#include "Config.h"
#include <QDir>
#include <QFile>
#include <QStandardPaths>

QString Config::escape(const QString &s) {
    return QString(s).replace("\\","\\\\").replace("\"","\\\"");
}
QString Config::unescape(const QString &s) {
    return QString(s).replace("\\\\","\\").replace("\\\"","\"").replace("\\/","/");
}

QString Config::extractString(const QString &json, const QString &key) {
    QString needle = "\"" + key + "\"";
    int ki = json.indexOf(needle);
    if (ki < 0) return {};
    int colon = json.indexOf(':', ki + needle.size());
    if (colon < 0) return {};
    int open = json.indexOf('"', colon + 1);
    if (open < 0) return {};
    int close = open + 1;
    while (close < json.size()) {
        if (json[close] == '\\') { close += 2; continue; }
        if (json[close] == '"')  break;
        ++close;
    }
    if (close >= json.size()) return {};
    return unescape(json.mid(open + 1, close - open - 1));
}

QString Config::loadMusicRoot() {
    QFile f(configFile());
    if (f.open(QIODevice::ReadOnly)) {
        QString json = QString::fromUtf8(f.readAll());
        QString path = extractString(json, "musicRoot");
        if (!path.isEmpty() && QDir(path).exists()) return path;
    }
    QString music = QStandardPaths::writableLocation(QStandardPaths::MusicLocation);
    return music.isEmpty() ? QDir::homePath() : music;
}

void Config::saveMusicRoot(const QString &root) {
    QDir().mkpath(configDir());
    QFile f(configFile());
    if (f.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
        f.write(("{\n  \"musicRoot\": \"" + escape(root) + "\"\n}\n").toUtf8());
    }
}