package command

import (
	"bufio"
	"context"
	"fmt"
	"io"
	"os"
	"runtime"
	"strings"

	configtypes "github.com/docker/cli/cli/config/types"
	"github.com/docker/cli/cli/streams"
	"github.com/docker/distribution/reference"
	"github.com/docker/docker/api/types"
	registrytypes "github.com/docker/docker/api/types/registry"
	"github.com/docker/docker/registry"
	"github.com/moby/term"
	"github.com/pkg/errors"
)

// RegistryAuthenticationPrivilegedFunc returns a RequestPrivilegeFunc from the specified registry index info
// for the given command.
func RegistryAuthenticationPrivilegedFunc(cli Cli, index *registrytypes.IndexInfo, cmdName string) types.RequestPrivilegeFunc {
	return func() (string, error) {
		fmt.Fprintf(cli.Out(), "\nPlease login prior to %s:\n", cmdName)
		indexServer := registry.GetAuthConfigKey(index)
		isDefaultRegistry := indexServer == registry.IndexServer
		authConfig, err := GetDefaultAuthConfig(cli, true, indexServer, isDefaultRegistry)
		if err != nil {
			fmt.Fprintf(cli.Err(), "Unable to retrieve stored credentials for %s, error: %s.\n", indexServer, err)
		}
		err = ConfigureAuth(cli, "", "", &authConfig, isDefaultRegistry)
		if err != nil {
			return "", err
		}
		return registrytypes.EncodeAuthConfig(authConfig)
	}
}

// ResolveAuthConfig returns auth-config for the given registry from the
// credential-store. It returns an empty AuthConfig if no credentials were
// found.
//
// It is similar to [registry.ResolveAuthConfig], but uses the credentials-
// store, instead of looking up credentials from a map.
func ResolveAuthConfig(_ context.Context, cli Cli, index *registrytypes.IndexInfo) registrytypes.AuthConfig {
	configKey := index.Name
	if index.Official {
		configKey = registry.IndexServer
	}

	a, _ := cli.ConfigFile().GetAuthConfig(configKey)
	return registrytypes.AuthConfig(a)
}

// GetDefaultAuthConfig gets the default auth config given a serverAddress
// If credentials for given serverAddress exists in the credential store, the configuration will be populated with values in it
func GetDefaultAuthConfig(cli Cli, checkCredStore bool, serverAddress string, isDefaultRegistry bool) (registrytypes.AuthConfig, error) {
	if !isDefaultRegistry {
		serverAddress = registry.ConvertToHostname(serverAddress)
	}
	authconfig := configtypes.AuthConfig{}
	var err error
	if checkCredStore {
		authconfig, err = cli.ConfigFile().GetAuthConfig(serverAddress)
		if err != nil {
			return registrytypes.AuthConfig{
				ServerAddress: serverAddress,
			}, err
		}
	}
	authconfig.ServerAddress = serverAddress
	authconfig.IdentityToken = ""
	res := registrytypes.AuthConfig(authconfig)
	return res, nil
}

// ConfigureAuth handles prompting of user's username and password if needed
func ConfigureAuth(cli Cli, flUser, flPassword string, authconfig *registrytypes.AuthConfig, isDefaultRegistry bool) error {
	// On Windows, force the use of the regular OS stdin stream.
	//
	// See:
	// - https://github.com/moby/moby/issues/14336
	// - https://github.com/moby/moby/issues/14210
	// - https://github.com/moby/moby/pull/17738
	//
	// TODO(thaJeztah): we need to confirm if this special handling is still needed, as we may not be doing this in other places.
	if runtime.GOOS == "windows" {
		cli.SetIn(streams.NewIn(os.Stdin))
	}

	// Some links documenting this:
	// - https://code.google.com/archive/p/mintty/issues/56
	// - https://github.com/docker/docker/issues/15272
	// - https://mintty.github.io/ (compatibility)
	// Linux will hit this if you attempt `cat | docker login`, and Windows
	// will hit this if you attempt docker login from mintty where stdin
	// is a pipe, not a character based console.
	if flPassword == "" && !cli.In().IsTerminal() {
		return errors.Errorf("Error: Cannot perform an interactive login from a non TTY device")
	}

	authconfig.Username = strings.TrimSpace(authconfig.Username)

	if flUser = strings.TrimSpace(flUser); flUser == "" {
		if isDefaultRegistry {
			// if this is a default registry (docker hub), then display the following message.
			fmt.Fprintln(cli.Out(), "Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.")
		}
		promptWithDefault(cli.Out(), "Username", authconfig.Username)
		var err error
		flUser, err = readInput(cli.In())
		if err != nil {
			return err
		}
		if flUser == "" {
			flUser = authconfig.Username
		}
	}
	if flUser == "" {
		return errors.Errorf("Error: Non-null Username Required")
	}
	if flPassword == "" {
		oldState, err := term.SaveState(cli.In().FD())
		if err != nil {
			return err
		}
		fmt.Fprintf(cli.Out(), "Password: ")
		_ = term.DisableEcho(cli.In().FD(), oldState)
		defer func() {
			_ = term.RestoreTerminal(cli.In().FD(), oldState)
		}()
		flPassword, err = readInput(cli.In())
		if err != nil {
			return err
		}
		fmt.Fprint(cli.Out(), "\n")
		if flPassword == "" {
			return errors.Errorf("Error: Password Required")
		}
	}

	authconfig.Username = flUser
	authconfig.Password = flPassword

	return nil
}

// readInput reads, and returns user input from in. It tries to return a
// single line, not including the end-of-line bytes, and trims leading
// and trailing whitespace.
func readInput(in io.Reader) (string, error) {
	line, _, err := bufio.NewReader(in).ReadLine()
	if err != nil {
		return "", errors.Wrap(err, "error while reading input")
	}
	return strings.TrimSpace(string(line)), nil
}

func promptWithDefault(out io.Writer, prompt string, configDefault string) {
	if configDefault == "" {
		fmt.Fprintf(out, "%s: ", prompt)
	} else {
		fmt.Fprintf(out, "%s (%s): ", prompt, configDefault)
	}
}

// RetrieveAuthTokenFromImage retrieves an encoded auth token given a complete
// image. The auth configuration is serialized as a base64url encoded RFC4648,
// section 5) JSON string for sending through the X-Registry-Auth header.
//
// For details on base64url encoding, see:
// - RFC4648, section 5:   https://tools.ietf.org/html/rfc4648#section-5
func RetrieveAuthTokenFromImage(ctx context.Context, cli Cli, image string) (string, error) {
	// Retrieve encoded auth token from the image reference
	authConfig, err := resolveAuthConfigFromImage(ctx, cli, image)
	if err != nil {
		return "", err
	}
	encodedAuth, err := registrytypes.EncodeAuthConfig(authConfig)
	if err != nil {
		return "", err
	}
	return encodedAuth, nil
}

// resolveAuthConfigFromImage retrieves that AuthConfig using the image string
func resolveAuthConfigFromImage(ctx context.Context, cli Cli, image string) (registrytypes.AuthConfig, error) {
	registryRef, err := reference.ParseNormalizedNamed(image)
	if err != nil {
		return registrytypes.AuthConfig{}, err
	}
	repoInfo, err := registry.ParseRepositoryInfo(registryRef)
	if err != nil {
		return registrytypes.AuthConfig{}, err
	}
	return ResolveAuthConfig(ctx, cli, repoInfo.Index), nil
}