//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:       Command line parsing utilities                                //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2019 The OS/K Team                                       //
//                                                                            //
//  This file is part of OS/K.                                                //
//                                                                            //
//  OS/K is free software: you can redistribute it and/or modify              //
//  it under the terms of the GNU General Public License as published by      //
//  the Free Software Foundation, either version 3 of the License, or         //
//  any later version.                                                        //
//                                                                            //
//  OS/K 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 General Public License for more details.                              //
//                                                                            //
//  You should have received a copy of the GNU General Public License         //
//  along with OS/K.  If not, see <https://www.gnu.org/licenses/>.            //
//----------------------------------------------------------------------------//

#ifndef _KALBASE_H
#include <kalbase.h>
#endif

#ifndef _KALEXTRAS_ARGV_H
#define _KALEXTRAS_ARGV_H

#ifdef __cplusplus
extern "C" {
#endif

typedef enum CmdOptionFlag_t            CmdOptionFlag_t;
typedef enum CmdParserFlags_t           CmdParserFlags_t;
typedef enum CmdParserReturn_t          CmdParserReturn_t;

typedef struct CmdOption_t              CmdOption_t;
typedef struct CmdDocStrings_t          CmdDocStrings_t;
typedef struct CmdParserState_t         CmdParserState_t;

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

//
// Maximal total size of argv, including the pointers,
// the pointed-to strings and their null-terminators
// This is a 32-bit integer
//
#define ARG_MAX (1 << 16) // 64 KB

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

//
// Flags for options
//
enum CmdOptionFlag_t
{
    // The option parameter is optional
    KALOPT_OPTIONAL = (1 << 0),

    // Do not show option in any help message
    KALOPT_HIDDEN   = (1 << 1),

    // This option is an alias for the previous one
    KALOPT_ALIAS    = (1 << 2),

    // This isn't an option but a docstring
    KALOPT_DOCSTR   = (1 << 3),

    // Only show in long help messages
    KALOPT_LONGDOC  = (1 << 4),

};

//
// Flags for KalParse(CmdLine|ArgVec)
//
enum CmdParserFlags_t
{
    // Don't exit on errors=
    KALOPT_NO_EXIT = (1 << 0),

    // Don't react to --help
    KALOPT_NO_HELP = (1 << 1),

    // Don't react to --version
    KALOPT_NO_VERSION = (1 << 2),

    // Alias -h for --help and -V for --version
    KALOPT_ALIASES = (1 << 3),

    // Don't print any error message
    // Implies KALOPT_NO_EXIT
    KALOPT_NO_ERRORS = (1 << 4) | KALOPT_NO_EXIT,

    // Use KalGetProgName() instead of argv[0]
    // as program name
    KALOPT_DONT_USE_ARGV0 = (1 << 5),

    // Call argument parser for non-options
    // Non-options arguments will be indicated by
    // a key of 0, the argument passed as a parameter
    KALOPT_PARSE_ALL = (1 << 6),

    // Call argument parser with options and non-options in the
    // order they were found, instead of parsing options first
    KALOPT_IN_ORDER = (1 << 7) | KALOPT_PARSE_ALL,

    // Stay silent all along
    KALOPT_SILENT = KALOPT_NO_EXIT | KALOPT_NO_ERRORS
                  | KALOPT_NO_HELP | KALOPT_NO_VERSION,
};

//
// Return values for the command parser
// These flags can be combined and are applied in order
//
// "Continue" and "Break" actions do not prevent
// later actions from applying
//
enum CmdParserReturn_t
{
    // Continue parsing new options
    KALOPT_CONTINUE = 0,

    // Stop parsing further options
    KALOPT_BREAK    = (1 << 0),

    // Show help/version message (by default, continue parsing)
    KALOPT_SHOWHELP = (1 << 1),
    KALOPT_SHOWVERS = (1 << 2),
};

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

//
// An option for a command, e.g. "-o file" in "cc -o file"
//
struct CmdOption_t
{
    // The option's name, e.g. "help" for "--help"
    // May be 0, but only if letter is not zero
    const char         *longName;

    // The option's letter, e.g. 'h' for '-h'
    int                 letter;

    // Address of the variable to put the parameter into
    const char         *param;

    // Option flags, see above
    CmdOptionFlag_t     flags;

    // The option's help text
    // If this is 0, this option is hidden
    const char         *helpText;

    // The option's group, for sorting during --help
    // Must be positive and < 256, or option won't shop up
    // during help texts
    int                 group;
};

//
// Program help/documentation strings; any can be 0
//
// Help messages are printed in this format:
// (letting "this" be a CmdDocStrings_t* variable)
//
// Usage: (this->usage)
// (this->header)
//
// (this->groups[0])
//      -o, --option-name       option description
//      ...
// ...
//
// (this->bottom)
//
// XXX progname/version
//
struct CmdDocStrings_t
{
    const char  *usage;
    const char  *header;
    const char  *bottom;

    // Groups documentation
    // groups[n] should be either 0 or contain the
    // description of the option group n
    const char **groups;
};

//
// The state variable passed to the parser containing useful infos
//
struct CmdParserState_t {

    // Option we're currently parsing
    const CmdOption_t  *option;

    // Index (in argv) of the option we're parsing
    int                 argvIndex;

    // Flags passed to KalParse(CmdLine|ArgV)
    CmdParserFlags_t    flags;

    // Has help/version messages been displayed already?
    bool                shownHelp;
    bool                shownVersion;

    // Output streams (may be NULL)
    /*FILE*/ void      *outStream;
    /*FILE*/ void      *errStream;

    // Private, internal data; do not touch
    void               *priv;

};

//
// The argument parser function
//
typedef CmdParserReturn_t (*CmdParser_t)(int                key,
                                         const char        *param,
                                         CmdParserState_t  *state);

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

//
// Misc. simple functions
//
int KalComputeArgCount(const char **argv);
size_t KalComputeArgVecSize(const char **argv);

//
// Command line to argument vector
//
error_t KalCmdLineToArgVecEx(const char  *cmdLine,
                             int         *argcPtr,
                             char       **argv,
                             bool         doEscaping);

//
// KalCmdLineToArgVecEx but doEscaping = false
//
error_t KalCmdLineToArgVec(const char  *cmdLine,
                           int         *argcPtr,
                           char       **argv);

//
// Argument vector to command line
//
error_t KalArgVecToCmdLineEx(char        *cmdLine,
                             size_t       lengthMax,
                             int          argc,
                             const char **argv,
                             bool         doUnEscaping);

//
// KalArgVecToCmdLineEx but doUnEscapign = false
//
error_t KalArgVecToCmdLine(char        *cmdLine,
                           size_t       lengthMax,
                           int          argc,
                           const char **argv);
//
// Command line parser; only takes an argument vector
// The argv argument *will* be modified and all parsed
// options and arguments will be removed, except argv[0]
// which is guanranteed to be left
//
error_t KalParseArgVecEx(int                     argc,
                         char                  **argv,
                         const CmdOption_t      *options,
                         const CmdDocStrings_t  *docStrings,
                         CmdParserFlags_t       *flags,
                         CmdParser_t            *parser,
                         /*FILE*/ void          *outStream,
                         /*FILE*/ void          *errStream);
//
// KalParseArgVecEx(argc, argv, options, docString, stdin, stdout, parser, NULL)
//
error_t KalParseArgVec(int                     argc,
                       char                  **argv,
                       const CmdOption_t      *options,
                       const CmdDocStrings_t  *docStrings,
                       CmdParserFlags_t       *flags,
                       CmdParser_t            *parser);

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

#ifdef __cplusplus
}
#endif

#endif