feat: image and link parser (#1744)

* feat: image and link parser

* chore: update

plugin/gomark/parser/link.go

@@ -0,0 +1,58 @@
+package parser
+
+import "github.com/usememos/memos/plugin/gomark/parser/tokenizer"
+
+type LinkParser struct {
+	ContentTokens []*tokenizer.Token
+	URL           string
+}
+
+func NewLinkParser() *LinkParser {
+	return &LinkParser{}
+}
+
+func (*LinkParser) Match(tokens []*tokenizer.Token) *LinkParser {
+	if len(tokens) < 4 {
+		return nil
+	}
+	if tokens[0].Type != tokenizer.LeftSquareBracket {
+		return nil
+	}
+	cursor, contentTokens := 1, []*tokenizer.Token{}
+	for ; cursor < len(tokens)-2; cursor++ {
+		if tokens[cursor].Type == tokenizer.Newline {
+			return nil
+		}
+		if tokens[cursor].Type == tokenizer.RightSquareBracket {
+			break
+		}
+		contentTokens = append(contentTokens, tokens[cursor])
+	}
+	if tokens[cursor+1].Type != tokenizer.LeftParenthesis {
+		return nil
+	}
+	matched, url := false, ""
+	for _, token := range tokens[cursor+2:] {
+		if token.Type == tokenizer.Newline || token.Type == tokenizer.Space {
+			return nil
+		}
+		if token.Type == tokenizer.RightParenthesis {
+			matched = true
+			break
+		}
+		url += token.Value
+	}
+	if !matched || url == "" {
+		return nil
+	}
+	if len(contentTokens) == 0 {
+		contentTokens = append(contentTokens, &tokenizer.Token{
+			Type:  tokenizer.Text,
+			Value: url,
+		})
+	}
+	return &LinkParser{
+		ContentTokens: contentTokens,
+		URL:           url,
+	}
+}