soundboard/pipewire.cpp

#include "pipewire.hpp"

#include <algorithm>

#include <QJsonArray>
#include <QJsonDocument>
#include <QJsonObject>

namespace Pipewire
{

QString Node::get_display_name() const
{
    if (!application_name.isEmpty()) return application_name;
    if (!node_name.isEmpty()) return node_name;
    return "Unknown App";
}

Graph::Graph()
{
    refresh();
}

bool Graph::refresh()
{
    QProcess process;
    process.start("pw-dump");
    if (!process.waitForFinished()) {
        return false;
    }

    QJsonParseError error;
    QJsonDocument json = QJsonDocument::fromJson(process.readAllStandardOutput(), &error);
    if (error.error != QJsonParseError::NoError) {
        return false;
    }

    m_nodes.clear();
    m_ports.clear();
    m_links.clear();

    for (const QJsonValue& value : json.array()) {
        QJsonObject obj = value.toObject();
        QString type = obj["type"].toString();
        int id = obj["id"].toInt();
        QJsonObject props = obj["info"].toObject()["props"].toObject();

        if (type == "PipeWire:Interface:Node") {
            m_nodes[id] = {
                id,
                props["node.name"].toString(),
                props["application.name"].toString(),
                props["media.class"].toString()
            };
        } else if (type == "PipeWire:Interface:Port") {
            m_ports[id] = {
                id,
                props["node.id"].toInt(),
                props["port.direction"].toString(),
                props["audio.channel"].toString()
            };
        } else if (type == "PipeWire:Interface:Link") {
            m_links[id] = {
                id,
                props["link.output.node"].toInt(),
                props["link.input.node"].toInt()
            };
        }
    }

    return true;
}

std::vector<Node> Graph::get_input_apps() const
{
    std::vector<Node> apps;
    for (const auto& [id, node] : m_nodes) {
        if (node.media_class == "Stream/Input/Audio") {
            apps.push_back(node);
        }
    }
    return apps;
}

std::optional<Node> Graph::get_node_by_name(const QString& name) const
{
    for (const auto& [id, node] : m_nodes) {
        if (node.node_name == name) return node;
    }
    return std::nullopt;
}

std::vector<Port> Graph::get_ports_for_node(int node_id, const QString& direction) const
{
    std::vector<Port> ports;
    for (const auto& [id, port] : m_ports) {
        if (port.node_id == node_id && port.direction == direction) {
            ports.push_back(port);
        }
    }
    return ports;
}

std::vector<Link> Graph::get_links_from_node(int output_node_id) const
{
    std::vector<Link> links;
    for (const auto& [id, link] : m_links) {
        if (link.output_node_id == output_node_id) {
            links.push_back(link);
        }
    }
    return links;
}

std::vector<Node> Graph::get_all_sinks() const
{
    std::vector<Node> sinks;
    for (const auto& [id, node] : m_nodes) {
        if (node.media_class == "Audio/Sink") {
            sinks.push_back(node);
        }
    }
    return sinks;
}

Player::~Player()
{
    stop_all();
}

void Player::play_file(const QString& file_path,
        const QString& target_sink/* = "auto" */, float speed/* = 1.0f */)
{
    QString target = target_sink;
    if (target_sink != "auto") {
        target = "pipewire/" + target_sink;
    }

    QStringList args;
    args << "--vo=null" << "--no-video"
         << "--audio-pitch-correction=no"
         << "--audio-device=" + target
         << "--speed=" + QString::number(speed, 'f', 2)
         << file_path;

    auto process = std::make_unique<QProcess>();
    process->start("mpv", args);
    m_playing_processes.push_back(std::move(process));
}

void Player::stop_all()
{
    for (const auto& process : m_playing_processes) {
        if (process->state() == QProcess::Running) {
            process->terminate();
            process->waitForFinished();
        }
    }

    m_playing_processes.clear();
}

std::optional<Sink> Sink::create(const QString& name, Graph& graph)
{
    QProcess process;
    process.start("pactl", {
        "load-module", "module-null-sink",
        "sink_name=" + name,
        "sink_properties=device.description=" + name,
    });

    if (!process.waitForFinished()) {
        return std::nullopt;
    }

    QByteArray output = process.readAllStandardOutput().trimmed();
    bool ok = false;
    int pulse_audio_id = output.toInt(&ok);
    if (!ok) {
        return std::nullopt;
    }

    if (!graph.refresh()) {
        destroy(pulse_audio_id);
        return std::nullopt;
    }

    auto node = graph.get_node_by_name(name);
    if (!node) {
        destroy(pulse_audio_id);
        return std::nullopt;
    }

    Sink sink;
    sink.m_name = name;
    sink.m_pulse_audio_id = pulse_audio_id;
    sink.m_pipewire_id = node->id;

    return sink;
}

Sink::~Sink()
{
    destroy(m_pulse_audio_id);
}

Sink::Sink(Sink&& other) :
    m_name(std::move(other.m_name)),
    m_pulse_audio_id(std::exchange(other.m_pulse_audio_id, -1)),
    m_pipewire_id(std::exchange(other.m_pipewire_id, -1))
{
}

Sink& Sink::operator=(Sink&& other)
{
    if (this == &other) {
        return *this;
    }

    destroy(m_pulse_audio_id);

    m_name = std::move(other.m_name);
    m_pulse_audio_id = std::exchange(other.m_pulse_audio_id, -1);
    m_pipewire_id = std::exchange(other.m_pipewire_id, -1);

    return *this;
}

int Sink::get_id() const
{
    return m_pipewire_id;
}

QString Sink::get_name() const
{
    return m_name;
}

void Sink::destroy(int pulse_audio_id)
{
    if (pulse_audio_id == -1) {
        return;
    }

    QProcess process;
    process.start("pactl", { "unload-module", QString::number(pulse_audio_id) });
    process.waitForFinished();
}

bool link_ports(int out_port_id, int in_port_id)
{
    QProcess process;
    process.start("pw-link", { QString::number(out_port_id), QString::number(in_port_id) });
    return process.waitForFinished() && process.exitCode() == 0;
}

bool link_nodes(int out_node_id, int in_node_id, const Graph& graph)
{
    auto out_ports = graph.get_ports_for_node(out_node_id, "out");
    auto in_ports = graph.get_ports_for_node(in_node_id, "in");

    for (const Port& out_port : out_ports) {
        for (const Port& in_port : in_ports) {
            if (out_port.channel != in_port.channel) {
                continue;
            }

            if (!link_ports(out_port.id, in_port.id)) {
                return false;
            }
        }
    }

    return true;
}

bool destroy_link(int link_id)
{
    QProcess process;
    process.start("pw-cli", { "destroy", QString::number(link_id) });
    return process.waitForFinished() && process.exitCode() == 0;
}

void set_volume(const QString& target_node, int volume_percent)
{
    volume_percent = std::max(0, std::min(100, volume_percent));

    QProcess process;
    process.startDetached("pactl", {
        "set-sink-volume", target_node,
        QString::number(volume_percent) + "%"
    });
}

} // namespace Pipewire