feat: choose an avatar fill and derive its colour

2 files changed, 50 insertions, 0 deletions

diff --git a/src/avatar.cpp b/src/avatar.cpp
index 4cedae2..0e2b25f 100644
--- a/src/avatar.cpp
+++ b/src/avatar.cpp
@@ -75,4 +75,26 @@ QString initialsFor(const QString &displayName, const QString &address,
     return QStringLiteral("??");
 }
 
+Fill fillFor(const QString &displayName, bool isBusinessSender)
+{
+    // The list first: it is the user's explicit override and must beat the
+    // heuristic, or a listed sender could never be pinned.
+    if (isBusinessSender)
+        return Fill::TwoTone;
+    return displayName.trimmed().isEmpty() ? Fill::TwoTone : Fill::Identicon;
+}
+
+QColor colourFor(const QString &address)
+{
+    // The same construction TagColors::colourFor() uses for a tag with nothing
+    // configured: hashed so it is stable, at a fixed saturation and lightness
+    // so it cannot come out neon and cannot lose its contrast with the
+    // initials. The lightness differs from that function's deliberately: a
+    // chip carries dark text, a squircle carries white.
+    const QByteArray digest =
+        QCryptographicHash::hash(address.toUtf8(), QCryptographicHash::Md5);
+    const int hue = static_cast<quint8>(digest.at(0)) * 360 / 256;
+    return QColor::fromHsl(hue, 110, 95);
+}
+
 } // namespace Avatar
diff --git a/tests/test_avatar.cpp b/tests/test_avatar.cpp
index 225b4f1..b53dfc1 100644
--- a/tests/test_avatar.cpp
+++ b/tests/test_avatar.cpp
@@ -30,6 +30,9 @@ private slots:
     void bareAddressTakesLocalAndDomain();
     void nothingUsableFallsBackToTheAccountLabel();
     void initialsAreAlwaysTwoLetters();
+    void aDisplayNameMeansAPerson();
+    void theListOverridesADisplayName();
+    void aColourIsStablePerAddress();
 };
 
 void TestAvatar::twoWordNameTakesOneLetterFromEach()
@@ -91,5 +94,30 @@ void TestAvatar::initialsAreAlwaysTwoLetters()
     }
 }
 
+void TestAvatar::aDisplayNameMeansAPerson()
+{
+    // The case the user asked for by name: a corporate address that presents
+    // itself as a person reads as a person.
+    QCOMPARE(Avatar::fillFor(QStringLiteral("Ian Farrell"), false),
+             Avatar::Fill::Identicon);
+    QCOMPARE(Avatar::fillFor(QString(), false), Avatar::Fill::TwoTone);
+}
+
+void TestAvatar::theListOverridesADisplayName()
+{
+    // A listed address stays a business even when it sets a friendly name.
+    QCOMPARE(Avatar::fillFor(QStringLiteral("Cofidis"), true),
+             Avatar::Fill::TwoTone);
+}
+
+void TestAvatar::aColourIsStablePerAddress()
+{
+    const QColor first = Avatar::colourFor(QStringLiteral("a@example.org"));
+    const QColor again = Avatar::colourFor(QStringLiteral("a@example.org"));
+    QCOMPARE(first, again);
+    QVERIFY(first.isValid());
+    QVERIFY(Avatar::colourFor(QStringLiteral("b@example.org")) != first);
+}
+
 QTEST_MAIN(TestAvatar)
 #include "test_avatar.moc"