package dependencies

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"

	"github.com/blang/semver"
	"github.com/juju/errors"

	log "github.com/sirupsen/logrus"
)

// minimum minor required for the app to work
const minimumSwaggerVersion = "0.29.0"

// installation directory for fresh install.
// will be prefixed by $HOME
const defaultSwaggerInstallDir = "/bin"

var regexSwaggerVersion = regexp.MustCompile(`^version: v(\d+\.\d+\.\d+)`)

type Swagger struct{}

// regroup all swagger dependencies function

// GetName
func (s Swagger) GetName() string {
	return "Go Swagger"
}

// GetMinimumVersion
func (s Swagger) GetMinimumVersion() string {
	return minimumSwaggerVersion
}

// IsInstalled
func (s Swagger) IsInstalled() (bool, error) {

	_, err := s.GetBinaryPath()
	if err != nil && !errors.Is(err, exec.ErrNotFound) {
		return false, errors.Trace(err)
	} else if err != nil && errors.Is(err, exec.ErrNotFound) {
		return false, nil
	}

	return true, nil
}

// GetBinaryPath
func (s Swagger) GetBinaryPath() (string, error) {
	log.Debug("looking for swagger binary")

	path, err := exec.LookPath("swagger")
	if err != nil {
		return "", errors.Trace(err)
	}

	log.Debug("found swagger binary in", path)

	return path, nil
}

// GetVersion
func (s Swagger) GetVersion() (string, error) {

	isInstalled, err := s.IsInstalled()
	if err != nil {
		return "", errors.Trace(err)
	}

	if !isInstalled {
		return "", errors.NotFoundf("swagger is not installed on the system")
	}

	binaryPath, err := s.GetBinaryPath()
	if err != nil {
		return "", errors.Trace(err)
	}

	log.Debug("executing swagger version command")

	cmd := exec.Command(binaryPath, "version")
	stdout, err := cmd.Output()
	if err != nil {
		return "", errors.Trace(err)
	}
	cleanOut := strings.TrimSpace(string(stdout))

	log.Debugf("swagger version returned %s", cleanOut)

	parseOutput := regexSwaggerVersion.FindStringSubmatch(cleanOut)
	if len(parseOutput) != 2 {
		return "", errors.NotSupportedf("failed to parse swagger version output: %s", cleanOut)
	}

	return parseOutput[1], nil
}

// IsVersionSupported
func (s Swagger) IsVersionSupported() (bool, error) {

	isInstalled, err := s.IsInstalled()
	if err != nil {
		return false, errors.Trace(err)
	}
	if !isInstalled {
		return false, nil
	}

	version, err := s.GetVersion()
	if err != nil {
		return false, errors.Trace(err)
	}

	installedVersion, err := semver.Make(version)
	if err != nil {
		return false, errors.Trace(err)
	}

	requiredVersion, _ := semver.Make(minimumSwaggerVersion)
	if err != nil {
		return false, errors.Trace(err)
	}

	if installedVersion.LT(requiredVersion) {
		return false, nil
	}

	return true, nil
}

// CanBeInstalled
func (s Swagger) CanBeInstalled() bool {
	return true
}

// DescribeInstall
func (s Swagger) DescribeInstall(path string) string {

	commands := []string{
		"The following commands will be executed",
		fmt.Sprintf("rm -rf %s/swagger ", path),
		fmt.Sprintf("wget %s -O %s/swagger", s.getDownloadUrl(), path),
		fmt.Sprintf("chmod 644 %s/swagger", path),
	}

	return strings.Join(commands, "\n")
}

// Install
func (s Swagger) Install(path string) error {

	downloadUrl := s.getDownloadUrl()
	content, err := downloadFile(downloadUrl)
	if err != nil {
		log.Warnf("fail to download file from %s", downloadUrl)
		return errors.Trace(err)
	}

	fh, err := os.OpenFile(
		filepath.Join(path, "swagger"),
		os.O_RDWR|os.O_CREATE|os.O_TRUNC,
		0744,
	)
	if err != nil {
		return errors.Trace(err)
	}
	defer fh.Close()

	bContent, err := ioutil.ReadAll(content)
	if err != nil {
		return errors.Trace(err)
	}

	_, err = fh.Write(bContent)
	if err != nil {
		return errors.Trace(err)
	}

	return nil
}

// DescribePostInstall
func (s Swagger) DescribePostInstall(path string) string {

	return `For your environment to work correctly, we will add if needed the following environment variable to your .bashrc:

	PATH=\"$HOME/bin:$PATH\"

You will have to reopen a new terminal to apply the changes or execute the following command:

	source $HOME/.bashrc

`
}

// PostInstall
func (s Swagger) PostInstall(path string) error {

	lineBashRc := []string{
		"# Swagger - Added by goguik",
	}

	// checking if swagger binary is found after installation
	// if not it's probably not in the path
	isInstalled, err := s.IsInstalled()
	if err != nil {
		return errors.Trace(err)
	}

	if !isInstalled {
		lineBashRc = append(lineBashRc, "PATH=\"$HOME/bin:$PATH\"")
	}

	homeDir, err := os.UserHomeDir()
	if err != nil {
		return errors.Trace(err)
	}

	if len(lineBashRc) > 1 {
		log.Debug("Adding env variable to .bashrc")

		fh, err := os.OpenFile(
			filepath.Join(homeDir, ".bashrc"),
			os.O_APPEND|os.O_CREATE|os.O_WRONLY,
			0644,
		)
		if err != nil {
			return errors.Trace(err)
		}
		defer fh.Close()

		_, err = fh.WriteString(
			fmt.Sprintf("\n\n%s\n", strings.Join(lineBashRc, "\n")),
		)
		if err != nil {
			return errors.Trace(err)
		}
	}

	return nil
}

// GetInstallDirectory will try to find the current swagger directory. If it doesn't exist or if it's in a
// not userspace directory, it will provide the "default"
// It doesn't mean that the directory is "writable"
func (s Swagger) GetInstallDirectory() (string, error) {

	homeDir, err := os.UserHomeDir()
	if err != nil {
		return "", errors.Trace(err)
	}

	isInstalled, err := s.IsInstalled()
	if err != nil {
		return "", errors.Trace(err)
	}

	// concat default install dir with home and we have our path
	if !isInstalled {
		return filepath.Join(homeDir, defaultSwaggerInstallDir), nil
	}

	// now let's play and find the current install path
	binaryPath, err := s.GetBinaryPath()
	if err != nil {
		return "", errors.Trace(err)
	}

	return strings.TrimSuffix(binaryPath, "/swagger"), nil
}

func (s Swagger) getDownloadUrl() string {

	return fmt.Sprintf("https://github.com/go-swagger/go-swagger/releases/download/v%s/swagger_%s_%s", minimumSwaggerVersion, runtime.GOOS, runtime.GOARCH)
}