/*
 * @BEGIN LICENSE
 *
 * Psi4: an open-source quantum chemistry software package
 *
 * Copyright (c) 2007-2019 The Psi4 Developers.
 *
 * The copyrights for code used from other parties are included in
 * the corresponding files.
 *
 * This file is part of Psi4.
 *
 * Psi4 is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * Psi4 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with Psi4; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * @END LICENSE
 */

#ifndef _psi_src_lib_libpsio_psio_hpp_
#define _psi_src_lib_libpsio_psio_hpp_

#include <string>
#include <map>
#include <set>
#include <queue>
#include <memory>

#include "psi4/libpsio/config.h"

namespace psi {

class PSIO;
class PSIOManager;
extern PSI_API std::shared_ptr<PSIO> _default_psio_lib_;
extern PSI_API std::shared_ptr<PSIOManager> _default_psio_manager_;

/**
    PSIOManager is a class designed to be used as a static object to track all
    PSIO operations in a given PSI4 computation

    This will allow PSICLEAN to be trivially executed.
    Now supports a .psirc and interactive file placement
   */
class PSI_API PSIOManager {
private:
    /// Default path for unspec'd file numbers. Defaults to /tmp/
    std::string default_path_;
    /// Specific paths for arbitrary file numbers
    std::map<int, std::string> specific_paths_;
    /// Default retained files
    std::set<int> specific_retains_;

    /// Map of files, bool denotes open or closed
    std::map<std::string, bool> files_;
    /// Set of files to retain after psiclean
    std::set<std::string> retained_files_;

    std::string pid_;
public:
    /// Default constructor (does nothing)
    PSIOManager();
    /// Default destructor (does nothing)
    ~PSIOManager();

    /**
            * Mirror the current delete-able files to "psi.clean"
            **/
    void mirror_to_disk();
    /**
            * Build from "psi.clean"
            **/
    void build_from_disk();

    /**
            * Set the default path for files to be stored
            * \param path full path to scratch
            */
    void set_default_path(const std::string& path);
    /**
            * Set the path for specific file numbers
            * \param fileno PSI4 file number
            * \param path full path to file-specific scratch
            */
    void set_specific_path(int fileno, const std::string& path);
    /**
            * Set the specific file number to be retained
            * \param fileno PSI4 file number
            * \param retain keep or not? (Allows override)
            */
    void set_specific_retention(int fileno, bool retain);
    /**
            * Inquire whether a specific file number is set to be retained
            * \param fileno PSI4 file number
            * \return keeping or not?
            */
    bool get_specific_retention(int fileno);

    /**
            * Get the path for a specific file number
            * \param fileno PSI4 file number
            * \return the appropriate full path
            */
    std::string get_file_path(int fileno);

    /**
      * Returns the default path.
      * \return the default path.
      */
    std::string get_default_path() { return default_path_; }

    /**
     * Write a string to a temporary file.  The scratch file is opened and closed by this function.
     * @param full_path The fill path to the scratch file
     * @param text The text to be placed in the file
     */
    void write_scratch_file(const std::string &full_path, const std::string &text);

    /**
            * Record the opening of a file
            * \param full_path filename
            */
    void open_file(const std::string & full_path, int fileno);
    /**
            * Record the opening of a file
            * \param fileno PSI4 file number
            * \param full_path filename
            * \param keep TRUE : the file is closed and retained by PSIO
                          FALSE: the file is closed and deleted by PSIO
            */
    void close_file(const std::string & full_path, int fileno, bool keep);
    /**
            * Move a file from one location to another, retaining status
            * Useful for changing namespaces
            * \param old_full_path old filename
            * \param new_full_path new filename
            */
    void move_file(const std::string & old_full_path, const std::string & new_full_path);
    /**
            * Mark a file to be retained after a psiclean operation, ie for use in
            * a later computation
            * \param full_path filename
            * \param retain keep or not? (Allows override)
            */
    void mark_file_for_retention(const std::string & full_path, bool retain);
    /**
            * Print the current status of PSI4 files
            * \param out file to print to
            */
    void print(std::string out = "outfile");
    /**
            * Print the current status of PSI4 files
            */
    void print_out() { print("outfile"); }
    /**
            * Execute the psiclean protocol, deleting all recorded files
            * except for those currently marked for retention.
            *
            * Those files marked for retention are not deleted, and their
            * traces in the files_ set and retained_files set remain.
            * Deleted files are removed from the files_ set.
            *
            * This is useful for intermediate calls to psiclean
            */
    void psiclean();
    /**
            * Clean from disk-mirrored image after crash
            * NOT to be called during regular computation
            **/
    void crashclean();
    /// The one and (should be) only instance of PSIOManager for a PSI4 instance
    static std::shared_ptr<PSIOManager> shared_object();
};

/**
   PSIO is an instance of libpsio library. Multiple instances of PSIO are supported.

   Each instance can be configured using filecfg_kwd().
   The following example best demonstrates how to configure a PSIO instance Lib:
   Lib->filecfg_kwd("DEFAULT","NAME",-1,"newwfn")      // all modules will set filename prefix to newwfn for all units
   Lib->filecfg_kwd("DEFAULT","NVOLUME",34,"2")        // all modules will stripe unit 34 over 2 volumes
   Lib->filecfg_kwd("CINTS","VOLUME1",-1,"/scratch1/") // module CINTS will access volume 1 of all units under /scratch
   etc.

   */
class PSI_API PSIO {
public:
    PSIO();
    ~PSIO();

    /// return 1 if activated
    int state() {
        return state_;
    }
    /**
       set keyword kwd describing some aspect of configuration of PSIO file unit
       to value kwdval. kwdgrp specifies the keyword group (useful values are: "DEFAULT", "PSI", and the name of
       the current executable). If unit is set to -1, this keyword will set the default for all units (this keyword
       can be further overridden for some units). To specify a keyword that works for a specific unit, set unit to the
       appropriate number between 0 to PSIO_MAXUNIT.

       PSIO understands the following keywords: "name" (specifies the prefix for the filename,
       i.e. if name is set to "psi" then unit 35 will be named "psi.35"), "nvolume" (number of files over which
       to stripe this unit, cannot be greater than PSIO_MAXVOL), "volumeX", where X is a positive integer less than or equal to
       the value of "nvolume".
       */
    void filecfg_kwd(const char* kwdgrp, const char* kwd, int unit,
                     const char* kwdval);
    /// returns the keyword value. If not defined, returns empty string.
    const std::string& filecfg_kwd(const char* kwdgrp, const char* kwd,
                                   int unit);

    /// moves a file from old_unit to new_unit
    void rename_file(size_t old_unit,size_t new_unit);

    /// check if a psi unit already exists or not
    bool exists(size_t unit);
    /// open unit. status can be PSIO_OPEN_OLD (if existing file is to be opened) or PSIO_OPEN_NEW if new file should be open
    void open(size_t unit, int status);
    /// close unit. if keep == 0, will remove the file, else keep it
    void close(size_t unit, int keep);
    /// lookup process id
    std::string getpid();
    /// sync up the object to the file on disk by closing and opening the file, if necessary
    void rehash(size_t unit);
    /// return 1 if unit is open
    int open_check(size_t unit);
    /** Reads data from within a TOC entry from a PSI file.
       **
       **  \param unit   = The PSI unit number used to identify the file to all
       **                  read and write functions.
       **  \param key    = The TOC keyword identifying the desired entry.
       **  \param buffer = The buffer to store the data as it is read.
       **  \param size   = The number of bytes to read.
       **  \param start  = The entry-relative starting page/offset of the desired data.
       **  \param end    = A pointer to the entry-relative page/offset for the next
       **                  byte after the end of the read request.
       */
    void read(size_t unit, const char *key, char *buffer, size_t size,
              psio_address start, psio_address *end);
    /** Writes data to a TOC entry in a PSI file.
       **
       **  \param unit    = The PSI unit number used to identify the file to all read
       **                   and write functions.
       **  \param key     = The TOC keyword identifying the desired entry.
       **  \param buffer  = The buffer from which the data is written.
       **  \param size    = The number of bytes to write.
       **  \param start   = The entry-relative starting page/offset to write the data.
       **  \param end     = A pointer to the entry-relative page/offset for the next
       **                   byte after the end of the write request.
       */
    void write(size_t unit, const char *key, char *buffer, size_t size,
               psio_address start, psio_address *end);

    void read_entry(size_t unit, const char *key, char *buffer, size_t size);
    void write_entry(size_t unit, const char *key, char *buffer, size_t size);

    /** Zeros out a double precision array in a PSI file.
       ** Typically used before striping out a transposed array
       **  Total fill size is rows*cols*sizeof(double)
       **  Buffer memory of cols*sizeof(double) is used
       **
       **  \param unit    = The PSI unit number used to identify the file
       **  \param key     = The TOC keyword identifying the desired entry.
       **  \param rows    = The number of rows in the full array
       **  \param cols    = The number of columnss in the full array
       **
       */
    void zero_disk(size_t unit, const char *key, size_t rows, size_t cols);

    /** Central function for all reads and writes on a PSIO unit.
       **
       ** \param unit    = The PSI unit number.
       ** \param buffer  = The buffer containing the bytes for the read/write event.
       ** \param address = the PSIO global address for the start of the read/write.
       ** \param size    = The number of bytes to read/write.
       ** \param wrt      = Indicates if the call is to read (0) or write (0) the input data.
       **
       */
    void rw(size_t unit, char *buffer, psio_address address, size_t size,
            int wrt);

    /// Delete all TOC entries after the given key. If a blank key is given, the entire TOC will be wiped.
    void tocclean(size_t unit, const char *key);
    /// Print the table of contents for the given unit
    void tocprint(size_t unit);
    /// Scans the TOC for a particular keyword and returns either a pointer to the entry or nullptr to the caller.
    psio_tocentry* tocscan(size_t unit, const char *key);
    /// Checks the TOC to see if a particular keyword exists there or not
    bool tocentry_exists(size_t unit, const char *key);
    ///  Write the table of contents for file number 'unit'. NB: This function should NOT call psio_error because the latter calls it!
    void tocwrite(size_t unit);

    /// Upon catastrophic failure, the library will exit() with this code. The default is 1, but can be overridden.
    static int _error_exit_code_;

    /// Set the current namespace (for PREFIX.NAMESPACE.UNIT file numbering)
    static void set_default_namespace(const std::string &_ns) { default_namespace_ = _ns; }

    /// Get the default namespace (for PREFIX.NAMESPACE.UNIT file numbering)
    static std::string get_default_namespace() { return default_namespace_; }

    /// Change file FILENO from NS1 to NS2
    static void change_file_namespace(size_t fileno, const std::string & ns1, const std::string & ns2);

    /// Return the global shared object
    static std::shared_ptr<PSIO> shared_object();

    /** Read the length of the TOC for a given unit directly from the file.
       **
       ** \param unit = PSI unit number from which to read the toclen.
       **
       ** NB: Note that we do not exit if the read request of the toclen from
       ** the file fails. This is because the request may be to an new file
       ** for which the toclen has not yet been written.  (We allow the user
       ** to open files with status PSIO_OPEN_OLD even if they don't exist,
       ** because sometimes you can't know this in advance.)
       */
    size_t rd_toclen(size_t unit);

    /// grab the filename of unit and strdup into name.
    void get_filename(size_t unit, char **name, bool remove_namespace = false);

    /// delete a specific TOC entry (only deletes entry, not data)
    bool tocdel(size_t unit, const char *key);

private:
    /// vector of units
    psio_ud *psio_unit;

    /// Process ID
    std::string pid_;


    /// Current default namespace (for PREFIX.NAMESPACE.UNIT numbering)
    static std::string default_namespace_;

    typedef std::map<std::string,std::string> KWDMap;
    /// library configuration is described by a set of keywords
    KWDMap files_keywords_;

#ifdef PSIO_STATS
    size_t *psio_readlen;
    size_t *psio_writlen;
#endif

    /// Library state variable
    int state_;
    /// return the number of volumes over which unit will be striped
    size_t get_numvols(size_t unit);
    /// grab the path to volume of unit and strdup into path.
    void get_volpath(size_t unit, size_t volume, char **path);
    /// return the last TOC entry
    psio_tocentry* toclast(size_t unit);
    /// Compute the length of the TOC for a given unit using the in-core TOC list.
    size_t toclen(size_t unit);
    /** Write the length of the TOC for a given unit directly to the file.
       **
       ** \param unit = PSI unit number to which to write the toclen.
       **
       ** \ingroup PSIO
       */
    void wt_toclen(size_t unit, size_t toclen);
    /// Read the table of contents for file number 'unit'.
    void tocread(size_t unit);

    friend class AIO_Handler;

public:
    void set_pid(const std::string &pid) { pid_ = pid; }
};

}

#endif /* header guard */
