From d100cebfbe9930b7c736cf90b1be336578df7069 Mon Sep 17 00:00:00 2001
From: Stephen Searles <stephen.searles@gmail.com>
Date: Sat, 24 Jun 2017 00:55:35 -0700
Subject: [PATCH] cleaning up a little bit

---
 media.go | 153 ++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 105 insertions(+), 48 deletions(-)

diff --git a/media.go b/media.go
index d52e902..b8a2de9 100644
--- a/media.go
+++ b/media.go
@@ -11,6 +11,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 
@@ -26,6 +27,27 @@ func (ms *MediaSource) LocationOrig(m Media) string {
 	return path.Join(ms.StorageDir, m.Name)
 }
 
+func (ms *MediaSource) ThumbPath(m Media, size image.Rectangle) string {
+	w := size.Dx()
+	h := size.Dy()
+
+	var ws, hs string
+
+	if w != 0 {
+		ws = fmt.Sprint(w)
+	}
+	if h != 0 {
+		hs = fmt.Sprint(h)
+	}
+
+	thumbSlug := filepath.Join(fmt.Sprintf("%sx%s", ws, hs), m.Name)
+	return path.Join("/media", thumbSlug)
+}
+
+func (ms *MediaSource) ThumbFilename(m Media, size image.Rectangle) string {
+	return filepath.Join(ms.ThumbDir, ms.ThumbPath(m, size))
+}
+
 func (ms *MediaSource) receiveNewMedia(name string, r io.Reader) error {
 	dest := path.Join(ms.StorageDir, name)
 	f, err := os.OpenFile(dest, os.O_WRONLY|os.O_CREATE, 0644)
@@ -46,21 +68,20 @@ type Media struct {
 	Name string
 }
 
-func (ms *MediaSource) ThumbMax(m Media, maxDim int) (string, int, int, error) {
+func (ms *MediaSource) ThumbMax(m Media, maxDim int) (string, image.Rectangle, error) {
 	f, err := os.Open(ms.LocationOrig(m))
 	if err != nil {
-		return "", 0, 0, err
+		return "", image.ZR, err
 	}
 	defer f.Close()
 
-	img, _, err := image.Decode(f)
+	cfg, _, err := image.DecodeConfig(f)
 	if err != nil {
-		return "", 0, 0, err
+		return "", image.ZR, err
 	}
 
-	rect := img.Bounds()
-	width := rect.Dx()
-	height := rect.Dy()
+	width := cfg.Width
+	height := cfg.Height
 
 	if width > height {
 		height = height * maxDim / width
@@ -70,8 +91,28 @@ func (ms *MediaSource) ThumbMax(m Media, maxDim int) (string, int, int, error) {
 		height = maxDim
 	}
 
-	src, err := ms.ThumbImage(img, m, width, height)
-	return src, width, height, err
+	size := image.Rect(0, 0, width, height)
+	if ms.HasThumb(m, size) {
+		return ms.ThumbPath(m, size), size, nil
+	}
+
+	_, err = f.Seek(0, io.SeekStart)
+	if err != nil {
+		return "", image.ZR, err
+	}
+
+	img, _, err := image.Decode(f)
+	if err != nil {
+		return "", image.ZR, err
+	}
+
+	src, err := ms.ThumbImage(img, m, size)
+	return src, size, err
+}
+
+func (ms *MediaSource) HasThumb(m Media, size image.Rectangle) bool {
+	_, err := os.Stat(ms.ThumbFilename(m, size))
+	return err == nil
 }
 
 func (ms *MediaSource) ByName(name string) *Media {
@@ -81,7 +122,11 @@ func (ms *MediaSource) ByName(name string) *Media {
 	}
 }
 
-func (ms *MediaSource) Thumb(m Media, width, height int) (string, error) {
+func (ms *MediaSource) Thumb(m Media, size image.Rectangle) (string, error) {
+	if ms.HasThumb(m, size) {
+		return ms.ThumbPath(m, size), nil
+	}
+
 	f, err := os.Open(ms.LocationOrig(m))
 	if err != nil {
 		return "", err
@@ -93,21 +138,19 @@ func (ms *MediaSource) Thumb(m Media, width, height int) (string, error) {
 		return "", err
 	}
 
-	return ms.ThumbImage(img, m, width, height)
+	return ms.ThumbImage(img, m, size)
 }
 
-func (ms *MediaSource) ThumbImage(img image.Image, m Media, width, height int) (string, error) {
-
-	thumbSlug := filepath.Join(m.Name, fmt.Sprintf("%d/%d.jpg", width, height))
-	thumbLoc := filepath.Join(ms.ThumbDir, thumbSlug)
+func (ms *MediaSource) ThumbImage(img image.Image, m Media, size image.Rectangle) (string, error) {
 
+	thumbLoc := ms.ThumbFilename(m, size)
 	os.MkdirAll(path.Dir(thumbLoc), 0755)
 	fthumb, err := os.OpenFile(thumbLoc, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0655)
 	if err != nil {
 		return "", err
 	}
 
-	img = resize.Resize(uint(width), uint(height), img, resize.Bilinear)
+	img = resize.Resize(uint(size.Dx()), uint(size.Dy()), img, resize.Bilinear)
 
 	err = jpeg.Encode(fthumb, img, nil)
 	if err != nil {
@@ -119,7 +162,7 @@ func (ms *MediaSource) ThumbImage(img image.Image, m Media, width, height int) (
 		return "", err
 	}
 
-	return path.Join("/media", thumbSlug), nil
+	return ms.ThumbPath(m, size), nil
 }
 
 func (ms *MediaSource) Walk() ([]*Media, error) {
@@ -197,12 +240,12 @@ func (ch *CaddyHugo) serveMediaPage(w http.ResponseWriter, r *http.Request) (int
 
 		for _, m := range media {
 
-			src, width, height, err := ch.Media.ThumbMax(*m, 100)
+			src, size, err := ch.Media.ThumbMax(*m, 100)
 			if err != nil {
 				fmt.Fprintf(w, `<div class="img">error rendering %q: %v</div>`, m.Name, err)
 				continue
 			}
-			fmt.Fprintf(w, `<div class="img"><img width=%d height=%d src=%q /><br /><input type="text" readonly value=%q /><span class="copy">&#x1F4CB;</span></div>`, width, height, src, src)
+			fmt.Fprintf(w, `<div class="img"><img width=%d height=%d src=%q /><br /><input type="text" readonly value=%q /><span class="copy">&#x1F4CB;</span></div>`, size.Dx(), size.Dy(), src, src)
 		}
 	}
 	io.WriteString(w, `<script>
@@ -224,6 +267,38 @@ func (ch *CaddyHugo) serveMediaPage(w http.ResponseWriter, r *http.Request) (int
 	return 200, nil
 }
 
+var (
+	sizeString = regexp.MustCompile(`([0-9]*)x([0-9]*)`)
+)
+
+func parseSizeString(str string) (image.Rectangle, error) {
+	var err = fmt.Errorf("expected a size string {width}x{height}, saw %q", str)
+
+	strs := sizeString.FindStringSubmatch(str)
+	if len(strs) < 3 {
+		return image.ZR, err
+	}
+
+	var w, h int
+	var strconvErr error
+
+	if strs[1] != "" {
+		w, strconvErr = strconv.Atoi(strs[1])
+		if strconvErr != nil {
+			return image.ZR, err
+		}
+	}
+
+	if strs[2] != "" {
+		h, strconvErr = strconv.Atoi(strs[2])
+		if strconvErr != nil {
+			return image.ZR, err
+		}
+	}
+
+	return image.Rect(0, 0, w, h), nil
+}
+
 func (ch *CaddyHugo) serveMedia(w http.ResponseWriter, r *http.Request) (int, error) {
 	if ch.Media == nil {
 		http.NotFound(w, r)
@@ -231,41 +306,22 @@ func (ch *CaddyHugo) serveMedia(w http.ResponseWriter, r *http.Request) (int, er
 	}
 
 	segs := strings.Split(r.URL.Path, "/")
-	name := segs[2]
-	file := ""
-	var err error
-	m := ch.Media.ByName(name)
+	name := segs[len(segs)-1] // the last segment is the filename
 
-	switch len(segs) {
-	case 3:
-		file = name
-	case 4:
-		var max int
-		max, err = strconv.Atoi(removeExtension(segs[3]))
-		if err != nil {
-			http.Error(w, fmt.Sprintf("expected /media/filename, /media/filename/maxDim, or /media/filename/width/height..."), http.StatusBadRequest)
-			return 400, nil
-		}
+	size := image.Rectangle{}
 
-		file, _, _, err = ch.Media.ThumbMax(*m, max)
-	case 5:
-		var width, height int
-		width, err = strconv.Atoi(segs[3])
-		if err != nil {
-			http.Error(w, fmt.Sprintf("expected /media/filename, /media/filename/maxDim, or /media/filename/width/height.."), http.StatusBadRequest)
-			return 400, nil
-		}
-		height, err = strconv.Atoi(removeExtension(segs[4]))
+	m := ch.Media.ByName(name)
+
+	if len(segs) >= 4 && len(segs) > 2 {
+		var err error
+		size, err = parseSizeString(segs[len(segs)-2])
 		if err != nil {
-			http.Error(w, fmt.Sprintf("expected /media/filename, /media/filename/maxDim, or /media/filename/width/height."), http.StatusBadRequest)
+			http.Error(w, err.Error(), http.StatusBadRequest)
 			return 400, nil
 		}
-		file, err = ch.Media.Thumb(*m, width, height)
-	default:
-		http.Error(w, fmt.Sprintf("expected /media/filename, /media/filename/maxDim, or /media/filename/width/height"), http.StatusBadRequest)
-		return 400, nil
 	}
 
+	file, err := ch.Media.Thumb(*m, size)
 	if err != nil {
 		http.Error(w, fmt.Sprintf("unable to load thumb"), http.StatusInternalServerError)
 		return 500, nil
@@ -275,7 +331,8 @@ func (ch *CaddyHugo) serveMedia(w http.ResponseWriter, r *http.Request) (int, er
 		file = file[1:]
 	}
 
-	file = path.Join(ch.Media.ThumbDir, file[len("media/"):])
+	file = path.Join(ch.Media.ThumbDir, file)
+
 	http.ServeFile(w, r, file)
 
 	return 200, nil