1 files changed, 94 insertions, 4 deletions

diff --git a/lib/serve.js b/lib/serve.js
index f975f4b..d87880c 100644
--- a/lib/serve.js
+++ b/lib/serve.js
@@ -386,6 +386,7 @@ Serve.prototype.path = function (url) {
     case '/npm-registry': return this.npmRegistry(m[2])
     case '/markdown': return this.markdown(m[2])
     case '/edit-diff': return this.editDiff(m[2])
+    case '/about-diff': return this.aboutDiff(m[2])
     case '/shard': return this.shard(m[2])
     case '/zip': return this.zip(m[2])
     case '/web': return this.web(m[2])
@@ -3837,14 +3838,14 @@ Serve.prototype.editDiff = function (url) {
   return pull(
     ph('section', {}, [
       'diff: ',
-      ph('a', {href: self.app.render.toUrl(id)}, id.substr(0, 8) + '…'),
+      ph('a', {href: self.app.render.toUrl(id)}, ph('code', id.substr(0, 8) + '…')),
       u.readNext(function (cb) {
         self.getMsgDecryptedMaybeOoo(id, function (err, msg) {
           if (err) return cb(null, pull.once(u.renderError(err).outerHTML))
           var c = msg.value.content || {}
           self.getMsgDecryptedMaybeOoo(c.updated, function (err, oldMsg) {
             if (err) return cb(null, pull.once(u.renderError(err).outerHTML))
-            cb(null, self.postEditDiffTable(oldMsg, msg))
+            cb(null, self.textEditDiffTable(oldMsg, msg))
           })
         })
       })
@@ -3854,10 +3855,99 @@ Serve.prototype.editDiff = function (url) {
   )
 }
 
-Serve.prototype.postEditDiffTable = function (oldMsg, newMsg) {
+function findMsg(msgs, id) {
+  for (var i = 0; i < msgs.length; i++) {
+    if (msgs[i].key === id) return i
+  }
+  return -1
+}
+
+Serve.prototype.aboutDiff = function (url) {
+  var self = this
+  var id
+  try {
+    id = decodeURIComponent(url.substr(1))
+  } catch(err) {
+    return pull(
+      pull.once(u.renderError(err).outerHTML),
+      self.wrapPage('diff: ' + id),
+      self.respondSink(400)
+    )
+  }
+  return pull(
+    ph('section', {}, [
+      'diff: ',
+      ph('a', {href: self.app.render.toUrl(id)}, ph('code', id.substr(0, 8) + '…')),
+      u.readNext(function (cb) {
+        // About messages don't always include branch links. So get the whole thread
+        // and use ssb-sort to find what to consider the previous message(s).
+        self.getMsgDecryptedMaybeOoo(id, function (err, msg) {
+          if (err) return cb(null, pull.once(u.renderError(err).outerHTML))
+          var c = msg.value.content || {}
+          var rootId = c.about
+          if (!rootId) return gotLinks(new Error('Missing about root'))
+          var msgDate = new Date(msg.value.timestamp)
+          cb(null, ph('div', [
+            self.phIdLink(msg.value.author), ' ',
+            ph('span', {title: msgDate.toLocaleString()}, htime(msgDate)),
+            ph('div', u.readNext(next.bind(this, rootId, msg)))
+          ]))
+        })
+      })
+    ]),
+    self.wrapPage('diff: ' + id),
+    self.respondSink(200)
+  )
+
+  function next(rootId, msg, cb) {
+    pull(
+      self.app.getLinks(rootId),
+      pull.unique('key'),
+      self.app.unboxMessages(),
+      pull.collect(function (err, links) {
+        if (err) return gotLinks(err)
+        if (!self.useOoo) return gotLinks(null, links)
+        self.app.expandOoo({msgs: links, dest: id}, gotLinks)
+      })
+    )
+    function gotLinks(err, links) {
+      if (err) return cb(null, pull.once(u.renderError(err).outerHTML))
+
+      sort(links)
+      links = links.filter(function (msg) {
+        var c = msg && msg.value && msg.value.content
+        return c && c.type === 'about' && c.about === rootId
+          && typeof c.description === 'string'
+      })
+      var i = findMsg(links, id)
+      if (i < 0) return cb(null, ph('div', 'Unable to find previous message'))
+      var prevMsg = links[i-1]
+      var nextMsg = links[i+1]
+      var prevHref = prevMsg ?
+        self.app.render.toUrl('/about-diff/' + encodeURIComponent(prevMsg.key)) : null
+      var nextHref = nextMsg ?
+        self.app.render.toUrl('/about-diff/' + encodeURIComponent(nextMsg.key)) : null
+      cb(null, cat([
+        prevMsg
+          ? pull.values(['prev: ', ph('a', {href: prevHref}, ph('code',
+            prevMsg.key.substr(0, 8) + '…')), ', '])
+          : pull.empty(),
+        nextMsg
+          ? pull.values(['next: ', ph('a', {href: nextHref}, ph('code',
+            nextMsg.key.substr(0, 8) + '…'))])
+          : pull.empty(),
+        prevMsg ? self.textEditDiffTable(prevMsg, msg) : pull.empty()
+      ]))
+    }
+  }
+}
+
+Serve.prototype.textEditDiffTable = function (oldMsg, newMsg) {
   var oldC = oldMsg.value.content || {}
   var newC = newMsg.value.content || {}
-  var diff = Diff.structuredPatch('', '', String(oldC.text), String(newC.text))
+  var oldText = String(oldC.text || oldC.description)
+  var newText = String(newC.text || newC.description)
+  var diff = Diff.structuredPatch('', '', oldText, newText)
   var self = this
   return pull(
     ph('table', [