/*!
  \file lib/gis/parser_dependencies.c
  
  \brief GIS Library - Argument parsing functions (dependencies between options)
  
  (C) 2014 by the GRASS Development Team
  
  This program is free software under the GNU General Public License
  (>=v2). Read the file COPYING that comes with GRASS for details.
  
  \author Glynn Clements Jun. 2014
*/

#include <stdarg.h>
#include <string.h>
#include <stdio.h>

#include <grass/gis.h>
#include <grass/glocale.h>

#include "parser_local_proto.h"

enum rule_type {
    RULE_EXCLUSIVE,
    RULE_REQUIRED,
    RULE_REQUIRES,
    RULE_REQUIRES_ALL,
    RULE_EXCLUDES,
    RULE_COLLECTIVE
};

struct vector {
    size_t elsize;
    size_t increment;
    size_t count;
    size_t limit;
    void *data;
};

static void vector_new(struct vector *v, size_t elsize, size_t increment)
{
    v->elsize = elsize;
    v->increment = increment;
    v->count = 0;
    v->limit = 0;
    v->data = NULL;
}

static void vector_append(struct vector *v, const void *data)
{
    void *p;

    if (v->count >= v->limit) {
	v->limit += v->increment;
	v->data = G_realloc(v->data, v->limit * v->elsize);
    }

    p = G_incr_void_ptr(v->data, v->count * v->elsize);
    memcpy(p, data, v->elsize);
    v->count++;
}

struct rule {
    int type;
    int count;
    void **opts;
};

static struct vector rules = {sizeof(struct rule), 50};

static void make_rule(int type, void *first, va_list ap)
{
    struct vector opts;
    void *opt;
    struct rule rule;

    vector_new(&opts, sizeof(void *), 10);

    opt = first;
    vector_append(&opts, &opt);
    for (;;) {
	opt = va_arg(ap, void*);
	if (!opt)
	    break;
	vector_append(&opts, &opt);
    }

    rule.type = type;
    rule.count = opts.count;
    rule.opts = (void**) opts.data;

    vector_append(&rules, &rule);
}

static int is_flag(const void *p)
{
    if (st->n_flags) {
	const struct Flag *flag;
	for (flag = &st->first_flag; flag; flag = flag->next_flag)
	    if ((const void *) flag == p)
		return 1;
    }

    if (st->n_opts) {
	const struct Option *opt;
	for (opt = &st->first_option; opt; opt = opt->next_opt)
	    if ((const void *) opt == p)
		return 0;
    }

    G_fatal_error(_("Internal error: option or flag not found"));
}

static int is_present(const void *p)
{
    if (is_flag(p)) {
	const struct Flag *flag = p;
	return (int) flag->answer;
    }
    else {
	const struct Option *opt = p;
	return opt->count > 0;
    }
}

static char *get_name(const void *p)
{
    if (is_flag(p)) {
	char *s;
	G_asprintf(&s, "-%c", ((const struct Flag *) p)->key);
	return s;
    }
    else
	return G_store(((const struct Option *) p)->key);
}

static int count_present(const struct rule *rule, int start)
{
    int i;
    int count = 0;

    for (i = start; i < rule->count; i++)
	if (is_present(rule->opts[i]))
	    count++;

    return count;
}

static const char *describe_rule(const struct rule *rule, int start,
				 int disjunction)
{
    char *s = get_name(rule->opts[start]);
    int i;

    for (i = start + 1; i < rule->count - 1; i++) {
	char *s0 = s;
	char *ss = get_name(rule->opts[i]);
	s = NULL;
	G_asprintf(&s, "%s, %s", s0, ss);
	G_free(s0);
	G_free(ss);
    }

    if (rule->count - start > 1) {
	char *s0 = s;
	char *ss = get_name(rule->opts[i]);
	s = NULL;
	G_asprintf(&s, disjunction ? _("%s or %s") : _("%s and %s"), s0, ss);
	G_free(s0);
	G_free(ss);
    }

    return s;
}

static void append_error(const char *msg)
{
    st->error = G_realloc(st->error, sizeof(char *) * (st->n_errors + 1));
    st->error[st->n_errors++] = G_store(msg);
}

/* at most one option from a set */
void G_option_exclusive(void *first, ...)
{
    va_list ap;
    va_start(ap, first);
    make_rule(RULE_EXCLUSIVE, first, ap);
    va_end(ap);
}

static void check_exclusive(const struct rule *rule)
{
    if (count_present(rule, 0) > 1) {
	char *err;
	G_asprintf(&err, _("Options %s are mutually exclusive"),
		   describe_rule(rule, 0, 0));
	append_error(err);
    }
}

/* at least one option from a set */
void G_option_required(void *first, ...)
{
    va_list ap;
    va_start(ap, first);
    make_rule(RULE_REQUIRED, first, ap);
    va_end(ap);
}

static void check_required(const struct rule *rule)
{
    if (count_present(rule, 0) < 1) {
	char *err;
	G_asprintf(&err, _("At least one of %s is required"),
		   describe_rule(rule, 0, 0));
	append_error(err);
    }
}

/* if the first option is present, at least one of the other
   options must also be present */
void G_option_requires(void *first, ...)
{
    va_list ap;
    va_start(ap, first);
    make_rule(RULE_REQUIRES, first, ap);
    va_end(ap);
}

static void check_requires(const struct rule *rule)
{
    if (!is_present(rule->opts[0]))
	return;
    if (count_present(rule, 1) < 1) {
	char *err;
	G_asprintf(&err, _("Option %s requires at least one of %s"),
		   get_name(rule->opts[0]), describe_rule(rule, 1, 1));
	append_error(err);
    }
}

/* if the first option is present, all the other options must also
   be present. */
void G_option_requires_all(void *first, ...)
{
    va_list ap;
    va_start(ap, first);
    make_rule(RULE_REQUIRES_ALL, first, ap);
    va_end(ap);
}

static void check_requires_all(const struct rule *rule)
{
    if (!is_present(rule->opts[0]))
	return;
    if (count_present(rule, 1) < rule->count - 1) {
	char *err;
	G_asprintf(&err, _("Option %s requires all of %s"),
		   get_name(rule->opts[0]), describe_rule(rule, 1, 0));
	append_error(err);
    }
}

/* if the first option is present, none of the other options may also
   be present. */
void G_option_excludes(void *first, ...)
{
    va_list ap;
    va_start(ap, first);
    make_rule(RULE_EXCLUDES, first, ap);
    va_end(ap);
}

static void check_excludes(const struct rule *rule)
{
    if (!is_present(rule->opts[0]))
	return;
    if (count_present(rule, 1) > 0) {
	char *err;
	G_asprintf(&err, _("Option %s is mutually exclusive with all of %s"),
		   get_name(rule->opts[0]), describe_rule(rule, 1, 0));
	append_error(err);
    }
}

/* if any option is present, all the other options must also be present
   all or nothing from a set */
void G_option_collective(void *first, ...)
{
    va_list ap;
    va_start(ap, first);
    make_rule(RULE_COLLECTIVE, first, ap);
    va_end(ap);
}

static void check_collective(const struct rule *rule)
{
    int count = count_present(rule, 0);
    if (count > 0 && count < rule->count) {
	char *err;
	G_asprintf(&err, _("Either all or none of %s must be given"),
		   describe_rule(rule, 0, 0));
	append_error(err);
    }
}

void G__check_option_rules(void)
{
    int i;

    for (i = 0; i < rules.count; i++) {
	const struct rule *rule = &((const struct rule *) rules.data)[i];
	switch (rule->type) {
	case RULE_EXCLUSIVE:
	    check_exclusive(rule);
	    break;
	case RULE_REQUIRED:
	    check_required(rule);
	    break;
	case RULE_REQUIRES:
	    check_requires(rule);
	    break;
	case RULE_REQUIRES_ALL:
	    check_requires_all(rule);
	    break;
	case RULE_EXCLUDES:
	    check_excludes(rule);
	    break;
	case RULE_COLLECTIVE:
	    check_collective(rule);
	    break;
	default:
	    G_fatal_error(_("Internal error: invalid rule type: %d"),
			  rule->type);
	    break;
	}
    }
}

void G__describe_option_rules(void)
{
    int i;

    for (i = 0; i < rules.count; i++) {
	const struct rule *rule = &((const struct rule *) rules.data)[i];
	switch (rule->type) {
	case RULE_EXCLUSIVE:
	    fprintf(stderr, "Exclusive: %s", describe_rule(rule, 0, 0));
	    break;
	case RULE_REQUIRED:
	    fprintf(stderr, "Required: %s", describe_rule(rule, 0, 1));
	    break;
	case RULE_REQUIRES:
	    fprintf(stderr, "Requires: %s => %s", get_name(rule->opts[0]),
		    describe_rule(rule, 1, 1));
	    break;
	case RULE_REQUIRES_ALL:
	    fprintf(stderr, "Requires: %s => %s", get_name(rule->opts[0]),
		    describe_rule(rule, 1, 0));
	    break;
	case RULE_EXCLUDES:
	    fprintf(stderr, "Excludes: %s => %s", get_name(rule->opts[0]),
		    describe_rule(rule, 1, 0));
	    break;
	case RULE_COLLECTIVE:
	    fprintf(stderr, "Collective: %s", describe_rule(rule, 0, 0));
	    break;
	default:
	    G_fatal_error(_("Internal error: invalid rule type: %d"),
			  rule->type);
	    break;
	}
    }
}