package ntime

import "git.noahlan.cn/noahlan/ntool/nstr/ac"

var matches = []string{
	"ddd", "dd", "d",
	"HH", "hh", "h", // HH:0-23 hh:0-12
	"mm", "m",
	"ss", "s",
	"yyyy", "yy", "y",
	"SSS",
	"a", "aa",
	"MMMM", "MMM", "MM", "M",
	"ZZ", "Z", "zz:zz", "zzzz", "z",
	"EEEE", "E",
}

var replaceWith = []string{
	"_2", "02", "2",
	"15", "03", "3",
	"04", "4",
	"05", "5",
	"2006", "06", "06",
	"000",
	"pm", "PM",
	"January", "Jan", "01", "1",
	"-0700", "-07", "Z07:00", "Z0700", "MST",
	"Monday", "Mon",
}

// ToLayout converts java date format,
// https://docs.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html#rfc822timezone into go date layout
func ToLayout(dateFormat string) string {
	acBuilder := ac.NewAhoCorasickBuilder(ac.Opts{
		AsciiCaseInsensitive: false, // 大小写敏感
		MatchOnlyWholeWords:  false,
		MatchKind:            ac.LeftMostLongestMatch, // 最左最长匹配
		DFA:                  true,
	})
	aho := acBuilder.Build(matches)
	replacer := ac.NewReplacer(aho)
	return replacer.ReplaceAll(dateFormat, replaceWith)
}