1 files changed, 150 insertions, 0 deletions
diff --git a/gemtext/internal/templates.go b/gemtext/internal/templates.go
new file mode 100644
index 0000000..dea528a
--- /dev/null
+++ b/gemtext/internal/templates.go
@@ -0,0 +1,150 @@
+package internal
+
+import (
+	htemplate "html/template"
+	"net/url"
+	"text/template"
+
+	"tildegit.org/tjp/gus/gemtext"
+)
+
+var Renderers = map[gemtext.LineType]string{
+	gemtext.LineTypeText:     "textline",
+	gemtext.LineTypeLink:     "linkline",
+	gemtext.LineTypeHeading1: "heading1line",
+	gemtext.LineTypeHeading2: "heading2line",
+	gemtext.LineTypeHeading3: "heading3line",
+	gemtext.LineTypeQuote:    "quoteline",
+}
+
+func AddAllTemplates(base *template.Template, additions *template.Template) (*template.Template, error) {
+	if additions == nil {
+		return base, nil
+	}
+
+	tmpl := base
+	var err error
+	for _, addition := range additions.Templates() {
+		tmpl, err = tmpl.AddParseTree(addition.Name(), addition.Tree)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return tmpl, nil
+}
+
+func AddHTMLTemplates(base *htemplate.Template, additions *htemplate.Template) (*htemplate.Template, error) {
+	if additions == nil {
+		return base, nil
+	}
+
+	tmpl := base
+	var err error
+	for _, addition := range additions.Templates() {
+		tmpl, err = tmpl.AddParseTree(addition.Name(), addition.Tree)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return tmpl, nil
+}
+
+func ValidateLinks(doc gemtext.Document) error {
+	for _, line := range doc {
+		if linkLine, ok := line.(gemtext.LinkLine); ok {
+			_, err := url.Parse(linkLine.URL())
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+type RenderItem struct {
+	Template string
+	Object   any
+}
+
+func RenderItems(doc gemtext.Document) []RenderItem {
+	out := make([]RenderItem, 0, len(doc))
+	out = append(out, RenderItem{
+		Template: "header",
+		Object:   doc,
+	})
+
+	inUL := false
+	ulStart := 0
+	inPF := false
+	pfStart := 0
+
+	for i, line := range doc {
+		switch line.Type() {
+		case gemtext.LineTypeListItem:
+			if !inUL {
+				inUL = true
+				ulStart = i
+			}
+		case gemtext.LineTypePreformatToggle:
+			if inUL {
+				inUL = false
+				out = append(out, RenderItem{
+					Template: "listitemlines",
+					Object:   doc[ulStart:i],
+				})
+			}
+			if !inPF {
+				inPF = true
+				pfStart = i
+			} else {
+				inPF = false
+				out = append(out, RenderItem{
+					Template: "preformattedtextlines",
+					Object:   doc[pfStart+1 : i],
+				})
+			}
+		case gemtext.LineTypePreformattedText:
+		default:
+			if inUL {
+				inUL = false
+				out = append(out, RenderItem{
+					Template: "listitemlines",
+					Object:   doc[ulStart:i],
+				})
+			}
+
+			if linkLine, ok := line.(gemtext.LinkLine); ok {
+				line = validatedLinkLine{linkLine}
+			}
+
+			out = append(out, RenderItem{
+				Template: Renderers[line.Type()],
+				Object:   line,
+			})
+		}
+	}
+
+	if inUL {
+		out = append(out, RenderItem{
+			Template: "listitemlines",
+			Object:   doc[ulStart:],
+		})
+	}
+
+	out = append(out, RenderItem{
+		Template: "footer",
+		Object:   doc,
+	})
+
+	return out
+}
+
+type validatedLinkLine struct {
+	gemtext.LinkLine
+}
+
+func (vll validatedLinkLine) ValidatedURL() htemplate.URL {
+	return htemplate.URL(vll.URL())
+}