vyre 0.4.0

use super::{Token, OP_ANY, OP_LITERAL, OP_MATCH, OP_STAR_ANY, OP_STAR_LITERAL};
use crate::ops::string_matching::search_contract::MatchError;

pub fn parse_program(program: &[u8]) -> Result<Vec<Token>, MatchError> {
    let mut tokens = Vec::new();
    let mut index = 0usize;
    while index < program.len() {
        match program[index] {
            OP_LITERAL => {
                let byte = *program.get(index + 1).ok_or_else(|| {
                    "Fix: literal opcode 1 must be followed by one byte".to_string()
                })?;
                tokens.push(Token::Literal(byte));
                index += 2;
            }
            OP_ANY => {
                tokens.push(Token::Any);
                index += 1;
            }
            OP_STAR_LITERAL => {
                let byte = *program.get(index + 1).ok_or_else(|| {
                    "Fix: star-literal opcode 3 must be followed by one byte".to_string()
                })?;
                tokens.push(Token::StarLiteral(byte));
                index += 2;
            }
            OP_STAR_ANY => {
                tokens.push(Token::StarAny);
                index += 1;
            }
            OP_MATCH => return Ok(tokens),
            opcode => {
                return Err(format!(
                    "Fix: replace unsupported NFA opcode {opcode} at byte offset {index}"
                ));
            }
        }
    }
    Err("Fix: terminate nfa_program with accept opcode 255".to_string())
}