rewrite code a bit

Signed-off-by: Naman Sood <mail@nsood.in>

tplmap/tplmap.go

@@ -0,0 +1,90 @@
+package tplmap
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"prose/common"
+	"prose/watcher"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/aymerick/raymond"
+)
+
+type tplMap struct {
+	mu        sync.RWMutex
+	templates map[string]*raymond.Template
+}
+
+func New() (watcher.AutoMap[string, *raymond.Template], error) {
+	folder, err := os.ReadDir("templates/")
+	if err != nil {
+		return nil, fmt.Errorf("could not load templates directory: %w", err)
+	}
+
+	tm := &tplMap{
+		templates: make(map[string]*raymond.Template),
+	}
+
+	for _, s := range folder {
+		err := tm.fetchLocked(s.Name())
+		if err != nil {
+			return nil, fmt.Errorf("could not load template %q: %w", s.Name(), err)
+		}
+		log.Printf("loaded template %q", s.Name())
+	}
+
+	go watcher.Watch("templates/", tm)
+
+	return tm, nil
+}
+
+func (tm *tplMap) Get(filename string) (*raymond.Template, bool) {
+	tm.mu.RLock()
+	defer tm.mu.RUnlock()
+	got, ok := tm.templates[filename]
+	return got, ok
+}
+
+func (tm *tplMap) Delete(filename string) error {
+	tm.mu.Lock()
+	defer tm.mu.Unlock()
+	delete(tm.templates, filename)
+	return nil
+}
+
+func (tm *tplMap) Fetch(filename string) error {
+	tm.mu.Lock()
+	defer tm.mu.Unlock()
+	return tm.fetchLocked(filename)
+}
+
+func (tm *tplMap) fetchLocked(filename string) error {
+	tpl, err := raymond.ParseFile("templates/" + filename)
+	if err != nil {
+		return fmt.Errorf("could not parse template %q: %w", filename, err)
+	}
+	tpl.RegisterHelper("datetime", func(timeStr string) string {
+		timestamp, err := strconv.ParseInt(timeStr, 10, 64)
+		if err != nil {
+			log.Printf("Could not parse timestamp '%v', falling back to current time", timeStr)
+			timestamp = time.Now().Unix()
+		}
+		return time.Unix(timestamp, 0).Format("Jan 2 2006, 3:04 PM")
+	})
+	tpl.RegisterHelper("rssDatetime", func(timeStr string) string {
+		timestamp, err := strconv.ParseInt(timeStr, 10, 64)
+		if err != nil {
+			log.Printf("Could not parse timestamp '%v', falling back to current time", timeStr)
+			timestamp = time.Now().Unix()
+		}
+		return common.RSSDatetime(timestamp)
+	})
+	tpl.RegisterHelper("getFullUrl", func(slug string) string {
+		return common.BlogURL + "/" + slug
+	})
+	tm.templates[filename] = tpl
+	return nil
+}