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package main

import (
	"fmt"
	"io"
	"net"
	"os"
	"os/exec"
	"strconv"
)

// =============================================================================
// Utilities
// =============================================================================

// termLink returns an OSC 8 hyperlink sequence: the text is displayed but
// the URL is what activates on click in supporting terminals (e.g. kitty,
// iTerm2, GNOME Terminal, WezTerm). Falls back gracefully — non-supporting
// terminals just print the raw text with the escape sequences stripped or
// ignored.
func termLink(url, text string) string {
	return fmt.Sprintf("\033]8;;%s\033\\%s\033]8;;\033\\", url, text)
}

// freePort asks the OS for a free TCP port by briefly binding on :0.
func freePort() (string, error) {
	l, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		return "", fmt.Errorf("finding free port: %w", err)
	}
	port := l.Addr().(*net.TCPAddr).Port
	l.Close()
	return strconv.Itoa(port), nil
}

func runCmd(name string, args ...string) error {
	cmd := exec.Command(name, args...)
	cmd.Stdout = os.Stderr // progress to stderr, not stdout
	cmd.Stderr = os.Stderr
	return cmd.Run()
}

func copyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()

	if _, err := io.Copy(out, in); err != nil {
		return err
	}
	return out.Close()
}

func fileExists(path string) bool {
	_, err := os.Stat(path)
	return err == nil
}

func dirExists(path string) bool {
	info, err := os.Stat(path)
	return err == nil && info.IsDir()
}