/*
    FUSE: Filesystem in Userspace
    Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>

    This file is borrowed from sshfs-fuse. It provides an implementation
    of the FUSE command line parsing functions which only appear in
    later version of FUSE but are used in afuse.
    
    This file can be distributed under the terms of the GNU LGPL.
    See the file COPYING.LIB
*/

#include "fuse_opt.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

struct fuse_opt_context {
    void *data;
    const struct fuse_opt *opt;
    fuse_opt_proc_t proc;
    int argctr;
    int argc;
    char **argv;
    struct fuse_args outargs;
    char *opts;
    int nonopt;
};

void fuse_opt_free_args(struct fuse_args *args)
{
    if (args && args->argv && args->allocated) {
        int i;
        for (i = 0; i < args->argc; i++)
            free(args->argv[i]);
        free(args->argv);
        args->argv = NULL;
        args->allocated = 0;
    }
}

static int alloc_failed(void)
{
    fprintf(stderr, "fuse: memory allocation failed\n");
    return -1;
}

int fuse_opt_add_arg(struct fuse_args *args, const char *arg)
{
    char **newargv;
    char *newarg;

    assert(!args->argv || args->allocated);

    newargv = realloc(args->argv, (args->argc + 2) * sizeof(char *));
    newarg = newargv ? strdup(arg) : NULL;
    if (!newargv || !newarg)
        return alloc_failed();

    args->argv = newargv;
    args->allocated = 1;
    args->argv[args->argc++] = newarg;
    args->argv[args->argc] = NULL;
    return 0;
}

static int next_arg(struct fuse_opt_context *ctx, const char *opt)
{
    if (ctx->argctr + 1 >= ctx->argc) {
        fprintf(stderr, "fuse: missing argument after `%s'\n", opt);
        return -1;
    }
    ctx->argctr++;
    return 0;
}

static int add_arg(struct fuse_opt_context *ctx, const char *arg)
{
    return fuse_opt_add_arg(&ctx->outargs, arg);
}

int fuse_opt_add_opt(char **opts, const char *opt)
{
    char *newopts;
    if (!*opts)
        newopts = strdup(opt);
    else {
        unsigned oldlen = strlen(*opts);
        newopts = realloc(*opts, oldlen + 1 + strlen(opt) + 1);
        if (newopts) {
            newopts[oldlen] = ',';
            strcpy(newopts + oldlen + 1, opt);
        }
    }
    if (!newopts)
        return alloc_failed();

    *opts = newopts;
    return 0;
}

static int add_opt(struct fuse_opt_context *ctx, const char *opt)
{
    return fuse_opt_add_opt(&ctx->opts, opt);
}

static int insert_arg(struct fuse_opt_context *ctx, int pos, const char *arg)
{
    assert(pos <= ctx->outargs.argc);
    if (add_arg(ctx, arg) == -1)
        return -1;

    if (pos != ctx->outargs.argc - 1) {
        char *newarg = ctx->outargs.argv[ctx->outargs.argc - 1];
        memmove(&ctx->outargs.argv[pos + 1], &ctx->outargs.argv[pos],
                sizeof(char *) * (ctx->outargs.argc - pos - 1));
        ctx->outargs.argv[pos] = newarg;
    }
    return 0;
}

static int call_proc(struct fuse_opt_context *ctx, const char *arg, int key,
                     int iso)
{
    if (ctx->proc) {
        int res = ctx->proc(ctx->data, arg, key, &ctx->outargs);
        if (res == -1 || !res)
            return res;
    }
    if (iso)
        return add_opt(ctx, arg);
    else
        return add_arg(ctx, arg);
}

static int match_template(const char *t, const char *arg, unsigned *sepp)
{
    int arglen = strlen(arg);
    const char *sep = strchr(t, '=');
    sep = sep ? sep : strchr(t, ' ');
    if (sep && (!sep[1] || sep[1] == '%')) {
        int tlen = sep - t;
        if (sep[0] == '=')
            tlen ++;
        if (arglen >= tlen && strncmp(arg, t, tlen) == 0) {
            *sepp = sep - t;
            return 1;
        }
    }
    if (strcmp(t, arg) == 0) {
        *sepp = 0;
        return 1;
    }
    return 0;
}

static const struct fuse_opt *find_opt(const struct fuse_opt *opt,
                                       const char *arg, unsigned *sepp)
{
    for (; opt && opt->template; opt++)
        if (match_template(opt->template, arg, sepp))
            return opt;
    return NULL;
}

int fuse_opt_match(const struct fuse_opt *opts, const char *opt)
{
    unsigned dummy;
    return find_opt(opts, opt, &dummy) ? 1 : 0;
}

static int process_opt_param(void *var, const char *format, const char *param,
                             const char *arg)
{
    assert(format[0] == '%');
    if (format[1] == 's') {
        char *copy = strdup(param);
        if (!copy)
            return alloc_failed();

        *(char **) var = copy;
    } else {
        if (sscanf(param, format, var) != 1) {
            fprintf(stderr, "fuse: invalid parameter in option `%s'\n", arg);
            return -1;
        }
    }
    return 0;
}

static int process_opt(struct fuse_opt_context *ctx,
                       const struct fuse_opt *opt, unsigned sep,
                       const char *arg, int iso)
{
    if (opt->offset == -1U) {
        if (call_proc(ctx, arg, opt->value, iso) == -1)
            return -1;
    } else {
        void *var = ctx->data + opt->offset;
        if (sep && opt->template[sep + 1]) {
            const char *param = arg + sep;
            if (opt->template[sep] == '=')
                param ++;
            if (process_opt_param(var, opt->template + sep + 1,
                                  param, arg) == -1)
                return -1;
        } else
            *(int *)var = opt->value;
    }
    return 0;
}

static int process_opt_sep_arg(struct fuse_opt_context *ctx,
                               const struct fuse_opt *opt, unsigned sep,
                               const char *arg, int iso)
{
    int res;
    char *newarg;
    char *param;

    if (next_arg(ctx, arg) == -1)
        return -1;

    param = ctx->argv[ctx->argctr];
    newarg = malloc(sep + strlen(param) + 1);
    if (!newarg)
        return alloc_failed();

    memcpy(newarg, arg, sep);
    strcpy(newarg + sep, param);
    res = process_opt(ctx, opt, sep, newarg, iso);
    free(newarg);

    return res;
}

static int process_gopt(struct fuse_opt_context *ctx, const char *arg, int iso)
{
    unsigned sep;
    const struct fuse_opt *opt = find_opt(ctx->opt, arg, &sep);
    if (opt) {
        for (; opt; opt = find_opt(opt + 1, arg, &sep)) {
            int res;
            if (sep && opt->template[sep] == ' ' && !arg[sep])
                res = process_opt_sep_arg(ctx, opt, sep, arg, iso);
            else
                res = process_opt(ctx, opt, sep, arg, iso);
            if (res == -1)
                return -1;
        }
        return 0;
    } else
        return call_proc(ctx, arg, FUSE_OPT_KEY_OPT, iso);
}

static int process_real_option_group(struct fuse_opt_context *ctx, char *opts)
{
    char *sep;

    do {
        int res;
        sep = strchr(opts, ',');
        if (sep)
            *sep = '\0';
        res = process_gopt(ctx, opts, 1);
        if (res == -1)
            return -1;
        opts = sep + 1;
    } while (sep);

    return 0;
}

static int process_option_group(struct fuse_opt_context *ctx, const char *opts)
{
    int res;
    char *copy;
    const char *sep = strchr(opts, ',');
    if (!sep)
        return process_gopt(ctx, opts, 1);

    copy = strdup(opts);
    if (!copy) {
        fprintf(stderr, "fuse: memory allocation failed\n");
        return -1;
    }
    res = process_real_option_group(ctx, copy);
    free(copy);
    return res;
}

static int process_one(struct fuse_opt_context *ctx, const char *arg)
{
    if (ctx->nonopt || arg[0] != '-')
        return call_proc(ctx, arg, FUSE_OPT_KEY_NONOPT, 0);
    else if (arg[1] == 'o') {
        if (arg[2])
            return process_option_group(ctx, arg + 2);
        else {
            if (next_arg(ctx, arg) == -1)
                return -1;

            return process_option_group(ctx, ctx->argv[ctx->argctr]);
        }
    } else if (arg[1] == '-' && !arg[2]) {
        if (add_arg(ctx, arg) == -1)
            return -1;
        ctx->nonopt = ctx->outargs.argc;
        return 0;
    } else
        return process_gopt(ctx, arg, 0);
}

static int opt_parse(struct fuse_opt_context *ctx)
{
    if (ctx->argc) {
        if (add_arg(ctx, ctx->argv[0]) == -1)
            return -1;
    }

    for (ctx->argctr = 1; ctx->argctr < ctx->argc; ctx->argctr++)
        if (process_one(ctx, ctx->argv[ctx->argctr]) == -1)
            return -1;

    if (ctx->opts) {
        if (insert_arg(ctx, 1, "-o") == -1 ||
            insert_arg(ctx, 2, ctx->opts) == -1)
            return -1;
    }
    if (ctx->nonopt && ctx->nonopt == ctx->outargs.argc)
        ctx->outargs.argv[--ctx->outargs.argc] = NULL;

    return 0;
}

int fuse_opt_parse(struct fuse_args *args, void *data,
                   const struct fuse_opt opts[], fuse_opt_proc_t proc)
{
    int res;
    struct fuse_opt_context ctx = {
        .data = data,
        .opt = opts,
        .proc = proc,
    };

    if (!args || !args->argv || !args->argc)
        return 0;

    ctx.argc = args->argc;
    ctx.argv = args->argv;

    res = opt_parse(&ctx);
    if (res != -1) {
        struct fuse_args tmp = *args;
        *args = ctx.outargs;
        ctx.outargs = tmp;
    }
    free(ctx.opts);
    fuse_opt_free_args(&ctx.outargs);
    return res;
}