/*
    Copyright (c) 2013 Insollo Entertainment, LLC.  All rights reserved.

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom
    the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    IN THE SOFTWARE.
*/

#include "options.h"

#include "../src/utils/err.c"

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

struct nn_parse_context {
    /*  Initial state  */
    struct nn_commandline *def;
    struct nn_option *options;
    void *target;
    int argc;
    char **argv;
    unsigned long requires;

    /*  Current values  */
    unsigned long mask;
    int args_left;
    char **arg;
    char *data;
    char **last_option_usage;
};

static int nn_has_arg (struct nn_option *opt)
{
    switch (opt->type) {
        case NN_OPT_INCREMENT:
        case NN_OPT_DECREMENT:
        case NN_OPT_SET_ENUM:
        case NN_OPT_HELP:
            return 0;
        case NN_OPT_ENUM:
        case NN_OPT_STRING:
        case NN_OPT_BLOB:
        case NN_OPT_FLOAT:
        case NN_OPT_INT:
        case NN_OPT_LIST_APPEND:
        case NN_OPT_LIST_APPEND_FMT:
        case NN_OPT_READ_FILE:
            return 1;
    }
    nn_assert (0);
}

static void nn_print_usage (struct nn_parse_context *ctx, FILE *stream)
{
    int i;
    int first;
    struct nn_option *opt;

    fprintf (stream, "    %s ", ctx->argv[0]);

    /* Print required options (long names)  */
    first = 1;
    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (opt->mask_set & ctx->requires) {
            if (first) {
                first = 0;
                fprintf (stream, "{--%s", opt->longname);
            } else {
                fprintf (stream, "|--%s", opt->longname);
            }
        }
    }
    if (!first) {
        fprintf (stream, "} ");
    }

    /* Print flag short options */
    first = 1;
    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (opt->mask_set & ctx->requires)
            continue;  /* already printed */
        if (opt->shortname && !nn_has_arg (opt)) {
            if (first) {
                first = 0;
                fprintf (stream, "[-%c", opt->shortname);
            } else {
                fprintf (stream, "%c", opt->shortname);
            }
        }
    }
    if (!first) {
        fprintf (stream, "] ");
    }

    /* Print short options with arguments */
    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (opt->mask_set & ctx->requires)
            continue;  /* already printed */
        if (opt->shortname && nn_has_arg (opt) && opt->metavar) {
            fprintf (stream, "[-%c %s] ", opt->shortname, opt->metavar);
        }
    }

    fprintf (stream, "[options] \n");  /* There may be long options too */
}

static char *nn_print_line (FILE *out, char *str, size_t width)
{
    int i;
    if (strlen (str) < width) {
        fprintf (out, "%s", str);
        return "";
    }
    for (i = width; i > 1; --i) {
        if (isspace (str[i])) {
            fprintf (out, "%.*s", i, str);
            return str + i + 1;
        }
    }  /* no break points, just print as is */
    fprintf (out, "%s", str);
    return "";
}

static void nn_print_help (struct nn_parse_context *ctx, FILE *stream)
{
    int i;
    int optlen;
    struct nn_option *opt;
    char *last_group;
    char *cursor;

    fprintf (stream, "Usage:\n");
    nn_print_usage (ctx, stream);
    fprintf (stream, "\n%s\n", ctx->def->short_description);

    last_group = NULL;
    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (!last_group || last_group != opt->group ||
            strcmp (last_group, opt->group))
        {
            fprintf (stream, "\n");
            fprintf (stream, "%s:\n", opt->group);
            last_group = opt->group;
        }
        fprintf (stream, " --%s", opt->longname);
        optlen = 3 + strlen (opt->longname);
        if (opt->shortname) {
            fprintf (stream, ",-%c", opt->shortname);
            optlen += 3;
        }
        if (nn_has_arg (opt)) {
            if (opt->metavar) {
                fprintf (stream, " %s", opt->metavar);
                optlen += strlen (opt->metavar) + 1;
            } else {
                fprintf (stream, " ARG");
                optlen += 4;
            }
        }
        if (optlen < 23) {
            fputs ("                        " + optlen, stream);
            cursor = nn_print_line (stream, opt->description, 80-24);
        } else {
            cursor = opt->description;
        }
        while (*cursor) {
            fprintf (stream, "\n                        ");
            cursor = nn_print_line (stream, cursor, 80-24);
        }
        fprintf (stream, "\n");
    }
}

static void nn_print_option (struct nn_parse_context *ctx, int opt_index,
                            FILE *stream)
{
    char *ousage;
    char *oend;
    size_t olen;
    struct nn_option *opt;

    opt = &ctx->options[opt_index];
    ousage = ctx->last_option_usage[opt_index];
    if (*ousage == '-') {  /* Long option */
        oend = strchr (ousage, '=');
        if (!oend) {
            olen = strlen (ousage);
        } else {
            olen = (oend - ousage);
        }
        if (olen != strlen (opt->longname)+2) {
            fprintf (stream, " %.*s[%s] ",
                (int)olen, ousage, opt->longname + (olen-2));
        } else {
            fprintf (stream, " %s ", ousage);
        }
    } else if (ousage == ctx->argv[0]) {  /* Binary name */
        fprintf (stream, " %s (executable) ", ousage);
    } else {  /* Short option */
        fprintf (stream, " -%c (--%s) ",
            *ousage, opt->longname);
    }
}

static void nn_option_error (char *message, struct nn_parse_context *ctx,
                     int opt_index)
{
    fprintf (stderr, "%s: Option", ctx->argv[0]);
    nn_print_option (ctx, opt_index, stderr);
    fprintf (stderr, "%s\n", message);
    exit (1);
}


static void nn_memory_error (struct nn_parse_context *ctx) {
    fprintf (stderr, "%s: Memory error while parsing command-line",
        ctx->argv[0]);
    abort ();
}

static void nn_invalid_enum_value (struct nn_parse_context *ctx,
    int opt_index, char *argument)
{
    struct nn_option *opt;
    struct nn_enum_item *items;

    opt = &ctx->options[opt_index];
    items = (struct nn_enum_item *)opt->pointer;
    fprintf (stderr, "%s: Invalid value ``%s'' for", ctx->argv[0], argument);
    nn_print_option (ctx, opt_index, stderr);
    fprintf (stderr, ". Options are:\n");
    for (;items->name; ++items) {
        fprintf (stderr, "    %s\n", items->name);
    }
    exit (1);
}

static void nn_option_conflict (struct nn_parse_context *ctx,
                              int opt_index)
{
    unsigned long mask;
    int i;
    int num_conflicts;
    struct nn_option *opt;

    fprintf (stderr, "%s: Option", ctx->argv[0]);
    nn_print_option (ctx, opt_index, stderr);
    fprintf (stderr, "conflicts with the following options:\n");

    mask = ctx->options[opt_index].conflicts_mask;
    num_conflicts = 0;
    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (i == opt_index)
            continue;
        if (ctx->last_option_usage[i] && opt->mask_set & mask) {
            num_conflicts += 1;
            fprintf (stderr, "   ");
            nn_print_option (ctx, i, stderr);
            fprintf (stderr, "\n");
        }
    }
    if (!num_conflicts) {
        fprintf (stderr, "   ");
        nn_print_option (ctx, opt_index, stderr);
        fprintf (stderr, "\n");
    }
    exit (1);
}

static void nn_print_requires (struct nn_parse_context *ctx, unsigned long mask)
{
    int i;
    struct nn_option *opt;

    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (opt->mask_set & mask) {
            fprintf (stderr, "    --%s\n", opt->longname);
            if (opt->shortname) {
                fprintf (stderr, "    -%c\n", opt->shortname);
            }
        }
    }
    exit (1);
}

static void nn_option_requires (struct nn_parse_context *ctx, int opt_index) {
    fprintf (stderr, "%s: Option", ctx->argv[0]);
    nn_print_option (ctx, opt_index, stderr);
    fprintf (stderr, "requires at least one of the following options:\n");

    nn_print_requires (ctx, ctx->options[opt_index].requires_mask);
    exit (1);
}

static void nn_append_string (struct nn_parse_context *ctx,
                             struct nn_option *opt, char *str)
{
    struct nn_string_list *lst;

    lst = (struct nn_string_list *)(
        ((char *)ctx->target) + opt->offset);
    if (lst->items) {
        lst->num += 1;
        lst->items = realloc (lst->items, sizeof (char *) * lst->num);
    } else {
        lst->items = malloc (sizeof (char *));
        lst->num = 1;
    }
    if (!lst->items) {
        nn_memory_error (ctx);
    }
    lst->items[lst->num-1] = str;
}

static void nn_process_option (struct nn_parse_context *ctx,
                              int opt_index, char *argument)
{
    struct nn_option *opt;
    struct nn_enum_item *items;
    char *endptr;
    struct nn_blob *blob;
    FILE *file;
    char *data;
    size_t data_len;
    size_t data_buf;
    int bytes_read;

    opt = &ctx->options[opt_index];
    if (ctx->mask & opt->conflicts_mask) {
        nn_option_conflict (ctx, opt_index);
    }
    ctx->mask |= opt->mask_set;

    switch (opt->type) {
        case NN_OPT_HELP:
            nn_print_help (ctx, stdout);
            exit (0);
            return;
        case NN_OPT_INT:
            *(long *)(((char *)ctx->target) + opt->offset) = strtol (argument,
                &endptr, 0);
            if (endptr == argument || *endptr != 0) {
                nn_option_error ("requires integer argument",
                                ctx, opt_index);
            }
            return;
        case NN_OPT_INCREMENT:
            *(int *)(((char *)ctx->target) + opt->offset) += 1;
            return;
        case NN_OPT_DECREMENT:
            *(int *)(((char *)ctx->target) + opt->offset) -= 1;
            return;
        case NN_OPT_ENUM:
            items = (struct nn_enum_item *)opt->pointer;
            for (;items->name; ++items) {
                if (!strcmp (items->name, argument)) {
                    *(int *)(((char *)ctx->target) + opt->offset) = \
                        items->value;
                    return;
                }
            }
            nn_invalid_enum_value (ctx, opt_index, argument);
            return;
        case NN_OPT_SET_ENUM:
            *(int *)(((char *)ctx->target) + opt->offset) = \
                *(int *)(opt->pointer);
            return;
        case NN_OPT_STRING:
            *(char **)(((char *)ctx->target) + opt->offset) = argument;
            return;
        case NN_OPT_BLOB:
            blob = (struct nn_blob *)(((char *)ctx->target) + opt->offset);
            blob->data = argument;
            blob->length = strlen (argument);
            return;
        case NN_OPT_FLOAT:
#if defined NN_HAVE_WINDOWS
            *(float *)(((char *)ctx->target) + opt->offset) =
                (float) atof (argument);
#else
            *(float *)(((char *)ctx->target) + opt->offset) =
                strtof (argument, &endptr);
            if (endptr == argument || *endptr != 0) {
                nn_option_error ("requires float point argument",
                                ctx, opt_index);
            }
#endif
            return;
        case NN_OPT_LIST_APPEND:
            nn_append_string (ctx, opt, argument);
            return;
        case NN_OPT_LIST_APPEND_FMT:
            data_buf = strlen (argument) + strlen (opt->pointer);
            data = malloc (data_buf);
#if defined NN_HAVE_WINDOWS
            data_len = _snprintf_s (data, data_buf, data_buf, opt->pointer,
                argument);
#else
            data_len = snprintf (data, data_buf, opt->pointer, argument);
#endif
            assert (data_len < data_buf);
            nn_append_string (ctx, opt, data);
            return;
        case NN_OPT_READ_FILE:
            if (!strcmp (argument, "-")) {
                file = stdin;
            } else {
#if defined NN_HAVE_WINDOWS
                if (fopen_s (&file, argument, "r") != 0) {
#else
                file = fopen (argument, "r");
                if (!file) {
#endif
                    fprintf (stderr, "Error opening file ``%s'': %s\n",
                        argument, strerror (errno));
                    exit (2);
                }
            }
            data = malloc (4096);
            if (!data)
                nn_memory_error (ctx);
            data_len = 0;
            data_buf = 4096;
            for (;;) {
                bytes_read = fread (data + data_len, 1, data_buf - data_len,
                                   file);
                data_len += bytes_read;
                if (feof (file))
                    break;
                if (data_buf - data_len < 1024) {
                    if (data_buf < (1 << 20)) {
                        data_buf *= 2;  /* grow twice until not too big */
                    } else {
                        data_buf += 1 << 20;  /* grow 1 Mb each time */
                    }
                    data = realloc (data, data_buf);
                    if (!data)
                        nn_memory_error (ctx);
                }
            }
            if (data_len != data_buf) {
                data = realloc (data, data_len);
                assert (data);
            }
            if (ferror (file)) {
                fprintf (stderr, "Error reading file ``%s'': %s\n",
                    argument, strerror (errno));
                exit (2);
            }
            if (file != stdin) {
                fclose (file);
            }
            blob = (struct nn_blob *)(((char *)ctx->target) + opt->offset);
            blob->data = data;
            blob->length = data_len;
            return;
    }
    abort ();
}

static void nn_parse_arg0 (struct nn_parse_context *ctx)
{
    int i;
    struct nn_option *opt;
    char *arg0;

    arg0 = strrchr (ctx->argv[0], '/');
    if (arg0 == NULL) {
        arg0 = ctx->argv[0];
    } else {
        arg0 += 1; /*  Skip slash itself  */
    }


    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            return;
        if (opt->arg0name && !strcmp (arg0, opt->arg0name)) {
            assert (!nn_has_arg (opt));
            ctx->last_option_usage[i] = ctx->argv[0];
            nn_process_option (ctx, i, NULL);
        }
    }
}


static void nn_error_ambiguous_option (struct nn_parse_context *ctx)
{
    struct nn_option *opt;
    char *a, *b;
    char *arg;

    arg = ctx->data+2;
    fprintf (stderr, "%s: Ambiguous option ``%s'':\n", ctx->argv[0], ctx->data);
    for (opt = ctx->options; opt->longname; ++opt) {
        for (a = opt->longname, b = arg; ; ++a, ++b) {
            if (*b == 0 || *b == '=') {  /* End of option on command-line */
                fprintf (stderr, "    %s\n", opt->longname);
                break;
            } else if (*b != *a) {
                break;
            }
        }
    }
    exit (1);
}

static void nn_error_unknown_long_option (struct nn_parse_context *ctx)
{
    fprintf (stderr, "%s: Unknown option ``%s''\n", ctx->argv[0], ctx->data);
    exit (1);
}

static void nn_error_unexpected_argument (struct nn_parse_context *ctx)
{
    fprintf (stderr, "%s: Unexpected argument ``%s''\n",
        ctx->argv[0], ctx->data);
    exit (1);
}

static void nn_error_unknown_short_option (struct nn_parse_context *ctx)
{
    fprintf (stderr, "%s: Unknown option ``-%c''\n", ctx->argv[0], *ctx->data);
    exit (1);
}

static int nn_get_arg (struct nn_parse_context *ctx)
{
    if (!ctx->args_left)
        return 0;
    ctx->args_left -= 1;
    ctx->arg += 1;
    ctx->data = *ctx->arg;
    return 1;
}

static void nn_parse_long_option (struct nn_parse_context *ctx)
{
    struct nn_option *opt;
    char *a, *b;
    int longest_prefix;
    int cur_prefix;
    int best_match;
    char *arg;
    int i;

    arg = ctx->data+2;
    longest_prefix = 0;
    best_match = -1;
    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        for (a = opt->longname, b = arg;; ++a, ++b) {
            if (*b == 0 || *b == '=') {  /* End of option on command-line */
                cur_prefix = a - opt->longname;
                if (!*a) {  /* Matches end of option name */
                    best_match = i;
                    longest_prefix = cur_prefix;
                    goto finish;
                }
                if (cur_prefix == longest_prefix) {
                    best_match = -1;  /* Ambiguity */
                } else if (cur_prefix > longest_prefix) {
                    best_match = i;
                    longest_prefix = cur_prefix;
                }
                break;
            } else if (*b != *a) {
                break;
            }
        }
    }
finish:
    if (best_match >= 0) {
        opt = &ctx->options[best_match];
        ctx->last_option_usage[best_match] = ctx->data;
        if (arg[longest_prefix] == '=') {
            if (nn_has_arg (opt)) {
                nn_process_option (ctx, best_match, arg + longest_prefix + 1);
            } else {
                nn_option_error ("does not accept argument", ctx, best_match);
            }
        } else {
            if (nn_has_arg (opt)) {
                if (nn_get_arg (ctx)) {
                    nn_process_option (ctx, best_match, ctx->data);
                } else {
                    nn_option_error ("requires an argument", ctx, best_match);
                }
            } else {
                nn_process_option (ctx, best_match, NULL);
            }
        }
    } else if (longest_prefix > 0) {
        nn_error_ambiguous_option (ctx);
    } else {
        nn_error_unknown_long_option (ctx);
    }
}

static void nn_parse_short_option (struct nn_parse_context *ctx)
{
    int i;
    struct nn_option *opt;

    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (!opt->shortname)
            continue;
        if (opt->shortname == *ctx->data) {
            ctx->last_option_usage[i] = ctx->data;
            if (nn_has_arg (opt)) {
                if (ctx->data[1]) {
                    nn_process_option (ctx, i, ctx->data+1);
                } else {
                    if (nn_get_arg (ctx)) {
                        nn_process_option (ctx, i, ctx->data);
                    } else {
                        nn_option_error ("requires an argument", ctx, i);
                    }
                }
                ctx->data = "";  /* end of short options anyway */
            } else {
                nn_process_option (ctx, i, NULL);
                ctx->data += 1;
            }
            return;
        }
    }
    nn_error_unknown_short_option (ctx);
}


static void nn_parse_arg (struct nn_parse_context *ctx)
{
    if (ctx->data[0] == '-') {  /* an option */
        if (ctx->data[1] == '-') {  /* long option */
            if (ctx->data[2] == 0) {  /* end of options */
                return;
            }
            nn_parse_long_option (ctx);
        } else {
            ctx->data += 1;  /* Skip minus */
            while (*ctx->data) {
                nn_parse_short_option (ctx);
            }
        }
    } else {
        nn_error_unexpected_argument (ctx);
    }
}

void nn_check_requires (struct nn_parse_context *ctx) {
    int i;
    struct nn_option *opt;

    for (i = 0;; ++i) {
        opt = &ctx->options[i];
        if (!opt->longname)
            break;
        if (!ctx->last_option_usage[i])
            continue;
        if (opt->requires_mask &&
            (opt->requires_mask & ctx->mask) != opt->requires_mask) {
            nn_option_requires (ctx, i);
        }
    }

    if ((ctx->requires & ctx->mask) != ctx->requires) {
        fprintf (stderr, "%s: At least one of the following required:\n",
            ctx->argv[0]);
        nn_print_requires (ctx, ctx->requires & ~ctx->mask);
        exit (1);
    }
}

void nn_parse_options (struct nn_commandline *cline,
    void *target, int argc, char **argv)
{
    struct nn_parse_context ctx;
    int num_options;

    ctx.def = cline;
    ctx.options = cline->options;
    ctx.target = target;
    ctx.argc = argc;
    ctx.argv = argv;
    ctx.requires = cline->required_options;

    for (num_options = 0; ctx.options[num_options].longname; ++num_options);
    ctx.last_option_usage = calloc (sizeof (char *), num_options);
    if  (!ctx.last_option_usage)
        nn_memory_error (&ctx);

    ctx.mask = 0;
    ctx.args_left = argc - 1;
    ctx.arg = argv;

    nn_parse_arg0 (&ctx);

    while (nn_get_arg (&ctx)) {
        nn_parse_arg (&ctx);
    }

    nn_check_requires (&ctx);

    free (ctx.last_option_usage);

}