/* Copyright (c) 2024 Freya Murphy */

#ifndef __PARSE_H__
#define __PARSE_H__

#include "lex.h"

#include <mlimits.h>
#include <mips.h>
#include <stdint.h>

struct const_expr {
	char name[MAX_LEX_LENGTH];
	uint32_t value;
};

enum expr_type {
	EXPR_INS,
	EXPR_DIRECTIVE,
	EXPR_CONSTANT,
	EXPR_LABEL,
};

struct expr {
	enum expr_type type;
	union {
		// instruction
		union mips_instruction ins;
		// directive
		union mips_directive directive;
		// constant
		struct const_expr constant;
		// segment or label
		char text[MAX_LEX_LENGTH];
	};
};

enum section_entry_type {
	ENT_INS,
	ENT_WORD,
	ENT_HALF,
	ENT_BYTE,
	ENT_NO_DATA,
};

struct section_entry {
	enum section_entry_type type;
	size_t size;

	union {
		char data; // to get memory address
		union mips_instruction ins;
		int32_t word;
		int16_t half;
		int8_t byte;
	};
};

struct section {
	uint32_t count;
	uint32_t len;
	uint32_t alignment;
	uint32_t index; // what index is my section
	char name[MAX_LEX_LENGTH];
	bool read;
	bool write;
	bool execute;
	struct section_entry *entries;
};

struct section_table {
	uint32_t count;
	uint32_t len;
	struct section *sections;
	struct section *current;
	char name[MAX_LEX_LENGTH];
};

int sectbl_init(struct section_table *sec_tbl);
void sectbl_free(struct section_table *sec_tbl);

int sectbl_alloc(struct section_table *sec_tbl, struct section **sec,
		 const char name[MAX_LEX_LENGTH]);
int sectbl_get(struct section_table *sec_tbl, struct section **sec,
	       const char name[MAX_LEX_LENGTH]);
int sec_push(struct section *section, struct section_entry entry);
size_t sec_size(struct section *section);
size_t sec_index(struct section *section, uint32_t index);

enum reference_type {
	REF_OFFESET,
	REF_TARGET,
};

struct reference {
	enum reference_type type;
	struct section *section;
	uint32_t index;
	char name[MAX_LEX_LENGTH];
};

struct reference_table {
	uint32_t count;
	uint32_t len;
	struct reference *references;
};

int reftbl_init(struct reference_table *ref_tbl);
void reftbl_free(struct reference_table *ref_tbl);
int reftbl_push(struct reference_table *ref_tbl, struct reference reference);

struct parser {
	struct lexer *lexer;
	struct token peek;

	// sections
	struct section_table sec_tbl;

	// references
	struct reference_table ref_tbl;

	int (*parse_instruction)(struct parser *, union mips_instruction *,
			  struct token);
	int (*parse_directive)(struct parser *, union mips_directive *);
	int (*is_instruction)(const char *ident);
};

/* get the next token in the parser */
int next_token(struct parser *parser, struct token *tok);

/* peek the next token in the parser */
int peek_token(struct parser *parser, struct token *tok);

/* assert the next token is a specific type */
int assert_token(struct parser *parser, enum token_type type,
		 struct token *tok);

/* assert the next token is EOF or NL */
int assert_eol(struct parser *parser);

/* get the next expression in the parser */
int parser_next(struct parser *parser, struct expr *expr);

/* initalize the base parser */
int parser_init(struct lexer *lexer, struct parser *parser);

/* free the base parser */
void parser_free(struct parser *parser);

#endif /* __PARSE_H__ */