package gitkit

import (
	"fmt"
	"io"
	"log"
	"net/http"
	"os/exec"
	"regexp"
	"strings"
	"syscall"
)

var reSlashDedup = regexp.MustCompile(`\/{2,}`)

func fail500(w http.ResponseWriter, context string, err error) {
	http.Error(w, "Internal server error", 500)
	logError(context, err)
}

func logError(context string, err error) {
	log.Printf("%s: %v\n", context, err)
}

func logInfo(context string, message string) {
	log.Printf("%s: %s\n", context, message)
}

func cleanUpProcessGroup(cmd *exec.Cmd) {
	if cmd == nil {
		return
	}

	process := cmd.Process
	if process != nil && process.Pid > 0 {
		syscall.Kill(-process.Pid, syscall.SIGTERM)
	}

	go cmd.Wait()
}

func packLine(w io.Writer, s string) error {
	_, err := fmt.Fprintf(w, "%04x%s", len(s)+4, s)
	return err
}

func packFlush(w io.Writer) error {
	_, err := fmt.Fprint(w, "0000")
	return err
}

func subCommand(rpc string) string {
	return strings.TrimPrefix(rpc, "git-")
}

// Parse out namespace and repository name from the path.
// Examples:
// repo -> "", "repo"
// org/repo -> "org", "repo"
// org/suborg/rpeo -> "org/suborg", "repo"
func getNamespaceAndRepo(input string) (string, string) {
	if input == "" || input == "/" {
		return "", ""
	}

	// Remove duplicate slashes
	input = reSlashDedup.ReplaceAllString(input, "/")

	// Remove leading slash
	if input[0] == '/' && input != "/" {
		input = input[1:]
	}

	blocks := strings.Split(input, "/")
	num := len(blocks)

	if num < 2 {
		return "", blocks[0]
	}

	return strings.Join(blocks[0:num-1], "/"), blocks[num-1]
}