// Copyright © 2020 The Knative Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package templates

import (
	"strings"
	"unicode"
)

// Templates for help & usage messages. These has been initially taken over from
// https://github.com/kubernetes/kubectl/blob/f9e4fa6b9cff11b6e2949b76680b8cd5b8192eab/pkg/util/templates/templates.go
// and adapted to the specific needs of `kn`

const (
	// sectionUsage is the help template section that displays the command's usage.
	sectionUsage = `{{if and .Runnable (ne .UseLine "") (not (isRootCmd .))}}Usage:
  {{useLine .}}

{{end}}`

	// sectionAliases is the help template section that displays the command's aliases.
	sectionAliases = `{{ if ne (len .Aliases) 0}}Aliases: 
  {{.NameAndAliases}}

{{end}}`

	// sectionExamples is the help template section that displays command examples.
	sectionExamples = `{{if .HasExample}}Examples:
{{trimRight .Example}}

{{end}}`

	// sectionCommandGroups is the grouped help message
	sectionCommandGroups = `{{if isRootCmd .}}{{cmdGroupsString}}

{{end}}`

	// sectionSubCommands is the help template section that displays the command's subcommands.
	sectionSubCommands = `{{if and (not (isRootCmd .)) .HasAvailableSubCommands}}{{subCommandsString .}}

{{end}}`

	// sectionPlugins lists all plugins (if any)
	sectionPlugins = `{{$plugins := listPlugins .}}{{ if ne (len $plugins) 0}}Plugins:
{{trimRight $plugins}}

{{end}}
`

	// sectionFlags is the help template section that displays the command's flags.
	sectionFlags = `{{$visibleFlags := visibleFlags .}}{{ if $visibleFlags.HasFlags}}Options:
{{trimRight (flagsUsages $visibleFlags)}}

{{end}}`

	// sectionTipsHelp is the help template section that displays the '--help' hint.
	sectionTipsHelp = `{{if .HasSubCommands}}Use "{{rootCmdName}} <command> --help" for more information about a given command.
{{end}}`

	// sectionTipsGlobalOptions is the help template section that displays the 'options' hint for displaying global flags.
	sectionTipsGlobalOptions = `Use "{{rootCmdName}} options" for a list of global command-line options (applies to all commands).`
)

// usageTemplate if the template for 'usage' used by most commands.
func usageTemplate() string {
	sections := []string{
		"\n\n",
		sectionUsage,
		sectionAliases,
		sectionExamples,
		sectionCommandGroups,
		sectionSubCommands,
		sectionPlugins,
		sectionFlags,
		sectionTipsHelp,
		sectionTipsGlobalOptions,
	}
	return strings.TrimRightFunc(strings.Join(sections, ""), unicode.IsSpace) + "\n"
}

// helpTemplate is the template for 'help' used by most commands.
func helpTemplate() string {
	return `{{with or .Long .Short }}{{. | trim}}{{end}}{{if or .Runnable .HasSubCommands}}{{.UsageString}}{{end}}`
}

// optionsTemplate is the template used by "kn options"
func optionsTemplate() string {
	return `{{ if .HasInheritedFlags}}The following options can be passed to any command:

{{flagsUsages .InheritedFlags}}{{end}}`
}