From eaed263d06cb7fe57daf08cb46fa614486fff4fb Mon Sep 17 00:00:00 2001
From: Christian Muehlhaeuser <muesli@gmail.com>
Date: Thu, 5 Dec 2019 14:05:35 +0100
Subject: [PATCH] Cascade Heading style into new H1, H2, ..., H6 styles

---
 blockstack.go |  2 +-
 heading.go    | 16 ++++++++++++++++
 list.go       |  2 +-
 paragraph.go  |  2 +-
 style.go      | 40 +++++++++++++++++++++++++++++++++++++++-
 5 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/blockstack.go b/blockstack.go
index c3a7cf4..7b5670c 100644
--- a/blockstack.go
+++ b/blockstack.go
@@ -70,5 +70,5 @@ func (s BlockStack) Current() BlockElement {
 }
 
 func (s BlockStack) With(child *ElementStyle) *ElementStyle {
-	return cascadeStyle(s.Current().Style, child)
+	return cascadeStyle(s.Current().Style, child, true)
 }
diff --git a/heading.go b/heading.go
index 844975c..4057c90 100644
--- a/heading.go
+++ b/heading.go
@@ -16,6 +16,22 @@ func (e *HeadingElement) Render(w io.Writer, node *bf.Node, tr *TermRenderer) er
 	var indent uint
 	var margin uint
 	rules := tr.style[Heading]
+
+	switch node.HeadingData.Level {
+	case 1:
+		rules = cascadeStyles(false, rules, tr.style[H1])
+	case 2:
+		rules = cascadeStyles(false, rules, tr.style[H2])
+	case 3:
+		rules = cascadeStyles(false, rules, tr.style[H3])
+	case 4:
+		rules = cascadeStyles(false, rules, tr.style[H4])
+	case 5:
+		rules = cascadeStyles(false, rules, tr.style[H5])
+	case 6:
+		rules = cascadeStyles(false, rules, tr.style[H6])
+	}
+
 	if rules != nil {
 		indent = rules.Indent
 		margin = rules.Margin
diff --git a/list.go b/list.go
index cbbc1c8..be0c148 100644
--- a/list.go
+++ b/list.go
@@ -19,7 +19,7 @@ func (e *ListElement) Render(w io.Writer, node *bf.Node, tr *TermRenderer) error
 
 	be := BlockElement{
 		Block: &bytes.Buffer{},
-		Style: cascadeStyle(tr.blockStack.Current().Style, rules),
+		Style: cascadeStyle(tr.blockStack.Current().Style, rules, true),
 	}
 	tr.blockStack.Push(be)
 
diff --git a/paragraph.go b/paragraph.go
index 61e70d8..f0a5a42 100644
--- a/paragraph.go
+++ b/paragraph.go
@@ -22,7 +22,7 @@ func (e *ParagraphElement) Render(w io.Writer, node *bf.Node, tr *TermRenderer)
 		_, _ = w.Write([]byte("\n"))
 		be := BlockElement{
 			Block: &bytes.Buffer{},
-			Style: cascadeStyle(tr.blockStack.Current().Style, rules),
+			Style: cascadeStyle(tr.blockStack.Current().Style, rules, true),
 		}
 		tr.blockStack.Push(be)
 	}
diff --git a/style.go b/style.go
index a4d29c7..cfac3e0 100644
--- a/style.go
+++ b/style.go
@@ -16,6 +16,12 @@ const (
 	Enumeration
 	Paragraph
 	Heading
+	H1
+	H2
+	H3
+	H4
+	H5
+	H6
 	HorizontalRule
 	Emph
 	Strong
@@ -57,7 +63,16 @@ type ElementStyle struct {
 	Suffix          string `json:"suffix"`
 }
 
-func cascadeStyle(parent *ElementStyle, child *ElementStyle) *ElementStyle {
+func cascadeStyles(onlyColors bool, s ...*ElementStyle) *ElementStyle {
+	var r *ElementStyle
+
+	for _, v := range s {
+		r = cascadeStyle(r, v, onlyColors)
+	}
+	return r
+}
+
+func cascadeStyle(parent *ElementStyle, child *ElementStyle, onlyColors bool) *ElementStyle {
 	if parent == nil {
 		return child
 	}
@@ -70,6 +85,11 @@ func cascadeStyle(parent *ElementStyle, child *ElementStyle) *ElementStyle {
 	s.Color = parent.Color
 	s.BackgroundColor = parent.BackgroundColor
 
+	if !onlyColors {
+		s.Margin = parent.Margin
+		s.Indent = parent.Indent
+	}
+
 	if child != nil {
 		if child.Color != "" {
 			s.Color = child.Color
@@ -77,6 +97,12 @@ func cascadeStyle(parent *ElementStyle, child *ElementStyle) *ElementStyle {
 		if child.BackgroundColor != "" {
 			s.BackgroundColor = child.BackgroundColor
 		}
+		if child.Margin > 0 {
+			s.Margin = child.Margin
+		}
+		if child.Indent > 0 {
+			s.Indent = child.Indent
+		}
 	}
 
 	return &s
@@ -148,6 +174,18 @@ func keyToType(key string) (StyleType, error) {
 		return Paragraph, nil
 	case "heading":
 		return Heading, nil
+	case "h1":
+		return H1, nil
+	case "h2":
+		return H2, nil
+	case "h3":
+		return H3, nil
+	case "h4":
+		return H4, nil
+	case "h5":
+		return H5, nil
+	case "h6":
+		return H6, nil
 	case "hr":
 		return HorizontalRule, nil
 	case "emph":