database.h

#pragma once
#include <QSqlDatabase>
#include <QSqlQuery>
#include <QSqlError>
#include <QString>
#include "models.h"

class Database {
public:
    static Database& instance();

    bool init(const QString& path);
    QString lastError() const;

    // Items
    QList<Item> getItems();
    Item        getItem(int id);
    int         addItem(const Item& item);
    bool        updateItem(const Item& item);
    bool        deleteItem(int id);

    // Item recipes
    QList<ItemRecipe> getRecipes(int item_id);
    bool              setRecipes(int item_id, const QList<ItemRecipe>& recipes);

    // Market prices
    QList<MarketPrice> getMarketPrices();
    double             getMarketPrice(int item_id);   // -1 se não encontrado
    bool               setMarketPrice(int item_id, double price, const QString& notes = "");
    bool               deleteMarketPrice(int id);

    // Equipment
    QList<EquipmentType> getEquipmentTypes();
    int                  addEquipmentType(const EquipmentType& eq);
    bool                 updateEquipmentType(const EquipmentType& eq);
    bool                 deleteEquipmentType(int id);

    // Techniques
    QList<Technique> getTechniques();
    Technique        getTechnique(int id);
    int              addTechnique(const Technique& t);
    bool             updateTechnique(const Technique& t);
    bool             deleteTechnique(int id);

    // Sessions
    QList<Session> getSessions(int technique_id = -1);
    Session        getSession(int id);
    int            addSession(const Session& s);
    bool           updateSession(const Session& s);
    bool           deleteSession(int id);

    // Session items
    QList<SessionItem> getSessionItems(int session_id);
    bool               setSessionItems(int session_id, const QList<SessionItem>& items);

    // Session equipment
    QList<SessionEquipment> getSessionEquipment(int session_id);
    bool                    setSessionEquipment(int session_id, const QList<SessionEquipment>& equips);

    // Global settings
    double  getMelt();
    bool    setMelt(double value);

    // Own prices / sell list
    QList<OwnPrice>     getOwnPrices();
    QList<SellableItem> getSellableItems();
    double          getOwnPrice(int item_id, int exclude_technique_id = -1);   // -1 se não encontrado
    bool            setOwnPrice(int item_id, int technique_id, double price);
    bool            deleteOwnPrice(int item_id);
    bool            deleteOwnPricesByTechnique(int technique_id);

    // Calculations
    AverageSession          calculateAverageSession(int technique_id);
    PriceCalculationResult  calculatePrice(const AverageSession& avg);
    // exclude_technique_id: ignora preços próprios gerados por essa técnica (evita circularidade)
    double                  getEffectivePrice(int item_id, int exclude_technique_id = -1);
    double                  getRecipePrice(int item_id, int depth = 0, int exclude_technique_id = -1);

private:
    Database() = default;
    QSqlDatabase m_db;
    QString      m_last_error;
    bool createTables();
};