#pragma once

#include <map>
#include <string>
#include <utility>

#include <QByteArray>
#include <QPixmap>
#include <QString>

// Rasterizes and caches the per-building chip SVGs (REQ-UI-BUILD-ICON). A chip is a
// rounded colored background bearing a white line glyph, loaded from a directory with
// one file per building named after the building's id (e.g. "belt.svg"). Shared by the
// build button bar and the selection panel's card header (REQ-UI-SELECTION-CARD) so the
// rasterization is not duplicated.
//
// A missing icon file is not an error: hasIcon() returns false for it and the caller
// falls back (a name caption on a build button, a bare title in the panel header).
class BuildingIconCache
{
public:
    // iconDir is the directory holding the "<id>.svg" chip files (typically
    // "<configDir>/../icons/buildings").
    explicit BuildingIconCache(const QString& iconDir);

    // True if a chip SVG file exists for the given icon name. Loads the file's bytes on
    // first query and remembers the result (including absence) so repeated calls are
    // cheap. The name is a building id for the building buttons, but need not be one --
    // the Deconstruct button's "deconstruct" chip goes through the same path.
    bool hasIcon(const std::string& iconName);

    // The chip rasterized to a transparent sizePx*sizePx pixmap at the device pixel
    // ratio, cached per (name, size). Returns a null pixmap when the file is missing.
    QPixmap getChip(const std::string& iconName, int sizePx);

    // As getChip(), but with the chip background recolored grey and the glyph left
    // alone, for a build button the player cannot currently afford
    // (REQ-UI-BUILD-DISABLED).
    QPixmap getGreyChip(const std::string& iconName, int sizePx);

private:
    // Raw SVG bytes for an icon name, loading and caching them on first access. An
    // absent file caches an empty QByteArray so it is not retried.
    const QByteArray& getSvg(const std::string& iconName);
    // The same SVG with its background fill replaced by grey, cached alongside.
    const QByteArray& getGreySvg(const std::string& iconName);
    // Shared rasterize-and-cache step. cacheKey distinguishes the normal and grey
    // variants of one icon name within the single pixmap cache.
    QPixmap getPixmap(const std::string& cacheKey, const QByteArray& svg, int sizePx);

    QString                           m_iconDir;
    std::map<std::string, QByteArray> m_svgByName;
    std::map<std::string, QByteArray> m_greySvgByName;
    std::map<std::pair<std::string, int>, QPixmap> m_pixmapCache;
};