/* 
 * 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/>.
 */

#ifndef APLWC_INTERNAL_H
#define APLWC_INTERNAL_H

#include <aplwc.h>
#include <aplwc_macros.h>
#include <assert.h>
#include <stdalign.h>
#include <stdbool.h>
#include <string.h>

typedef int symbol_t;

enum keyword {
	KW_MODULE,
	KW_SYMBOL,
	KW_EXPORT
};

#define N_KWDS KW_EXPORT+1

struct aplwc {
	struct aplwc_fns fns;
	enum aplwc_rc last_error;
	struct aplwc_module *modules;
	struct symbol *symtab;
	symbol_t keyword_symbols[N_KWDS];

	/* Memory management */
	uint8_t *data;
	uint8_t *unaligned_data;
	size_t size;
	struct memory_ptr_frame *memptrs;
	struct aplwc_ref *refs;
	unsigned int reachable_bit:1;
};

struct memory_ptr_frame {
	struct memory_ptr_frame *link;
	void ***ptrs;
	size_t count;
};

struct aplwc_line {
	struct string *text;
	struct token_list *tokens;
};

struct string {
	size_t bytes;
	size_t chars;
	uint8_t utf8[FLEXIBLE_ARRAY_MEMBER];
};

enum token_tag {
	TOKEN_TAG_IDENTIFIER,
	TOKEN_TAG_NEWLINE,
	TOKEN_TAG_NUMBER,
	TOKEN_TAG_LEFT_ARROW,
	TOKEN_TAG_DIAMOND,
	TOKEN_TAG_KEYWORD,
	TOKEN_TAG_TEXT,
	TOKEN_TAG_DEL,
	TOKEN_TAG_LEFT_PAREN,
	TOKEN_TAG_RIGHT_PAREN,
	TOKEN_TAG_IBEAM,
	TOKEN_TAG_QUAD,
	TOKEN_TAG_UNKNOWN_SYM,
	TOKEN_TAG_COMMENT
};

struct token {
	enum token_tag tag;
	size_t start;
	size_t end;
	union {
		symbol_t symbol;
		enum keyword keyword;
	} data;
};

struct token_list {
	struct string *text;
	size_t length;
	struct token tokens[FLEXIBLE_ARRAY_MEMBER];
};

enum value_tag {
	VALUE_NULL,
	VALUE_NUMBER
};

struct aplwc_value {
	enum value_tag tag;
};

struct aplwc_module {
	struct string *name;
	struct token_list *tokens;
	struct module_member *imports;
	struct module_member *members;
	struct aplwc_module *link;
};

struct module_member {
	int exported;
	struct aplwc_module *module;
	symbol_t name;
	struct module_member *real_member; /* a symbol points to its identifier member. An imported symbol points to the defining member */
	struct module_member *link;
};

struct symbol {
	symbol_t id;
	struct string *text;
	struct symbol *link;
};

/* eval.c */
struct aplwc_value *eval_line(struct aplwc *, struct aplwc_line *);

/* memory.c */
void memory_init(struct aplwc *);
void memory_destroy(struct aplwc *);
struct aplwc_line *memory_alloc_aplwc_line(struct aplwc *);
struct string *memory_alloc_string(struct aplwc *, size_t);
struct token_list *memory_alloc_token_list(struct aplwc *, size_t);
struct aplwc_value *memory_alloc_aplwc_value(struct aplwc *);
struct aplwc_module *memory_alloc_aplwc_module(struct aplwc *);
struct module_member *memory_alloc_module_member(struct aplwc *);
struct symbol *memory_alloc_symbol(struct aplwc *);
void memory_root_new(struct aplwc *, void *, struct aplwc_ref *);
void *memory_root_get(struct aplwc_ref *);
void memory_root_free(struct aplwc_ref *);
void memptrs_add(struct aplwc *, struct memory_ptr_frame *, void ***, size_t);
void memptrs_remove(struct aplwc *, struct memory_ptr_frame *);
void clear_ref(struct aplwc_ref *);
int valid_ref(struct aplwc_ref *);

#define MEMPTRS(aplwc, n) \
	void **memptrs[n]; \
	struct memory_ptr_frame memptrs_frame; \
	memptrs_add(aplwc, &memptrs_frame, memptrs, n);
#define MEMPTR(n, ptr) memptrs[n] = (void **)&ptr
#define MEMPTRS_EXIT(aplwc) memptrs_remove(aplwc, &memptrs_frame)

/* string.c */
struct string *chars_to_string(struct aplwc *, const char *, int len);
uint32_t string_char(struct string *, size_t);
size_t char_length(struct string *, size_t);
int string_compare(struct string *, struct string *);
struct string *substring(struct aplwc *, struct string *, size_t, size_t);

/* syntax.c */
struct token_list *scan_string(struct aplwc *, struct string *, int);
enum aplwc_rc check_tokens(struct aplwc_module *, struct token_list *);
enum aplwc_rc keyword_init(struct aplwc *);

/* symtab.c */
enum aplwc_rc getsym(struct aplwc *, struct string *, symbol_t *);

/* module.c */
enum aplwc_rc load_module(struct aplwc *, struct string *, struct token_list *);

/* unicode.c */
int is_id_start(uint32_t);
int is_id_continue(uint32_t);
int is_pattern_syntax(uint32_t);

#endif /* APLWC_INTERNAL_H */