feat(rulequery): compile a single term

3 files changed, 131 insertions, 0 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 926f6a9..6ae157b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -23,6 +23,7 @@ add_library(qtmaildir_lib STATIC
     messageview.cpp
     mainwindow.cpp
     querycompleter.cpp
+    rulequery.cpp
 )
 
 target_include_directories(qtmaildir_lib
diff --git a/src/rulequery.cpp b/src/rulequery.cpp
new file mode 100644
index 0000000..f80e6c4
--- /dev/null
+++ b/src/rulequery.cpp
@@ -0,0 +1,65 @@
+/*
+ * qtmaildir - a Qt6 mail client for notmuch-indexed Maildirs
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "rulequery.h"
+
+namespace {
+
+/// The notmuch prefix each field compiles to. Wire format, never translated.
+QString prefixFor(RuleTerm::Field field)
+{
+    switch (field) {
+    case RuleTerm::From:       return QStringLiteral("from");
+    case RuleTerm::To:         return QStringLiteral("to");
+    case RuleTerm::Cc:         return QStringLiteral("cc");
+    case RuleTerm::Subject:    return QStringLiteral("subject");
+    case RuleTerm::Tag:        return QStringLiteral("tag");
+    case RuleTerm::Folder:     return QStringLiteral("path");
+    case RuleTerm::Attachment: return QStringLiteral("attachment");
+    case RuleTerm::Date:       return QStringLiteral("date");
+    }
+    return QString();
+}
+
+} // namespace
+
+bool operator==(const RuleTerm &a, const RuleTerm &b)
+{
+    return a.field == b.field && a.op == b.op && a.value == b.value;
+}
+
+bool operator==(const RuleQuery &a, const RuleQuery &b)
+{
+    return a.parsed == b.parsed && a.join == b.join
+           && a.terms == b.terms && a.exclusions == b.exclusions;
+}
+
+QString RuleQuery::compile() const
+{
+    if (terms.isEmpty())
+        return QString();
+
+    return prefixFor(terms.first().field) + QLatin1Char(':')
+           + terms.first().value;
+}
+
+RuleQuery RuleQuery::parse(const QString &query)
+{
+    Q_UNUSED(query);
+    return RuleQuery();
+}
diff --git a/src/rulequery.h b/src/rulequery.h
new file mode 100644
index 0000000..9d487d2
--- /dev/null
+++ b/src/rulequery.h
@@ -0,0 +1,65 @@
+/*
+ * qtmaildir - a Qt6 mail client for notmuch-indexed Maildirs
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#pragma once
+
+#include <QList>
+#include <QString>
+
+/// One row in the builder: a field, an operator, and a value.
+struct RuleTerm
+{
+    enum Field { From, To, Cc, Subject, Tag, Folder, Attachment, Date };
+
+    enum Op {
+        Contains, ContainsNot,   ///< Unquoted term, optionally negated.
+        Is, IsNot,               ///< Quoted phrase, optionally negated.
+        Has, HasNot,             ///< attachment: only.
+        Before, After            ///< date: only. "not before" is "after", so
+                                 ///< these carry no negated twin.
+    };
+
+    Field field = From;
+    Op op = Contains;
+    QString value;
+};
+
+bool operator==(const RuleTerm &a, const RuleTerm &b);
+
+/// A tagging rule's query, as rows.
+///
+/// The STRING is the stored format, shared with mailctl and executed by the
+/// notmuch post-new hook. This type is a view over it, never the store: a
+/// query it cannot represent must still open, save and run unchanged.
+struct RuleQuery
+{
+    enum Join { All, Any };   ///< and / or, over the positive terms only.
+
+    Join join = All;
+    QList<RuleTerm> terms;        ///< Positive section.
+    QList<RuleTerm> exclusions;   ///< The "but not" block, joined `and not`.
+
+    /// False when the query cannot be shown as rows. NOT an error and NOT a
+    /// claim that the query is invalid: the rule opens in text mode.
+    bool parsed = false;
+
+    static RuleQuery parse(const QString &query);
+    QString compile() const;
+};
+
+bool operator==(const RuleQuery &a, const RuleQuery &b);