package notes

import (
	"encoding/base64"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"local/notes-server/filetree"
	"strings"

	"github.com/gomarkdown/markdown"
	"github.com/gomarkdown/markdown/ast"
	"github.com/gomarkdown/markdown/html"
	"github.com/gomarkdown/markdown/parser"
)

func (n *Notes) File(urlPath string) (string, error) {
	p := filetree.NewPathFromURL(urlPath)
	if p.IsDir() {
		return "", errors.New("path is dir")
	}
	b, _ := ioutil.ReadFile(p.Local)
	renderer := html.NewRenderer(html.RendererOptions{
		Flags:          html.CommonFlags | html.TOC,
		RenderNodeHook: n.commentFormer(),
	})
	parser := parser.NewWithExtensions(parser.CommonExtensions | parser.HeadingIDs | parser.AutoHeadingIDs | parser.Titleblock)
	content := markdown.ToHTML(b, parser, renderer)
	return string(content) + "\n", nil
}

func (n *Notes) commentFormer() html.RenderNodeFunc {
	header_n := 0
	return func(w io.Writer, node ast.Node, entering bool) (ast.WalkStatus, bool) {
		if heading, ok := node.(*ast.Heading); ok {
			if !entering {
				literal := ""
				ast.WalkFunc(heading, func(n ast.Node, e bool) ast.WalkStatus {
					if leaf := n.AsLeaf(); e && leaf != nil {
						if literal != "" {
							literal += ".*"
						}
						literal += string(leaf.Literal)
					}
					return ast.GoToNext
				})
				level := heading.Level
				id := base64.URLEncoding.EncodeToString([]byte(fmt.Sprintf(`^[ \t]*%s\s*%s(].*)?\s*$`, strings.Repeat("#", level), literal)))
				fmt.Fprintf(w, `
            <form method="POST" target="/comment" name="%s" class="comment">
               <input autocomplete="off" name="content" type="text"/>
               <input type="submit"/>
            </form>
         `, id)
			}
		}
		return ast.GoToNext, false
	}
}