/******************************************************************************
 *
 * Project:  netCDF read/write Driver
 * Purpose:  GDAL bindings over netCDF library.
 * Author:   Winor Chen <wchen329 at wisc.edu>
 *
 ******************************************************************************
 * Copyright (c) 2019, Winor Chen <wchen329 at wisc.edu>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/
#ifndef __NETCDFVIRTUAL_H__
#define __NETCDFVIRTUAL_H__
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "netcdfsg.h"
#include "netcdf.h"

class netCDFDataset;

// netCDF Virtual
// Provides a layer of "virtual ncID"
// that can be mapped to a real netCDF ID
namespace nccfdriver
{
// Exceptions
class SG_Exception_NVOOB final : public SG_Exception
{
  public:
    explicit SG_Exception_NVOOB(const char *dsname)
        : SG_Exception(std::string("An attempt to read an undefined ID from ") +
                       std::string(dsname) + std::string(" was made"))
    {
    }
};

class SG_Exception_DupName final : public SG_Exception
{
  public:
    SG_Exception_DupName(const char *keyn, const char *dsname)
        : SG_Exception(std::string("The key ") + std::string(keyn) +
                       std::string(" already exists in") + std::string(dsname))
    {
    }
};

class SG_Exception_BadMapping final : public SG_Exception
{
  public:
    SG_Exception_BadMapping(const char *key, const char *where)
        : SG_Exception(std::string(key) + std::string(" not found in ") +
                       std::string(where))
    {
    }
};

class SG_Exception_VWrite_Failure final : public SG_Exception
{
  public:
    SG_Exception_VWrite_Failure(const char *where, const char *type)
        : SG_Exception(std::string("Failed to write ") + std::string(type) +
                       std::string(" to ") + std::string(where))
    {
    }
};

/* netCDFVAttribute
 * -
 * Contains attribute name and data.
 * Central to derived types are reimplementations of vsync
 */
class netCDFVAttribute /* non final */
{
  public:
    /* vsync(...)
     * Implementation: Given the REAL ncID and REAL variable ID
     * Write the attribute to the variable
     */
    virtual void vsync(int realncid, int realvarid) = 0;

    /*  ~netCDFVAttribute()
     * Virtual destructor
     */
    virtual ~netCDFVAttribute();
};

template <class VClass, nc_type ntype>
class netCDFVGeneralAttribute final : public netCDFVAttribute
{
    std::string name;
    VClass value;

  public:
    netCDFVGeneralAttribute(const char *a_name, const VClass *a_value)
        : name(a_name), value(*a_value)
    {
    }

    void vsync(int realncid, int realvarid) override
    {
        if (nc_put_att(realncid, realvarid, name.c_str(), ntype, 1, &value) !=
            NC_NOERR)
        {
            throw SG_Exception_VWrite_Failure("variable", "attribute");
        }
    }
};

/* netCDFVTextAttribute
 * -
 * Attribute that has a text string value
 */
class netCDFVTextAttribute final : public netCDFVAttribute
{
    std::string name;
    std::string value;

  public:
    netCDFVTextAttribute(const char *a_name, const char *a_value)
        : name(a_name), value(a_value)
    {
    }

    void vsync(int realncid, int realvarid) override;
};

typedef netCDFVGeneralAttribute<signed char, NC_BYTE> netCDFVByteAttribute;
typedef netCDFVGeneralAttribute<int, NC_INT> netCDFVIntAttribute;
typedef netCDFVGeneralAttribute<double, NC_DOUBLE> netCDFVDoubleAttribute;
typedef netCDFVGeneralAttribute<float, NC_FLOAT> netCDFVFloatAttribute;

/* netCDFVDimension
 * -
 * Contains the real dim id, real dimension name, and dimension length
 */
class netCDFVDimension final
{
    friend class netCDFVID;

    std::string real_dim_name;
    int r_did = INVALID_DIM_ID;
    int v_did;
    size_t dim_len;
    bool valid = true;

  protected:
    void setRealID(int realID)
    {
        this->r_did = realID;
    }

    void invalidate();

    void setLen(size_t len)
    {
        this->dim_len = len;
    }

  public:
    netCDFVDimension(const char *name, size_t len, int dimid)
        : real_dim_name(name), v_did(dimid), dim_len(len)
    {
    }

    std::string &getName()
    {
        return this->real_dim_name;
    }

    size_t getLen()
    {
        return this->dim_len;
    }

    int getRealID()
    {
        return this->r_did;
    }

    int getVirtualID()
    {
        return this->v_did;
    }

    bool isValid()
    {
        return this->valid;
    }
};

/* netCDFVVariable
 * -
 * Contains the variable name, variable type, etc.
 */
class netCDFVVariable final
{
    friend class netCDFVID;

    std::string real_var_name;
    nc_type ntype;
    int r_vid = INVALID_VAR_ID;
    int ndimc;
    std::unique_ptr<int, std::default_delete<int[]>> dimid;
    std::vector<std::shared_ptr<netCDFVAttribute>> attribs;
    bool valid = true;

  protected:
    std::vector<std::shared_ptr<netCDFVAttribute>> &getAttributes()
    {
        return attribs;
    }

    void invalidate();

    void setRealID(int realID)
    {
        this->r_vid = realID;
    }

  public:
    netCDFVVariable(const char *name, nc_type xtype, int ndims,
                    const int *dimidsp);

    std::string &getName()
    {
        return real_var_name;
    }

    int getRealID()
    {
        return r_vid;
    }

    nc_type getType()
    {
        return ntype;
    }

    int getDimCount()
    {
        return this->ndimc;
    }

    const int *getDimIds()
    {
        return this->dimid.get();
    }

    bool isValid()
    {
        return this->valid;
    }
};

/* netCDFVID
 * -
 * A netCDF ID that sits on top of an actual netCDF ID
 * And manages actual interaction with the real netCDF file
 *
 * A bit difference is that netCDFVID
 * doesn't have fixed dim sizes, until defines are committed
 *
 * Also, virtual attributes only exist until the variable is committed. Use
 * "real" attributes and "real" IDs for a variable after its been committed.
 *
 * ** Do not mix netCDF virtual dim and variable IDs with regular netCDF dim
 * (a.k.a. "real") ids and variable ids. They are NOT necessarily compatible,
 * and must be translated first, to be used in this manner **
 *
 * The netCDFVID can also be used in what is called "direct mode" and the
 * netCDFVID will just act as a wrapper to the netCDF Library. In such a case
 * netCDFVID should take real IDs, not real ones. However, the big advantages of
 * using netCDFVID (such as quick dim resizing) are no longer are available.
 */
class netCDFVID final
{
    netCDFDataset *m_poDS = nullptr;
    int &ncid;  // ncid REF. which tracks ncID changes that may be made upstream
    int dimTicket = 0;
    int varTicket = 0;
    bool directMode = true;

    std::vector<netCDFVVariable> varList;
    std::vector<netCDFVDimension> dimList;

    std::map<std::string, int> nameDimTable;
    std::map<std::string, int> nameVarTable;

  public:
    // Each of these returns an ID, NOT an error code

    /* nc_def_vdim(...)
     * Defines a virtual dim given the parameters NAME and LENGTH.
     * Returns: virtual dimID
     */
    int nc_def_vdim(
        const char *name,
        size_t dimlen);  // for dims that don't already exist in netCDF file

    /* nc_def_vvar(...)
     * Defines a virtual var given the parameters NAME, NC TYPE, NUMBER OF DIMS,
     * and DIM IDS The dim IDs in dimidsp given are to be virtual dim IDs, using
     * real dim IDs is undefined
     */
    int nc_def_vvar(const char *name, nc_type xtype, int ndims,
                    const int *dimidsp);

    /* nc_del_vdim(...)
     * Delete a virtual dimension
     * NOTES:
     *     This doesn't work on committed IDs.
     *     Also the dimension (for now) will be only invalidated, doesn't
     * completely *delete* it in memory.
     */
    void nc_del_vdim(int dimid);

    /* nc_del_vvar(...)
     * Delete a virtual variable
     * NOTES:
     *     This doesn't work on committed IDs.
     *     Also the variable (for now) will be only invalidated, doesn't
     * completely *delete* it in memory.
     */
    void nc_del_vvar(int varid);

    /* nc_resize_vdim(...)
     * Change the size of a virtual dim to the given size.
     * NOTE: if the dim has committed using nc_vmap then this has no effect.
     */
    void nc_resize_vdim(
        int dimid,
        size_t dimlen);  // for dims that haven't been mapped to physical yet

    /* nc_set_define_mode()
     * Convenience function for setting the ncid to define mode
     */
    void nc_set_define_mode();

    /* nc_set_data_mode()
     * Convenience function for setting the ncid to data mode
     */
    void nc_set_data_mode();

    /* nc_vmap()
     * Maps virtual IDs to real physical ID if that mapping doesn't already
     * exist This is required before writing data to virtual IDs that do not
     * exist yet in the netCDF file
     */
    void nc_vmap();

    /* void enableFullVirtualMode
     * Enables full virtual mode (i.e. allows netCDFVID to use its full
     * capabilities).
     */
    void enableFullVirtualMode()
    {
        this->directMode = false;
    }

    // Attribute function(s)
    template <class attrC, class attrT>
    void nc_put_vatt_generic(int varid, const char *name, const attrT *value)
    {

        if (varid >= static_cast<int>(varList.size()) || varid < 0)
        {
            throw SG_Exception_NVOOB("virtual variable collection");
        }

        netCDFVVariable &v = virtualVIDToVar(varid);
        v.getAttributes().push_back(
            std::shared_ptr<netCDFVAttribute>(new attrC(name, value)));
    }

    void nc_put_vatt_text(int varid, const char *name, const char *value);
    void nc_put_vatt_int(int varid, const char *name, const int *value);
    void nc_put_vatt_double(int varid, const char *name, const double *value);
    void nc_put_vatt_float(int varid, const char *name, const float *value);
    void nc_put_vatt_byte(int varid, const char *name,
                          const signed char *value);

    // Writing Functions
    template <class out_T>
    void nc_put_vvar_generic(int varid, const size_t *index, const out_T *value)
    {
        int rvarid = !directMode ? virtualVIDToVar(varid).getRealID() : varid;

        if (rvarid == INVALID_VAR_ID)
            return;  // invalidated variable, specific condition that Scribe
                     // relies on

        if (nc_put_var1(ncid, rvarid, index, value) != NC_NOERR)
        {
            throw SG_Exception_VWrite_Failure("variable", "datum");
        }
    }

    template <class outArr_T>
    void nc_put_vvara_generic(int varid, const size_t *index,
                              const size_t *count, const outArr_T *value)
    {
        int rvarid = !directMode ? virtualVIDToVar(varid).getRealID() : varid;

        if (rvarid == INVALID_VAR_ID)
            return;  // invalidated variable, specific condition that Scribe
                     // relies on

        if (nc_put_vara(ncid, rvarid, index, count, value) != NC_NOERR)
        {
            throw SG_Exception_VWrite_Failure("variable", "data array");
        }
    }

    void nc_put_vvar1_text(int varid, const size_t *index, const char *value);
    void nc_put_vvara_text(int varid, const size_t *start, const size_t *index,
                           const char *value);
    void nc_put_vvar1_string(int varid, const size_t *index,
                             const char **value);

    // Equivalent "enquiry" functions
    netCDFVVariable &
    virtualVIDToVar(int virtualID);  // converts a virtual var ID to a real ID
    netCDFVDimension &
    virtualDIDToDim(int virtualID);  // converts a virtual dim ID to a real ID
    int nameToVirtualVID(const std::string &name);
    int nameToVirtualDID(const std::string &name);

    bool virtualVarNameDefined(const std::string &nm)
    {
        return nameVarTable.count(nm) > 0;
    }

    // Constructor
    explicit netCDFVID(netCDFDataset *poDS, int &ncid_in)
        : m_poDS(poDS), ncid(ncid_in)
    {
    }
};

}  // namespace nccfdriver
#endif