// In this example, a parser is created which can parse and normalize Dutch postcodes.
package parsekit_test

import (
	"fmt"

	"git.makaay.nl/mauricem/go-parsekit"
)

func createPostcodeMatcher() *parsekit.MatcherWrapper {
	// Easy access to the parsekit definitions.
	var c, a, m = parsekit.C, parsekit.A, parsekit.M

	// Matcher functions are created and combined to satisfy these rules:
	// - A Dutch postcode consists of 4 digits and 2 letters (1234XX).
	// - The first digit is never a zero.
	// - A space between letters and digits is optional.
	// - It is good form to write the letters in upper case.
	// - It is good form to use a single space between digits and letters.
	var digitNotZero = c.Except(c.Rune('0'), a.Digit)
	var pcDigits = c.Seq(digitNotZero, c.Rep(3, a.Digit))
	var pcLetter = c.Any(a.ASCIILower, a.ASCIIUpper)
	var pcLetters = m.ToUpper(c.Seq(pcLetter, pcLetter))
	var space = m.Replace(c.Opt(a.Whitespace), " ")
	var postcode = c.Seq(pcDigits, space, pcLetters)

	return parsekit.NewMatcher(postcode, "a Dutch postcode")
}

func Example_dutchPostcodeUsingMatcher() {
	pcParser := createPostcodeMatcher()

	for i, input := range []string{
		"1234  AB",
		"2233Ab",
		"1001\t\tab",
		"1818ab",
		"1234",
		"huh",
	} {
		output, err, ok := pcParser.Parse(input)
		if !ok {
			fmt.Printf("[%d] Input: %q Error: %s\n", i, input, err)
		} else {
			fmt.Printf("[%d] Input: %q Output: %s\n", i, input, output)
		}
	}
	// Output:
	// [0] Input: "1234  AB" Output: 1234 AB
	// [1] Input: "2233Ab" Output: 2233 AB
	// [2] Input: "1001\t\tab" Output: 1001 AB
	// [3] Input: "1818ab" Output: 1818 AB
	// [4] Input: "1234" Error: unexpected character '1' (expected a Dutch postcode)
	// [5] Input: "huh" Error: unexpected character 'h' (expected a Dutch postcode)
}