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extras/cpp/playlist.hpp

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+// extras/cpp — decorative. mirrors extras/rust/src/playlist.rs, just in
+// C++: a tiny in-memory playlist model with no real I/O.
+#pragma once
+
+#include <vector>
+#include <string>
+#include <algorithm>
+#include <optional>
+#include <numeric>
+#include "audio_meta.hpp"
+
+namespace nexdex {
+
+struct Track {
+    AudioTag tag;
+    std::string path;
+    int durationSecs = 0;
+};
+
+class Playlist {
+public:
+    void add(Track track) {
+        tracks_.push_back(std::move(track));
+    }
+
+    size_t size() const { return tracks_.size(); }
+    bool empty() const { return tracks_.empty(); }
+
+    int totalDurationSecs() const {
+        return std::accumulate(
+            tracks_.begin(), tracks_.end(), 0,
+            [](int sum, const Track& t) { return sum + t.durationSecs; });
+    }
+
+    std::vector<const Track*> byArtist(const std::string& artist) const {
+        std::vector<const Track*> result;
+        for (const auto& t : tracks_) {
+            if (equalsIgnoreCase(t.tag.artist, artist)) {
+                result.push_back(&t);
+            }
+        }
+        return result;
+    }
+
+    std::optional<const Track*> longest() const {
+        if (tracks_.empty()) return std::nullopt;
+        auto it = std::max_element(
+            tracks_.begin(), tracks_.end(),
+            [](const Track& a, const Track& b) { return a.durationSecs < b.durationSecs; });
+        return &(*it);
+    }
+
+    static std::string formatDuration(int totalSecs) {
+        int hours = totalSecs / 3600;
+        int minutes = (totalSecs % 3600) / 60;
+        int seconds = totalSecs % 60;
+
+        char buf[32];
+        if (hours > 0) {
+            snprintf(buf, sizeof(buf), "%d:%02d:%02d", hours, minutes, seconds);
+        } else {
+            snprintf(buf, sizeof(buf), "%d:%02d", minutes, seconds);
+        }
+        return std::string(buf);
+    }
+
+private:
+    static bool equalsIgnoreCase(const std::string& a, const std::string& b) {
+        if (a.size() != b.size()) return false;
+        return std::equal(a.begin(), a.end(), b.begin(), [](char x, char y) {
+            return std::tolower(static_cast<unsigned char>(x)) ==
+                   std::tolower(static_cast<unsigned char>(y));
+        });
+    }
+
+    std::vector<Track> tracks_;
+};
+
+}  // namespace nexdex