12 files changed, 172 insertions, 30 deletions
diff --git a/plugins/base/public/foot.html b/plugins/base/public/foot.html
index 284d779..b605728 100644
--- a/plugins/base/public/foot.html
+++ b/plugins/base/public/foot.html
@@ -1,3 +1,2 @@
-    <script src="/plugins/base/assets/script.js"></script>
   </body>
 </html>
diff --git a/plugins/base/public/head.html b/plugins/base/public/head.html
index bed1bb3..bb47cfc 100644
--- a/plugins/base/public/head.html
+++ b/plugins/base/public/head.html
@@ -3,6 +3,5 @@
   <head>
     <meta charset="utf-8">
     <title>koushin</title>
-    <link rel="stylesheet" href="/plugins/base/assets/style.css">
   </head>
   <body>
diff --git a/plugins/base/public/message.html b/plugins/base/public/message.html
index a973881..5457627 100644
--- a/plugins/base/public/message.html
+++ b/plugins/base/public/message.html
@@ -110,7 +110,7 @@
 
 <hr>
 
-{{if .Body}}
+{{if .View}}
   <p>
     {{if .Message.HasFlag "\\Draft"}}
       <a href="{{.Message.Uid}}/edit?part={{.PartPath}}">Edit draft</a>
@@ -118,13 +118,7 @@
       <a href="{{.Message.Uid}}/reply?part={{.PartPath}}">Reply</a>
     {{end}}
   </p>
-  {{if .IsHTML}}
-    <!-- allow-same-origin is required to resize the frame with its content -->
-    <!-- allow-popups is required for target="_blank" links -->
-    <iframe id="email-frame" srcdoc="{{.Body}}" sandbox="allow-same-origin allow-popups"></iframe>
-  {{else}}
-    <pre>{{.Body}}</pre>
-  {{end}}
+  {{.View}}
 {{else}}
   <p>Can't preview this message part.</p>
   <a href="{{.Message.Uid}}/raw?part={{.PartPath}}">Download</a>
diff --git a/plugins/base/routes.go b/plugins/base/routes.go
index ec22d1b..ad4d121 100644
--- a/plugins/base/routes.go
+++ b/plugins/base/routes.go
@@ -176,8 +176,7 @@ type MessageRenderData struct {
 	Mailboxes   []*imap.MailboxInfo
 	Mailbox     *imap.MailboxStatus
 	Message     *IMAPMessage
-	Body        string
-	IsHTML      bool
+	View        interface{}
 	PartPath    string
 	MailboxPage int
 	Flags       map[string]bool
@@ -255,21 +254,9 @@ func handleGetPart(ctx *koushin.Context, raw bool) error {
 		}
 	}
 
-	var body []byte
-	if strings.HasPrefix(strings.ToLower(mimeType), "text/") {
-		body, err = ioutil.ReadAll(part.Body)
-		if err != nil {
-			return fmt.Errorf("failed to read part body: %v", err)
-		}
-	}
-
-	isHTML := false
-	if strings.EqualFold(mimeType, "text/html") {
-		body, err = sanitizeHTML(body)
-		if err != nil {
-			return fmt.Errorf("failed to sanitize HTML part: %v", err)
-		}
-		isHTML = true
+	view, err := viewMessagePart(ctx, msg, part)
+	if err == ErrViewUnsupported {
+		view = nil
 	}
 
 	flags := make(map[string]bool)
@@ -286,8 +273,7 @@ func handleGetPart(ctx *koushin.Context, raw bool) error {
 		Mailboxes:      mailboxes,
 		Mailbox:        mbox,
 		Message:        msg,
-		Body:           string(body),
-		IsHTML:         isHTML,
+		View:           view,
 		PartPath:       partPathString,
 		MailboxPage:    int(mbox.Messages-msg.SeqNum) / messagesPerPage,
 		Flags:          flags,
diff --git a/plugins/base/viewer.go b/plugins/base/viewer.go
new file mode 100644
index 0000000..a76ecf9
--- /dev/null
+++ b/plugins/base/viewer.go
@@ -0,0 +1,38 @@
+package koushinbase
+
+import (
+	"fmt"
+
+	"git.sr.ht/~emersion/koushin"
+	"github.com/emersion/go-message"
+)
+
+// ErrViewUnsupported is returned by Viewer.ViewMessagePart when the message
+// part isn't supported.
+var ErrViewUnsupported = fmt.Errorf("cannot generate message view: unsupported part")
+
+// Viewer is a message part viewer.
+type Viewer interface {
+	// ViewMessagePart renders a message part. The returned value is displayed
+	// in a template. ErrViewUnsupported is returned if the message part isn't
+	// supported.
+	ViewMessagePart(*koushin.Context, *IMAPMessage, *message.Entity) (interface{}, error)
+}
+
+var viewers []Viewer
+
+// RegisterViewer registers a message part viewer.
+func RegisterViewer(viewer Viewer) {
+	viewers = append(viewers, viewer)
+}
+
+func viewMessagePart(ctx *koushin.Context, msg *IMAPMessage, part *message.Entity) (interface{}, error) {
+	for _, viewer := range viewers {
+		v, err := viewer.ViewMessagePart(ctx, msg, part)
+		if err == ErrViewUnsupported {
+			continue
+		}
+		return v, err
+	}
+	return nil, ErrViewUnsupported
+}
diff --git a/plugins/viewhtml/plugin.go b/plugins/viewhtml/plugin.go
new file mode 100644
index 0000000..f22364e
--- /dev/null
+++ b/plugins/viewhtml/plugin.go
@@ -0,0 +1,10 @@
+package koushinviewhtml
+
+import (
+	"git.sr.ht/~emersion/koushin"
+)
+
+func init() {
+	p := koushin.GoPlugin{Name: "viewhtml"}
+	koushin.RegisterPluginLoader(p.Loader())
+}
diff --git a/plugins/base/public/assets/script.js b/plugins/viewhtml/public/assets/script.js
index fd7a1d5..fd7a1d5 100644
--- a/plugins/base/public/assets/script.js
+++ b/plugins/viewhtml/public/assets/script.js
diff --git a/plugins/base/public/assets/style.css b/plugins/viewhtml/public/assets/style.css
index 4f91f63..4f91f63 100644
--- a/plugins/base/public/assets/style.css
+++ b/plugins/viewhtml/public/assets/style.css
diff --git a/plugins/base/sanitize_html.go b/plugins/viewhtml/sanitize.go
index a82c852..8cee481 100644
--- a/plugins/base/sanitize_html.go
+++ b/plugins/viewhtml/sanitize.go
@@ -1,4 +1,4 @@
-package koushinbase
+package koushinviewhtml
 
 import (
 	"bytes"
diff --git a/plugins/viewhtml/viewer.go b/plugins/viewhtml/viewer.go
new file mode 100644
index 0000000..9734c37
--- /dev/null
+++ b/plugins/viewhtml/viewer.go
@@ -0,0 +1,57 @@
+package koushinviewhtml
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"io/ioutil"
+	"strings"
+
+	"git.sr.ht/~emersion/koushin"
+	koushinbase "git.sr.ht/~emersion/koushin/plugins/base"
+	"github.com/emersion/go-message"
+)
+
+const tpl = `
+<!-- allow-same-origin is required to resize the frame with its content -->
+<!-- allow-popups is required for target="_blank" links -->
+<iframe id="email-frame" srcdoc="{{.}}" sandbox="allow-same-origin allow-popups"></iframe>
+<script src="/plugins/viewhtml/assets/script.js"></script>
+<link rel="stylesheet" href="/plugins/viewhtml/assets/style.css">
+`
+
+type viewer struct{}
+
+func (viewer) ViewMessagePart(ctx *koushin.Context, msg *koushinbase.IMAPMessage, part *message.Entity) (interface{}, error) {
+	mimeType, _, err := part.Header.ContentType()
+	if err != nil {
+		return nil, err
+	}
+	if !strings.EqualFold(mimeType, "text/html") {
+		return nil, koushinbase.ErrViewUnsupported
+	}
+
+	body, err := ioutil.ReadAll(part.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read part body: %v", err)
+	}
+
+	body, err = sanitizeHTML(body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to sanitize HTML part: %v", err)
+	}
+
+	t := template.Must(template.New("view-html.html").Parse(tpl))
+
+	var buf bytes.Buffer
+	err = t.Execute(&buf, string(body))
+	if err != nil {
+		return nil, err
+	}
+
+	return template.HTML(buf.String()), nil
+}
+
+func init() {
+	koushinbase.RegisterViewer(viewer{})
+}
diff --git a/plugins/viewtext/plugin.go b/plugins/viewtext/plugin.go
new file mode 100644
index 0000000..c7a2bcc
--- /dev/null
+++ b/plugins/viewtext/plugin.go
@@ -0,0 +1,10 @@
+package koushinviewtext
+
+import (
+	"git.sr.ht/~emersion/koushin"
+)
+
+func init() {
+	p := koushin.GoPlugin{Name: "viewtext"}
+	koushin.RegisterPluginLoader(p.Loader())
+}
diff --git a/plugins/viewtext/viewer.go b/plugins/viewtext/viewer.go
new file mode 100644
index 0000000..cca38a8
--- /dev/null
+++ b/plugins/viewtext/viewer.go
@@ -0,0 +1,49 @@
+package koushinviewtext
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"io/ioutil"
+	"strings"
+
+	"git.sr.ht/~emersion/koushin"
+	koushinbase "git.sr.ht/~emersion/koushin/plugins/base"
+	"github.com/emersion/go-message"
+)
+
+// TODO: dim quotes and "On xxx, xxx wrote:" lines
+// TODO: turn URLs into links
+
+const tpl = `<pre>{{.}}</pre>`
+
+type viewer struct{}
+
+func (viewer) ViewMessagePart(ctx *koushin.Context, msg *koushinbase.IMAPMessage, part *message.Entity) (interface{}, error) {
+	mimeType, _, err := part.Header.ContentType()
+	if err != nil {
+		return nil, err
+	}
+	if !strings.EqualFold(mimeType, "text/plain") {
+		return nil, koushinbase.ErrViewUnsupported
+	}
+
+	body, err := ioutil.ReadAll(part.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read part body: %v", err)
+	}
+
+	t := template.Must(template.New("view-text.html").Parse(tpl))
+
+	var buf bytes.Buffer
+	err = t.Execute(&buf, string(body))
+	if err != nil {
+		return nil, err
+	}
+
+	return template.HTML(buf.String()), nil
+}
+
+func init() {
+	koushinbase.RegisterViewer(viewer{})
+}