const std = @import("std");

pub const TokenType = enum {
    // Single-character tokens.
    LEFT_PAREN,
    RIGHT_PAREN,
    LEFT_BRACE,
    RIGHT_BRACE,
    COMMA,
    DOT,
    MINUS,
    PLUS,
    SEMICOLON,
    SLASH,
    STAR,

    // One or two character tokens.
    BANG,
    BANG_EQUAL,
    EQUAL,
    EQUAL_EQUAL,
    GREATER,
    GREATER_EQUAL,
    LESS,
    LESS_EQUAL,

    // Literals.
    IDENTIFIER,
    STRING,
    NUMBER,

    // Keywords.
    AND,
    CLASS,
    ELSE,
    FALSE,
    FUN,
    FOR,
    IF,
    NIL,
    OR,
    PRINT,
    RETURN,
    SUPER,
    THIS,
    TRUE,
    VAR,
    WHILE,

    EOF,
};

pub fn TokenFactory(
    comptime T: type,
) type {
    return struct {
        const Self = @This();

        ttype: TokenType,
        lexeme: []u8,
        line: usize,
        literal: T,

        pub fn init(
            ttype: TokenType,
            lexeme: []u8,
            line: usize,
            literal: T,
        ) Self {
            return Self{
                .ttype = ttype,
                .lexeme = lexeme,
                .line = line,
                .literal = literal,
            };
        }

        pub fn printToken(self: Self, stdout: var) !void {
            if (T == void) {
                try stdout.print(
                    "Token(type={x}, lexeme='{}', line={})\n",
                    self.ttype,
                    self.lexeme,
                    self.line,
                );
            } else {
                try stdout.print(
                    "Token(type={x}, lexeme='{}', line={} literal='{}')\n",
                    self.ttype,
                    self.lexeme,
                    self.line,
                    self.literal,
                );
            }
        }
    };
}

pub const SimpleToken = TokenFactory(void);
pub const SliceToken = TokenFactory([]u8);

pub const Token = union(enum) {
    Simple: SimpleToken,
    Slice: SliceToken,
};