zt/ziti/cmd/templates/templater.go

/*
	Copyright NetFoundry Inc.

	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

	https://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 (
	"bytes"
	"fmt"
	"io"
	"strings"
	"text/template"
	"unicode"

	"github.com/spf13/cobra"
	flag "github.com/spf13/pflag"
)

type FlagExposer interface {
	ExposeFlags(cmd *cobra.Command, flags ...string) FlagExposer
}

func ActsAsRootCommand(cmd *cobra.Command, filters []string, groups ...CommandGroup) FlagExposer {
	if cmd == nil {
		panic("nil root command")
	}
	templater := &templater{
		RootCmd:       cmd,
		UsageTemplate: MainUsageTemplate(),
		HelpTemplate:  MainHelpTemplate(),
		CommandGroups: groups,
		Filtered:      filters,
	}
	cmd.SetUsageFunc(templater.UsageFunc())
	cmd.SetHelpFunc(templater.HelpFunc())
	return templater
}

type templater struct {
	UsageTemplate string
	HelpTemplate  string
	RootCmd       *cobra.Command
	CommandGroups
	Filtered []string
}

func (templater *templater) ExposeFlags(cmd *cobra.Command, flags ...string) FlagExposer {
	cmd.SetUsageFunc(templater.UsageFunc(flags...))
	return templater
}

func (templater *templater) HelpFunc() func(*cobra.Command, []string) {
	return func(c *cobra.Command, s []string) {
		t := template.New("help")
		t.Funcs(templater.templateFuncs())
		template.Must(t.Parse(templater.HelpTemplate))
		out := newResponsiveWriter(c.OutOrStdout())
		err := t.Execute(out, c)
		if err != nil {
			c.Println(err)
		}
	}
}

func (templater *templater) UsageFunc(exposedFlags ...string) func(*cobra.Command) error {
	return func(c *cobra.Command) error {
		t := template.New("usage")
		t.Funcs(templater.templateFuncs(exposedFlags...))
		template.Must(t.Parse(templater.UsageTemplate))
		out := newResponsiveWriter(c.OutOrStderr())
		return t.Execute(out, c)
	}
}

func (templater *templater) templateFuncs(exposedFlags ...string) template.FuncMap {
	return template.FuncMap{
		"trim":                strings.TrimSpace,
		"trimRight":           func(s string) string { return strings.TrimRightFunc(s, unicode.IsSpace) },
		"trimLeft":            func(s string) string { return strings.TrimLeftFunc(s, unicode.IsSpace) },
		"gt":                  cobra.Gt,
		"eq":                  cobra.Eq,
		"rpad":                rpad,
		"appendIfNotPresent":  appendIfNotPresent,
		"flagsNotIntersected": flagsNotIntersected,
		"visibleFlags":        visibleFlags,
		"flagsUsages":         flagsUsages,
		"cmdGroups":           templater.cmdGroups,
		"cmdGroupsString":     templater.cmdGroupsString,
		"rootCmd":             templater.rootCmdName,
		"isRootCmd":           templater.isRootCmd,
		"optionsCmdFor":       templater.optionsCmdFor,
		"usageLine":           templater.usageLine,
		"exposed": func(c *cobra.Command) *flag.FlagSet {
			exposed := flag.NewFlagSet("exposed", flag.ContinueOnError)
			if len(exposedFlags) > 0 {
				for _, name := range exposedFlags {
					if flag := c.Flags().Lookup(name); flag != nil {
						exposed.AddFlag(flag)
					}
				}
			}
			return exposed
		},
	}
}

func newResponsiveWriter(out io.Writer) io.Writer {
	// TODO term.NewResponsiveWriter(out)
	return out
}

func (templater *templater) cmdGroups(c *cobra.Command, all []*cobra.Command) []CommandGroup {
	if len(templater.CommandGroups) > 0 && c == templater.RootCmd {
		all = filter(all, templater.Filtered...)
		return AddAdditionalCommands(templater.CommandGroups, "Other Commands:", all)
	}
	all = filter(all, "options")
	return []CommandGroup{
		{
			Message:  "Available Commands:",
			Commands: all,
		},
	}
}

func (t *templater) groupPath(c *cobra.Command) string {
	parentText := ""
	parent := c.Parent()
	if parent != nil {
		parentText = t.groupPath(parent)
		if parentText != "" {
			parentText += " "
		}
	}
	return strings.TrimPrefix(parentText, "ziti ") + c.Name()
}

func (t *templater) cmdGroupsString(c *cobra.Command) string {
	groups := []string{}
	maxLen := 1
	for _, cmdGroup := range t.cmdGroups(c, c.Commands()) {
		for _, cmd := range cmdGroup.Commands {
			if cmd.Runnable() {
				path := t.groupPath(cmd)
				l := len(path)
				if l > maxLen {
					maxLen = l
				}
			}
		}
	}
	for _, cmdGroup := range t.cmdGroups(c, c.Commands()) {
		cmds := []string{cmdGroup.Message}
		for _, cmd := range cmdGroup.Commands {
			if cmd.Runnable() {
				path := t.groupPath(cmd)
				//cmds = append(cmds, "  "+rpad(path, maxLen - len(path))+" "+cmd.Short)
				cmds = append(cmds, "  "+padRight(path, " ", maxLen)+" "+cmd.Short)
			}
		}
		groups = append(groups, strings.Join(cmds, "\n"))
	}
	return strings.Join(groups, "\n\n")
}

func padRight(s, pad string, width int) string {
	gap := width - len(s)
	if gap > 0 {
		return s + strings.Repeat(pad, gap)
	}
	return s
}

func (t *templater) rootCmdName(c *cobra.Command) string {
	return t.rootCmd(c).CommandPath()
}

func (t *templater) isRootCmd(c *cobra.Command) bool {
	return t.rootCmd(c) == c
}

func (t *templater) parents(c *cobra.Command) []*cobra.Command {
	parents := []*cobra.Command{c}
	for current := c; !t.isRootCmd(current) && current.HasParent(); {
		current = current.Parent()
		parents = append(parents, current)
	}
	return parents
}

func (t *templater) rootCmd(c *cobra.Command) *cobra.Command {
	if c != nil && !c.HasParent() {
		return c
	}
	if t.RootCmd == nil {
		panic("nil root cmd")
	}
	return t.RootCmd
}

func (t *templater) optionsCmdFor(c *cobra.Command) string {
	if !c.Runnable() {
		return ""
	}
	rootCmdStructure := t.parents(c)
	for i := len(rootCmdStructure) - 1; i >= 0; i-- {
		cmd := rootCmdStructure[i]
		if _, _, err := cmd.Find([]string{"options"}); err == nil {
			return cmd.CommandPath() + " options"
		}
	}
	return ""
}

func (t *templater) usageLine(c *cobra.Command) string {
	usage := c.UseLine()
	suffix := "[options]"
	if c.HasFlags() && !strings.Contains(usage, suffix) {
		usage += " " + suffix
	}
	return usage
}

func flagsUsages(f *flag.FlagSet) string {
	x := new(bytes.Buffer)

	f.VisitAll(func(flag *flag.Flag) {
		if flag.Hidden {
			return
		}
		format := "--%s=%s: %s\n"

		if flag.Value.Type() == "string" {
			format = "--%s='%s': %s\n"
		}

		if len(flag.Shorthand) > 0 {
			format = "  -%s, " + format
		} else {
			format = "   %s   " + format
		}

		fmt.Fprintf(x, format, flag.Shorthand, flag.Name, flag.DefValue, flag.Usage)
	})

	return x.String()
}

func rpad(s string, padding int) string {
	template := fmt.Sprintf("%%-%ds", padding)
	return fmt.Sprintf(template, s)
}

func appendIfNotPresent(s, stringToAppend string) string {
	if strings.Contains(s, stringToAppend) {
		return s
	}
	return s + " " + stringToAppend
}

func flagsNotIntersected(l *flag.FlagSet, r *flag.FlagSet) *flag.FlagSet {
	f := flag.NewFlagSet("notIntersected", flag.ContinueOnError)
	l.VisitAll(func(flag *flag.Flag) {
		if r.Lookup(flag.Name) == nil {
			f.AddFlag(flag)
		}
	})
	return f
}

func visibleFlags(l *flag.FlagSet) *flag.FlagSet {
	hidden := "help"
	f := flag.NewFlagSet("visible", flag.ContinueOnError)
	l.VisitAll(func(flag *flag.Flag) {
		if flag.Name != hidden {
			f.AddFlag(flag)
		}
	})
	return f
}

func filter(cmds []*cobra.Command, names ...string) []*cobra.Command {
	out := []*cobra.Command{}
	for _, c := range cmds {
		if c.Hidden {
			continue
		}
		skip := false
		for _, name := range names {
			if name == c.Name() {
				skip = true
				break
			}
		}
		if skip {
			continue
		}
		out = append(out, c)
	}
	return out
}