// 8.2 Storing UTF-8 Encoded Text with Strings

// "strings" in Rust means String and &str for Owned and Borrowed form respectively.
// They both are UTF-8 encoded

fn main() {
    // Create a new string
    {
        let mut s = String::new(); // create empty string, to load data into it later

        let data = "initial contents";
        let s = data.to_string(); // convert from other type that implement Display trait

        let s = "initial contents".to_string(); // load directly from string literal

        let s = String::from("initial contents"); // use String associate function

        let hello = String::from("สวัสดีครับ");
        println!("{}", hello);
    }

    // Update a string
    {
        let mut s1 = String::from("foo");
        let s2 = "bar";
        s1.push_str(s2); // push_str take a string slice, in this case complier will coerce s2 into &s2[..]
        println!("{}, {}", s1, s2);

        s1.push('!'); // append only one character
        println!("{}", s1);
    }

    // Concatenation with + Operator
    {
        let s1 = String::from("Hello, ");
        let s2 = String::from("World!");
        let s3 = s1 + &s2;  // add operator will deref coerce &String into &str -- &s2 into &s2[..]
                            // so s2 still available here, as add operator does'nt take ownership
                            // but s1 is no longer valid after this, as ownership has moved into s3
    }

    // Concatenation with format! Macro
    {
        let s1 = String::from("tic");
        let s2 = String::from("tac");
        let s3 = String::from("toe");
        let s = format!("{}-{}-{}", s1, s2, s3);    // format! works the same way as println!
                                                    // it also never take ownership of any of its parameters
    }

    // Indexing to Strings
    {
        let s1 = String::from("Hello");
        // let h = s1[0]; <- this statement will get error as indexing on Unicode Char might return unexpedted result

        let len1 = String::from("Hello").len(); // this is just 5 bytes
        let len2 = String::from("สวัสดี").len();  // this is 18 bytes
        println!("len1: {}, len2: {}", len1, len2);

        let hello = "สวัสดี";
        let s = &hello[0..3]; // this is valid as long as range is in the char boundary
        // let s = &hello[0..2] <- this slice has invalid range for first char boundary
        println!("{}", s);
    }

    // Interating over Strings
    {
        // fetching each char out of string
        for c in "สวัสดี".chars() {
            println!("{}", c);
        }

        // fetching each raw byte out of string
        for b in "สวัสดี".bytes() {
            println!("{}", b);
        }
    }

}