/*
 * Copyright (C) 2009 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "public/web/WebSearchableFormData.h"

#include "core/HTMLNames.h"
#include "core/InputTypeNames.h"
#include "core/dom/Document.h"
#include "core/html/FormData.h"
#include "core/html/HTMLFormControlElement.h"
#include "core/html/HTMLFormElement.h"
#include "core/html/HTMLInputElement.h"
#include "core/html/HTMLOptionElement.h"
#include "core/html/HTMLSelectElement.h"
#include "platform/network/FormDataEncoder.h"
#include "public/web/WebFormElement.h"
#include "public/web/WebInputElement.h"
#include "wtf/text/TextEncoding.h"

namespace blink {

using namespace HTMLNames;

namespace {

// Gets the encoding for the form.
// TODO(tkent): Use FormDataEncoder::encodingFromAcceptCharset().
void getFormEncoding(const HTMLFormElement& form, WTF::TextEncoding* encoding)
{
    String str(form.fastGetAttribute(HTMLNames::accept_charsetAttr));
    str.replace(',', ' ');
    Vector<String> charsets;
    str.split(' ', charsets);
    for (const String& charset : charsets) {
        *encoding = WTF::TextEncoding(charset);
        if (encoding->isValid())
            return;
    }
    if (form.document().loader())
        *encoding = WTF::TextEncoding(form.document().encoding());
}

// Returns true if the submit request results in an HTTP URL.
bool isHTTPFormSubmit(const HTMLFormElement& form)
{
    // FIXME: This function is insane. This is an overly complicated way to get
    // this information.
    String action(form.action());
    // The isNull() check is trying to avoid completeURL returning KURL() when
    // passed a null string.
    return form.document().completeURL(action.isNull() ? "" : action).protocolIs("http");
}

// If the form does not have an activated submit button, the first submit
// button is returned.
HTMLFormControlElement* buttonToActivate(const HTMLFormElement& form)
{
    HTMLFormControlElement* firstSubmitButton = nullptr;
    for (auto& element : form.associatedElements()) {
        if (!element->isFormControlElement())
            continue;
        HTMLFormControlElement* control = toHTMLFormControlElement(element);
        if (control->isActivatedSubmit()) {
            // There's a button that is already activated for submit, return
            // nullptr.
            return nullptr;
        }
        if (!firstSubmitButton && control->isSuccessfulSubmitButton())
            firstSubmitButton = control;
    }
    return firstSubmitButton;
}

// Returns true if the selected state of all the options matches the default
// selected state.
bool isSelectInDefaultState(const HTMLSelectElement& select)
{
    const WillBeHeapVector<RawPtrWillBeMember<HTMLElement>>& listItems = select.listItems();
    if (select.multiple() || select.size() > 1) {
        for (const auto& item : listItems) {
            if (!isHTMLOptionElement(*item))
                continue;
            HTMLOptionElement* optionElement = toHTMLOptionElement(item);
            if (optionElement->selected() != optionElement->fastHasAttribute(selectedAttr))
                return false;
        }
        return true;
    }

    // The select is rendered as a combobox (called menulist in WebKit). At
    // least one item is selected, determine which one.
    HTMLOptionElement* initialSelected = nullptr;
    for (const auto& item : listItems) {
        if (!isHTMLOptionElement(*item))
            continue;
        HTMLOptionElement* optionElement = toHTMLOptionElement(item);
        if (optionElement->fastHasAttribute(selectedAttr)) {
            // The page specified the option to select.
            initialSelected = optionElement;
            break;
        }
        if (!initialSelected)
            initialSelected = optionElement;
    }
    return !initialSelected || initialSelected->selected();
}

// Returns true if the form element is in its default state, false otherwise.
// The default state is the state of the form element on initial load of the
// page, and varies depending upon the form element. For example, a checkbox is
// in its default state if the checked state matches the state of the checked
// attribute.
bool isInDefaultState(const HTMLFormControlElement& formElement)
{
    if (isHTMLInputElement(formElement)) {
        const HTMLInputElement& inputElement = toHTMLInputElement(formElement);
        if (inputElement.type() == InputTypeNames::checkbox || inputElement.type() == InputTypeNames::radio)
            return inputElement.checked() == inputElement.fastHasAttribute(checkedAttr);
    } else if (isHTMLSelectElement(formElement)) {
        return isSelectInDefaultState(toHTMLSelectElement(formElement));
    }
    return true;
}

// Look for a suitable search text field in a given HTMLFormElement
// Return nothing if one of those items are found:
//  - A text area field
//  - A file upload field
//  - A Password field
//  - More than one text field
HTMLInputElement* findSuitableSearchInputElement(const HTMLFormElement& form)
{
    HTMLInputElement* textElement = nullptr;
    for (const auto& item : form.associatedElements()) {
        if (!item->isFormControlElement())
            continue;

        HTMLFormControlElement& control = toHTMLFormControlElement(*item);

        if (control.isDisabledFormControl() || control.name().isNull())
            continue;

        if (!isInDefaultState(control) || isHTMLTextAreaElement(control))
            return nullptr;

        if (isHTMLInputElement(control) && control.willValidate()) {
            const HTMLInputElement& input = toHTMLInputElement(control);

            // Return nothing if a file upload field or a password field are
            // found.
            if (input.type() == InputTypeNames::file || input.type() == InputTypeNames::password)
                return nullptr;

            if (input.isTextField()) {
                if (textElement) {
                    // The auto-complete bar only knows how to fill in one
                    // value.  This form has multiple fields; don't treat it as
                    // searchable.
                    return nullptr;
                }
                textElement = toHTMLInputElement(&control);
            }
        }
    }
    return textElement;
}

// Build a search string based on a given HTMLFormElement and HTMLInputElement
//
// Search string output example from www.google.com:
// "hl=en&source=hp&biw=1085&bih=854&q={searchTerms}&btnG=Google+Search&aq=f&aqi=&aql=&oq="
//
// Return false if the provided HTMLInputElement is not found in the form
bool buildSearchString(const HTMLFormElement& form, Vector<char>* encodedString, const WTF::TextEncoding& encoding, const HTMLInputElement* textElement)
{
    bool isElementFound = false;
    for (const auto& item : form.associatedElements()) {
        if (!item->isFormControlElement())
            continue;

        HTMLFormControlElement& control = toHTMLFormControlElement(*item);
        if (control.isDisabledFormControl() || control.name().isNull())
            continue;

        FormData* formData = FormData::create(encoding);
        control.appendToFormData(*formData);

        for (const auto& entry : formData->entries()) {
            if (!encodedString->isEmpty())
                encodedString->append('&');
            FormDataEncoder::encodeStringAsFormData(*encodedString, entry->name());
            encodedString->append('=');
            if (&control == textElement) {
                encodedString->append("{searchTerms}", 13);
                isElementFound = true;
            } else {
                FormDataEncoder::encodeStringAsFormData(*encodedString, entry->value());
            }
        }
    }
    return isElementFound;
}

} // namespace

WebSearchableFormData::WebSearchableFormData(const WebFormElement& form, const WebInputElement& selectedInputElement)
{
    RefPtrWillBeRawPtr<HTMLFormElement> formElement = static_cast<PassRefPtrWillBeRawPtr<HTMLFormElement>>(form);
    HTMLInputElement* inputElement = static_cast<PassRefPtrWillBeRawPtr<HTMLInputElement>>(selectedInputElement).get();

    // Only consider forms that GET data.
    // Allow HTTPS only when an input element is provided.
    if (equalIgnoringCase(formElement->getAttribute(methodAttr), "post")
        || (!isHTTPFormSubmit(*formElement) && !inputElement))
        return;

    WTF::TextEncoding encoding;
    getFormEncoding(*formElement, &encoding);
    if (!encoding.isValid()) {
        // Need a valid encoding to encode the form elements.
        // If the encoding isn't found webkit ends up replacing the params with
        // empty strings. So, we don't try to do anything here.
        return;
    }

    // Look for a suitable search text field in the form when a
    // selectedInputElement is not provided.
    if (!inputElement) {
        inputElement = findSuitableSearchInputElement(*formElement);

        // Return if no suitable text element has been found.
        if (!inputElement)
            return;
    }

    HTMLFormControlElement* firstSubmitButton = buttonToActivate(*formElement);
    if (firstSubmitButton) {
        // The form does not have an active submit button, make the first button
        // active. We need to do this, otherwise the URL will not contain the
        // name of the submit button.
        firstSubmitButton->setActivatedSubmit(true);
    }

    Vector<char> encodedString;
    bool isValidSearchString = buildSearchString(*formElement, &encodedString, encoding, inputElement);

    if (firstSubmitButton)
        firstSubmitButton->setActivatedSubmit(false);

    // Return if the search string is not valid.
    if (!isValidSearchString)
        return;

    String action(formElement->action());
    KURL url(formElement->document().completeURL(action.isNull() ? "" : action));
    RefPtr<EncodedFormData> formData = EncodedFormData::create(encodedString);
    url.setQuery(formData->flattenToString());
    m_url = url;
    m_encoding = String(encoding.name());
}

} // namespace blink