/* 
 * Copyright (C) 2026 Peter Mikkelsen <petermikkelsen10@gmail.com>
 *
 * This file is part of aplwc.
 *
 * Aplwc 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.
 *
 * Aplwc 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 aplwc.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "aplwc_internal.h"

static int
read_keyword_decl(struct aplwc_module *module, size_t offset)
{
	int len;

	for(len = 1; (offset + len) < module->tokens->length; len++)
		if(module->tokens->tokens[offset+len].tag == TOKEN_TAG_NEWLINE)
			break;
	return len;
}

static int
read_function_decl(struct aplwc_module *module, size_t offset)
{
	int len;

	for(len = 1; (offset + len) < module->tokens->length; len++)
		if(module->tokens->tokens[offset+len].tag == TOKEN_TAG_DEL)
			break;
	return len;
}

static int
read_decl(struct aplwc_module *module, size_t offset)
{
	switch(module->tokens->tokens[offset].tag){
	case TOKEN_TAG_NEWLINE:
		return 0;
	case TOKEN_TAG_KEYWORD:
		return read_keyword_decl(module, offset);
	case TOKEN_TAG_DEL:
		return read_function_decl(module, offset);
	default:
		return -1;
	}
}

static enum aplwc_rc
read_decls(struct aplwc_module *module)
{
	size_t offset;
	int skip;

	for(offset = 0; offset < module->tokens->length; offset++){
		skip = read_decl(module, offset);
		if(skip == -1)
			return APLWC_INVALID_SYNTAX;
		offset += skip;
	}
	return APLWC_OK;
}

enum aplwc_rc
load_module(struct aplwc *aplwc, struct string *name, struct token_list *tokens)
{
	enum aplwc_rc rc;
	struct aplwc_module *module;

	MEMPTRS(aplwc, 2);

	MEMPTR(0, name);
	MEMPTR(1, tokens);

	module = memory_alloc_aplwc_module(aplwc);
	if(module == NULL){
		rc = aplwc_last_error(aplwc);
		goto end;
	}

	module->name = name;
	module->tokens = tokens;
	module->link = NULL;

	rc = read_decls(module);
	if(rc == APLWC_OK){
		module->link = aplwc->modules;
		aplwc->modules = module;
	}else
		aplwc->last_error = rc;

end:
	MEMPTRS_EXIT(aplwc);
	return rc;
}

struct aplwc_module *
module_lookup(struct aplwc *aplwc, struct string *name)
{
	struct aplwc_module *m;

	for(m = aplwc->modules; m; m = m->link){
		if(string_compare(m->name, name) == 0)
			break;
	}
	return m;
}