From 00f27f0cbe29cd720dd212c2e5fd9ea385e4b1b3 Mon Sep 17 00:00:00 2001
From: Naman Sood <mail@nsood.in>
Date: Mon, 15 Mar 2021 19:20:25 -0400
Subject: [PATCH] markdown hotplugging

Signed-off-by: Naman Sood <mail@nsood.in>
---
 page.go                 | 49 ++++++++++++++++++++++++++++++++++++++++-
 server.go               | 45 +++++++++++++++++++++++++++++++++++--
 templates/fullpost.html |  2 +-
 templates/summary.html  |  2 +-
 4 files changed, 93 insertions(+), 5 deletions(-)

diff --git a/page.go b/page.go
index 6fd634c..d155ca3 100644
--- a/page.go
+++ b/page.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"os"
+	"sort"
 
 	"github.com/aymerick/raymond"
 	"github.com/mitchellh/mapstructure"
@@ -20,7 +21,7 @@ import (
 type Metadata struct {
 	Title   string
 	Summary string
-	Date    string // TODO: better representation? time.Time might cause timezone issues...
+	Time    int64 // unix timestamp
 }
 
 // Page stores the contents of a blog post.
@@ -76,3 +77,49 @@ func newPage(slug string) (*Page, error) {
 func (p *Page) render(tpl *raymond.Template) (string, error) {
 	return tpl.Exec(p)
 }
+
+func (p *Page) String() string {
+	return p.Slug
+}
+
+type pages []*Page
+
+func insertOrUpdate(ps pages, p *Page) pages {
+	defer sort.Sort(ps)
+	for i, pg := range ps {
+		if pg.Slug == p.Slug {
+			ps[i] = p
+			return ps
+		}
+	}
+	ps = append(ps, p)
+	return ps
+}
+
+func remove(ps pages, slug string) pages {
+	for i, pg := range ps {
+		if pg.Slug == slug {
+			ps = append(ps[:i], ps[i+1:]...)
+			break
+		}
+	}
+	fmt.Println(ps)
+	return ps
+}
+
+// Len implements sort.Interface
+func (ps pages) Len() int {
+	return len(ps)
+}
+
+// Less implements sort.Interface
+func (ps pages) Less(i, j int) bool {
+	return ps[i].Metadata.Time > ps[j].Metadata.Time
+}
+
+// Swap implements sort.Interface
+func (ps pages) Swap(i, j int) {
+	temp := ps[i]
+	ps[i] = ps[j]
+	ps[j] = temp
+}
diff --git a/server.go b/server.go
index cc23424..133e2b9 100644
--- a/server.go
+++ b/server.go
@@ -7,8 +7,11 @@ import (
 	"net/http"
 	"os"
 	"runtime"
+	"sort"
+	"strconv"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/aymerick/raymond"
 	"github.com/rjeczalik/notify"
@@ -16,11 +19,13 @@ import (
 )
 
 type server struct {
-	pages         []*Page
 	staticHandler http.Handler
 
 	tplMutex  sync.RWMutex
 	templates map[string]*raymond.Template
+
+	pgMutex sync.RWMutex
+	pages
 }
 
 func newServer() (*server, error) {
@@ -43,6 +48,27 @@ func newServer() (*server, error) {
 		return nil, err
 	}
 
+	pagesLn := &listener{
+		folder: "posts/",
+		update: func(file string) error {
+			s.pgMutex.Lock()
+			defer s.pgMutex.Unlock()
+			page, err := newPage(strings.TrimSuffix(file, ".md"))
+			if err != nil {
+				return err
+			}
+			s.pages = insertOrUpdate(s.pages, page)
+			return nil
+		},
+		clean: func(file string) error {
+			s.pgMutex.Lock()
+			defer s.pgMutex.Unlock()
+			s.pages = remove(s.pages, strings.TrimSuffix(file, ".md"))
+			return nil
+		},
+	}
+	go pagesLn.listen()
+
 	templatesLn := &listener{
 		folder: "templates/",
 		update: func(file string) error {
@@ -99,7 +125,9 @@ func (s *server) refreshPages() error {
 		return err
 	}
 
-	s.pages = make([]*Page, 0, len(files))
+	s.pgMutex.Lock()
+	defer s.pgMutex.Unlock()
+	s.pages = make(pages, 0, len(files))
 	for _, f := range files {
 		filename := f.Name()
 
@@ -112,6 +140,7 @@ func (s *server) refreshPages() error {
 			log.Printf("Loaded page %s", filename)
 		}
 	}
+	sort.Sort(s.pages)
 
 	return nil
 }
@@ -121,6 +150,14 @@ func loadTemplate(file string) (*raymond.Template, error) {
 	if err != nil {
 		return nil, fmt.Errorf("Could not parse %s template: %w", file, 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")
+	})
 	log.Printf("Loaded template: %s", file)
 	return tpl, nil
 }
@@ -303,6 +340,8 @@ func (s *server) router(res http.ResponseWriter, req *http.Request) {
 		return
 	}
 
+	s.pgMutex.RLock()
+	defer s.pgMutex.RUnlock()
 	for _, p := range s.pages {
 		if p.Slug == slug {
 			s.renderPage(p, res, req)
@@ -345,6 +384,8 @@ func (s *server) homePage(res http.ResponseWriter, req *http.Request) {
 
 	var posts string
 
+	s.pgMutex.RLock()
+	defer s.pgMutex.RUnlock()
 	for _, p := range s.pages {
 		summary, err := p.render(s.templates["summary"])
 		if err != nil {
diff --git a/templates/fullpost.html b/templates/fullpost.html
index ec14f9f..6605caa 100644
--- a/templates/fullpost.html
+++ b/templates/fullpost.html
@@ -1,5 +1,5 @@
 <article>
-	<date>{{metadata.date}}</date>
+	<date>{{datetime metadata.time}}</date>
 	<h1>{{metadata.title}}</h1>
 	<h2>{{metadata.summary}}</h2>
 	<section class="content">
diff --git a/templates/summary.html b/templates/summary.html
index 9bd0031..f7e3518 100644
--- a/templates/summary.html
+++ b/templates/summary.html
@@ -1,5 +1,5 @@
 <article>
-	<date>{{metadata.date}}</date>
+	<date>{{datetime metadata.time}}</date>
 	<h1>{{metadata.title}}</h1>
 	<h2>{{metadata.summary}}</h2>
 	<a class="load-content" href="/{{slug}}">Read more &rarr;</a>