, err := loadConfig(configPath)
+		if err != nil {
+			return fmt.Errorf("%s: %w", entry.Name(), err)
+		}
+
+		targetRoot, err := selectTarget(cfg.targets)
+		if err != nil {
+			return fmt.Errorf("%s: %w", entry.Name(), err)
+		}
+
+		filesDir := filepath.Join(pkgDir, filesDirName)
+		if _, err := os.Stat(filesDir); err != nil {
+			if errors.Is(err, os.ErrNotExist) {
+				continue
+			}
+			return err
+		}
+
+		if err := applyPackage(filesDir, targetRoot); err != nil {
+			return fmt.Errorf("%s: %w", entry.Name(), err)
+		}
+	}
+
+	return nil
+}
+
+func addCmd(args []string) error {
+	if len(args) < 1 {
+		return errors.New("missing path")
+	}
+
+	absPath, err := filepath.Abs(args[0])
+	if err != nil {
+		return err
+	}
+
+	info, err := os.Lstat(absPath)
+	if err != nil {
+		return err
+	}
+	if info.Mode()&os.ModeSymlink != 0 {
+		return fmt.Errorf("%s is a symlink; refusing to add", absPath)
+	}
+
+	repo, err := repoPath()
+	if err != nil {
+		return err
+	}
+	if err := os.MkdirAll(repo, 0o755); err != nil {
+		return err
+	}
+
+	defaultTarget := absPath
+	if !info.IsDir() {
+		defaultTarget = filepath.Dir(absPath)
+	}
+
+	defaultPkg := filepath.Base(defaultTarget)
+	if info.IsDir() {
+		defaultPkg = filepath.Base(absPath)
+	}
+
+	reader := bufio.NewReader(os.Stdin)
+	pkgName := promptWithDefault(reader, "Package name", defaultPkg)
+	if pkgName == "" {
+		return errors.New("package name cannot be empty")
+	}
+
+	targetRootInput := promptWithDefault(reader, "Target path", defaultTarget)
+	targetRoot, err := filepath.Abs(expandHome(targetRootInput))
+	if err != nil {
+		return err
+	}
+
+	pkgDir := filepath.Join(repo, pkgName)
+	if _, err := os.Stat(pkgDir); err == nil {
+		return fmt.Errorf("package %q already exists", pkgName)
+	} else if !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+
+	filesDir := filepath.Join(pkgDir, filesDirName)
+	if err := os.MkdirAll(filesDir, 0o755); err != nil {
+		return err
+	}
+
+	configPath := filepath.Join(pkgDir, configFileName)
+	if err := writeConfig(configPath, targetRoot); err != nil {
+		return err
+	}
+
+	if info.IsDir() {
+		if err := moveDirContents(absPath, filesDir); err != nil {
+			return err
+		}
+	} else {
+		rel, err := filepath.Rel(targetRoot, absPath)
+		if err != nil {
+			return err
+		}
+		if strings.HasPrefix(rel, "..") {
+			return fmt.Errorf("path %s is outside target %s", absPath, targetRoot)
+		}
+
+		destPath := filepath.Join(filesDir, rel)
+		if err := os.MkdirAll(filepath.Dir(destPath), 0o755); err != nil {
+			return err
+		}
+		if err := os.Rename(absPath, destPath); err != nil {
+			return err
+		}
+	}
+
+	return applyPackage(filesDir, targetRoot)
+}
+
+func applyPackage(filesDir, targetRoot string) error {
+	if err := ensureDir(targetRoot); err != nil {
+		return err
+	}
+
+	return filepath.WalkDir(filesDir, func(path string, entry fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if path == filesDir {
+			return nil
+		}
+
+		rel, err := filepath.Rel(filesDir, path)
+		if err != nil {
+			return err
+		}
+		targetPath := filepath.Join(targetRoot, rel)
+
+		if entry.IsDir() {
+			return ensureDir(targetPath)
+		}
+
+		srcAbs, err := filepath.Abs(path)
+		if err != nil {
+			return err
+		}
+		return linkFile(srcAbs, targetPath)
+	})
+}
+
+func linkFile(src, dst string) error {
+	if err := os.MkdirAll(filepath.Dir(dst), 0o755); err != nil {
+		return err
+	}
+
+	if info, err := os.Lstat(dst); err == nil {
+		if info.Mode()&os.ModeSymlink != 0 {
+			current, err := os.Readlink(dst)
+			if err != nil {
+				return err
+			}
+			if current == src {
+				return nil
+			}
+			return fmt.Errorf("conflict at %s (points to %s)", dst, current)
+		}
+		return fmt.Errorf("conflict at %s (exists and is not a symlink)", dst)
+	} else if !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+
+	return os.Symlink(src, dst)
+}
+
+func ensureDir(path string) error {
+	info, err := os.Lstat(path)
+	if err == nil {
+		if info.IsDir() {
+			return nil
+		}
+		return fmt.Errorf("%s exists and is not a directory", path)
+	}
+	if !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+	return os.MkdirAll(path, 0o755)
+}
+
+func loadConfig(path string) (*packageConfig, error) {
+	L := lua.NewState()
+	defer L.Close()
+	lua.OpenLibraries(L)
+
+	if err := L.DoFile(path); err != nil {
+		return nil, err
+	}
+	if L.GetTop() == 0 {
+		return nil, errors.New("config.lua must return a table")
+	}
+
+	value := L.Get(-1)
+	tbl, ok := value.(*lua.LTable)
+	if !ok {
+		return nil, errors.New("config.lua must return a table")
+	}
+
+	targetVal := tbl.RawGetString("target")
+	targetTbl, ok := targetVal.(*lua.LTable)
+	if !ok {
+		return nil, errors.New("config.target must be a table")
+	}
+
+	targets := make(map[string]string)
+	targetTbl.ForEach(func(k, v lua.LValue) {
+		ks, ok1 := k.(lua.LString)
+		vs, ok2 := v.(lua.LString)
+		if ok1 && ok2 {
+			targets[string(ks)] = expandHome(string(vs))
+		}
+	})
+
+	if len(targets) == 0 {
+		return nil, errors.New("config.target is empty")
+	}
+
+	return &packageConfig{targets: targets}, nil
+}
+
+func selectTarget(targets map[string]string) (string, error) {
+	osKey := runtime.GOOS
+	if osKey == "darwin" {
+		osKey = "macos"
+	}
+	if target, ok := targets[osKey]; ok {
+		return expandHome(target), nil
+	}
+	if target, ok := targets["default"]; ok {
+		return expandHome(target), nil
+	}
+	return "", fmt.Errorf("missing target for %s and default", osKey)
+}
+
+func repoPath() (string, error) {
+	if override := os.Getenv("SIGIL_REPO"); override != "" {
+		return filepath.Abs(expandHome(override))
+	}
+	return filepath.Abs(expandHome("~/.dotfiles"))
+}
+
+func expandHome(path string) string {
+	if path == "~" {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return path
+		}
+		return home
+	}
+	if strings.HasPrefix(path, "~/") {
+		home, err := os.UserHomeDir()
+		if err != nil {
+			return path
+		}
+		return filepath.Join(home, path[2:])
+	}
+	return path
+}
+
+func compressHome(path string) string {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return path
+	}
+	clean := filepath.Clean(path)
+	homeClean := filepath.Clean(home)
+	if clean == homeClean {
+		return "~"
+	}
+	if strings.HasPrefix(clean, homeClean+string(os.PathSeparator)) {
+		rel := strings.TrimPrefix(clean, homeClean+string(os.PathSeparator))
+		return filepath.Join("~", rel)
+	}
+	return path
+}
+
+func writeConfig(path, targetRoot string) error {
+	osKey := "linux"
+	if runtime.GOOS == "darwin" {
+		osKey = "macos"
+	}
+
+	prettyTarget := compressHome(targetRoot)
+	content := fmt.Sprintf("return {\n\ttarget = {\n\t\t%s = %q,\n\t\tdefault = %q,\n\t},\n}\n", osKey, prettyTarget, prettyTarget)
+	return os.WriteFile(path, []byte(content), 0o644)
+}
+
+func promptWithDefault(reader *bufio.Reader, label, def string) string {
+	if def != "" {
+		fmt.Printf("%s [%s]: ", label, def)
+	} else {
+		fmt.Printf("%s: ", label)
+	}
+
+	text, _ := reader.ReadString('\n')
+	text = strings.TrimSpace(text)
+	if text == "" {
+		return def
+	}
+	return text
+}
+
+func moveDirContents(srcDir, destDir string) error {
+	entries, err := os.ReadDir(srcDir)
+	if err != nil {
+		return err
+	}
+
+	for _, entry := range entries {
+		srcPath := filepath.Join(srcDir, entry.Name())
+		destPath := filepath.Join(destDir, entry.Name())
+
+		if _, err := os.Stat(destPath); err == nil {
+			return fmt.Errorf("destination already exists: %s", destPath)
+		} else if !errors.Is(err, os.ErrNotExist) {
+			return err
+		}
+
+		if err := os.Rename(srcPath, destPath); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}