/*
 *  Render C declarations.
 *  Copyright © 2011, 2021, 2023 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 <inttypes.h>
#include <assert.h>

#include "cdecl.h"
#include "cdecl-internal.h"

static void
declare_declarator(struct output_state *dst, struct cdecl_declarator *d);

static void declare_decl(struct output_state *dst, struct cdecl *decl)
{
	cdecl__emit_specs(dst, decl->specifiers, -1);
	if (decl->declarators->type != CDECL_DECL_NULL)
		cdecl__emit(dst, " ");

	declare_declarator(dst, decl->declarators);
}

static void
declare_postfix_child(struct output_state *dst, struct cdecl_declarator *d)
{
	if (d->type == CDECL_DECL_POINTER)
		cdecl__emit(dst, "(");

	declare_declarator(dst, d);

	if (d->type == CDECL_DECL_POINTER)
		cdecl__emit(dst, ")");
}

static void declare_pointer(struct output_state *dst, struct cdecl_pointer *p)
{
	struct cdecl_declspec *q = p->qualifiers;

	if (q) {
		cdecl__emit(dst, "* ");
		cdecl__emit_specs(dst, q, -1);
		cdecl__emit(dst, " ");
	} else {
		cdecl__emit(dst, "*");
	}
}

static void declare_array(struct output_state *dst, struct cdecl_array *a)
{
	cdecl__emit(dst, "[");

	if (a->vla) {
		const char *s = a->vla[0] ? a->vla : "*";
		cdecl__emit(dst, s);
	} else {
		size_t rc = snprintf(dst->dst, dst->dstlen, "%.0" PRIuMAX, a->length);
		cdecl__advance(dst, rc);
	}

	cdecl__emit(dst, "]");
}

static void
declare_function(struct output_state *dst, struct cdecl_function *f)
{
	struct cdecl *p;

	cdecl__emit(dst, "(");

	for (p = f->parameters; p; p = p->next) {
		declare_decl(dst, p);

		if (p->next)
			cdecl__emit(dst, ", ");
		else if (f->variadic)
			cdecl__emit(dst, ", ...");
	}

	cdecl__emit(dst, ")");
}

static void
declare_declarator(struct output_state *dst, struct cdecl_declarator *d)
{
	for (; d; d = d->child) {
		switch (d->type) {
		case CDECL_DECL_NULL:
			break;
		case CDECL_DECL_IDENT:
			cdecl__emit(dst, d->u.ident);
			break;
		case CDECL_DECL_POINTER:
			declare_pointer(dst, &d->u.pointer);
			break;
		/*
		 * Arrays and functions are special: since they are postfix,
		 * we need to render the children before rendering their
		 * "bodies".
		 */
		case CDECL_DECL_ARRAY:
			declare_postfix_child(dst, d->child);
			declare_array(dst, &d->u.array);
			return;
		case CDECL_DECL_FUNCTION:
			declare_postfix_child(dst, d->child);
			declare_function(dst, &d->u.function);
			return;
		default:
			assert(0);
		}
	}
}

size_t cdecl_declare(char *buf, size_t n, struct cdecl *decl)
{
	struct output_state dst = { buf, n };

	declare_decl(&dst, decl);

	return dst.accum;
}