1 files changed, 50 insertions, 0 deletions
diff --git a/src/htmlbuilder.h b/src/htmlbuilder.h
new file mode 100644
index 0000000..ac24e28
--- /dev/null
+++ b/src/htmlbuilder.h
@@ -0,0 +1,50 @@
+#pragma once
+
+#include <QList>
+
+#include "mimeparser.h"
+
+/// One message's place in a rendered thread.
+struct ThreadRenderItem
+{
+    ParsedMessage message;
+
+    /// Matched messages render in full; unmatched collapse to a one-line stub.
+    bool expanded = true;
+
+    /// Disambiguates cid: references. Two newsletters in one thread commonly
+    /// use the same Content-ID (cid:logo@example.org), which would collide in
+    /// a single document, so every reference is rewritten to
+    /// cid:<prefix>!<id>.
+    QString cidPrefix;
+};
+
+/// Turns parsed messages into the HTML string handed to the web view.
+///
+/// Plain text goes through the same path as HTML so the view has one render
+/// path rather than two. A whole thread renders as ONE document rather than one
+/// view per message: a thread of newsletters can hold dozens of messages, and a
+/// QWebEngineView each would spawn a Chromium render process each.
+class HtmlBuilder
+{
+public:
+    enum Mode {
+        PreferHtml,  ///< Use the HTML part when the message has one.
+        ForcePlain,  ///< Always render the plain part, escaped.
+    };
+
+    /// Single message, used for the error card and for tests.
+    static QString build(const ParsedMessage &message, Mode mode);
+
+    /// The whole thread, oldest first.
+    static QString buildThread(const QList<ThreadRenderItem> &items, Mode mode);
+
+    /// Rewrites cid: URLs in an HTML body to their namespaced form.
+    static QString namespaceCids(const QString &html, const QString &prefix);
+
+private:
+    static QString renderPlain(const QString &text);
+    static QString renderBody(const ThreadRenderItem &item, Mode mode);
+    static QString renderStub(const ParsedMessage &message);
+    static QString document(const QString &bodyHtml);
+};