package main

import (
	"time"

	"github.com/restic/restic/internal/errors"
	"github.com/spf13/cobra"
	"github.com/spf13/cobra/doc"
)

var cmdGenerate = &cobra.Command{
	Use:   "generate [command]",
	Short: "Generate manual pages and auto-completion files (bash, zsh)",
	Long: `
The "generate" command writes automatically generated files like the man pages
and the auto-completion files for bash and zsh).
`,
	DisableAutoGenTag: true,
	RunE:              runGenerate,
}

type generateOptions struct {
	ManDir             string
	BashCompletionFile string
	ZSHCompletionFile  string
}

var genOpts generateOptions

func init() {
	cmdRoot.AddCommand(cmdGenerate)
	fs := cmdGenerate.Flags()
	fs.StringVar(&genOpts.ManDir, "man", "", "write man pages to `directory`")
	fs.StringVar(&genOpts.BashCompletionFile, "bash-completion", "", "write bash completion `file`")
	fs.StringVar(&genOpts.ZSHCompletionFile, "zsh-completion", "", "write zsh completion `file`")
}

func writeManpages(dir string) error {
	// use a fixed date for the man pages so that generating them is deterministic
	date, err := time.Parse("Jan 2006", "Jan 2017")
	if err != nil {
		return err
	}

	header := &doc.GenManHeader{
		Title:   "restic backup",
		Section: "1",
		Source:  "generated by `restic generate`",
		Date:    &date,
	}

	Verbosef("writing man pages to directory %v\n", dir)
	return doc.GenManTree(cmdRoot, header, dir)
}

func writeBashCompletion(file string) error {
	Verbosef("writing bash completion file to %v\n", file)
	return cmdRoot.GenBashCompletionFile(file)
}

func writeZSHCompletion(file string) error {
	Verbosef("writing zsh completion file to %v\n", file)
	return cmdRoot.GenZshCompletionFile(file)
}

func runGenerate(cmd *cobra.Command, args []string) error {
	if genOpts.ManDir != "" {
		err := writeManpages(genOpts.ManDir)
		if err != nil {
			return err
		}
	}

	if genOpts.BashCompletionFile != "" {
		err := writeBashCompletion(genOpts.BashCompletionFile)
		if err != nil {
			return err
		}
	}

	if genOpts.ZSHCompletionFile != "" {
		err := writeZSHCompletion(genOpts.ZSHCompletionFile)
		if err != nil {
			return err
		}
	}

	var empty generateOptions
	if genOpts == empty {
		return errors.Fatal("nothing to do, please specify at least one output file/dir")
	}

	return nil
}
