From 9b72dac5c8913388218ca38c6d8badad038f885f Mon Sep 17 00:00:00 2001
From: Nick Dumas <nobodys@business.com>
Date: Tue, 15 Aug 2023 17:13:00 -0400
Subject: [PATCH] broken runnable example of goldmark extension

---
 cmd/goldmark/main.go | 35 +++++++++++++++++
 goldmark/links.go    | 89 +++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 118 insertions(+), 6 deletions(-)
 create mode 100644 cmd/goldmark/main.go

diff --git a/cmd/goldmark/main.go b/cmd/goldmark/main.go
new file mode 100644
index 0000000..e62b17a
--- /dev/null
+++ b/cmd/goldmark/main.go
@@ -0,0 +1,35 @@
+package main
+
+import (
+	"bytes"
+	// "fmt"
+
+	ofm "code.ndumas.com/ndumas/obsidian-markdown/goldmark"
+	"github.com/yuin/goldmark"
+	"github.com/yuin/goldmark/parser"
+)
+
+func main() {
+	m := goldmark.New(goldmark.WithExtensions(
+		ofm.ObsidianLinkExtension,
+	))
+
+	source := `
+		# Hello goldmark-extensions
+		this is a [[wikilink]] in text
+
+		[[wikilink]] starting a line
+
+		ending a line with a [[wikilink]]
+		`
+
+	var buf bytes.Buffer
+
+	context := parser.NewContext()
+
+	err := m.Convert([]byte(source), &buf, parser.WithContext(context))
+	if err != nil {
+		panic(err)
+	}
+	// fmt.Printf("%#+v\n", context)
+}
diff --git a/goldmark/links.go b/goldmark/links.go
index d39647d..7e09004 100644
--- a/goldmark/links.go
+++ b/goldmark/links.go
@@ -2,7 +2,8 @@ package goldmark
 
 import (
 	"bytes"
-	"errors"
+	"fmt"
+	// "errors"
 	"regexp"
 
 	"github.com/yuin/goldmark"
@@ -10,14 +11,90 @@ import (
 	"github.com/yuin/goldmark/parser"
 	"github.com/yuin/goldmark/text"
 	"github.com/yuin/goldmark/util"
-
-	"gopkg.in/yaml.v2"
 )
 
-type ObsidianLinkExtension struct{}
+var contextKeyMeta = parser.NewContextKey()
+
+func isSeparator(line []byte) bool {
+	r := regexp.MustCompile(`^\s*-{3,}\s*$`)
+
+	return r.Match(line)
+}
+
+type obsidianLinkParser struct{}
+
+var defaultLinkParser = &obsidianLinkParser{}
+
+func (b *obsidianLinkParser) Trigger() []byte {
+	// return []byte{'!', '[', ']'}
+	fmt.Println("obsidianLinkParser.Trigger()")
+	return []byte{'[', ']'}
+}
+
+func (b *obsidianLinkParser) Parse(parent ast.Node, block text.Reader, pc parser.Context) ast.Node {
+	fmt.Println("obsidianLinkParser.Parse()")
+	return nil
+}
+
+func (b *obsidianLinkParser) Open(parent ast.Node, block text.Reader, pc parser.Context) (ast.Node, parser.State) {
+	fmt.Println("obsidianLinkParser.Open()")
+	linenum, _ := block.Position()
+	if linenum != 0 {
+		return nil, parser.NoChildren
+	}
+
+	line, _ := block.PeekLine()
+
+	if isSeparator(line) {
+		return ast.NewTextBlock(), parser.NoChildren
+	}
+
+	return nil, parser.NoChildren
+}
+
+func (b *obsidianLinkParser) Continue(node ast.Node, reader text.Reader, pc parser.Context) parser.State {
+	line, segment := reader.PeekLine()
 
-func (ole *ObsidianLinkExtension) Extend(m goldmark.Markdown) {
+	if isSeparator(line) {
+		reader.Advance(segment.Len())
+
+		return parser.Close
+	}
+
+	node.Lines().Append(segment)
+
+	return parser.Continue | parser.NoChildren
+}
+
+func (b *obsidianLinkParser) Close(node ast.Node, reader text.Reader, pc parser.Context) {
+	lines := node.Lines()
+
+	var buf bytes.Buffer
+
+	for i := 0; i < lines.Len(); i++ {
+		segment := lines.At(i)
+		buf.Write(segment.Value(reader.Source()))
+	}
+	pc.Set(contextKeyMeta, buf)
+	node.Parent().RemoveChild(node.Parent(), node)
+}
+
+func (b *obsidianLinkParser) CanInterruptParagraph() bool {
+	return false
+}
+
+func (b *obsidianLinkParser) CanAcceptIndentedLine() bool {
+	return false
+}
+
+type obsidianLinkExtension struct{}
+
+func (ole *obsidianLinkExtension) Extend(m goldmark.Markdown) {
 	m.Parser().AddOptions(
-		parser.WithBlockParsers(),
+		parser.WithInlineParsers(
+			util.Prioritized(defaultLinkParser, 0),
+		),
 	)
 }
+
+var ObsidianLinkExtension = &obsidianLinkExtension{}