package browser

import (
	"errors"
	"fmt"
	"os/exec"
	"runtime"
	"strings"
)

// Opens a new browser window pointing to url.
func OpenURL(url string) error {
	goos := runtime.GOOS

	switch goos {
	case "darwin":
		return runCmd("open", url)
	case "linux":
		return linux(url)
	case "netbsd":
		return netbsd(url)
	case "openbsd":
		return openbsd(url)
	case "windows":
		return runCmd("cmd", fmt.Sprintf("start %s", url))
	default:
		return fmt.Errorf("openBrowser: unsupported operating system: %v", goos)
	}
}

func linux(url string) error {
	providers := []string{"xdg-open", "x-www-browser", "www-browser"}

	// There are multiple possible providers to open a browser on linux
	// One of them is xdg-open, another is x-www-browser, then there's www-browser, etc.
	// Look for one that exists and run it
	for _, provider := range providers {
		if _, err := exec.LookPath(provider); err == nil {
			return runCmd(provider, url)
		}
	}

	return &exec.Error{Name: strings.Join(providers, ","), Err: exec.ErrNotFound}
}

func netbsd(url string) error {
	err := runCmd("xdg-open", url)
	if e, ok := err.(*exec.Error); ok && e.Err == exec.ErrNotFound {
		return errors.New("xdg-open: command not found - install xdg-utils from pkgsrc(7)")
	}
	return err
}

func openbsd(url string) error {
	err := runCmd("xdg-open", url)
	if e, ok := err.(*exec.Error); ok && e.Err == exec.ErrNotFound {
		return errors.New("xdg-open: command not found - install xdg-utils from ports(8)")
	}
	return err
}

func runCmd(prog string, args ...string) error {
	cmd := exec.Command(prog, args...)
	return cmd.Run()
}