/******************************************************************************

 * Project:  PROJ

 * Purpose:  Functionality related to TIN based transformations using a

 *GeoPackage file Author:   Even Rouault, <even.rouault at spatialys.com>

 *

 ******************************************************************************

 * Copyright (c) 2025, Even Rouault, <even.rouault at spatialys.com>

 *

 * SPDX-License-Identifier: MIT

 *****************************************************************************/

#ifndef TINSHIFT_GEOPACKAGE_H

#define TINSHIFT_GEOPACKAGE_H

#include <array>

#include <exception>

#include <memory>

#include <string>

#include <vector>

#include "sqlite3_utils.hpp"

#include "tinshift_iface.hpp"

struct sqlite3;

struct sqlite3_stmt;

// ---------------------------------------------------------------------------

class TINShiftGeopackageException : public std::exception {

  public:

    explicit TINShiftGeopackageException(const std::string &msg) : msg_(msg) {}

    const char *what() const noexcept override;

  private:

    std::string msg_;

};

// ---------------------------------------------------------------------------

class TINShiftGeopackageFile {

  public:

    /** Open the provided GeoPackage and return an object.

     *

     * @throws TINShiftGeopackageException in case of error.

     */

    static std::unique_ptr<TINShiftGeopackageFile>

    open(PJ_CONTEXT *ctx, const std::string &filename);

    /** Destructor */

    ~TINShiftGeopackageFile();

    /** Find the triangle into which (x, y) is located */

    bool findTriangle(double x, double y, bool forwardDirection,

                      double &lambda1, double &lambda2, double &lambda3,

                      std::vector<double> &valsVertex1,

                      std::vector<double> &valsVertex2,

                      std::vector<double> &valsVertex3);

    bool hasHorizontalTransformation() const {

        return horizontalTransformation_;

    }

    bool hasVerticalTransformation() const { return verticalTransformation_; }

    bool hasOffsetZ() const { return offsetZ_; }

  private:

    std::unique_ptr<NS_PROJ::SQLite3VFS> sqlite_vfs_{};

    sqlite3 *sqlite_handle_ = nullptr;

    sqlite3_stmt *select_stmt_ = nullptr;

    std::vector<std::string> vertices_cols_{};

    int numVertices_ = 0;

    bool horizontalTransformation_ = false;

    bool verticalTransformation_ = false;

    bool sourceZ_ = false;

    bool targetX_ = false;

    bool targetY_ = false;

    bool targetZ_ = false;

    bool offsetZ_ = false;

    double min_x_ = 0;

    double min_y_ = 0;

    double max_x_ = 0;

    double max_y_ = 0;

    double min_shift_x_ = 0;

    double min_shift_y_ = 0;

    double max_shift_x_ = 0;

    double max_shift_y_ = 0;

    enum FallbackStrategy {

        FALLBACK_NONE,

        FALLBACK_NEAREST_SIDE,

        FALLBACK_NEAREST_CENTROID,

    };

    FallbackStrategy fallbackStrategy_ = FALLBACK_NONE;

    // Cached results

    bool cachedForwardDirection_ = false;

    std::array<double, 3> cachedVerticesX_{0, 0, 0};

    std::array<double, 3> cachedVerticesY_{0, 0, 0};

    std::vector<double> cachedValsVertex1_{};

    std::vector<double> cachedValsVertex2_{};

    std::vector<double> cachedValsVertex3_{};

  private:

    TINShiftGeopackageFile() = default;

    TINShiftGeopackageFile(const TINShiftGeopackageFile &) = delete;

    TINShiftGeopackageFile &operator=(const TINShiftGeopackageFile &) = delete;

    void getMetadata();

    void prepareDatabaseQuery();

};

// ---------------------------------------------------------------------------

/** Class to evaluate the transformation of a coordinate */

class TINShiftGeopackageEvaluator : public TINShiftEvaluator {

  public:

    /** Constructor. */

    explicit TINShiftGeopackageEvaluator(

        std::unique_ptr<TINShiftGeopackageFile> fileIn);

    bool forward(double x, double y, double z, double &x_out, double &y_out,

                 double &z_out) override;

    bool inverse(double x, double y, double z, double &x_out, double &y_out,

                 double &z_out) override;

  private:

    std::unique_ptr<TINShiftGeopackageFile> file_;

    bool transform(bool forwardDirection, double x, double y, double z,

                   double &x_out, double &y_out, double &z_out);

};

// ---------------------------------------------------------------------------

#endif