From 8f2cb1e1d5648ead0291267813a8b7dc982c5938 Mon Sep 17 00:00:00 2001
From: mappu <mappu04@gmail.com>
Date: Sun, 9 Jul 2017 12:13:16 +1200
Subject: [PATCH] working bbcode support

---
 bbcode.go | 188 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 regex.go  |  15 +++++
 2 files changed, 203 insertions(+)
 create mode 100644 bbcode.go
 create mode 100644 regex.go

diff --git a/bbcode.go b/bbcode.go
new file mode 100644
index 0000000..807e13d
--- /dev/null
+++ b/bbcode.go
@@ -0,0 +1,188 @@
+package yatwiki3
+
+import (
+	"encoding/json"
+	"html/template"
+	"regexp"
+	"strings"
+)
+
+// An embarassing cascade of half-working hacks follows.
+type BBCodeRenderer struct {
+	baseUrl               string
+	CodePresent           bool
+	DynamicContentWarning string
+}
+
+func NewBBCodeRenderer(baseUrl string) *BBCodeRenderer {
+	return &BBCodeRenderer{
+		baseUrl:               baseUrl,
+		CodePresent:           false,
+		DynamicContentWarning: `&#x26a0; run dynamic content`,
+	}
+}
+
+type pregReplaceRule struct {
+	match       *regexp.Regexp
+	replace     string
+	replaceFunc func([]string) string
+}
+
+// Internal part of BBCode rendering.
+// It handles most leaf-level tags.
+func (this *BBCodeRenderer) bbcode(data string) string {
+
+	s_to_r := []pregReplaceRule{
+		pregReplaceRule{regexp.MustCompile(`(?si)\[h\](.*?)\[/h\]`), `<h2>$1</h2>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[b\](.*?)\[/b\]`), `<b>$1</b>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[i\](.*?)\[/i\]`), `<i>$1</i>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[u\](.*?)\[/u\]`), `<u>$1</u>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[s\](.*?)\[/s\]`), `<span class="s">$1</span>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[spoiler\](.*?)\[/spoiler\]`), `<span class="spoiler">$1</span>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[img\](.*?)\[/img\]`), `<img alt="" src="$1">`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[list\](.*?)\[/list\]`), `<ul><li>$1</li></ul>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[\*\]`), `</li><li>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[url=(.*?)\](.*?)\[/url\]`), `<a rel="noreferrer" href="$1">$2</a>`, nil},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[article=(.*?)\](.*?)\[/article\]`), "", func(m []string) string {
+			return `<a href="` + this.baseUrl + `view/` + template.HTMLEscapeString(m[1]) + `">` + m[2] + `</a>`
+		}},
+		pregReplaceRule{regexp.MustCompile(`(?si)\[rev=(.*?)\](.*?)\[/rev\]`), "", func(m []string) string {
+			return `<a href="` + this.baseUrl + `archive/` + template.HTMLEscapeString(m[1]) + `">` + m[2] + `</a>`
+		}},
+
+		pregReplaceRule{regexp.MustCompile(`(?si)\[imgur\](.*?)\.(...)\[/imgur\]`),
+			`<a href="https://i.imgur.com/${1}.${2}"><img class="imgur" alt="" src="https://i.imgur.com/${1}s.${2}" ></a>`,
+			nil,
+		},
+
+		pregReplaceRule{regexp.MustCompile(`(?si)\[section=(.*?)](.*?)\[/section\]`), "", func(m []string) string {
+			return `<div class="section"><a class="sectionheader" href="javascript:;" onclick="ts(this);">` + m[1] + `</a><span style="display:none;">` + strings.TrimSpace(m[2]) + `</span></div>`
+		}},
+	}
+
+	for _, prr := range s_to_r {
+
+		for prr.match.MatchString(data) { // repeat until all recursive replacements are consumed
+			if len(prr.replace) > 0 {
+				data = prr.match.ReplaceAllString(data, prr.replace)
+
+			} else {
+				data = PregReplaceCallback(prr.match, prr.replaceFunc, data)
+			}
+		}
+	}
+	return data
+}
+
+// Internal part of BBCode rendering.
+// It extracts tables and then passes the remainder to bbcode().
+func (this *BBCodeRenderer) bbtables(s string) string {
+	lines := strings.Split(s, "\n")
+	lastct := 0
+
+	ret := make([]string, 0)
+	tbl := make([]string, 0)
+	buffer := make([]string, 0)
+
+	maybe_close_previous_table := func() {
+		if lastct > 0 { // Close previous table
+			tbl = append(tbl, "</table>")
+			ret = append(ret, strings.Join(tbl, ""))
+			tbl = []string{}
+			lastct = 0
+		}
+	}
+
+	inner_formatter := func(s string) string {
+		return this.bbcode(template.HTMLEscapeString(s))
+	}
+
+	flush_buffer := func() {
+		if len(buffer) > 0 {
+			ret = append(ret, inner_formatter(strings.Join(buffer, "\n")))
+			buffer = []string{}
+		}
+	}
+
+	for _, line := range lines {
+		if len(line) > 0 && line[0] == '|' {
+			flush_buffer()
+
+			cols := strings.Split(line, "|")
+			if lastct != len(cols) {
+				maybe_close_previous_table()
+
+				// Start new table
+				lastct = len(cols)
+				tbl = append(tbl, "<table class=ti>")
+			}
+
+			for i := 0; i < len(cols); i += 1 {
+				cols[i] = inner_formatter(strings.Replace(cols[i], ";", "\n", -1))
+			}
+
+			// Add these columns
+			tbl = append(tbl, "<tr><td>"+strings.Join(cols[1:], "</td><td>")+"</td></tr>")
+
+		} else {
+			maybe_close_previous_table()
+			buffer = append(buffer, line)
+		}
+	}
+
+	flush_buffer()
+	maybe_close_previous_table()
+
+	return strings.Join(ret, "\n")
+}
+
+// Internal part of BBCode rendering.
+// It extracts [code] sections and then passes the remainder to bbtables().
+func (this *BBCodeRenderer) bbformat(str string) string {
+	return PregReplaceCallback(
+		regexp.MustCompile(`(?si)\[code\](.*?)\[/code\]`),
+		func(m []string) string {
+			this.CodePresent = true
+			return "<pre><code>" + strings.Replace(m[1], "<br>\r\n", "\r\n", -1) + "</code></pre>"
+		},
+		strings.Replace(
+			strings.Replace(this.bbtables(str), "\r\n", "<br>", -1), //bbtables(bbcode(h($str)))
+			"</ul><br>\r\n<br>",
+			"</ul><br>",
+			-1, // replace all
+		),
+	)
+}
+
+// Internal part of BBCode rendering.
+// It extracts [html] sections and then passes the remainder to bbformat().
+func (this *BBCodeRenderer) displayfmt(s string) string {
+	hpos := 0
+	ret := ""
+
+	for {
+		spos := strings.Index(s[hpos:], "[html]")
+		if spos == -1 {
+			break
+		}
+
+		ret += this.bbformat(s[hpos : spos-hpos])
+		spos += 6
+
+		epos := strings.Index(s[spos:], "[/html]")
+		if epos == -1 {
+			break // no matching [/html] tag found
+		}
+
+		jsonInnerContent, _ := json.Marshal(s[spos : epos-spos])
+
+		ret += `<div class="html"><a href="javascript:;" onclick="` + template.HTMLEscapeString(`els(this, `+string(jsonInnerContent)+`);`) + `">` + this.DynamicContentWarning + `</a></div>`
+		hpos = epos + 7
+	}
+	return ret + this.bbformat(s[hpos:])
+}
+
+// RenderHTML converts the input string to HTML.
+func (this *BBCodeRenderer) RenderHTML(s string) template.HTML {
+	return template.HTML(this.displayfmt(s))
+}
diff --git a/regex.go b/regex.go
new file mode 100644
index 0000000..54aca17
--- /dev/null
+++ b/regex.go
@@ -0,0 +1,15 @@
+package yatwiki3
+
+import (
+	"regexp"
+)
+
+func PregReplaceCallback(pattern *regexp.Regexp, cb func([]string) string, content string) string {
+	// FIXME avoid double-matching
+	// Submit to upstream https://github.com/golang/go/issues/5690
+	return pattern.ReplaceAllStringFunc(content, func(fullmatch string) string {
+		parts := pattern.FindStringSubmatch(fullmatch)
+		return cb(parts)
+	})
+
+}