package app

import (
	"dy-pkg/app/flagsets"
	version2 "dy-pkg/app/version"
	"dy-pkg/logs"
	"fmt"
	"github.com/fatih/color"
	"github.com/moby/term"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"io"
	"os"
	"runtime"
	"strings"
)

var progressMessage = color.GreenString("==>")

type App struct {
	basename    string
	name        string
	description string
	options     CommandLineOptions
	runFunc     RunFunc
	silence     bool
	noVersion   bool
	noConfig    bool
	commands    []*Command
	args        cobra.PositionalArgs
	cmd         *cobra.Command
}

type RunFunc func(basename string) error

type Option func(*App)

func WithOptions(opt CommandLineOptions) Option {
	return func(a *App) {
		a.options = opt
	}
}

func WithRunFunc(run RunFunc) Option {
	return func(a *App) {
		a.runFunc = run
	}
}

func WithDescription(desc string) Option {
	return func(a *App) {
		a.description = desc
	}
}

func WithSilence() Option {
	return func(a *App) {
		a.silence = true
	}
}

func WithNoVersion() Option {
	return func(a *App) {
		a.noVersion = true
	}
}

func WithNoConfig() Option {
	return func(a *App) {
		a.noConfig = true
	}
}

func WithValidArgs(args cobra.PositionalArgs) Option {
	return func(a *App) {
		a.args = args
	}
}

func WithDefaultValidArgs() Option {
	return func(a *App) {
		a.args = func(cmd *cobra.Command, args []string) error {
			for _, arg := range args {
				if len(arg) > 0 {
					return fmt.Errorf("%q does not take any arguments, got %q", cmd.CommandPath(), args)
				}
			}

			return nil
		}
	}
}

func NewApp(name string, basename string, opts ...Option) *App {
	a := &App{
		name:     name,
		basename: basename,
	}

	for _, o := range opts {
		o(a)
	}

	a.buildCommand()

	return a
}

func (a *App) buildCommand() {
	cmd := cobra.Command{
		Use:   FormatBaseName(a.basename),
		Short: a.name,
		Long:  a.description,
		// stop printing usage when the command errors
		SilenceUsage:  true,
		SilenceErrors: true,
		Args:          a.args,
	}
	// cmd.SetUsageTemplate(usageTemplate)
	cmd.SetOut(os.Stdout)
	cmd.SetErr(os.Stderr)
	cmd.Flags().SortFlags = true

	//cliflag.InitFlags(cmd.Flags())

	if len(a.commands) > 0 {
		for _, command := range a.commands {
			cmd.AddCommand(command.cobraCommand())
		}
		cmd.SetHelpCommand(helpCommand(FormatBaseName(a.basename)))
	}
	if a.runFunc != nil {
		cmd.RunE = a.runCommand
	}

	var namedFlagSets flagsets.NamedFlagSets
	if a.options != nil {
		namedFlagSets = a.options.Flags()
		fs := cmd.Flags()
		for _, f := range namedFlagSets.FlagSets {
			fs.AddFlagSet(f)
		}
	}

	if !a.noVersion {
		version2.AddFlags(namedFlagSets.FlagSet("global"))
	}
	if !a.noConfig {
		addConfigFlag(a.basename, namedFlagSets.FlagSet("global"))
	}

	cmd.Flags().AddFlagSet(namedFlagSets.FlagSet("global"))

	addCmdTemplate(&cmd, namedFlagSets)
	a.cmd = &cmd
}

func (a *App) runCommand(cmd *cobra.Command, args []string) error {

	if !a.noVersion {
		// display application version information
		version2.PrintAndExitIfRequested()
	}

	if !a.noConfig {
		if err := viper.BindPFlags(cmd.Flags()); err != nil {
			return err
		}

		if err := viper.Unmarshal(a.options); err != nil {
			return err
		}
	}

	if !a.silence {
		logs.Infof("%v Starting %s ...", progressMessage, a.name)
		if !a.noVersion {
			logs.Infof("%v Version: `%s`", progressMessage, version2.Get().ToJSON())
		}
		if !a.noConfig {
			logs.Infof("%v Config file used: `%s`", progressMessage, viper.ConfigFileUsed())
		}
	}
	if a.options != nil {
		if err := a.applyOptionRules(); err != nil {
			return err
		}
	}
	// run application
	if a.runFunc != nil {
		return a.runFunc(a.basename)
	}

	return nil
}

func (a *App) applyOptionRules() error {
	if completeableOptions, ok := a.options.(CompleteOptions); ok {
		if err := completeableOptions.Complete(); err != nil {
			return err
		}
	}

	if errs := a.options.Validate(); len(errs) != 0 {
		return errs[0]
	}

	if printableOptions, ok := a.options.(PrintOptions); ok && !a.silence {
		logs.Infof("%v Config: `%s`", progressMessage, printableOptions.String())
	}

	return nil
}

func (a *App) Run() {
	if err := a.cmd.Execute(); err != nil {
		fmt.Printf("%v %v\n", color.RedString("Error:"), err)
		os.Exit(1)
	}
}

func FormatBaseName(basename string) string {
	// Make case-insensitive and strip executable suffix if present
	if runtime.GOOS == "windows" {
		basename = strings.ToLower(basename)
		basename = strings.TrimSuffix(basename, ".exe")
	}

	return basename
}

func addCmdTemplate(cmd *cobra.Command, namedFlagSets flagsets.NamedFlagSets) {
	usageFmt := "Usage:\n  %s\n"
	cols, _, _ := TerminalSize(cmd.OutOrStdout())
	cmd.SetUsageFunc(func(cmd *cobra.Command) error {
		fmt.Fprintf(cmd.OutOrStderr(), usageFmt, cmd.UseLine())
		flagsets.PrintSections(cmd.OutOrStderr(), namedFlagSets, cols)

		return nil
	})
	cmd.SetHelpFunc(func(cmd *cobra.Command, args []string) {
		fmt.Fprintf(cmd.OutOrStdout(), "%s\n\n"+usageFmt, cmd.Long, cmd.UseLine())
		flagsets.PrintSections(cmd.OutOrStdout(), namedFlagSets, cols)
	})
}

// TerminalSize  获取当前终端宽高,非终端返回err,同时宽高返回0值
func TerminalSize(w io.Writer) (int, int, error) {
	outFd, isTerminal := term.GetFdInfo(w)
	if !isTerminal {
		return 0, 0, fmt.Errorf("given writer is no terminal")
	}
	winSize, err := term.GetWinsize(outFd)
	if err != nil {
		return 0, 0, err
	}
	return int(winSize.Width), int(winSize.Height), nil
}