#pragma once

#include <qhash.h>
#include <qjsonobject.h>
#include <qnetworkaccessmanager.h>
#include <qnetworkreply.h>
#include <qtimer.h>

#include "lyriccandidate.hpp"

namespace ZShell::services {

struct LyricLine {
	qreal time = 0.0;
	QString text;
};

class Lyrics : public QObject {
	Q_OBJECT
	QML_ELEMENT
	QML_SINGLETON

	Q_PROPERTY(QStringList lyrics READ lyrics NOTIFY lyricsChanged)
	Q_PROPERTY(
		ZShell::config::LyricsBackend::Enum backend READ backend NOTIFY
			backendChanged)
	Q_PROPERTY(
		ZShell::config::LyricsBackend::Enum preferredBackend READ
			preferredBackend WRITE setPreferredBackend NOTIFY
				preferredBackendChanged)
	Q_PROPERTY(
		QList<ZShell::services::LyricCandidate> lyricCandidates READ
			lyricCandidates NOTIFY lyricCandidatesChanged)
	Q_PROPERTY(
		ZShell::services::LyricCandidate selectedCandidate READ selectedCandidate
			WRITE setSelectedCandidate NOTIFY selectedCandidateChanged)
	Q_PROPERTY(bool loading READ loading NOTIFY loadingChanged)
	Q_PROPERTY(bool hasLyrics READ hasLyrics NOTIFY hasLyricsChanged)
	Q_PROPERTY(qreal offset READ offset WRITE setOffset NOTIFY offsetChanged)
	Q_PROPERTY(QString trackArtist READ trackArtist NOTIFY trackChanged)
	Q_PROPERTY(QString trackTitle READ trackTitle NOTIFY trackChanged)

	public:
	explicit Lyrics(QObject* parent = nullptr);

	[[nodiscard]] QStringList lyrics() const;
	[[nodiscard]] LyricsBackend backend() const;
	[[nodiscard]] LyricsBackend preferredBackend() const;
	void setPreferredBackend(LyricsBackend value);
	[[nodiscard]] QList<LyricCandidate> lyricCandidates() const;
	[[nodiscard]] LyricCandidate selectedCandidate() const;
	void setSelectedCandidate(const LyricCandidate& value);
	[[nodiscard]] bool loading() const;
	[[nodiscard]] bool hasLyrics() const;
	[[nodiscard]] qreal offset() const;
	void setOffset(qreal value);
	[[nodiscard]] QString trackArtist() const;
	[[nodiscard]] QString trackTitle() const;

	[[nodiscard]] Q_INVOKABLE int indexForTime(qreal time) const;
	[[nodiscard]] Q_INVOKABLE qreal timeForIndex(int index) const;
	Q_INVOKABLE void setTrack(
		const QString& artist,
		const QString& title,
		const QString& album = {},
		qreal duration = 0.0);
	Q_INVOKABLE void clearTrack();
	Q_INVOKABLE void refresh();

	signals:
	void lyricsChanged();
	void backendChanged();
	void preferredBackendChanged();
	void lyricCandidatesChanged();
	void selectedCandidateChanged();
	void loadingChanged();
	void hasLyricsChanged();
	void offsetChanged();
	void trackChanged();

	private:
	void setBackend(LyricsBackend value);
	void setLoading(bool value);
	void setLines(QVector<LyricLine> lines, LyricsBackend source);
	void clearLines();
	void appendCandidates(const QList<LyricCandidate>& add);
	void clearCandidates();

	void scheduleLoad();
	void doLoad();
	void cancelInFlight();
	int newRequestId();

	void tryLocal(int reqId);
	void tryLrclib(int reqId);
	void tryNetEase(int reqId);
	void chainNext(LyricsBackend justFailed, int reqId);

	void searchLrclibCandidates(int reqId);
	void searchNetEaseCandidates(int reqId);

	void fetchLrclibById(const QString& id, int reqId);
	void fetchNetEaseLyricsById(const QString& id, int reqId);

	QNetworkReply* getJson(
		const QUrl& url, const QHash<QByteArray, QByteArray>& headers = {});
	void trackReply(int reqId, QNetworkReply* reply);

	void onPreferredBackendConfigChanged();
	void onLyricsDirChanged();

	void loadLyricsMap();
	void persistTrackPrefs();

	[[nodiscard]] static QString lyricsDir();
	[[nodiscard]] static QString lyricsMapPath();
	[[nodiscard]] QString trackKey() const;
	[[nodiscard]] static QString backendKey(LyricsBackend value);
	[[nodiscard]] static LyricsBackend backendFromKey(const QString& key);

	[[nodiscard]] static const QString& stateDir();
	[[nodiscard]] static const QString& cacheDir();
	[[nodiscard]] static QString cachePathFor(
		LyricsBackend backend, const QString& id);
	[[nodiscard]] static QString readCachedLrc(
		LyricsBackend backend, const QString& id);
	static void writeCachedLrc(
		LyricsBackend backend, const QString& id, const QString& text);

	[[nodiscard]] static QVector<LyricLine> parseLrc(const QString& text);
	[[nodiscard]] static QString tryReadLocalLrc(
		const QString& dir, const QString& artist, const QString& title);
	[[nodiscard]] static QString findLocalLrcRecursive(
		const QString& dir, const QString& artist, const QString& title);

	QNetworkAccessManager* m_nam;
	QTimer* m_loadDebounce;

	QVector<LyricLine> m_lines;
	QStringList m_lyrics;
	LyricsBackend m_backend = LyricsBackend::Auto;
	LyricsBackend m_preferredBackend = LyricsBackend::Auto;
	QList<LyricCandidate> m_candidates;
	LyricCandidate m_selected;
	bool m_loading = false;
	bool m_hasLyrics = false;
	qreal m_offset = 0.0;

	QString m_artist;
	QString m_title;
	QString m_album;
	qreal m_duration = 0.0;

	int m_currentRequestId = 0;
	QHash<int, QList<QPointer<QNetworkReply>>> m_pendingReplies;

	QJsonObject m_lyricsMap;
	bool m_lyricsMapLoaded = false;
	bool m_settingFromPrefs = false;
};

} // namespace ZShell::services