Impletment sessions completion

Sessions completion let us provide completions for the `:undo` ex
command, which can be useful if you need to restore an older tab.

Closes https://github.com/tridactyl/tridactyl/issues/1127.

src/commandline_frame.ts

@@ -30,6 +30,7 @@ import { HelpCompletionSource } from "@src/completions/Help"
 import { HistoryCompletionSource } from "@src/completions/History"
 import { PreferenceCompletionSource } from "@src/completions/Preferences"
 import { RssCompletionSource } from "@src/completions/Rss"
+import { SessionsCompletionSource } from "@src/completions/Sessions"
 import { SettingsCompletionSource } from "@src/completions/Settings"
 import * as Messaging from "@src/lib/messaging"
 import * as Config from "@src/lib/config"
@@ -101,8 +102,9 @@ export function enableCompletions() {
             HelpCompletionSource,
             HistoryCompletionSource,
             PreferenceCompletionSource,
-            SettingsCompletionSource,
             RssCompletionSource,
+            SessionsCompletionSource,
+            SettingsCompletionSource,
         ]
             .map(constructorr => {
                 try {

src/completions/Sessions.ts

@@ -0,0 +1,85 @@
+import { browserBg } from "@src/lib/webext.ts"
+import * as Completions from "@src/completions"
+
+function computeDate(session) {
+    let howLong = Math.round(
+        ((new Date() as any) - session.lastModified) / 1000,
+    )
+    let qualifier = "s"
+    if (howLong > 60) {
+        qualifier = "m"
+        howLong = Math.round(howLong / 60)
+        if (howLong > 60) {
+            qualifier = "h"
+            howLong = Math.round(howLong / 60)
+            if (howLong > 24) {
+                qualifier = "d"
+                howLong = Math.round(howLong / 24)
+            }
+        }
+    }
+    return [howLong, qualifier]
+}
+
+function getTabInfo(session) {
+    let tab
+    let extraInfo
+    if (session.tab) {
+        tab = session.tab
+        extraInfo = tab.url
+    } else {
+        tab = session.window.tabs.sort(
+            (a, b) => b.lastAccessed - a.lastAccessed,
+        )[0]
+        const tabCount = session.window.tabs.length
+        if (tabCount < 2) {
+            extraInfo = tab.url
+        } else {
+            extraInfo = `${tabCount - 1} more tab${tabCount > 2 ? "s" : ""}.`
+        }
+    }
+    return [tab, extraInfo]
+}
+
+class SessionCompletionOption extends Completions.CompletionOptionHTML
+    implements Completions.CompletionOptionFuse {
+    public fuseKeys = []
+
+    constructor(public session) {
+        super()
+        this.value = (session.tab || session.window).sessionId
+        const [howLong, qualifier] = computeDate(session)
+        const [tab, extraInfo] = getTabInfo(session)
+        this.fuseKeys.push(tab.title)
+        this.html = html`<tr class="SessionCompletionOption option">
+            <td class="type">${session.tab ? "T" : "W"}</td>
+            <td class="time">${howLong}${qualifier}</td>
+            <td class="icon"><img src="${tab.favIconUrl ||
+                Completions.DEFAULT_FAVICON}"/></td>
+            <td class="title">${tab.title}</td>
+            <td class="extraInfo">${extraInfo}</td>
+        </tr>`
+    }
+}
+
+export class SessionsCompletionSource extends Completions.CompletionSourceFuse {
+    public options: SessionCompletionOption[]
+    private shouldSetStateFromScore = true
+
+    constructor(private _parent) {
+        super(["undo"], "SessionCompletionSource", "sessions")
+
+        this.updateOptions()
+        this._parent.appendChild(this.node)
+    }
+
+    private async updateOptions(exstr = "") {
+        const [prefix, query] = this.splitOnPrefix(exstr)
+        const sessions = await browserBg.sessions.getRecentlyClosed()
+        this.options = sessions.map(s => new SessionCompletionOption(s))
+    }
+
+    async onInput(exstr) {
+        return this.updateOptions(exstr)
+    }
+}

src/excmds.ts

@@ -2064,6 +2064,13 @@ export async function undo(item = "recent"): Promise<Number> {
                 return lastSession.window.id
             }
         }
+    } else if (!isNaN(parseInt(item))) {
+        const sessionId = item
+        const session = sessions.find(s => (s.tab || s.window).sessionId == sessionId)
+        if (session) {
+            browser.sessions.restore(sessionId)
+            return (session.tab || session.window).id
+        }
     } else {
         throw new Error(`[undo] Invalid argument: ${item}. Must be one of "tab", "window", "recent"`)
     }

src/static/css/commandline.css

@@ -240,3 +240,14 @@ a.url:hover {
 .HelpCompletionOption td.name {
     max-width: 25%;
 }
+
+#completions .SessionCompletionOption td.type {
+    width: 1ch !important;
+    padding: 0px 3pt;
+}
+
+#completions .SessionCompletionOption td.time {
+    width: 5ch !important;
+    padding: 0px 3pt;
+    text-align: right;
+}