// Copyright 2016 The Hugo Authors. All rights reserved.
//
// 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 commands

import (
	"fmt"
	"path"
	"path/filepath"
	"strings"

	"github.com/gohugoio/hugo/helpers"
	"github.com/gohugoio/hugo/hugofs"
	"github.com/spf13/cobra"
	"github.com/spf13/cobra/doc"
	jww "github.com/spf13/jwalterweatherman"
)

var _ cmder = (*genDocCmd)(nil)

type genDocCmd struct {
	gendocdir string
	*baseCmd
}

func newGenDocCmd() *genDocCmd {
	const gendocFrontmatterTemplate = `---
title: "%s"
slug: %s
url: %s
---
`

	cc := &genDocCmd{}

	cc.baseCmd = newBaseCmd(&cobra.Command{
		Use:   "doc",
		Short: "Generate Markdown documentation for the Hugo CLI.",
		Long: `Generate Markdown documentation for the Hugo CLI.

This command is, mostly, used to create up-to-date documentation
of Hugo's command-line interface for http://gohugo.io/.

It creates one Markdown file per command with front matter suitable
for rendering in Hugo.`,

		RunE: func(cmd *cobra.Command, args []string) error {
			cmd.VisitParents(func(c *cobra.Command) {
				// Disable the "Auto generated by spf13/cobra on DATE"
				// as it creates a lot of diffs.
				c.DisableAutoGenTag = true
			})

			if !strings.HasSuffix(cc.gendocdir, helpers.FilePathSeparator) {
				cc.gendocdir += helpers.FilePathSeparator
			}
			if found, _ := helpers.Exists(cc.gendocdir, hugofs.Os); !found {
				jww.FEEDBACK.Println("Directory", cc.gendocdir, "does not exist, creating...")
				if err := hugofs.Os.MkdirAll(cc.gendocdir, 0777); err != nil {
					return err
				}
			}
			prepender := func(filename string) string {
				name := filepath.Base(filename)
				base := strings.TrimSuffix(name, path.Ext(name))
				url := "/commands/" + strings.ToLower(base) + "/"
				return fmt.Sprintf(gendocFrontmatterTemplate, strings.Replace(base, "_", " ", -1), base, url)
			}

			linkHandler := func(name string) string {
				base := strings.TrimSuffix(name, path.Ext(name))
				return "/commands/" + strings.ToLower(base) + "/"
			}
			jww.FEEDBACK.Println("Generating Hugo command-line documentation in", cc.gendocdir, "...")
			doc.GenMarkdownTreeCustom(cmd.Root(), cc.gendocdir, prepender, linkHandler)
			jww.FEEDBACK.Println("Done.")

			return nil
		},
	})

	cc.cmd.PersistentFlags().StringVar(&cc.gendocdir, "dir", "/tmp/hugodoc/", "the directory to write the doc.")

	// For bash-completion
	cc.cmd.PersistentFlags().SetAnnotation("dir", cobra.BashCompSubdirsInDir, []string{})

	return cc
}