//
// Copyright (c) 2020-2022 science+computing ag and other contributors
//
// This program and the accompanying materials are made
// available under the terms of the Eclipse Public License 2.0
// which is available at https://www.eclipse.org/legal/epl-2.0/
//
// SPDX-License-Identifier: EPL-2.0
//

use pom::parser::Parser as PomParser;
use pom::parser::*;

pub fn numbers<'a>() -> PomParser<'a, u8, Vec<u8>> {
    one_of(b"0123456789").repeat(1..)
}

pub fn letters<'a>() -> PomParser<'a, u8, Vec<u8>> {
    pom::parser::is_a(pom::char_class::alpha).repeat(1..)
}

pub fn dash<'a>() -> PomParser<'a, u8, Vec<u8>> {
    sym(b'-').map(|b| vec![b])
}

pub fn under<'a>() -> PomParser<'a, u8, Vec<u8>> {
    sym(b'_').map(|b| vec![b])
}

pub fn dot<'a>() -> PomParser<'a, u8, Vec<u8>> {
    sym(b'.').map(|b| vec![b])
}

pub fn equal<'a>() -> PomParser<'a, u8, Vec<u8>> {
    sym(b'=').map(|b| vec![b])
}

pub fn nonempty_string_with_optional_quotes<'a>() -> Parser<'a, u8, String> {
    let special_char = || {
        sym(b'\\')
            | sym(b'/')
            | sym(b'"')
            | sym(b'b').map(|_| b'\x08')
            | sym(b'f').map(|_| b'\x0C')
            | sym(b'n').map(|_| b'\n')
            | sym(b'r').map(|_| b'\r')
            | sym(b't').map(|_| b'\t')
    };
    let escape_sequence = || sym(b'\\') * special_char();

    let inner_string = || (none_of(b"\\\"") | escape_sequence()).repeat(1..);

    let string = (sym(b'"') * inner_string() - sym(b'"')) | inner_string();
    string.convert(String::from_utf8)
}