Form Handling

public class HtmlForm extends HtmlElement {
    /**
     * Submit the form using the default submit method
     * @return the Page that loads as a result of form submission
     * @throws IOException if submission fails
     */
    public <P extends Page> P submit() throws IOException;
    
    /**
     * Submit the form using a specific submit element
     * @param submitElement the button or input element to use for submission
     * @return the Page that loads as a result of form submission  
     * @throws IOException if submission fails
     */
    public <P extends Page> P submit(SubmittableElement submitElement) throws IOException;
    
    /**
     * Get a form input element by its name attribute
     * @param name the name attribute value
     * @return HtmlElement with matching name, or null if not found
     */
    public HtmlElement getInputByName(String name);
    
    /**
     * Get all form input elements with the specified name
     * @param name the name attribute value
     * @return List of HtmlElement objects with matching names
     */
    public List<HtmlElement> getInputsByName(String name);
    
    /**
     * Get a form input element by its value attribute
     * @param value the value attribute to search for
     * @return HtmlElement with matching value, or null if not found
     */
    public HtmlElement getInputByValue(String value);
    
    /**
     * Get a textarea element by its name attribute
     * @param name the name attribute value
     * @return HtmlTextArea with matching name, or null if not found
     */
    public HtmlTextArea getTextAreaByName(String name);
    
    /**
     * Get a select element by its name attribute
     * @param name the name attribute value
     * @return HtmlSelect with matching name, or null if not found
     */
    public HtmlSelect getSelectByName(String name);
    
    /**
     * Get a button element by its name attribute
     * @param name the name attribute value
     * @return HtmlButton with matching name, or null if not found
     */
    public HtmlButton getButtonByName(String name);
    
    /**
     * Get the form's method attribute (GET or POST)
     * @return the HTTP method for form submission
     */
    public String getMethodAttribute();
    
    /**
     * Get the form's action attribute (submission URL)
     * @return the URL where the form will be submitted
     */
    public String getActionAttribute();
    
    /**
     * Get the form's encoding type attribute
     * @return the encoding type (e.g., "application/x-www-form-urlencoded")
     */
    public String getEnctypeAttribute();
}

HtmlPage page = webClient.getPage("https://example.com/login");
HtmlForm loginForm = page.getFormByName("loginForm");

// Get form information
String method = loginForm.getMethodAttribute(); // "POST"
String action = loginForm.getActionAttribute();  // "/authenticate"

// Find form elements
HtmlTextInput username = (HtmlTextInput) loginForm.getInputByName("username");
HtmlPasswordInput password = (HtmlPasswordInput) loginForm.getInputByName("password");
HtmlSubmitInput submitBtn = (HtmlSubmitInput) loginForm.getInputByValue("Log In");

// Fill and submit form
username.setValue("myuser");
password.setValue("mypass");
HtmlPage result = loginForm.submit(submitBtn);

// Or submit without specific button
HtmlPage result2 = loginForm.submit();

public abstract class HtmlInput extends HtmlElement {
    /**
     * Get the input's current value
     * @return the current value of the input
     */
    public String getValue();
    
    /**
     * Set the input's value
     * @param value the new value to set
     */
    public void setValue(String value);
    
    /**
     * Get the input's name attribute
     * @return the name attribute value
     */
    public String getName();
    
    /**
     * Get the input's type attribute
     * @return the input type (e.g., "text", "password", "checkbox")
     */
    public String getType();
    
    /**
     * Check if the input is checked (for checkboxes and radio buttons)
     * @return true if the input is checked
     */
    public boolean isChecked();
    
    /**
     * Set the checked state (for checkboxes and radio buttons)
     * @param checked true to check, false to uncheck
     */
    public void setChecked(boolean checked);
    
    /**
     * Check if the input is read-only
     * @return true if the input is read-only
     */
    public boolean isReadOnly();
    
    /**
     * Check if the input is disabled
     * @return true if the input is disabled
     */
    public boolean isDisabled();
}

public class HtmlTextInput extends HtmlInput {
    /**
     * Type text into the field (simulates keyboard input)
     * @param text the text to type
     * @throws IOException if typing fails
     */
    public void type(String text) throws IOException;
    
    /**
     * Select all text in the field
     */
    public void select();
    
    /**
     * Get the maximum length allowed for this input
     * @return the maxlength attribute value, or -1 if not set
     */
    public int getMaxLength();
    
    /**
     * Get the placeholder text
     * @return the placeholder attribute value
     */
    public String getPlaceholder();
}

public class HtmlPasswordInput extends HtmlInput {
    // Inherits all HtmlInput methods
    // Values are handled securely but API is identical
}

HtmlTextInput nameField = (HtmlTextInput) form.getInputByName("fullName");
HtmlPasswordInput passField = (HtmlPasswordInput) form.getInputByName("password");

// Set values directly
nameField.setValue("John Doe");
passField.setValue("secretpass");

// Or simulate typing
nameField.type("John Doe");

// Text field specific methods
nameField.select(); // Select all text
int maxLen = nameField.getMaxLength();
String placeholder = nameField.getPlaceholder();

public class HtmlCheckBoxInput extends HtmlInput {
    // Inherits all HtmlInput methods
    // Primary interaction through isChecked() and setChecked()
}

public class HtmlRadioButtonInput extends HtmlInput {  
    // Inherits all HtmlInput methods
    // Setting one radio button in a group unchecks others automatically
}

// Checkbox handling
HtmlCheckBoxInput newsletter = (HtmlCheckBoxInput) form.getInputByName("newsletter");
newsletter.setChecked(true); // Check the box
boolean isChecked = newsletter.isChecked();

// Radio button handling  
List<HtmlElement> genderOptions = form.getInputsByName("gender");
for (HtmlElement element : genderOptions) {
    if (element instanceof HtmlRadioButtonInput) {
        HtmlRadioButtonInput radio = (HtmlRadioButtonInput) element;
        if ("female".equals(radio.getValue())) {
            radio.setChecked(true); // This unchecks other radios in the group
        }
    }
}

public class HtmlSubmitInput extends HtmlInput {
    // Inherits all HtmlInput methods
    // Can be used with form.submit(submitElement)
}

public class HtmlButton extends HtmlElement {
    // Inherits all HtmlElement methods including click()
    // Can contain complex content unlike input elements
}

// Submit input
HtmlSubmitInput submitBtn = (HtmlSubmitInput) form.getInputByValue("Submit");
HtmlPage result = form.submit(submitBtn);

// Button element
HtmlButton cancelBtn = (HtmlButton) form.getButtonByName("cancel");
Page result2 = cancelBtn.click();

public class HtmlTextArea extends HtmlElement {
    /**
     * Get the text content of the textarea
     * @return the current text content
     */
    public String getText();
    
    /**
     * Set the text content of the textarea
     * @param text the new text content
     */
    public void setText(String text);
    
    /**
     * Type text into the textarea (simulates keyboard input)
     * @param text the text to type
     * @throws IOException if typing fails
     */
    public void type(String text) throws IOException;
    
    /**
     * Get the number of rows
     * @return the rows attribute value
     */
    public int getRows();
    
    /**
     * Get the number of columns
     * @return the cols attribute value
     */
    public int getColumns();
}

HtmlTextArea comments = form.getTextAreaByName("comments");

// Set content
comments.setText("This is my feedback about the product...");

// Or simulate typing
comments.type("Additional comments here");

// Get textarea properties
String currentText = comments.getText();
int rows = comments.getRows();
int cols = comments.getColumns();

public class HtmlSelect extends HtmlElement {
    /**
     * Get all option elements in the select
     * @return List of HtmlOption objects
     */
    public List<HtmlOption> getOptions();
    
    /**
     * Get a specific option by index
     * @param index the option index (0-based)
     * @return HtmlOption at the specified index
     */
    public HtmlOption getOption(int index);
    
    /**
     * Get all currently selected options
     * @return List of selected HtmlOption objects
     */
    public List<HtmlOption> getSelectedOptions();
    
    /**
     * Select an option by index
     * @param index the index of the option to select
     */
    public void setSelectedIndex(int index);
    
    /**
     * Check if this is a multiple selection dropdown
     * @return true if multiple selections are allowed
     */
    public boolean isMultiple();
}

public class HtmlOption extends HtmlElement {
    /**
     * Check if this option is currently selected
     * @return true if the option is selected
     */
    public boolean isSelected();
    
    /**
     * Set the selection state of this option
     * @param selected true to select, false to deselect
     */
    public void setSelected(boolean selected);
    
    /**
     * Get the option's value attribute
     * @return the value that will be submitted if this option is selected
     */
    public String getValue();
    
    /**
     * Get the option's display text
     * @return the text content displayed to the user
     */
    public String getText();
}

HtmlSelect countrySelect = form.getSelectByName("country");

// Select by index
countrySelect.setSelectedIndex(2); // Select third option

// Select by finding specific option
List<HtmlOption> options = countrySelect.getOptions();
for (HtmlOption option : options) {
    if ("US".equals(option.getValue())) {
        option.setSelected(true);
        break;
    }
}

// Get selected values
List<HtmlOption> selected = countrySelect.getSelectedOptions();
for (HtmlOption option : selected) {
    System.out.println("Selected: " + option.getText() + " (" + option.getValue() + ")");
}

// Check if multiple selection is allowed
boolean allowsMultiple = countrySelect.isMultiple();

public class FormEncodingType {
    public static final FormEncodingType URL_ENCODED;
    public static final FormEncodingType MULTIPART;
    public static final FormEncodingType TEXT_PLAIN;
    
    /**
     * Get the encoding type name
     * @return the MIME type string for this encoding
     */
    public String getName();
    
    /**
     * Get an encoding type instance by name
     * @param name the encoding type name
     * @return FormEncodingType instance
     */
    public static FormEncodingType getInstance(String name);
}

// Check form encoding type
String enctype = form.getEnctypeAttribute();
FormEncodingType encodingType = FormEncodingType.getInstance(enctype);

// Common encoding types
FormEncodingType urlEncoded = FormEncodingType.URL_ENCODED; // application/x-www-form-urlencoded
FormEncodingType multipart = FormEncodingType.MULTIPART;    // multipart/form-data
FormEncodingType textPlain = FormEncodingType.TEXT_PLAIN;   // text/plain