module regex

import strings

// compile_opt compile RE pattern string
pub fn (mut re RE) compile_opt(pattern string) ! {
    re_err, err_pos := re.impl_compile(pattern)

    if re_err != compile_ok {
        mut err_msg := strings.new_builder(300)
        err_msg.write_string('\nquery: ${pattern}\n')
        line := '-'.repeat(err_pos)
        err_msg.write_string('err  : ${line}^\n')
        err_str := re.get_parse_error_string(re_err)
        err_msg.write_string('ERROR: ${err_str}\n')
        return error_with_code(err_msg.str(), re_err)
    }
}

// new_regex create a RE of small size, usually sufficient for ordinary use
pub fn new() RE {
    // init regex
    mut re := RE{}
    re.prog = []Token{len: max_code_len + 1} // max program length, can not be longer then the pattern
    re.cc = []CharClass{len: max_code_len} // can not be more char class the the length of the pattern
    re.group_csave_flag = false // enable continuos group saving
    re.group_max_nested = 128 // set max 128 group nested
    re.group_max = max_code_len >> 1 // we can't have more groups than the half of the pattern legth

    re.group_stack = []int{len: re.group_max, init: -1}
    re.group_data = []int{len: re.group_max, init: -1}

    return re
}

// regex_opt create new RE object from RE pattern string
pub fn regex_opt(pattern string) !RE {
    // init regex
    mut re := RE{}
    re.prog = []Token{len: pattern.len + 1} // max program length, can not be longer then the pattern
    re.cc = []CharClass{len: pattern.len} // can not be more char class the the length of the pattern
    re.group_csave_flag = false // enable continuos group saving
    re.group_max_nested = pattern.len >> 1 // set max 128 group nested
    re.group_max = pattern.len >> 1 // we can't have more groups than the half of the pattern legth

    re.group_stack = []int{len: re.group_max, init: -1}
    re.group_data = []int{len: re.group_max, init: -1}

    // compile the pattern
    re.compile_opt(pattern)!

    return re
}