// SPDX-License-Identifier: Unlicense

package bytes

import (
	"git.codemonkeysoftware.net/b/gigaparsec"
)

// Token wraps a parser to discard all whitespace after the parsed input.
// whitespace is a parser that will consume non-empty whitespace.
func Token[Out any](whitespace gigaparsec.Parser[byte, struct{}]) func(p gigaparsec.Parser[byte, Out]) gigaparsec.Parser[byte, Out] {
	mappedWS := gigaparsec.Map(whitespace, func(struct{}) struct{} { return struct{}{} })
	var ignoreWS gigaparsec.Parser[byte, struct{}] = func(s gigaparsec.State[byte]) (gigaparsec.Result[byte, struct{}], error) {
		result, err := mappedWS(s)
		return result.Consume(false), err
	}
	return func(p gigaparsec.Parser[byte, Out]) gigaparsec.Parser[byte, Out] {
		return gigaparsec.Seq(p, gigaparsec.Repeat(0, ignoreWS), func(val Out, _ []struct{}) Out { return val })
	}
}

func isWhitespaceASCII(b byte) bool {
	return b == ' ' || (b >= '\t' && b <= '\r')
}

// WhitespaceASCII consumes one ASCII whitespace character: space, tab, LF, CR, vertical tab, or form feed.
func WhitespaceASCII() gigaparsec.Parser[byte, struct{}] {
	return gigaparsec.Map(gigaparsec.Satisfy(isWhitespaceASCII), func(byte) struct{} { return struct{}{} })
}