/*
 *  Render C declarations.
 *  Copyright © 2011 Nick Bowler
 *
 *  This program 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
 *  (at your option) any later version.
 *
 *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <config.h>
#include <stdio.h>
#include <stdbool.h>
#include <assert.h>

#include "cdecl.h"
#include "output.h"

static size_t declare_specs(char *buf, size_t n, struct cdecl_declspec *s)
{
	size_t ret = 0, rc;

	if (!s)
		return 0;

	rc = cdecl__explain_pre_specs(buf, n, s);
	ret += cdecl__advance(&buf, &n, rc);

	rc = cdecl__explain_post_specs(buf, n, s);
	return ret + rc;
}

static size_t
declare_declarator(char *buf, size_t n, struct cdecl_declarator *d);

static size_t declare_decl(char *buf, size_t n, struct cdecl *decl)
{
	size_t ret = 0, rc;

	rc = declare_specs(buf, n, decl->specifiers);
	if (decl->declarators->type != CDECL_DECL_NULL)
		ret += cdecl__advance(&buf, &n, rc);
	else
		ret += cdecl__advance_(&buf, &n, rc);

	return ret + declare_declarator(buf, n, decl->declarators);
}

static size_t
declare_postfix_child(char *buf, size_t n, struct cdecl_declarator *d)
{
	size_t ret = 0, rc;

	if (d->type == CDECL_DECL_POINTER) {
		rc = snprintf(buf, n, "(");
		ret += cdecl__advance_(&buf, &n, rc);
	}

	rc = declare_declarator(buf, n, d);
	ret += cdecl__advance_(&buf, &n, rc);

	if (d->type == CDECL_DECL_POINTER) {
		rc = snprintf(buf, n, ")");
		ret += cdecl__advance_(&buf, &n, rc);
	}

	return ret;
}

static size_t declare_pointer(char *buf, size_t n, struct cdecl_pointer *p)
{
	size_t ret = 0, rc;

	rc = snprintf(buf, n, "*");
	if (p->qualifiers)
		ret += cdecl__advance(&buf, &n, rc);
	else
		ret += cdecl__advance_(&buf, &n, rc);

	rc = cdecl__explain_specs(buf, n, p->qualifiers, CDECL_SPEC_QUAL);
	return ret + rc;
}

static bool pointer_needs_space(struct cdecl_declarator *d)
{
	assert(d->type == CDECL_DECL_POINTER);

	if (d->u.pointer.qualifiers)
		return d->child->type != CDECL_DECL_NULL;

	return false;
}

static size_t declare_array(char *buf, size_t n, struct cdecl_array *a)
{
	size_t ret = 0, rc;

	rc = snprintf(buf, n, "[");
	ret += cdecl__advance_(&buf, &n, rc);

	if (a->vla)
		rc = snprintf(buf, n, "%s", a->vla[0] ? a->vla : "*");
	else
		rc = snprintf(buf, n, "%.0ju", a->length);
	ret += cdecl__advance_(&buf, &n, rc);

	return ret + snprintf(buf, n, "]");
}

static size_t declare_function(char *buf, size_t n, struct cdecl_function *f)
{
	size_t ret = 0, rc;

	rc = snprintf(buf, n, "(");
	ret += cdecl__advance_(&buf, &n, rc);

	for (struct cdecl *p = f->parameters; p; p = p->next) {
		rc = declare_decl(buf, n, p);
		ret += cdecl__advance_(&buf, &n, rc);

		rc = 0;
		if (p->next)
			rc = snprintf(buf, n, ", ");
		else if (f->variadic)
			rc = snprintf(buf, n, ", ...");
		ret += cdecl__advance_(&buf, &n, rc);
	}

	return ret + snprintf(buf, n, ")");
}

static size_t
declare_declarator(char *buf, size_t n, struct cdecl_declarator *d)
{
	size_t ret = 0, rc;

	for (; d; d = d->child) {
		switch (d->type) {
		case CDECL_DECL_NULL:
			break;
		case CDECL_DECL_IDENT:
			rc = snprintf(buf, n, "%s", d->u.ident);
			ret += cdecl__advance_(&buf, &n, rc);
			break;
		case CDECL_DECL_POINTER:
			rc = declare_pointer(buf, n, &d->u.pointer);
			if (pointer_needs_space(d))
				ret += cdecl__advance(&buf, &n, rc);
			else
				ret += cdecl__advance_(&buf, &n, rc);
			break;
		/*
		 * Arrays and functions are special: since they are postfix,
		 * we need to render the children before rendering their
		 * "bodies".
		 */
		case CDECL_DECL_ARRAY:
			rc = declare_postfix_child(buf, n, d->child);
			ret += cdecl__advance_(&buf, &n, rc);
			return ret + declare_array(buf, n, &d->u.array);
		case CDECL_DECL_FUNCTION:
			rc = declare_postfix_child(buf, n, d->child);
			ret += cdecl__advance_(&buf, &n, rc);
			return ret + declare_function(buf, n, &d->u.function);
		default:
			assert(0);
		}
	}

	return ret;
}

size_t cdecl_declare(char *buf, size_t n, struct cdecl *decl)
{
	return declare_decl(buf, n, decl);
}