package command

import (
	"context"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/docker/cli/cli/config"
	"github.com/docker/cli/cli/config/configfile"
	dcontext "github.com/docker/cli/cli/context"
	"github.com/docker/cli/cli/context/docker"
	"github.com/docker/cli/cli/context/store"
	"github.com/docker/cli/cli/debug"
	cliflags "github.com/docker/cli/cli/flags"
	manifeststore "github.com/docker/cli/cli/manifest/store"
	registryclient "github.com/docker/cli/cli/registry/client"
	"github.com/docker/cli/cli/streams"
	"github.com/docker/cli/cli/trust"
	"github.com/docker/cli/cli/version"
	dopts "github.com/docker/cli/opts"
	"github.com/docker/docker/api"
	"github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/registry"
	"github.com/docker/docker/api/types/swarm"
	"github.com/docker/docker/client"
	"github.com/docker/go-connections/tlsconfig"
	"github.com/pkg/errors"
	"github.com/spf13/cobra"
	notaryclient "github.com/theupdateframework/notary/client"
)

const defaultInitTimeout = 2 * time.Second

// Streams is an interface which exposes the standard input and output streams
type Streams interface {
	In() *streams.In
	Out() *streams.Out
	Err() io.Writer
}

// Cli represents the docker command line client.
type Cli interface {
	Client() client.APIClient
	Out() *streams.Out
	Err() io.Writer
	In() *streams.In
	SetIn(in *streams.In)
	Apply(ops ...DockerCliOption) error
	ConfigFile() *configfile.ConfigFile
	ServerInfo() ServerInfo
	NotaryClient(imgRefAndAuth trust.ImageRefAndAuth, actions []string) (notaryclient.Repository, error)
	DefaultVersion() string
	CurrentVersion() string
	ManifestStore() manifeststore.Store
	RegistryClient(bool) registryclient.RegistryClient
	ContentTrustEnabled() bool
	BuildKitEnabled() (bool, error)
	ContextStore() store.Store
	CurrentContext() string
	DockerEndpoint() docker.Endpoint
}

// DockerCli is an instance the docker command line client.
// Instances of the client can be returned from NewDockerCli.
type DockerCli struct {
	configFile         *configfile.ConfigFile
	options            *cliflags.ClientOptions
	in                 *streams.In
	out                *streams.Out
	err                io.Writer
	client             client.APIClient
	serverInfo         ServerInfo
	contentTrust       bool
	contextStore       store.Store
	currentContext     string
	init               sync.Once
	initErr            error
	dockerEndpoint     docker.Endpoint
	contextStoreConfig store.Config
	initTimeout        time.Duration
}

// DefaultVersion returns api.defaultVersion.
func (cli *DockerCli) DefaultVersion() string {
	return api.DefaultVersion
}

// CurrentVersion returns the API version currently negotiated, or the default
// version otherwise.
func (cli *DockerCli) CurrentVersion() string {
	_ = cli.initialize()
	if cli.client == nil {
		return api.DefaultVersion
	}
	return cli.client.ClientVersion()
}

// Client returns the APIClient
func (cli *DockerCli) Client() client.APIClient {
	if err := cli.initialize(); err != nil {
		_, _ = fmt.Fprintf(cli.Err(), "Failed to initialize: %s\n", err)
		os.Exit(1)
	}
	return cli.client
}

// Out returns the writer used for stdout
func (cli *DockerCli) Out() *streams.Out {
	return cli.out
}

// Err returns the writer used for stderr
func (cli *DockerCli) Err() io.Writer {
	return cli.err
}

// SetIn sets the reader used for stdin
func (cli *DockerCli) SetIn(in *streams.In) {
	cli.in = in
}

// In returns the reader used for stdin
func (cli *DockerCli) In() *streams.In {
	return cli.in
}

// ShowHelp shows the command help.
func ShowHelp(err io.Writer) func(*cobra.Command, []string) error {
	return func(cmd *cobra.Command, args []string) error {
		cmd.SetOut(err)
		cmd.HelpFunc()(cmd, args)
		return nil
	}
}

// ConfigFile returns the ConfigFile
func (cli *DockerCli) ConfigFile() *configfile.ConfigFile {
	// TODO(thaJeztah): when would this happen? Is this only in tests (where cli.Initialize() is not called first?)
	if cli.configFile == nil {
		cli.configFile = config.LoadDefaultConfigFile(cli.err)
	}
	return cli.configFile
}

// ServerInfo returns the server version details for the host this client is
// connected to
func (cli *DockerCli) ServerInfo() ServerInfo {
	_ = cli.initialize()
	return cli.serverInfo
}

// ContentTrustEnabled returns whether content trust has been enabled by an
// environment variable.
func (cli *DockerCli) ContentTrustEnabled() bool {
	return cli.contentTrust
}

// BuildKitEnabled returns buildkit is enabled or not.
func (cli *DockerCli) BuildKitEnabled() (bool, error) {
	// use DOCKER_BUILDKIT env var value if set
	if v, ok := os.LookupEnv("DOCKER_BUILDKIT"); ok {
		enabled, err := strconv.ParseBool(v)
		if err != nil {
			return false, errors.Wrap(err, "DOCKER_BUILDKIT environment variable expects boolean value")
		}
		return enabled, nil
	}
	// if a builder alias is defined, we are using BuildKit
	aliasMap := cli.ConfigFile().Aliases
	if _, ok := aliasMap["builder"]; ok {
		return true, nil
	}
	// otherwise, assume BuildKit is enabled but
	// not if wcow reported from server side
	return cli.ServerInfo().OSType != "windows", nil
}

// ManifestStore returns a store for local manifests
func (cli *DockerCli) ManifestStore() manifeststore.Store {
	// TODO: support override default location from config file
	return manifeststore.NewStore(filepath.Join(config.Dir(), "manifests"))
}

// RegistryClient returns a client for communicating with a Docker distribution
// registry
func (cli *DockerCli) RegistryClient(allowInsecure bool) registryclient.RegistryClient {
	resolver := func(ctx context.Context, index *registry.IndexInfo) types.AuthConfig {
		return ResolveAuthConfig(ctx, cli, index)
	}
	return registryclient.NewRegistryClient(resolver, UserAgent(), allowInsecure)
}

// InitializeOpt is the type of the functional options passed to DockerCli.Initialize
type InitializeOpt func(dockerCli *DockerCli) error

// WithInitializeClient is passed to DockerCli.Initialize by callers who wish to set a particular API Client for use by the CLI.
func WithInitializeClient(makeClient func(dockerCli *DockerCli) (client.APIClient, error)) InitializeOpt {
	return func(dockerCli *DockerCli) error {
		var err error
		dockerCli.client, err = makeClient(dockerCli)
		return err
	}
}

// Initialize the dockerCli runs initialization that must happen after command
// line flags are parsed.
func (cli *DockerCli) Initialize(opts *cliflags.ClientOptions, ops ...InitializeOpt) error {
	for _, o := range ops {
		if err := o(cli); err != nil {
			return err
		}
	}
	cliflags.SetLogLevel(opts.LogLevel)

	if opts.ConfigDir != "" {
		config.SetDir(opts.ConfigDir)
	}

	if opts.Debug {
		debug.Enable()
	}
	if opts.Context != "" && len(opts.Hosts) > 0 {
		return errors.New("conflicting options: either specify --host or --context, not both")
	}

	cli.options = opts
	cli.configFile = config.LoadDefaultConfigFile(cli.err)
	cli.currentContext = resolveContextName(cli.options, cli.configFile)
	cli.contextStore = &ContextStoreWithDefault{
		Store: store.New(config.ContextStoreDir(), cli.contextStoreConfig),
		Resolver: func() (*DefaultContext, error) {
			return ResolveDefaultContext(cli.options, cli.contextStoreConfig)
		},
	}
	return nil
}

// NewAPIClientFromFlags creates a new APIClient from command line flags
func NewAPIClientFromFlags(opts *cliflags.ClientOptions, configFile *configfile.ConfigFile) (client.APIClient, error) {
	if opts.Context != "" && len(opts.Hosts) > 0 {
		return nil, errors.New("conflicting options: either specify --host or --context, not both")
	}

	storeConfig := DefaultContextStoreConfig()
	contextStore := &ContextStoreWithDefault{
		Store: store.New(config.ContextStoreDir(), storeConfig),
		Resolver: func() (*DefaultContext, error) {
			return ResolveDefaultContext(opts, storeConfig)
		},
	}
	endpoint, err := resolveDockerEndpoint(contextStore, resolveContextName(opts, configFile))
	if err != nil {
		return nil, errors.Wrap(err, "unable to resolve docker endpoint")
	}
	return newAPIClientFromEndpoint(endpoint, configFile)
}

func newAPIClientFromEndpoint(ep docker.Endpoint, configFile *configfile.ConfigFile) (client.APIClient, error) {
	clientOpts, err := ep.ClientOpts()
	if err != nil {
		return nil, err
	}
	customHeaders := make(map[string]string, len(configFile.HTTPHeaders))
	for k, v := range configFile.HTTPHeaders {
		customHeaders[k] = v
	}
	customHeaders["User-Agent"] = UserAgent()
	clientOpts = append(clientOpts, client.WithHTTPHeaders(customHeaders))
	return client.NewClientWithOpts(clientOpts...)
}

func resolveDockerEndpoint(s store.Reader, contextName string) (docker.Endpoint, error) {
	if s == nil {
		return docker.Endpoint{}, fmt.Errorf("no context store initialized")
	}
	ctxMeta, err := s.GetMetadata(contextName)
	if err != nil {
		return docker.Endpoint{}, err
	}
	epMeta, err := docker.EndpointFromContext(ctxMeta)
	if err != nil {
		return docker.Endpoint{}, err
	}
	return docker.WithTLSData(s, contextName, epMeta)
}

// Resolve the Docker endpoint for the default context (based on config, env vars and CLI flags)
func resolveDefaultDockerEndpoint(opts *cliflags.ClientOptions) (docker.Endpoint, error) {
	host, err := getServerHost(opts.Hosts, opts.TLSOptions)
	if err != nil {
		return docker.Endpoint{}, err
	}

	var (
		skipTLSVerify bool
		tlsData       *dcontext.TLSData
	)

	if opts.TLSOptions != nil {
		skipTLSVerify = opts.TLSOptions.InsecureSkipVerify
		tlsData, err = dcontext.TLSDataFromFiles(opts.TLSOptions.CAFile, opts.TLSOptions.CertFile, opts.TLSOptions.KeyFile)
		if err != nil {
			return docker.Endpoint{}, err
		}
	}

	return docker.Endpoint{
		EndpointMeta: docker.EndpointMeta{
			Host:          host,
			SkipTLSVerify: skipTLSVerify,
		},
		TLSData: tlsData,
	}, nil
}

func (cli *DockerCli) getInitTimeout() time.Duration {
	if cli.initTimeout != 0 {
		return cli.initTimeout
	}
	return defaultInitTimeout
}

func (cli *DockerCli) initializeFromClient() {
	ctx := context.Background()
	if !strings.HasPrefix(cli.dockerEndpoint.Host, "ssh://") {
		// @FIXME context.WithTimeout doesn't work with connhelper / ssh connections
		// time="2020-04-10T10:16:26Z" level=warning msg="commandConn.CloseWrite: commandconn: failed to wait: signal: killed"
		var cancel func()
		ctx, cancel = context.WithTimeout(ctx, cli.getInitTimeout())
		defer cancel()
	}

	ping, err := cli.client.Ping(ctx)
	if err != nil {
		// Default to true if we fail to connect to daemon
		cli.serverInfo = ServerInfo{HasExperimental: true}

		if ping.APIVersion != "" {
			cli.client.NegotiateAPIVersionPing(ping)
		}
		return
	}

	cli.serverInfo = ServerInfo{
		HasExperimental: ping.Experimental,
		OSType:          ping.OSType,
		BuildkitVersion: ping.BuilderVersion,
		SwarmStatus:     ping.SwarmStatus,
	}
	cli.client.NegotiateAPIVersionPing(ping)
}

// NotaryClient provides a Notary Repository to interact with signed metadata for an image
func (cli *DockerCli) NotaryClient(imgRefAndAuth trust.ImageRefAndAuth, actions []string) (notaryclient.Repository, error) {
	return trust.GetNotaryRepository(cli.In(), cli.Out(), UserAgent(), imgRefAndAuth.RepoInfo(), imgRefAndAuth.AuthConfig(), actions...)
}

// ContextStore returns the ContextStore
func (cli *DockerCli) ContextStore() store.Store {
	return cli.contextStore
}

// CurrentContext returns the current context name, based on flags,
// environment variables and the cli configuration file, in the following
// order of preference:
//
//  1. The "--context" command-line option.
//  2. The "DOCKER_CONTEXT" environment variable.
//  3. The current context as configured through the in "currentContext"
//     field in the CLI configuration file ("~/.docker/config.json").
//  4. If no context is configured, use the "default" context.
//
// # Fallbacks for backward-compatibility
//
// To preserve backward-compatibility with the "pre-contexts" behavior,
// the "default" context is used if:
//
//   - The "--host" option is set
//   - The "DOCKER_HOST" ([DefaultContextName]) environment variable is set
//     to a non-empty value.
//
// In these cases, the default context is used, which uses the host as
// specified in "DOCKER_HOST", and TLS config from flags/env vars.
//
// Setting both the "--context" and "--host" flags is ambiguous and results
// in an error when the cli is started.
//
// CurrentContext does not validate if the given context exists or if it's
// valid; errors may occur when trying to use it.
func (cli *DockerCli) CurrentContext() string {
	return cli.currentContext
}

// CurrentContext returns the current context name, based on flags,
// environment variables and the cli configuration file. It does not
// validate if the given context exists or if it's valid; errors may
// occur when trying to use it.
//
// Refer to [DockerCli.CurrentContext] above for further details.
func resolveContextName(opts *cliflags.ClientOptions, config *configfile.ConfigFile) string {
	if opts != nil && opts.Context != "" {
		return opts.Context
	}
	if opts != nil && len(opts.Hosts) > 0 {
		return DefaultContextName
	}
	if os.Getenv(client.EnvOverrideHost) != "" {
		return DefaultContextName
	}
	if ctxName := os.Getenv("DOCKER_CONTEXT"); ctxName != "" {
		return ctxName
	}
	if config != nil && config.CurrentContext != "" {
		// We don't validate if this context exists: errors may occur when trying to use it.
		return config.CurrentContext
	}
	return DefaultContextName
}

// DockerEndpoint returns the current docker endpoint
func (cli *DockerCli) DockerEndpoint() docker.Endpoint {
	if err := cli.initialize(); err != nil {
		// Note that we're not terminating here, as this function may be used
		// in cases where we're able to continue.
		_, _ = fmt.Fprintf(cli.Err(), "%v\n", cli.initErr)
	}
	return cli.dockerEndpoint
}

func (cli *DockerCli) getDockerEndPoint() (ep docker.Endpoint, err error) {
	cn := cli.CurrentContext()
	if cn == DefaultContextName {
		return resolveDefaultDockerEndpoint(cli.options)
	}
	return resolveDockerEndpoint(cli.contextStore, cn)
}

func (cli *DockerCli) initialize() error {
	cli.init.Do(func() {
		cli.dockerEndpoint, cli.initErr = cli.getDockerEndPoint()
		if cli.initErr != nil {
			cli.initErr = errors.Wrap(cli.initErr, "unable to resolve docker endpoint")
			return
		}
		if cli.client == nil {
			if cli.client, cli.initErr = newAPIClientFromEndpoint(cli.dockerEndpoint, cli.configFile); cli.initErr != nil {
				return
			}
		}
		cli.initializeFromClient()
	})
	return cli.initErr
}

// Apply all the operation on the cli
func (cli *DockerCli) Apply(ops ...DockerCliOption) error {
	for _, op := range ops {
		if err := op(cli); err != nil {
			return err
		}
	}
	return nil
}

// ServerInfo stores details about the supported features and platform of the
// server
type ServerInfo struct {
	HasExperimental bool
	OSType          string
	BuildkitVersion types.BuilderVersion

	// SwarmStatus provides information about the current swarm status of the
	// engine, obtained from the "Swarm" header in the API response.
	//
	// It can be a nil struct if the API version does not provide this header
	// in the ping response, or if an error occurred, in which case the client
	// should use other ways to get the current swarm status, such as the /swarm
	// endpoint.
	SwarmStatus *swarm.Status
}

// NewDockerCli returns a DockerCli instance with all operators applied on it.
// It applies by default the standard streams, and the content trust from
// environment.
func NewDockerCli(ops ...DockerCliOption) (*DockerCli, error) {
	defaultOps := []DockerCliOption{
		WithContentTrustFromEnv(),
		WithDefaultContextStoreConfig(),
		WithStandardStreams(),
	}
	ops = append(defaultOps, ops...)

	cli := &DockerCli{}
	if err := cli.Apply(ops...); err != nil {
		return nil, err
	}
	return cli, nil
}

func getServerHost(hosts []string, tlsOptions *tlsconfig.Options) (string, error) {
	var host string
	switch len(hosts) {
	case 0:
		host = os.Getenv(client.EnvOverrideHost)
	case 1:
		host = hosts[0]
	default:
		return "", errors.New("Please specify only one -H")
	}

	return dopts.ParseHost(tlsOptions != nil, host)
}

// UserAgent returns the user agent string used for making API requests
func UserAgent() string {
	return "Docker-Client/" + version.Version + " (" + runtime.GOOS + ")"
}

var defaultStoreEndpoints = []store.NamedTypeGetter{
	store.EndpointTypeGetter(docker.DockerEndpoint, func() interface{} { return &docker.EndpointMeta{} }),
}

// RegisterDefaultStoreEndpoints registers a new named endpoint
// metadata type with the default context store config, so that
// endpoint will be supported by stores using the config returned by
// DefaultContextStoreConfig.
func RegisterDefaultStoreEndpoints(ep ...store.NamedTypeGetter) {
	defaultStoreEndpoints = append(defaultStoreEndpoints, ep...)
}

// DefaultContextStoreConfig returns a new store.Config with the default set of endpoints configured.
func DefaultContextStoreConfig() store.Config {
	return store.NewConfig(
		func() interface{} { return &DockerContext{} },
		defaultStoreEndpoints...,
	)
}
