From eca5dda9d62bdac48d1af74fd073c6ed3e44b004 Mon Sep 17 00:00:00 2001
From: Adnan Maolood <me@adnano.co>
Date: Sun, 9 May 2021 19:28:09 -0400
Subject: [PATCH] Implement support for base templates

---
 config.go    |  14 +++---
 main.go      |   9 +++-
 templates.go | 118 +++++++++++++++++++++++++++++++++++++++------------
 3 files changed, 107 insertions(+), 34 deletions(-)

diff --git a/config.go b/config.go
index 778c548..380b2e7 100644
--- a/config.go
+++ b/config.go
@@ -48,18 +48,13 @@ func LoadConfig(path string) (*Config, error) {
 		return nil, err
 	}
 
-	return c, nil
-}
-
-// LoadTemplates loads templates from the provided path.
-func (c *Config) LoadTemplates(path string) error {
 	// Site contains site metadata passed to templates
 	type Site struct {
 		Title string
 		URLs  []string
 	}
 
-	// Load templates
+	// Initialize templates
 	c.templates = NewTemplates()
 	c.templates.Funcs(map[string]interface{}{
 		"site": func() Site {
@@ -83,5 +78,10 @@ func (c *Config) LoadTemplates(path string) error {
 			return template.HTML(s)
 		},
 	})
-	return c.templates.Load(path)
+
+	return c, nil
+}
+
+func (c *Config) LoadTemplates(path string, exts []string) error {
+	return c.templates.Load(path, exts)
 }
diff --git a/main.go b/main.go
index 70e2fe0..a6ee2af 100644
--- a/main.go
+++ b/main.go
@@ -56,7 +56,14 @@ func build() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	if err := cfg.LoadTemplates("templates"); err != nil {
+
+	templateExts := []string{}
+	for _, task := range cfg.Tasks {
+		if task.TemplateExt != "" {
+			templateExts = append(templateExts, task.TemplateExt)
+		}
+	}
+	if err := cfg.LoadTemplates("templates", templateExts); err != nil {
 		log.Fatal(err)
 	}
 
diff --git a/templates.go b/templates.go
index 9b46c3b..94bd899 100644
--- a/templates.go
+++ b/templates.go
@@ -3,6 +3,7 @@ package main
 import (
 	htemplate "html/template"
 	"io"
+	"io/fs"
 	"io/ioutil"
 	"os"
 	pathpkg "path"
@@ -35,42 +36,107 @@ func (t *Templates) Funcs(funcs map[string]interface{}) {
 	t.funcs = funcs
 }
 
-// LoadTemplate loads a template from the provided path and content.
-func (t *Templates) LoadTemplate(path string, content []byte) {
-	tmpl := template.New(path)
-	tmpl.Funcs(t.funcs)
-	template.Must(tmpl.Parse(string(content)))
-	t.tmpls[path] = tmpl
+// LoadTemplate loads a template from the provided filenames.
+func (t *Templates) LoadTemplate(name string, filenames ...string) error {
+	if pathpkg.Ext(name) == ".html" {
+		return t.loadHTMLTemplate(name, filenames...)
+	}
+	return t.loadTextTemplate(name, filenames...)
 }
 
-func (t *Templates) LoadHTMLTemplate(path string, content []byte) {
-	tmpl := htemplate.New(path)
-	tmpl.Funcs(htemplate.FuncMap(t.funcs))
-	htemplate.Must(tmpl.Parse(string(content)))
-	t.tmpls[path] = tmpl
-}
-
-// Load loads templates from the provided directory
-func (t *Templates) Load(dir string) error {
-	return filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+func (t *Templates) loadTextTemplate(name string, filenames ...string) error {
+	tmpl := template.New(name).Funcs(t.funcs)
+	for i := range filenames {
+		b, err := ioutil.ReadFile(filenames[i])
 		if err != nil {
 			return err
 		}
-		if info.Mode().IsRegular() {
-			b, err := ioutil.ReadFile(path)
-			if err != nil {
-				return err
+		if _, err := tmpl.Parse(string(b)); err != nil {
+			return err
+		}
+	}
+	t.tmpls[name] = tmpl
+	return nil
+}
+
+func (t *Templates) loadHTMLTemplate(name string, filenames ...string) error {
+	tmpl := htemplate.New(name).Funcs(t.funcs)
+	for i := range filenames {
+		b, err := ioutil.ReadFile(filenames[i])
+		if err != nil {
+			return err
+		}
+		if _, err := tmpl.Parse(string(b)); err != nil {
+			return err
+		}
+	}
+	t.tmpls[name] = tmpl
+	return nil
+}
+
+// Load loads templates from the provided directory.
+func (t *Templates) Load(dir string, exts []string) error {
+	err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			name := d.Name()
+			if strings.HasPrefix(name, "_") && name != "_default" {
+				return fs.SkipDir
 			}
-			// Remove directory from beginning of path
-			path = strings.TrimPrefix(path, dir)
-			if pathpkg.Ext(path) == ".html" {
-				t.LoadHTMLTemplate(path, b)
-			} else {
-				t.LoadTemplate(path, b)
+
+			// Load atom.xml template
+			atom := pathpkg.Join(path, "atom.xml")
+			if _, err := os.Stat(atom); err == nil {
+				name := strings.TrimPrefix(atom, dir)
+				t.loadHTMLTemplate(name, atom)
+			}
+
+			// Load page templates
+			for _, ext := range exts {
+				for _, name := range []string{"index" + ext, "page" + ext} {
+					filename := pathpkg.Join(path, name)
+					if _, err := os.Stat(filename); err != nil {
+						// Template does not exist
+						continue
+					}
+
+					filenames := []string{filename}
+					base := pathpkg.Join(path, "base"+ext)
+					if _, err := os.Stat(base); err == nil {
+						filenames = append(filenames, base)
+					}
+
+					name := strings.TrimPrefix(filename, dir)
+					if err := t.LoadTemplate(name, filenames...); err != nil {
+						return err
+					}
+				}
 			}
 		}
 		return nil
 	})
+	if err != nil && !os.IsNotExist(err) {
+		return err
+	}
+
+	// Load partial templates
+	partials := pathpkg.Join(dir, "_partials")
+	err = filepath.WalkDir(partials, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.Type().IsRegular() {
+			name := strings.TrimPrefix(path, dir)
+			t.LoadTemplate(name, path)
+		}
+		return nil
+	})
+	if err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
 }
 
 // FindTemplate returns the template for the given path.