// Copyright (C) 2021 Marius Schellenberger

package render

import (
	"git.giftfish.de/ston1th/gowiki/pkg/core"
	"github.com/blevesearch/bleve/analysis"
	htmlchar "github.com/blevesearch/bleve/analysis/char/html"
	"github.com/russross/blackfriday"
	"html/template"
	"regexp"
	"strings"
)

const delim = "+"

var filter = makeFilter()

func makeFilter() analysis.CharFilter {
	f, _ := htmlchar.CharFilterConstructor(nil, nil)
	return f
}

var (
	titleRe    = regexp.MustCompile("[^a-zA-Z0-9 -]+")
	whiteSpace = regexp.MustCompile(`\s+`)
)

const (
	commonHtmlFlags = 0 |
		blackfriday.HTML_USE_XHTML |
		blackfriday.HTML_USE_SMARTYPANTS |
		blackfriday.HTML_SMARTYPANTS_FRACTIONS |
		blackfriday.HTML_SMARTYPANTS_DASHES |
		blackfriday.HTML_SMARTYPANTS_LATEX_DASHES |
		blackfriday.HTML_TOC |
		blackfriday.HTML_HREF_TARGET_BLANK |
		blackfriday.HTML_NOREFERRER_LINKS |
		blackfriday.HTML_NOFOLLOW_LINKS |
		blackfriday.HTML_NOOPENER_LINKS

	commonExtensions = 0 |
		blackfriday.EXTENSION_NO_INTRA_EMPHASIS |
		blackfriday.EXTENSION_TABLES |
		blackfriday.EXTENSION_FENCED_CODE |
		blackfriday.EXTENSION_AUTOLINK |
		blackfriday.EXTENSION_STRIKETHROUGH |
		blackfriday.EXTENSION_SPACE_HEADERS |
		blackfriday.EXTENSION_HEADER_IDS |
		blackfriday.EXTENSION_BACKSLASH_LINE_BREAK |
		blackfriday.EXTENSION_DEFINITION_LISTS |
		blackfriday.EXTENSION_AUTO_HEADER_IDS
)

func Render(p *core.Page) string {
	renderer := blackfriday.HtmlRenderer(commonHtmlFlags, "", "")
	rend := blackfriday.MarkdownOptions([]byte(p.Markdown), renderer,
		blackfriday.Options{Extensions: commonExtensions},
	)
	html := string(rend)
	html = strings.ReplaceAll(html, "<table>", `<table class="table">`)
	p.HTML = template.HTML(html)
	return whiteSpace.ReplaceAllString(string(filter.Filter(rend)), " ")
}

func Title(title string) string {
	return whiteSpace.ReplaceAllString(titleRe.ReplaceAllString(title, ""), delim)
}

func Untitle(title string) string {
	return strings.ReplaceAll(title, delim, " ")
}

func StoreTitle(section, title string) string {
	return section + "/" + title
}

func SplitStoreTitle(st string) (section, title string) {
	a := strings.Split(st, "/")
	switch len(a) {
	case 1:
		return a[0], ""
	case 2:
		return a[0], a[1]
	}
	return
}