package util

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

// IsGitRepo reports whether dir contains a .git entry.
func IsGitRepo(dir string) bool {
	_, err := os.Stat(filepath.Join(dir, ".git"))
	return err == nil
}

// ExpandHome replaces a leading "~" or "~/" with the user's home directory.
func ExpandHome(path string) string {
	if path == "~" || strings.HasPrefix(path, "~/") {
		if home, _ := os.UserHomeDir(); home != "" {
			return home + path[1:]
		}
	}
	return path
}

// RuntimeDir returns $XDG_RUNTIME_DIR or the standard fallback /run/user/UID.
func RuntimeDir() string {
	if d := os.Getenv("XDG_RUNTIME_DIR"); d != "" {
		return d
	}
	return fmt.Sprintf("/run/user/%d", os.Getuid())
}

// xdgConfigHome returns $XDG_CONFIG_HOME or ~/.config.
func xdgConfigHome() string {
	if p := os.Getenv("XDG_CONFIG_HOME"); p != "" {
		return p
	}
	home, _ := os.UserHomeDir()
	return filepath.Join(home, ".config")
}

// xdgDataHome returns $XDG_DATA_HOME or ~/.local/share.
func xdgDataHome() string {
	if p := os.Getenv("XDG_DATA_HOME"); p != "" {
		return p
	}
	home, _ := os.UserHomeDir()
	return filepath.Join(home, ".local", "share")
}

// CfgDir returns the ollie config root: $XDG_CONFIG_HOME/ollie.
func CfgDir() string {
	return filepath.Join(xdgConfigHome(), "ollie")
}

// UserDataHome returns $XDG_DATA_HOME or ~/.local/share (Linux),
// ~/Library/Application Support (macOS), or %LocalAppData% (Windows).
func UserDataHome() string {
	return xdgDataHome()
}

// DataDir returns the ollie data root: $XDG_DATA_HOME/ollie.
func DataDir() string {
	return filepath.Join(xdgDataHome(), "ollie")
}