package main

import (
	"fmt"
	"unicode/utf8"	
)

func main() {
	// s is a string assigned a literal value representing the
	// word "hello" in the Thai language.
	// Go string literals are UTF-8 encoded text.
	const s = "สวัสดี"
	//Since strings are equivalent to []byte,
	//this will produce the length of the raw bytes stored within
	fmt.Println("len:", len(s))

	// indexing into a string produces the raw byte values at each index.
	// This loop generates the hex values of all the bytes
	// that constitute the code points in s.
	for i := 0; i < len(s); i++ {
		fmt.Printf("%x ", s[i])
	}
	fmt.Println()
	// To count how many runes are in a string,
	// we ca can use the utf8 package. Note that
	// the run-time of RuneCountInString depends on the size of the string
	// due to having to decode each rune sequentially.
	// Some Thai characters are represented by multiple UTF-8 code points,
	// so the result of this count may be suprising.
	fmt.Println("Rune count:",utf8.RuneCountInString(s))
	// A range loop handles strings specially and decodes each rune
	// along with it's offset in the string
	for idx, runeValue := range s {
		fmt.Printf("%#U Starts at %d\n", runeValue, idx)
	}
	//we can achieve the same iteration by using the utf8.DecodeRuneInString function explicitly
	fmt.Println("\nUsing DecodeRuneInString")
	for i,w := 0,0; i < len(s); i += w {
		runeValue, width := utf8.DecodeRuneInString(s[i:])
		fmt.Printf("%#U starts at %d\n", runeValue, i)
		w = width
		// This demonstrates passing a rune to a func
		examineRune(runeValue)
	}
}

// Values enclosed in single quotes are rune literals.
// we can compare a rune value to a rune literal directly.
func examineRune(r rune) {
	if r == 't' {
		fmt.Println("found tee")
	} else if r == 'ส' {
		fmt.Println("found so sua")
	}
}