#ifndef LEXER_H
#define LEXER_H

#include <stdbool.h>
#include <stdlib.h>

typedef enum {
    TokenTypeInvalid,
    TokenTypeEof,
    TokenTypePlus,
    TokenTypeLParen,
    TokenTypeRParen,
    TokenTypeInt,
    TokenTypeId,
} TokenType;

const char* token_type_to_string(TokenType type);

typedef struct {
    TokenType type;
    size_t index, length;
    int line, column;
} Token;

void token_to_string(char* out, size_t out_size, Token token);

typedef struct {
    size_t index;
    int line, column;
} LexerPosition;

typedef struct {
    const char* text;
    size_t length;
    LexerPosition position;
} Lexer;

void lexer_construct(Lexer* self, const char* text, size_t length);
Token lexer_next(Lexer* self);

bool lexer_done(const Lexer* self);
void lexer_step(Lexer* self);
char lexer_current(const Lexer* self);
LexerPosition lexer_position(const Lexer* self);
Token lexer_token_from(const Lexer* self, TokenType type, LexerPosition start);
void lexer_skip_whitespace(Lexer* self);
Token lexer_make_int_token(Lexer* self);
Token lexer_make_id_token(Lexer* self);
Token lexer_make_single_char_token(Lexer* self, TokenType type);
Token lexer_make_static_token(Lexer* self);
Token lexer_make_token(Lexer* self);

typedef struct {
    Lexer* lexer;
    Token current;
} TokenIterator;

void token_iterator(TokenIterator* self, Lexer* lexer);
Token token_step(TokenIterator* self);
Token token_current(TokenIterator* self);

bool is_whitespace_char(char c);
bool is_int_char(char c);
bool is_id_char(char c);

#endif