/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright 2020 Joyent Inc.
 */

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <libintl.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <getopt.h>
#include "cmdparse.h"

/* Usage types */
#define GENERAL_USAGE   1
#define DETAIL_USAGE    2

/* printable ascii character set len */
#define MAXOPTIONS      (uint_t)('~' - '!' + 1)

/*
 * MAXOPTIONSTRING is the max length of the options string used in getopt and
 * will be the printable character set + ':' for each character,
 * providing for options with arguments. e.g. "t:Cs:hglr:"
 */
#define MAXOPTIONSTRING         MAXOPTIONS * 2

/* standard command options table to support -?, -V */
struct option standardCmdOptions[] = {
        {"help", no_argument, NULL, '?'},
        {"version", no_argument, NULL, 'V'},
        {NULL, 0, NULL, 0}
};

/* standard subcommand options table to support -? */
struct option standardSubCmdOptions[] = {
        {"help", no_argument, NULL, '?'},
        {NULL, 0, NULL, 0}
};

/* forward declarations */
static int getSubcommandProps(char *, subCommandProps_t **);
static char *getExecBasename(char *);
static void usage(uint_t);
static void subUsage(uint_t, subCommandProps_t *);
static const char *getLongOption(int);
static char *getOptionArgDesc(int);

/* global data */
static struct option *_longOptions;
static subCommandProps_t *_subCommandProps;
static optionTbl_t *_clientOptionTbl;
static char *commandName;


/*
 * input:
 *  subCommand - subcommand value
 * output:
 *  subCommandProps - pointer to subCommandProps_t structure allocated by caller
 *
 * On successful return, subCommandProps contains the properties for the value
 * in subCommand. On failure, the contents of subCommandProps is unspecified.
 *
 * Returns:
 *  zero on success
 *  non-zero on failure
 *
 */
static int
getSubcommandProps(char *subCommand, subCommandProps_t **subCommandProps)
{
        subCommandProps_t *sp;
        int len;

        for (sp = _subCommandProps; sp->name; sp++) {
                len = strlen(subCommand);
                if (len == strlen(sp->name) &&
                    strncasecmp(subCommand, sp->name, len) == 0) {
                        *subCommandProps = sp;
                        return (0);
                }
        }
        return (1);
}

/*
 * input:
 *  shortOption - short option character for which to return the
 *      associated long option string
 *
 * Returns:
 *  on success, long option name
 *  on failure, NULL
 */
static const char *
getLongOption(int shortOption)
{
        struct option *op;
        for (op = _longOptions; op->name; op++) {
                if (shortOption == op->val) {
                        return (op->name);
                }
        }
        return (NULL);
}

/*
 * input
 *  shortOption - short option character for which to return the
 *      option argument
 * Returns:
 *  on success, argument string
 *  on failure, NULL
 */
static char *
getOptionArgDesc(int shortOption)
{
        optionTbl_t *op;
        for (op = _clientOptionTbl; op->name; op++) {
                if (op->val == shortOption &&
                    op->has_arg == required_argument) {
                        return (op->argDesc);
                }
        }
        return (NULL);
}


/*
 * Print usage for a subcommand.
 *
 * input:
 *  usage type - GENERAL_USAGE, DETAIL_USAGE
 *  subcommand - pointer to subCommandProps_t structure
 *
 * Returns:
 *  none
 *
 */
static void
subUsage(uint_t usageType, subCommandProps_t *subcommand)
{
        int i;
        char *optionArgDesc;
        const char *longOpt;

        if (usageType == GENERAL_USAGE) {
            (void) printf("%s:\t%s %s [", gettext("Usage"), commandName,
                    subcommand->name);

            for (i = 0; standardSubCmdOptions[i].name; i++) {
                    (void) printf("-%c", standardSubCmdOptions[i].val);
                    if (standardSubCmdOptions[i+1].name)
                            (void) printf(",");
            }

            (void) fprintf(stdout, "]\n");
            return;
        }

        /* print subcommand usage */
        (void) printf("\n%s:\t%s %s ", gettext("Usage"), commandName,
            subcommand->name);

        /* print options if applicable */
        if (subcommand->optionString != NULL) {
                if (subcommand->required) {
                        (void) printf("%s", gettext("<"));
                } else {
                        (void) printf("%s", gettext("["));
                }
                (void) printf("%s", gettext("OPTIONS"));
                if (subcommand->required) {
                        (void) printf("%s ", gettext(">"));
                } else {
                        (void) printf("%s ", gettext("]"));
                }
        }

        /* print operand requirements */
        if (!(subcommand->operand & OPERAND_NONE) &&
            !(subcommand->operand & OPERAND_MANDATORY)) {
                (void) printf(gettext("["));
        }

        if (subcommand->operand & OPERAND_MANDATORY) {
                (void) printf(gettext("<"));
        }

        if (!(subcommand->operand & OPERAND_NONE)) {
                assert(subcommand->operandDefinition);
                (void) printf("%s", subcommand->operandDefinition);
        }

        if (subcommand->operand & OPERAND_MULTIPLE) {
                (void) printf(gettext(" ..."));
        }

        if (subcommand->operand & OPERAND_MANDATORY) {
                (void) printf(gettext(">"));
        }

        if (!(subcommand->operand & OPERAND_NONE) &&
            !(subcommand->operand & OPERAND_MANDATORY)) {
                (void) printf(gettext("]"));
        }

        /* print options for subcommand */
        if (subcommand->optionString != NULL) {
                (void) printf("\n\t%s:", gettext("OPTIONS"));
                for (i = 0; i < strlen(subcommand->optionString); i++) {
                        if ((longOpt = getLongOption(
                                            subcommand->optionString[i]))
                            == NULL) {
                            /* no long option exists for short option */
                                assert(0);
                        }
                        (void) printf("\n\t\t-%c, --%s  ",
                            subcommand->optionString[i], longOpt);
                        optionArgDesc =
                            getOptionArgDesc(subcommand->optionString[i]);
                        if (optionArgDesc != NULL) {
                                (void) printf("<%s>", optionArgDesc);
                        }
                        if (subcommand->exclusive &&
                            strchr(subcommand->exclusive,
                                    subcommand->optionString[i])) {
                                (void) printf(" (%s)", gettext("exclusive"));
                        }
                }
        }
        (void) fprintf(stdout, "\n");
}

/*
 * input:
 *  type of usage statement to print
 *
 * Returns:
 *  return value of subUsage
 */
static void
usage(uint_t usageType)
{
        int i;
        subCommandProps_t *sp;

        /* print general command usage */
        (void) printf("%s:\t%s ", gettext("Usage"), commandName);

        for (i = 0; standardCmdOptions[i].name; i++) {
                (void) printf("-%c", standardCmdOptions[i].val);
                if (standardCmdOptions[i+1].name)
                        (void) printf(",");
        }

        if (usageType == GENERAL_USAGE) {
                for (i = 0; standardSubCmdOptions[i].name; i++) {
                        (void) printf(",--%s", standardSubCmdOptions[i].name);
                        if (standardSubCmdOptions[i+1].name)
                                (void) printf(",");
                }
        }

        (void) fprintf(stdout, "\n");


        /* print all subcommand usage */
        for (sp = _subCommandProps; sp->name; sp++) {
                subUsage(usageType, sp);
        }
}

/*
 * input:
 *  execFullName - exec name of program (argv[0])
 *
 * Returns:
 *  command name portion of execFullName
 */
static char *
getExecBasename(char *execFullname)
{
        char *lastSlash, *execBasename;

        /* guard against '/' at end of command invocation */
        for (;;) {
                lastSlash = strrchr(execFullname, '/');
                if (lastSlash == NULL) {
                        execBasename = execFullname;
                        break;
                } else {
                        execBasename = lastSlash + 1;
                        if (*execBasename == '\0') {
                                *lastSlash = '\0';
                                continue;
                        }
                        break;
                }
        }
        return (execBasename);
}

/*
 * cmdParse is a parser that checks syntax of the input command against
 * various rules tables.
 *
 * It provides usage feedback based upon the passed rules tables by calling
 * two usage functions, usage, subUsage
 *
 * When syntax is successfully validated, the associated function is called
 * using the subcommands table functions.
 *
 * Syntax is as follows:
 *      command subcommand [<options>] [<operand>]
 *
 * There are two standard short and long options assumed:
 *      -?, --help      Provides usage on a command or subcommand
 *                      and stops further processing of the arguments
 *
 *      -V, --version   Provides version information on the command
 *                      and stops further processing of the arguments
 *
 *      These options are loaded by this function.
 *
 * input:
 *  argc, argv from main
 *  syntax rules tables (synTables_t structure)
 *  callArgs - void * passed by caller to be passed to subcommand function
 *
 * output:
 *  funcRet - pointer to int that holds subcommand function return value
 *
 * Returns:
 *
 *     zero on successful syntax parse and function call
 *
 *     1 on unsuccessful syntax parse (no function has been called)
 *              This could be due to a version or help call or simply a
 *              general usage call.
 *
 *     -1 check errno, call failed
 *
 *  This module is not MT-safe.
 *
 */
int
cmdParse(int argc, char *argv[], synTables_t synTable, void *callArgs,
    int *funcRet)
{
        int     getoptargc;
        char    **getoptargv;
        int     opt;
        int     operInd;
        int     i, j;
        int     len;
        char    *availOptions;
        char    *versionString;
        char    optionStringAll[MAXOPTIONSTRING + 1];
        subCommandProps_t *subcommand;
        cmdOptions_t cmdOptions[MAXOPTIONS + 1];
        optionTbl_t *optionTbl;
        struct option *lp;
        struct option intLongOpt[MAXOPTIONS + 1];

        /*
         * Check for NULLs on mandatory input arguments
         *
         * Note: longOptionTbl can be NULL in the case
         * where there is no caller defined options
         *
         */
        assert(synTable.versionString);
        assert(synTable.subCommandPropsTbl);
        assert(funcRet);

        versionString = synTable.versionString;

        /* set global command name */
        commandName = getExecBasename(argv[0]);

        /* Set unbuffered output */
        setbuf(stdout, NULL);

        /* load globals */
        _subCommandProps = synTable.subCommandPropsTbl;
        _clientOptionTbl = synTable.longOptionTbl;

        /* There must be at least two arguments */
        if (argc < 2) {
                usage(GENERAL_USAGE);
                return (1);
        }

        (void) memset(&intLongOpt[0], 0, sizeof (intLongOpt));

        /*
         * load standard subcommand options to internal long options table
         * Two separate getopt_long(3C) tables are used.
         */
        for (i = 0; standardSubCmdOptions[i].name; i++) {
                intLongOpt[i].name = standardSubCmdOptions[i].name;
                intLongOpt[i].has_arg = standardSubCmdOptions[i].has_arg;
                intLongOpt[i].flag = standardSubCmdOptions[i].flag;
                intLongOpt[i].val = standardSubCmdOptions[i].val;
        }

        /*
         * copy caller's long options into internal long options table
         * We do this for two reasons:
         *  1) We need to use the getopt_long option structure internally
         *  2) We need to prepend the table with the standard option
         *      for all subcommands (currently -?)
         */
        for (optionTbl = synTable.longOptionTbl;
            optionTbl && optionTbl->name; optionTbl++, i++) {
                if (i > MAXOPTIONS - 1) {
                        /* option table too long */
                        assert(0);
                }
                intLongOpt[i].name = optionTbl->name;
                intLongOpt[i].has_arg = optionTbl->has_arg;
                intLongOpt[i].flag = NULL;
                intLongOpt[i].val = optionTbl->val;
        }

        /* set option table global */
        _longOptions = &intLongOpt[0];


        /*
         * Check for help/version request immediately following command
         * '+' in option string ensures POSIX compliance in getopt_long()
         * which means that processing will stop at first non-option
         * argument.
         */
        while ((opt = getopt_long(argc, argv, "+?V", standardCmdOptions,
                            NULL)) != EOF) {
                switch (opt) {
                        case '?':
                                /*
                                 * getopt can return a '?' when no
                                 * option letters match string. Check for
                                 * the 'real' '?' in optopt.
                                 */
                                if (optopt == '?') {
                                        usage(DETAIL_USAGE);
                                        return (1);
                                } else {
                                        usage(GENERAL_USAGE);
                                        return (1);
                                }
                        case 'V':
                                (void) fprintf(stdout, "%s: %s %s\n",
                                    commandName, gettext("Version"),
                                    versionString);
                                return (1);
                        default:
                                break;
                }
        }

        /*
         * subcommand is always in the second argument. If there is no
         * recognized subcommand in the second argument, print error,
         * general usage and then return.
         */
        if (getSubcommandProps(argv[1], &subcommand) != 0) {
                (void) printf("%s: %s\n", commandName,
                    gettext("invalid subcommand"));
                usage(GENERAL_USAGE);
                return (1);
        }

        getoptargv = argv;
        getoptargv++;
        getoptargc = argc;
        getoptargc -= 1;

        (void) memset(optionStringAll, 0, sizeof (optionStringAll));
        (void) memset(&cmdOptions[0], 0, sizeof (cmdOptions));

        j = 0;
        /*
         * Build optionStringAll from long options table
         */
        for (lp = _longOptions;  lp->name; lp++, j++) {
                /* sanity check on string length */
                if (j + 1 >= sizeof (optionStringAll)) {
                        /* option table too long */
                        assert(0);
                }
                optionStringAll[j] = lp->val;
                if (lp->has_arg == required_argument) {
                        optionStringAll[++j] = ':';
                }
        }

        i = 0;
        /*
         * Run getopt for all arguments against all possible options
         * Store all options/option arguments in an array for retrieval
         * later.
         *
         * Once all options are retrieved, a validity check against
         * subcommand table is performed.
         */
        while ((opt = getopt_long(getoptargc, getoptargv, optionStringAll,
                            _longOptions, NULL)) != EOF) {
                switch (opt) {
                        case '?':
                                subUsage(DETAIL_USAGE, subcommand);
                                return (1);
                        default:
                                cmdOptions[i].optval = opt;
                                if (optarg) {
                                        len = strlen(optarg);
                                        if (len > sizeof (cmdOptions[i].optarg)
                                            - 1) {
                                                (void) printf("%s: %s\n",
                                                    commandName,
                                                    gettext("option too long"));
                                                errno = EINVAL;
                                                return (-1);
                                        }
                                        (void) strncpy(cmdOptions[i].optarg,
                                            optarg, len);
                                }
                                i++;
                                break;
                }
        }

        /*
         * increment past last option
         */
        operInd = optind + 1;

        /*
         * Check validity of given options, if any were given
         */

        /* get option string for this subcommand */
        availOptions = subcommand->optionString;

        if (cmdOptions[0].optval != 0) { /* options were input */
                if (availOptions == NULL) { /* no options permitted */
                        (void) printf("%s: %s\n", commandName,
                            gettext("no options permitted"));
                        subUsage(DETAIL_USAGE, subcommand);
                        return (1);
                }
                for (i = 0; cmdOptions[i].optval; i++) {
                        /* is the option in the available option string? */
                        if (!(strchr(availOptions, cmdOptions[i].optval))) {
                                (void) printf("%s: '-%c': %s\n", commandName,
                                    cmdOptions[i].optval,
                                    gettext("invalid option"));
                                subUsage(DETAIL_USAGE, subcommand);
                                return (1);

                        /* Check for exclusive options */
                        } else if (cmdOptions[1].optval != 0 &&
                                subcommand->exclusive &&
                                strchr(subcommand->exclusive,
                                        cmdOptions[i].optval)) {
                                        (void) printf("%s: '-%c': %s\n",
                                            commandName, cmdOptions[i].optval,
                                            gettext("is an exclusive option"));
                                subUsage(DETAIL_USAGE, subcommand);
                                        return (1);
                        }
                }
        } else { /* no options were input */
                if (availOptions != NULL && subcommand->required) {
                        (void) printf("%s: %s\n", commandName,
                            gettext("at least one option required"));
                        subUsage(DETAIL_USAGE, subcommand);
                        return (1);
                }
        }

        /*
         * If there are no operands,
         * check to see if this is okay
         */
        if ((operInd == argc) &&
                (subcommand->operand & OPERAND_MANDATORY)) {
                (void) printf("%s: %s %s\n", commandName, subcommand->name,
                    gettext("requires an operand"));
                subUsage(DETAIL_USAGE, subcommand);
                return (1);
        }

        /*
         * If there are more operands,
         * check to see if this is okay
         */
        if ((argc > operInd) &&
                (subcommand->operand & OPERAND_NONE)) {
                (void) fprintf(stderr, "%s: %s %s\n",
                        commandName, subcommand->name,
                        gettext("takes no operands"));
                subUsage(DETAIL_USAGE, subcommand);
                return (1);
        }

        /*
         * If there is more than one more operand,
         * check to see if this is okay
         */
        if ((argc > operInd) && ((argc - operInd) != 1) &&
                (subcommand->operand & OPERAND_SINGLE)) {
                (void) printf("%s: %s %s\n", commandName,
                    subcommand->name, gettext("accepts only a single operand"));
                subUsage(DETAIL_USAGE, subcommand);
                return (1);
        }

        /* Finished syntax checks */


        /* Call appropriate function */
        *funcRet = subcommand->handler(argc - operInd, &argv[operInd],
                &cmdOptions[0], callArgs);

        return (0);
}