package cli

import (
	"context"
	"errors"
	"fmt"
	"io"
	"regexp"
	"strings"

	"github.com/DavidGamba/go-getoptions"
	"github.com/hashicorp/go-hclog"
	"github.com/hashicorp/go-multierror"

	"github.com/hashicorp/vagrant-plugin-sdk/helper/paths"
	"github.com/hashicorp/vagrant-plugin-sdk/terminal"
	"github.com/hashicorp/vagrant/internal/clicontext"
	"github.com/hashicorp/vagrant/internal/client"
	clientpkg "github.com/hashicorp/vagrant/internal/client"
	"github.com/hashicorp/vagrant/internal/clierrors"
	"github.com/hashicorp/vagrant/internal/config"
	"github.com/hashicorp/vagrant/internal/server/proto/vagrant_server"
	"github.com/hashicorp/vagrant/internal/serverclient"
)

// baseCommand is embedded in all commands to provide common logic and data.
//
// The unexported values are not available until after Init is called. Some
// values are only available in certain circumstances, read the documentation
// for the field to determine if that is the case.
type baseCommand struct {
	// Ctx is the base context for the command. It is up to commands to
	// utilize this context so that cancellation works in a timely manner.
	Ctx context.Context

	// Log is the logger to use.
	Log hclog.Logger

	// LogOutput is the writer that Log points to. You SHOULD NOT use
	// this directly. We have access to this so you can use
	// hclog.OutputResettable if necessary.
	LogOutput io.Writer

	//---------------------------------------------------------------
	// The fields below are only available after calling Init.

	// cfg is the parsed configuration
	cfg *config.Config

	// UI is used to write to the CLI.
	ui terminal.UI

	// client for performing operations
	client *clientpkg.Client
	// basis to root these operations within
	basis *clientpkg.Basis
	// optional project to run operations within
	project *clientpkg.Project
	// optional target to run operations against
	target *clientpkg.Target

	// clientContext is set to the context information for the current
	// connection. This might not exist in the contextStorage yet if this
	// is from an env var or flags.
	clientContext *clicontext.Config

	// contextStorage is for CLI contexts.
	contextStorage *clicontext.Storage

	//---------------------------------------------------------------
	// Internal fields that should not be accessed directly

	// flagPlain is whether the output should be in plain mode.
	flagPlain bool

	// flagRemote is whether to execute using a remote runner or use
	// a local runner.
	flagRemote bool

	// flagBasis is the basis to work within.
	flagBasis string

	// flagProject is the project to work within.
	flagProject string

	// flagTarget is the machine to target.
	flagTarget string

	// flagConnection contains manual flag-based connection info.
	flagConnection clicontext.Config

	// args that were present after parsing flags
	args []string

	// options passed in at the global level
	globalOptions []Option
}

// Close cleans up any resources that the command created. This should be
// defered by any CLI command that embeds baseCommand in the Run command.
func (c *baseCommand) Close() (err error) {
	c.Log.Trace("starting command closing")
	if closer, ok := c.ui.(io.Closer); ok && closer != nil {
		c.Log.Trace("closing command ui")
		if e := closer.Close(); e != nil {
			err = multierror.Append(err, e)
		}
	}

	if c.client != nil {
		c.Log.Trace("closing command client")
		if e := c.client.Close(); e != nil {
			err = multierror.Append(err, e)
		}
	}

	return
}

func BaseCommand(ctx context.Context, log hclog.Logger, logOutput io.Writer, opts ...Option) (*baseCommand, error) {
	bc := &baseCommand{
		Ctx:       ctx,
		Log:       log,
		LogOutput: logOutput,
	}

	// Get just enough base configuration to
	// allow setting up our client connection
	c := &baseConfig{
		Client: true,
		Flags:  bc.flagSet(flagSetConnection, nil),
	}

	// Apply any options that were passed. These
	// should at least include the arguments so
	// we can extract the flags properly
	for _, opt := range opts {
		opt(c)
	}

	if c.UI == nil {
		c.UI = terminal.ConsoleUI(context.Background())
	}

	// Allow parser to not fail on unknown arguments
	c.Flags.SetUnknownMode(getoptions.Pass)
	if _, err := c.Flags.Parse(c.Args); err != nil {
		c.UI.Output(clierrors.Humanize(err), terminal.WithErrorStyle())
		return nil, err
	}

	// From the command side, the basis is simply where an extra Vagrantfile can
	// live, as well as our storage context
	if bc.flagBasis == "" {
		bc.flagBasis = "default"
	}

	homeConfigPath, err := paths.NamedVagrantConfig(bc.flagBasis)
	if err != nil {
		return nil, err
	}
	bc.Log.Info("vagrant home directory defined",
		"path", homeConfigPath)

	// Setup our directory for context storage
	contextStorage, err := clicontext.NewStorage(
		clicontext.WithDir(homeConfigPath.Join("context")))
	if err != nil {
		return nil, err
	}
	bc.contextStorage = contextStorage

	// We use our flag-based connection info if the user set an addr.
	var flagConnection *clicontext.Config
	if v := bc.flagConnection; v.Server.Address != "" {
		flagConnection = &v
	}

	// Get the context we'll use. The ordering here is purposeful and creates
	// the following precedence: (1) context (2) env (3) flags where the
	// later values override the former.

	connectOpts := []serverclient.ConnectOption{
		serverclient.FromContext(bc.contextStorage, ""),
		serverclient.FromEnv(),
		serverclient.FromContextConfig(flagConnection),
	}
	bc.clientContext, err = serverclient.ContextConfig(connectOpts...)
	if err != nil {
		return nil, err
	}

	// Start building our client options
	clientOpts := []clientpkg.Option{
		clientpkg.WithLogger(bc.Log.ResetNamed("vagrant.client")),
		clientpkg.WithClientConnect(connectOpts...),
	}
	if !bc.flagRemote {
		clientOpts = append(clientOpts, clientpkg.WithLocal())
	}

	if bc.ui != nil {
		clientOpts = append(clientOpts, clientpkg.WithUI(bc.ui))
	}

	// And build our client
	bc.client, err = clientpkg.New(ctx, clientOpts...)
	if err != nil {
		return nil, err
	}

	// We always have a basis, so load that
	if bc.basis, err = bc.client.LoadBasis(bc.flagBasis); err != nil {
		return nil, err
	}

	// A project is optional (though generally needed) and there are
	// two possibilites for how we load the project.
	if bc.flagProject != "" {
		// The first is that we are given a specific project that should be
		// used within the defined basis. So lets load that.
		if bc.project, err = bc.basis.LoadProject(bc.flagProject); err != nil {
			return nil, err
		}
	} else {
		if bc.project, err = bc.basis.DetectProject(); err != nil {
			return nil, err
		}
	}

	// Load in basis vagrantfile if there is one
	if err = bc.basis.LoadVagrantfile(); err != nil {
		return nil, err
	}

	// And if we have a project, load that vagrantfile too
	if bc.project != nil {
		if err = bc.project.LoadVagrantfile(); err != nil {
			return nil, err
		}
	}

	// There's also a chance we are supposed to be focused on
	// a specific target, so load that if so
	if bc.flagTarget != "" {
		if bc.project == nil {
			return nil, fmt.Errorf("cannot load target without valid project")
		}

		if bc.target, err = bc.project.LoadTarget(bc.flagTarget); err != nil {
			return nil, err
		}
	}

	return bc, err
}

// Init initializes the command by parsing flags, parsing the configuration,
// setting up the project, etc. You can control what is done by using the
// options.
//
// Init should be called FIRST within the Run function implementation. Many
// options will affect behavior of other functions that can be called later.
func (c *baseCommand) Init(opts ...Option) error {
	baseCfg := baseConfig{
		Config: true,
		Client: true,
	}

	for _, opt := range c.globalOptions {
		opt(&baseCfg)
	}

	for _, opt := range opts {
		opt(&baseCfg)
	}

	// Init our UI first so we can write output to the user immediately.
	ui := baseCfg.UI
	if ui == nil {
		ui = terminal.ConsoleUI(c.Ctx)
	}

	c.ui = ui

	// Parse flags
	remainingArgs, err := baseCfg.Flags.Parse(baseCfg.Args)
	if err != nil {
		c.ui.Output(clierrors.Humanize(err), terminal.WithErrorStyle())
		return err
	}
	c.args = remainingArgs

	// Reset the UI to plain if that was set
	if c.flagPlain {
		c.ui = terminal.NonInteractiveUI(c.Ctx)
	}

	// Parse the configuration
	c.cfg = &config.Config{}

	// If we have an app target requirement, we have to get it from the args
	// or the config.
	// if baseCfg.TargetRequired && c.project != nil {
	// 	// If we have args, attempt to extract there first.
	// 	if len(c.args) > 0 {
	// 		match := reTarget.FindStringSubmatch(c.args[0])
	// 		if match != nil {
	// 			// Set our target
	// 			t, err := c.project.LoadTarget(match[1])
	// 			if err != nil {
	// 				return err
	// 			}
	// 			c.target = t

	// 			// Shift the args
	// 			c.args = c.args[1:]

	// 			// Explicitly set remote (TODO: why?)
	// 			c.flagRemote = true
	// 		}
	// 	}

	// 	// If we didn't get our ref, then we need to load config
	// 	if c.target == nil {
	// 		baseCfg.Config = true
	// 	}
	// }

	// // If we're loading the config, then get it.
	// if baseCfg.Config {
	// 	cfg, err := c.initConfig(baseCfg.ConfigOptional)
	// 	if err != nil {
	// 		c.logError(c.Log, "failed to load configuration", err)
	// 		return err
	// 	}
	// 	c.cfg = cfg
	// 	if cfg != nil {
	// 		// If we require an app target and we still haven't set it,
	// 		// and the user provided it via the CLI, set it now. This code
	// 		// path is only reached if it wasn't set via the args either
	// 		// above.
	// 		if c.flagTarget == "" {
	// 			c.flagTarget = "default"
	// 		}
	// 		t, err := c.project.LoadTarget(c.flagTarget)

	// 		if err != nil {
	// 			return err
	// 		}

	// 		c.target = t
	// 	}
	// }

	// Validate remote vs. local operations.
	if c.flagRemote && c.target == nil {
		if c.cfg == nil || c.cfg.Runner == nil || !c.cfg.Runner.Enabled {
			err := errors.New(
				"The `-remote` flag was specified but remote operations are not supported\n" +
					"for this project.\n\n" +
					"Remote operations must be manually enabled by using setting the 'runner.enabled'\n" +
					"setting in your Vagrant configuration file. Please see the documentation\n" +
					"on this setting for more information.")
			c.logError(c.Log, "", err)
			return err
		}
	}

	if baseCfg.TargetRequired && c.project != nil {
		if c.target == nil {
			if len(c.cfg.Project.Targets) != 1 {
				c.ui.Output(errTargetModeSingle, terminal.WithErrorStyle())
				return ErrSentinel
			}

			target, err := c.project.LoadTarget(c.cfg.Project.Targets[0].Name)

			if err != nil {
				return err
			}

			c.target = target
		}
	}

	return nil
}

type Tasker interface {
	UI() terminal.UI
	Task(context.Context, *vagrant_server.Job_RunOp, client.JobModifier) (*vagrant_server.Job_RunResult, error)
	//CreateTask() *vagrant_server.Task
}

// Do calls the callback based on the loaded scope. This automatically handles any
// parallelization, waiting, and error handling. Your code should be
// thread-safe.
//
// Based on the scope the callback may be executed multiple times. When scoped by
// machine, it will be run against each requested machine. When the scope is basis
// or project, it will only be run once.
//
// If any error is returned, the caller should just exit. The error handling
// including messaging to the user is handling by this function call.
//
// If you want to early exit all the running functions, you should use
// the callback closure properties to cancel the passed in context. This
// will stop any remaining callbacks and exit early.
func (c *baseCommand) Do(ctx context.Context, f func(context.Context, *client.Client, client.JobModifier) error) (finalErr error) {
	return f(ctx, c.client, c.Modifier())
}

func (c *baseCommand) Modifier() client.JobModifier {
	return func(j *vagrant_server.Job) {
		if c.basis != nil {
			j.Basis = c.basis.Ref()
		}
		if c.project != nil {
			j.Project = c.project.Ref()
		}
		if c.target != nil {
			j.Target = c.target.Ref()
		}
	}
}

// logError logs an error and outputs it to the UI.
func (c *baseCommand) logError(log hclog.Logger, prefix string, err error) {
	if err == ErrSentinel {
		return
	}

	log.Error(prefix, "error", err)

	if prefix != "" {
		prefix += ": "
	}
	c.ui.Output("%s%s", prefix, err, terminal.WithErrorStyle())
}

// flagSet creates the flags for this command. The callback should be used
// to configure the set with your own custom options.
func (c *baseCommand) flagSet(bit flagSetBit, f func(*getoptions.GetOpt)) *getoptions.GetOpt {
	set := getoptions.New()
	set.BoolVar(
		&c.flagPlain,
		"plain",
		false,
		set.Description("Plain output: no colors, no animation."),
	)

	set.StringVar(
		&c.flagTarget,
		"target",
		"",
		set.Description("Target to apply. Certain commands require a single target for "+
			"Vagrant configurations with multiple apps. If you have a single target, "+
			"then this can be ignored."),
	)

	set.StringVar(
		&c.flagBasis,
		"basis",
		"default",
		set.Description("Basis to operate within."),
	)

	if bit&flagSetOperation != 0 {
		set.BoolVar(
			&c.flagRemote,
			"remote",
			false,
			set.Description("True to use a remote runner to execute. This defaults to false \n"+
				"unless 'runner.default' is set in your configuration."),
		)

		// set.StringMapVar(
		// 	&c.flagRemoteSource,
		// 	"remote-source",
		// 	1,
		// 	MaxStringMapArgs,
		// 	set.Description("Override configurations for how remote runners source data. "+
		// 		"This is specified to the data source type being used in your configuration. "+
		// 		"This is used for example to set a specific Git ref to run against."),
		// )
	}

	if bit&flagSetConnection != 0 {
		set.StringVar(
			&c.flagConnection.Server.Address,
			"server-addr",
			"",
			set.Description("Address for the server."),
		)

		set.BoolVar(
			&c.flagConnection.Server.Tls,
			"server-tls",
			true,
			set.Description("True if the server should be connected to via TLS."),
		)

		set.BoolVar(
			&c.flagConnection.Server.TlsSkipVerify,
			"server-tls-skip-verify",
			false,
			set.Description("True to skip verification of the TLS certificate advertised by the server."),
		)
	}

	if f != nil {
		// Configure our values
		f(set)
	}

	return set
}

// flagSetBit is used with baseCommand.flagSet
type flagSetBit uint

const (
	flagSetNone       flagSetBit = 1 << iota
	flagSetOperation             // shared flags for operations (build, deploy, etc)
	flagSetConnection            // shared flags for server connections
)

const MaxStringMapArgs int = 50

var (
	// ErrSentinel is a sentinel value that we can return from Init to force an exit.
	ErrSentinel = errors.New("error sentinel")

	errTargetModeSingle = strings.TrimSpace(`
This command requires a single targeted machine. You have multiple machines defined
so you can specify the machine to target using the "-machine" flag.
`)

	reTarget = regexp.MustCompile(`^(?P<machine>[-0-9A-Za-z_]+)$`)
)