#ifndef BDL_LEXER_H
#define BDL_LEXER_H

#include "string_view.h"

typedef enum TokenType {
    TOKEN_UNKNOWN = 0,

    // Parentheses.
    TOKEN_LPAREN,
    TOKEN_RPAREN,

    // Primitive types.
    TOKEN_FIXNUM,
    TOKEN_SYMBOL,
    TOKEN_STRING,

    // Keywords.
    TOKEN_NIL,
    TOKEN_QUOTE,
    TOKEN_TRUE,
    TOKEN_FALSE,
    TOKEN_IF,
    TOKEN_ELSE,
    TOKEN_DEF,
    TOKEN_SET,
    TOKEN_FUN,
    TOKEN_LAMBDA,
    TOKEN_DISPLAY,
    TOKEN_PRINT,
    TOKEN_NEWLINE,

    // Arithmetic.
    TOKEN_ADD,
    TOKEN_SUB,
    TOKEN_MUL,
    TOKEN_DIV,
    TOKEN_MOD,

    // Boolean comparisons.
    TOKEN_NOT,
    TOKEN_AND,
    TOKEN_OR,
    TOKEN_EQUAL,
    TOKEN_LESS,
    TOKEN_GREATER,
    TOKEN_LESS_EQUAL,
    TOKEN_GREATER_EQUAL,

    TOKEN_EOF,
} TokenType;

typedef struct Token {
    TokenType type;
    StringView value;
    size_t line;
    size_t column;
} Token;

typedef struct Scanner {
    StringView current;
    size_t line_number;
    size_t col_number;
    size_t offset;
} Scanner;

// Print a token to standard output for debugging purposes.
void print_token(Token tok);

// Same functionality as the ScanView pairs, but keeping track of line and
// column numbers.
char scan_next(Scanner *scanner);
char scan_peek(const Scanner *scanner);

// Check if the current scanner still have characters left.
bool scan_has_next(const Scanner *scanner);

// Advance the scanner until we ran out of whitespace.
void skip_whitespace(Scanner *scanner);

// Check if a given character is a delimiter.
bool is_delimiter(char c);

// Extract the token type from the current string.
TokenType find_primitive_type(const StringView value);

// Generate a list of tokens from the given string.
Token * tokenize(const StringView *sv);

#define TOK_BUF_CAP 256

#endif // BDL_LEXER_H