import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class BonusExercises {

    /*
        complete the method below, so it will validate an email address
        1. Must have exactly one @ (no more, no less)
        2. Split into local-part and domain (before @ and after @)
        3. Local-part rules:
            - Can't be empty
            - Can't start or end with dot
            - Can't have two dots in a row
        4. Domain rules:
            - Can't be empty
            - Can't start or end with hyphen
            - Can't have underscores
            - Each segment (between dots) must follow same hyphen rules
     */
    public boolean validateEmail(String email) {
        String regex = ""; // todo
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(email);

        return matcher.matches();
    }

    /*
        This method should find and return the first date in a string.

        Supported formats:
        - American:   MM/DD/YYYY   (e.g., 12/09/2023)
        - British:    DD/MM/YYYY   (e.g., 12/09/2023 — same pattern, context matters)
        - ISO:        YYYY-MM-DD   (e.g., 2024-07-15)
        - Slash variant: YYYY/MM/DD (e.g., 2025/01/01)

        If no match for a date is found in the string, return null.
    */
    public String findDate(String string) {
        String regex1 = "\\d{4}[-/](0[1-9]|1[0-2])[-/](0[1-9]|[12]\\d|3[01])";
        String regex2 = "(0[1-9]|[12]\\d|3[01])/(0[1-9]|1[0-2])/\\d{4}";

        Pattern pattern1 = Pattern.compile(regex1);
        Pattern pattern2 = Pattern.compile(regex2);
        Matcher matcher1 = pattern1.matcher(string);
        Matcher matcher2 = pattern2.matcher(string);

        if (matcher1.find()) {
            return matcher1.group();
        }

        if (matcher2.find()) {
            return matcher2.group();
        }
        return null;
    }

    /*
        given a string, implement the method to detect all valid passwords
        then, it should return the count of them

        a valid password has the following properties:
        - at least 8 characters
        - has to include at least one uppercase letter, and at least a lowercase
        - at least one number and at least a special char "!@#$%^&*"
        - has no white-space in it
     */
    public int findValidPasswords(String string) {
        int count = 0;
        String[] parts = string.split(" ");

        for (String p : parts) {
            if (p.length() < 8) {
                continue;
            }
            boolean hasUpper = false;
            boolean hasLower = false;
            boolean hasNumber = false;
            boolean hasSpecial = false;
            boolean hasSpace = false;

            for (int i = 0; i < p.length(); i++) {
                char c = p.charAt(i);
                if (Character.isUpperCase(c)) {
                    hasUpper = true;
                }
                else if (Character.isLowerCase(c)) {
                    hasLower = true;
                }
                else if (Character.isDigit(c)) {
                    hasNumber = true;
                }
                else if (Character.isWhitespace(c)) {
                    hasSpace = true;
                }
                else {
                    hasSpecial = true;
                }
            }
            if (!hasSpace && hasUpper && hasLower && hasNumber && hasSpecial) {
                count++;
            }
        }
        return count;
    }

    /*
        you should return a list of *words* which are palindromic
        by word we mean at least 3 letters with no whitespace in it

        note: your implementation should be case-insensitive, e.g. Aba -> is palindrome
     */
    public List<String> findPalindromes(String string) {
        List<String> list = new ArrayList<>();
        String[] words = string.split(" ");

        for (String w : words) {
            String clean = w.replaceAll("[^A-Za-z]", "");
            if (clean.length() >= 3) {
                String lower = clean.toLowerCase() ;
                String reversed = new StringBuilder(lower).reverse().toString();
                if (lower.equals(reversed)) {
                    list.add(clean);
                }
            }
        }
        return list;
    }

    public static void main(String[] args) {
        // you can test your code here
    }
}