// Copyright 2020 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

package flags

import (
	"os"
	"path/filepath"

	"github.com/ethereum/go-ethereum/params"
	cli "gopkg.in/urfave/cli.v1"
)

var (
	CommandHelpTemplate = `{{.cmd.Name}}{{if .cmd.Subcommands}} command{{end}}{{if .cmd.Flags}} [command options]{{end}} [arguments...]
{{if .cmd.Description}}{{.cmd.Description}}
{{end}}{{if .cmd.Subcommands}}
SUBCOMMANDS:
  {{range .cmd.Subcommands}}{{.Name}}{{with .ShortName}}, {{.}}{{end}}{{ "\t" }}{{.Usage}}
  {{end}}{{end}}{{if .categorizedFlags}}
{{range $idx, $categorized := .categorizedFlags}}{{$categorized.Name}} OPTIONS:
{{range $categorized.Flags}}{{"\t"}}{{.}}
{{end}}
{{end}}{{end}}`

	OriginCommandHelpTemplate = `{{.Name}}{{if .Subcommands}} command{{end}}{{if .Flags}} [command options]{{end}} [arguments...]
{{if .Description}}{{.Description}}
{{end}}{{if .Subcommands}}
SUBCOMMANDS:
  {{range .Subcommands}}{{.Name}}{{with .ShortName}}, {{.}}{{end}}{{ "\t" }}{{.Usage}}
  {{end}}{{end}}{{if .Flags}}
OPTIONS:
{{range $.Flags}}   {{.}}
{{end}}
{{end}}`

	// AppHelpTemplate is the test template for the default, global app help topic.
	AppHelpTemplate = `NAME:
   {{.App.Name}} - {{.App.Usage}}

   Copyright 2013-2019 The go-ethereum Authors

USAGE:
   {{.App.HelpName}} [options]{{if .App.Commands}} command [command options]{{end}} {{if .App.ArgsUsage}}{{.App.ArgsUsage}}{{else}}[arguments...]{{end}}
   {{if .App.Version}}
VERSION:
   {{.App.Version}}
   {{end}}{{if len .App.Authors}}
AUTHOR(S):
   {{range .App.Authors}}{{ . }}{{end}}
   {{end}}{{if .App.Commands}}
COMMANDS:
   {{range .App.Commands}}{{join .Names ", "}}{{ "\t" }}{{.Usage}}
   {{end}}{{end}}{{if .FlagGroups}}
{{range .FlagGroups}}{{.Name}} OPTIONS:
  {{range .Flags}}{{.}}
  {{end}}
{{end}}{{end}}{{if .App.Copyright }}
COPYRIGHT:
   {{.App.Copyright}}
   {{end}}
`
	// ClefAppHelpTemplate is the template for the default, global app help topic.
	ClefAppHelpTemplate = `NAME:
   {{.App.Name}} - {{.App.Usage}}

   Copyright 2013-2019 The go-ethereum Authors

USAGE:
   {{.App.HelpName}} [options]{{if .App.Commands}} command [command options]{{end}} {{if .App.ArgsUsage}}{{.App.ArgsUsage}}{{else}}[arguments...]{{end}}
   {{if .App.Version}}
COMMANDS:
   {{range .App.Commands}}{{join .Names ", "}}{{ "\t" }}{{.Usage}}
   {{end}}{{end}}{{if .FlagGroups}}
{{range .FlagGroups}}{{.Name}} OPTIONS:
  {{range .Flags}}{{.}}
  {{end}}
{{end}}{{end}}{{if .App.Copyright }}
COPYRIGHT:
   {{.App.Copyright}}
   {{end}}
`
)

// HelpData is a one shot struct to pass to the usage template
type HelpData struct {
	App        interface{}
	FlagGroups []FlagGroup
}

// FlagGroup is a collection of flags belonging to a single topic.
type FlagGroup struct {
	Name  string
	Flags []cli.Flag
}

// byCategory sorts an array of FlagGroup by Name in the order
// defined in AppHelpFlagGroups.
type ByCategory []FlagGroup

func (a ByCategory) Len() int      { return len(a) }
func (a ByCategory) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByCategory) Less(i, j int) bool {
	iCat, jCat := a[i].Name, a[j].Name
	iIdx, jIdx := len(a), len(a) // ensure non categorized flags come last

	for i, group := range a {
		if iCat == group.Name {
			iIdx = i
		}
		if jCat == group.Name {
			jIdx = i
		}
	}

	return iIdx < jIdx
}

func FlagCategory(flag cli.Flag, flagGroups []FlagGroup) string {
	for _, category := range flagGroups {
		for _, flg := range category.Flags {
			if flg.GetName() == flag.GetName() {
				return category.Name
			}
		}
	}
	return "MISC"
}

// NewApp creates an app with sane defaults.
func NewApp(gitCommit, gitDate, usage string) *cli.App {
	app := cli.NewApp()
	app.Name = filepath.Base(os.Args[0])
	app.Author = ""
	app.Email = ""
	app.Version = params.VersionWithCommit(gitCommit, gitDate)
	app.Usage = usage
	return app
}