/*
 * Copyright (C) 2010 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 "config.h"

#if ENABLE(BLOB)

#include "FileReader.h"

#include "Base64.h"
#include "Blob.h"
#include "BlobURL.h"
#include "CrossThreadTask.h"
#include "File.h"
#include "Logging.h"
#include "ProgressEvent.h"
#include "ResourceError.h"
#include "ResourceRequest.h"
#include "ScriptExecutionContext.h"
#include "TextResourceDecoder.h"
#include "ThreadableBlobRegistry.h"
#include "ThreadableLoader.h"
#include <wtf/CurrentTime.h>

namespace WebCore {

const double progressNotificationIntervalMS = 50;

FileReader::FileReader(ScriptExecutionContext* context)
    : ActiveDOMObject(context, this)
    , m_state(None)
    , m_readType(ReadFileAsBinaryString)
    , m_result("")
    , m_isRawDataConverted(false)
    , m_bytesLoaded(0)
    , m_totalBytes(0)
    , m_lastProgressNotificationTimeMS(0)
{
}

FileReader::~FileReader()
{
    terminate();
}

bool FileReader::hasPendingActivity() const
{
    return (m_state != None && m_state != Completed) || ActiveDOMObject::hasPendingActivity();
}

bool FileReader::canSuspend() const
{
    // FIXME: It is not currently possible to suspend a FileReader, so pages with FileReader can not go into page cache.
    return false;
}

void FileReader::stop()
{
    terminate();
}

void FileReader::readAsBinaryString(Blob* blob)
{
    if (!blob)
        return;

    LOG(FileAPI, "FileReader: reading as binary: %s %s\n", blob->url().string().utf8().data(), blob->isFile() ? static_cast<File*>(blob)->path().utf8().data() : "");

    readInternal(blob, ReadFileAsBinaryString);
}

void FileReader::readAsText(Blob* blob, const String& encoding)
{
    if (!blob)
        return;

    LOG(FileAPI, "FileReader: reading as text: %s %s\n", blob->url().string().utf8().data(), blob->isFile() ? static_cast<File*>(blob)->path().utf8().data() : "");

    if (!encoding.isEmpty())
        m_encoding = TextEncoding(encoding);
    readInternal(blob, ReadFileAsText);
}

void FileReader::readAsDataURL(Blob* blob)
{
    if (!blob)
        return;

    LOG(FileAPI, "FileReader: reading as data URL: %s %s\n", blob->url().string().utf8().data(), blob->isFile() ? static_cast<File*>(blob)->path().utf8().data() : "");

    m_fileType = blob->type();
    readInternal(blob, ReadFileAsDataURL);
}

static void delayedStart(ScriptExecutionContext*, FileReader* reader)
{
    reader->start();
}

void FileReader::readInternal(Blob* blob, ReadType type)
{
    // readAs*** methods() can be called multiple times. Only the last call before the actual reading happens is processed.
    if (m_state != None && m_state != Starting)
        return;

    if (m_state == None)
        scriptExecutionContext()->postTask(createCallbackTask(&delayedStart, this));

    m_blob = blob;
    m_readType = type;
    m_state = Starting;
}

static void delayedAbort(ScriptExecutionContext*, FileReader* reader)
{
    reader->doAbort();
}

void FileReader::abort()
{
    LOG(FileAPI, "FileReader: aborting\n");

    if (m_state == Aborting)
        return;
    m_state = Aborting;

    // Schedule to have the abort done later since abort() might be called from the event handler and we do not want the resource loading code to be in the stack.
    scriptExecutionContext()->postTask(createCallbackTask(&delayedAbort, this));
}

void FileReader::doAbort()
{
    terminate();

    m_result = "";
    m_error = FileError::create(FileError::ABORT_ERR);

    fireEvent(eventNames().errorEvent);
    fireEvent(eventNames().abortEvent);
    fireEvent(eventNames().loadendEvent);
}

void FileReader::terminate()
{
    if (m_loader) {
        m_loader->cancel();
        cleanup();
    }
    m_state = Completed;
}

void FileReader::cleanup()
{
    m_loader = 0;
    ThreadableBlobRegistry::unregisterBlobURL(m_urlForReading);
    m_urlForReading = KURL();
}

void FileReader::start()
{
    m_state = Opening;

    // The blob is read by routing through the request handling layer given a temporary public url.
    m_urlForReading = BlobURL::createPublicURL(scriptExecutionContext()->securityOrigin());
    ThreadableBlobRegistry::registerBlobURL(m_urlForReading, m_blob->url());

    ResourceRequest request(m_urlForReading);
    request.setHTTPMethod("GET");

    ThreadableLoaderOptions options;
    options.sendLoadCallbacks = true;
    options.sniffContent = false;
    options.forcePreflight = false;
    options.allowCredentials = true;
    options.crossOriginRequestPolicy = DenyCrossOriginRequests;

    m_loader = ThreadableLoader::create(scriptExecutionContext(), this, request, options);
}

void FileReader::didReceiveResponse(const ResourceResponse& response)
{
    if (response.httpStatusCode() != 200) {
        failed(response.httpStatusCode());
        return;
    }

    m_state = Reading;
    fireEvent(eventNames().loadstartEvent);

    m_totalBytes = response.expectedContentLength();
}

void FileReader::didReceiveData(const char* data, int lengthReceived)
{
    ASSERT(data && lengthReceived);

    // Bail out if we have aborted the reading.
    if (m_state == Completed)
        return;

    switch (m_readType) {
    case ReadFileAsBinaryString:
        m_result += String(data, static_cast<unsigned>(lengthReceived));
        break;
    case ReadFileAsText:
    case ReadFileAsDataURL:
        m_rawData.append(data, static_cast<unsigned>(lengthReceived));
        m_isRawDataConverted = false;
        break;
    default:
        ASSERT_NOT_REACHED();
    }

    m_bytesLoaded += lengthReceived;

    // Fire the progress event at least every 50ms.
    double now = WTF::currentTimeMS();
    if (!m_lastProgressNotificationTimeMS)
        m_lastProgressNotificationTimeMS = now;
    else if (now - m_lastProgressNotificationTimeMS > progressNotificationIntervalMS) {
        fireEvent(eventNames().progressEvent);
        m_lastProgressNotificationTimeMS = now;
    }
}

void FileReader::didFinishLoading(unsigned long)
{
    m_state = Completed;

    fireEvent(eventNames().loadEvent);
    fireEvent(eventNames().loadendEvent);

    cleanup();
}

void FileReader::didFail(const ResourceError&)
{
    // If we're aborting, do not proceed with normal error handling since it is covered in aborting code.
    if (m_state == Aborting)
        return;

    // Treat as internal error.
    failed(500);
}

void FileReader::failed(int httpStatusCode)
{
    m_state = Completed;

    m_error = FileError::create(httpStatusCodeToErrorCode(httpStatusCode));
    fireEvent(eventNames().errorEvent);
    fireEvent(eventNames().loadendEvent);

    cleanup();
}

FileError::ErrorCode FileReader::httpStatusCodeToErrorCode(int httpStatusCode)
{
    switch (httpStatusCode) {
        case 403:
            return FileError::SECURITY_ERR;
        case 404:
            return FileError::NOT_FOUND_ERR;
        default:
            return FileError::NOT_READABLE_ERR;
    }
}

void FileReader::fireEvent(const AtomicString& type)
{
    // FIXME: the current ProgressEvent uses "unsigned long" for total and loaded attributes. Need to talk with the spec writer to resolve the issue.
    dispatchEvent(ProgressEvent::create(type, true, static_cast<unsigned>(m_bytesLoaded), static_cast<unsigned>(m_totalBytes)));
}

FileReader::ReadyState FileReader::readyState() const
{
    switch (m_state) {
    case None:
    case Starting:
        return EMPTY;
    case Opening:
    case Reading:
    case Aborting:
        return LOADING;
    case Completed:
        return DONE;
    }
    ASSERT_NOT_REACHED();
    return EMPTY;
}

const ScriptString& FileReader::result()
{
    // If reading as binary string, we can return the result immediately.
    if (m_readType == ReadFileAsBinaryString)
        return m_result;

    // If we already convert the raw data received so far, we can return the result now.
    if (m_isRawDataConverted)
        return m_result;
    m_isRawDataConverted = true;

    if (m_readType == ReadFileAsText)
        convertToText();
    // For data URL, we only do the coversion until we receive all the raw data.
    else if (m_readType == ReadFileAsDataURL && m_state == Completed)
        convertToDataURL(m_rawData, m_fileType, m_result);

    return m_result;
}

void FileReader::convertToText()
{
    if (!m_rawData.size()) {
        m_result = "";
        return;
    }

    // Decode the data.
    // The File API spec says that we should use the supplied encoding if it is valid. However, we choose to ignore this
    // requirement in order to be consistent with how WebKit decodes the web content: always has the BOM override the
    // provided encoding.     
    // FIXME: consider supporting incremental decoding to improve the perf.
    if (!m_decoder)
        m_decoder = TextResourceDecoder::create("text/plain", m_encoding.isValid() ? m_encoding : UTF8Encoding());
    m_result = m_decoder->decode(&m_rawData.at(0), m_rawData.size());

    if (m_state == Completed && !m_error)
        m_result += m_decoder->flush();
}

void FileReader::convertToDataURL(const Vector<char>& rawData, const String& fileType, ScriptString& result)
{
    result = "data:";

    if (!rawData.size())
        return;

    result += fileType;
    if (!fileType.isEmpty())
        result += ";";
    result += "base64,";

    Vector<char> out;
    base64Encode(rawData, out);
    out.append('\0');
    result += out.data();
}

} // namespace WebCore
 
#endif // ENABLE(BLOB)