// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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
//These codes copy from kubectl pkg/templates/markdown.go

import (
    "fmt"
    "io"
    "strings"

    "github.com/russross/blackfriday/v2"
)

const linebreak = "\n"

// ASCIIRenderer implements blackfriday.Renderer
var _ blackfriday.Renderer = &ASCIIRenderer{}

// ASCIIRenderer is a blackfriday.Renderer intended for rendering markdown
// documents as plain text, well suited for human reading on terminals.
type ASCIIRenderer struct {
    Indentation string

    listItemCount uint
    listLevel     uint
}

// render markdown to text
func (r *ASCIIRenderer) RenderNode(w io.Writer, node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
    switch node.Type {
    case blackfriday.Text:
        raw := string(node.Literal)
        lines := strings.Split(raw, linebreak)
        for _, line := range lines {
            trimmed := strings.Trim(line, " \n\t")
            if len(trimmed) > 0 && trimmed[0] != '_' {
                w.Write([]byte(" "))
            }
            w.Write([]byte(trimmed))
        }
    case blackfriday.HorizontalRule, blackfriday.Hardbreak:
        w.Write([]byte(linebreak + "----------" + linebreak))
    case blackfriday.Code, blackfriday.CodeBlock:
        w.Write([]byte(linebreak))
        lines := []string{}
        for _, line := range strings.Split(string(node.Literal), linebreak) {
            trimmed := strings.Trim(line, " \t")
            // Adding 4 times of indentation will let blackfriday to accept
            // this literal as Code or CodeBlock again in next invocation
            indented := strings.Repeat(r.Indentation, 4) + trimmed
            lines = append(lines, indented)
        }
        w.Write([]byte(strings.Join(lines, linebreak)))
    case blackfriday.Image:
        w.Write(node.LinkData.Destination)
    case blackfriday.Link:
        w.Write([]byte(" "))
        w.Write(node.LinkData.Destination)
    case blackfriday.Paragraph:
        if r.listLevel == 0 {
            w.Write([]byte(linebreak))
        }
    case blackfriday.List:
        if entering {
            w.Write([]byte(linebreak))
            r.listLevel++
        } else {
            r.listLevel--
            r.listItemCount = 0
        }
    case blackfriday.Item:
        if entering {
            r.listItemCount++
            for i := 0; uint(i) < r.listLevel; i++ {
                w.Write([]byte(r.Indentation))
            }
            if node.ListFlags&blackfriday.ListTypeOrdered != 0 {
                w.Write([]byte(fmt.Sprintf("%d. ", r.listItemCount)))
            } else {
                w.Write([]byte("* "))
            }
        } else {
            w.Write([]byte(linebreak))
        }
    default:
        normalText(w, node.Literal)
    }
    return blackfriday.GoToNext
}

func normalText(w io.Writer, text []byte) {
    w.Write([]byte(strings.Trim(string(text), " \n\t")))
}

// RenderHeader writes document preamble and TOC if requested.
func (r *ASCIIRenderer) RenderHeader(w io.Writer, ast *blackfriday.Node) {

}

// RenderFooter writes document footer.
func (r *ASCIIRenderer) RenderFooter(w io.Writer, ast *blackfriday.Node) {
    io.WriteString(w, "\n")
}
