/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#include <sal/config.h>

#include <config_version.h>

#include <cppuhelper/factory.hxx>
#include <cppuhelper/supportsservice.hxx>
#include <cppuhelper/weak.hxx>
#include "languagetoolimp.hxx"

#include <i18nlangtag/languagetag.hxx>
#include <svtools/strings.hrc>
#include <unotools/resmgr.hxx>

#include <vector>
#include <set>
#include <string.h>

#include <curl/curl.h>
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
#include <algorithm>
#include <string_view>
#include <sal/log.hxx>
#include <svtools/languagetoolcfg.hxx>
#include <tools/color.hxx>
#include <tools/long.hxx>
#include <com/sun/star/uno/Any.hxx>
#include <comphelper/propertyvalue.hxx>
#include <unotools/lingucfg.hxx>
#include <osl/mutex.hxx>
#include <rtl/uri.hxx>

using namespace osl;
using namespace com::sun::star;
using namespace com::sun::star::beans;
using namespace com::sun::star::lang;
using namespace com::sun::star::uno;
using namespace com::sun::star::linguistic2;
using namespace linguistic;

#define COL_ORANGE Color(0xD1, 0x68, 0x20)

constexpr OUStringLiteral sDuden = u"duden";

namespace
{
Sequence<PropertyValue> lcl_GetLineColorPropertyFromErrorId(const std::string& rErrorId)
{
    Color aColor;
    if (rErrorId == "TYPOS" || rErrorId == "orth")
    {
        aColor = COL_LIGHTRED;
    }
    else if (rErrorId == "STYLE")
    {
        aColor = COL_LIGHTBLUE;
    }
    else
    {
        // Same color is used for other errorId's such as GRAMMAR, TYPOGRAPHY..
        aColor = COL_ORANGE;
    }
    Sequence<PropertyValue> aProperties{ comphelper::makePropertyValue("LineColor", aColor) };
    return aProperties;
}

OString encodeTextForLanguageTool(const OUString& text)
{
    // Let's be a bit conservative. I don't find a good description what needs encoding (and in
    // which way) at https://languagetool.org/http-api/; the "Try it out!" function shows that
    // different cases are handled differently by the demo; some percent-encode the UTF-8
    // representation, like %D0%90 (for cyrillic А); some turn into entities like &#33; (for
    // exclamation mark !); some other to things like \u0027 (for apostrophe ').
    static constexpr auto myCharClass = rtl::createUriCharClass(
        u8"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
    return OUStringToOString(
        rtl::Uri::encode(text, myCharClass.data(), rtl_UriEncodeStrict, RTL_TEXTENCODING_UTF8),
        RTL_TEXTENCODING_ASCII_US);
}

// Callback to get the response data from server.
size_t WriteCallback(void* ptr, size_t size, size_t nmemb, void* userp)
{
    if (!userp)
        return 0;

    std::string* response = static_cast<std::string*>(userp);
    size_t real_size = size * nmemb;
    response->append(static_cast<char*>(ptr), real_size);
    return real_size;
}

enum class HTTP_METHOD
{
    HTTP_GET,
    HTTP_POST
};

struct curl_cleanup_t
{
    void operator()(CURL* p) const { curl_easy_cleanup(p); }
};

std::string makeHttpRequest_impl(std::string_view aURL, HTTP_METHOD method,
                                 const OString& aPostData, curl_slist* pHttpHeader,
                                 tools::Long& nStatusCode)
{
    std::unique_ptr<CURL, curl_cleanup_t> curl(curl_easy_init());
    if (!curl)
        return {}; // empty string

    // Same useragent string as in CurlSession (ucp/webdav-curl/CurlSession.cxx)
    curl_version_info_data const* const pVersion(curl_version_info(CURLVERSION_NOW));
    assert(pVersion);
    OString const useragent(
        OString::Concat("LibreOffice " LIBO_VERSION_DOTTED " denylistedbackend/")
        + pVersion->version + " " + pVersion->ssl_version);
    (void)curl_easy_setopt(curl.get(), CURLOPT_USERAGENT, useragent.getStr());

    (void)curl_easy_setopt(curl.get(), CURLOPT_HTTPHEADER, pHttpHeader);
    (void)curl_easy_setopt(curl.get(), CURLOPT_FAILONERROR, 1L);
    (void)curl_easy_setopt(curl.get(), CURLOPT_URL, aURL.data());
    (void)curl_easy_setopt(curl.get(), CURLOPT_TIMEOUT, CURL_TIMEOUT);
    // (void)curl_easy_setopt(curl.get(), CURLOPT_VERBOSE, 1L);

    std::string response_body;
    (void)curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, WriteCallback);
    (void)curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &response_body);

    SvxLanguageToolOptions& rLanguageOpts = SvxLanguageToolOptions::Get();
    // allow unknown or self-signed certificates
    if (rLanguageOpts.getSSLVerification() == false)
    {
        (void)curl_easy_setopt(curl.get(), CURLOPT_SSL_VERIFYPEER, false);
        (void)curl_easy_setopt(curl.get(), CURLOPT_SSL_VERIFYHOST, false);
    }

    if (method == HTTP_METHOD::HTTP_POST)
    {
        (void)curl_easy_setopt(curl.get(), CURLOPT_POST, 1L);
        (void)curl_easy_setopt(curl.get(), CURLOPT_POSTFIELDS, aPostData.getStr());
    }

    CURLcode cc = curl_easy_perform(curl.get());
    if (cc != CURLE_OK)
    {
        SAL_WARN("languagetool",
                 "CURL request returned with error: " << static_cast<sal_Int32>(cc));
    }

    curl_easy_getinfo(curl.get(), CURLINFO_RESPONSE_CODE, &nStatusCode);
    return response_body;
}

std::string makeDudenHttpRequest(std::string_view aURL, const OString& aPostData,
                                 tools::Long& nStatusCode)
{
    struct curl_slist* pList = nullptr;
    SvxLanguageToolOptions& rLanguageOpts = SvxLanguageToolOptions::Get();
    OString sAccessToken = OUStringToOString(rLanguageOpts.getApiKey(), RTL_TEXTENCODING_UTF8);

    pList = curl_slist_append(pList, "Cache-Control: no-cache");
    pList = curl_slist_append(pList, "Content-Type: application/json");
    if (!sAccessToken.isEmpty())
    {
        sAccessToken = "access_token: " + sAccessToken;
        pList = curl_slist_append(pList, sAccessToken.getStr());
    }

    return makeHttpRequest_impl(aURL, HTTP_METHOD::HTTP_POST, aPostData, pList, nStatusCode);
}

std::string makeHttpRequest(std::string_view aURL, HTTP_METHOD method, const OString& aPostData,
                            tools::Long& nStatusCode)
{
    OString realPostData(aPostData);
    if (method == HTTP_METHOD::HTTP_POST)
    {
        SvxLanguageToolOptions& rLanguageOpts = SvxLanguageToolOptions::Get();
        OString apiKey = OUStringToOString(rLanguageOpts.getApiKey(), RTL_TEXTENCODING_UTF8);
        OString username = OUStringToOString(rLanguageOpts.getUsername(), RTL_TEXTENCODING_UTF8);
        if (!apiKey.isEmpty() && !username.isEmpty())
            realPostData += "&username=" + username + "&apiKey=" + apiKey;
    }

    return makeHttpRequest_impl(aURL, method, realPostData, nullptr, nStatusCode);
}

void parseDudenResponse(ProofreadingResult& rResult, std::string_view aJSONBody)
{
    size_t nSize;
    int nProposalSize;
    boost::property_tree::ptree aRoot;
    std::stringstream aStream(aJSONBody.data());
    boost::property_tree::read_json(aStream, aRoot);

    const boost::optional<boost::property_tree::ptree&> aPositions
        = aRoot.get_child_optional("check-positions");
    if (!aPositions || !(nSize = aPositions.get().size()))
    {
        return;
    }

    Sequence<SingleProofreadingError> aChecks(nSize);
    auto pChecks = aChecks.getArray();
    size_t nIndex1 = 0, nIndex2 = 0;
    auto itPos = aPositions.get().begin();
    while (itPos != aPositions.get().end())
    {
        const boost::property_tree::ptree& rTree = itPos->second;
        const std::string sType = rTree.get<std::string>("type", "");
        const int nOffset = rTree.get<int>("offset", 0);
        const int nLength = rTree.get<int>("length", 0);

        pChecks[nIndex1].nErrorStart = nOffset;
        pChecks[nIndex1].nErrorLength = nLength;
        pChecks[nIndex1].nErrorType = PROOFREADING_ERROR;
        //pChecks[nIndex1].aShortComment = ??
        //pChecks[nIndex1].aFullComment = ??
        pChecks[nIndex1].aProperties = lcl_GetLineColorPropertyFromErrorId(sType);

        const boost::optional<const boost::property_tree::ptree&> aProposals
            = rTree.get_child_optional("proposals");
        if (aProposals && (nProposalSize = aProposals.get().size()))
        {
            pChecks[nIndex1].aSuggestions.realloc(std::min(nProposalSize, MAX_SUGGESTIONS_SIZE));

            nIndex2 = 0;
            auto itProp = aProposals.get().begin();
            auto pSuggestions = pChecks[nIndex1].aSuggestions.getArray();
            while (itProp != aProposals.get().end() && nIndex2 < MAX_SUGGESTIONS_SIZE)
            {
                pSuggestions[nIndex2++]
                    = OStringToOUString(itProp->second.data(), RTL_TEXTENCODING_UTF8);
                itProp++;
            }
        }

        nIndex1++;
        itPos++;
    }

    rResult.aErrors = aChecks;
}

/*
    rResult is both input and output
    aJSONBody is the response body from the HTTP Request to LanguageTool API
*/
void parseProofreadingJSONResponse(ProofreadingResult& rResult, std::string_view aJSONBody)
{
    boost::property_tree::ptree root;
    std::stringstream aStream(aJSONBody.data());
    boost::property_tree::read_json(aStream, root);
    boost::property_tree::ptree& matches = root.get_child("matches");
    size_t matchSize = matches.size();

    if (matchSize <= 0)
    {
        return;
    }
    Sequence<SingleProofreadingError> aErrors(matchSize);
    auto pErrors = aErrors.getArray();
    size_t i = 0;
    for (auto it1 = matches.begin(); it1 != matches.end(); it1++, i++)
    {
        const boost::property_tree::ptree& match = it1->second;
        int offset = match.get<int>("offset");
        int length = match.get<int>("length");
        const std::string shortMessage = match.get<std::string>("message");
        const std::string message = match.get<std::string>("shortMessage");

        // Parse the error category for Line Color
        const boost::property_tree::ptree& rule = match.get_child("rule");
        const boost::property_tree::ptree& ruleCategory = rule.get_child("category");
        const std::string errorCategoryId = ruleCategory.get<std::string>("id");

        OUString aShortComment(shortMessage.c_str(), shortMessage.length(), RTL_TEXTENCODING_UTF8);
        OUString aFullComment(message.c_str(), message.length(), RTL_TEXTENCODING_UTF8);

        pErrors[i].nErrorStart = offset;
        pErrors[i].nErrorLength = length;
        pErrors[i].nErrorType = PROOFREADING_ERROR;
        pErrors[i].aShortComment = aShortComment;
        pErrors[i].aFullComment = aFullComment;
        pErrors[i].aProperties = lcl_GetLineColorPropertyFromErrorId(errorCategoryId);

        const boost::property_tree::ptree& replacements = match.get_child("replacements");
        int suggestionSize = replacements.size();

        if (suggestionSize <= 0)
        {
            continue;
        }
        pErrors[i].aSuggestions.realloc(std::min(suggestionSize, MAX_SUGGESTIONS_SIZE));
        auto pSuggestions = pErrors[i].aSuggestions.getArray();
        // Limit suggestions to avoid crash on context menu popup:
        // (soffice:17251): Gdk-CRITICAL **: 17:00:21.277: ../../../../../gdk/wayland/gdkdisplay-wayland.c:1399: Unable to create Cairo image
        // surface: invalid value (typically too big) for the size of the input (surface, pattern, etc.)
        int j = 0;
        for (auto it2 = replacements.begin(); it2 != replacements.end() && j < MAX_SUGGESTIONS_SIZE;
             it2++, j++)
        {
            const boost::property_tree::ptree& replacement = it2->second;
            std::string replacementStr = replacement.get<std::string>("value");
            pSuggestions[j]
                = OUString(replacementStr.c_str(), replacementStr.length(), RTL_TEXTENCODING_UTF8);
        }
    }
    rResult.aErrors = aErrors;
}
}

LanguageToolGrammarChecker::LanguageToolGrammarChecker()
    : mCachedResults(MAX_CACHE_SIZE)
{
}

LanguageToolGrammarChecker::~LanguageToolGrammarChecker() {}

sal_Bool SAL_CALL LanguageToolGrammarChecker::isSpellChecker() { return false; }

sal_Bool SAL_CALL LanguageToolGrammarChecker::hasLocale(const Locale& rLocale)
{
    bool bRes = false;
    if (!m_aSuppLocales.hasElements())
        getLocales();

    for (auto const& suppLocale : std::as_const(m_aSuppLocales))
    {
        if (rLocale == suppLocale)
        {
            bRes = true;
            break;
        }
    }

    return bRes;
}

Sequence<Locale> SAL_CALL LanguageToolGrammarChecker::getLocales()
{
    if (m_aSuppLocales.hasElements())
        return m_aSuppLocales;
    SvxLanguageToolOptions& rLanguageOpts = SvxLanguageToolOptions::Get();
    if (!rLanguageOpts.getEnabled())
    {
        return m_aSuppLocales;
    }

    OString localeUrl = OUStringToOString(rLanguageOpts.getLocaleListURL(), RTL_TEXTENCODING_UTF8);
    if (localeUrl.isEmpty())
    {
        return m_aSuppLocales;
    }
    tools::Long statusCode = 0;
    std::string response = makeHttpRequest(localeUrl, HTTP_METHOD::HTTP_GET, OString(), statusCode);
    if (statusCode != 200)
    {
        return m_aSuppLocales;
    }
    if (response.empty())
    {
        return m_aSuppLocales;
    }
    boost::property_tree::ptree root;
    std::stringstream aStream(response);
    boost::property_tree::read_json(aStream, root);

    size_t length = root.size();
    m_aSuppLocales.realloc(length);
    auto pArray = m_aSuppLocales.getArray();
    int i = 0;
    for (auto it = root.begin(); it != root.end(); it++, i++)
    {
        boost::property_tree::ptree& localeItem = it->second;
        const std::string longCode = localeItem.get<std::string>("longCode");
        Locale aLocale = LanguageTag::convertToLocale(
            OUString(longCode.c_str(), longCode.length(), RTL_TEXTENCODING_UTF8));
        pArray[i] = aLocale;
    }
    return m_aSuppLocales;
}

ProofreadingResult SAL_CALL LanguageToolGrammarChecker::doProofreading(
    const OUString& aDocumentIdentifier, const OUString& aText, const Locale& aLocale,
    sal_Int32 nStartOfSentencePosition, sal_Int32 nSuggestedBehindEndOfSentencePosition,
    const Sequence<PropertyValue>& aProperties)
{
    // ProofreadingResult declared here instead of parseHttpJSONResponse because of the early exists.
    ProofreadingResult xRes;
    xRes.aDocumentIdentifier = aDocumentIdentifier;
    xRes.aText = aText;
    xRes.aLocale = aLocale;
    xRes.nStartOfSentencePosition = nStartOfSentencePosition;
    xRes.nBehindEndOfSentencePosition = nSuggestedBehindEndOfSentencePosition;
    xRes.aProperties = Sequence<PropertyValue>();
    xRes.xProofreader = this;
    xRes.aErrors = Sequence<SingleProofreadingError>();

    if (aText.isEmpty())
    {
        return xRes;
    }

    if (nStartOfSentencePosition != 0)
    {
        return xRes;
    }

    xRes.nStartOfNextSentencePosition = aText.getLength();

    SvxLanguageToolOptions& rLanguageOpts = SvxLanguageToolOptions::Get();
    if (rLanguageOpts.getEnabled() == false)
    {
        return xRes;
    }

    OString checkerURL = OUStringToOString(rLanguageOpts.getCheckerURL(), RTL_TEXTENCODING_UTF8);
    if (checkerURL.isEmpty())
    {
        return xRes;
    }

    if (aProperties.getLength() > 0 && aProperties[0].Name == "Update")
    {
        // locale changed
        xRes.aText = "";
        return xRes;
    }

    sal_Int32 spaceIndex = std::min(xRes.nStartOfNextSentencePosition, aText.getLength() - 1);
    while (spaceIndex < aText.getLength() && aText[spaceIndex] == ' ')
    {
        xRes.nStartOfNextSentencePosition += 1;
        spaceIndex = xRes.nStartOfNextSentencePosition;
    }
    if (xRes.nStartOfNextSentencePosition == nSuggestedBehindEndOfSentencePosition
        && spaceIndex < aText.getLength())
    {
        xRes.nStartOfNextSentencePosition
            = std::min(nSuggestedBehindEndOfSentencePosition + 1, aText.getLength());
    }
    xRes.nBehindEndOfSentencePosition
        = std::min(xRes.nStartOfNextSentencePosition, aText.getLength());

    OString langTag(LanguageTag::convertToBcp47(aLocale, false).toUtf8());
    OString postData = encodeTextForLanguageTool(aText);
    if (rLanguageOpts.getRestProtocol() == sDuden)
    {
        std::stringstream aStream;
        boost::property_tree::ptree aTree;
        aTree.put("text-language", langTag.getStr());
        aTree.put("text", postData.getStr());
        aTree.put("hyphenation", false);
        aTree.put("spellchecking-level", 3);
        aTree.put("correction-proposals", true);
        boost::property_tree::write_json(aStream, aTree);
        postData = OString(aStream.str());
    }
    else
    {
        postData = "text=" + postData + "&language=" + langTag;
    }

    if (auto cachedResult = mCachedResults.find(postData); cachedResult != mCachedResults.end())
    {
        xRes.aErrors = cachedResult->second;
        return xRes;
    }

    tools::Long http_code = 0;
    std::string response_body;
    if (rLanguageOpts.getRestProtocol() == sDuden)
        response_body = makeDudenHttpRequest(checkerURL, postData, http_code);
    else
        response_body = makeHttpRequest(checkerURL, HTTP_METHOD::HTTP_POST, postData, http_code);

    if (http_code != 200)
    {
        return xRes;
    }

    if (response_body.length() <= 0)
    {
        return xRes;
    }

    if (rLanguageOpts.getRestProtocol() == sDuden)
    {
        parseDudenResponse(xRes, response_body);
    }
    else
    {
        parseProofreadingJSONResponse(xRes, response_body);
    }
    // cache the result
    mCachedResults.insert(std::make_pair(postData, xRes.aErrors));
    return xRes;
}

void SAL_CALL LanguageToolGrammarChecker::ignoreRule(const OUString& /*aRuleIdentifier*/,
                                                     const Locale& /*aLocale*/
)
{
}
void SAL_CALL LanguageToolGrammarChecker::resetIgnoreRules() {}

OUString SAL_CALL LanguageToolGrammarChecker::getServiceDisplayName(const Locale& rLocale)
{
    std::locale loc(Translate::Create("svt", LanguageTag(rLocale)));
    return Translate::get(STR_DESCRIPTION_LANGUAGETOOL, loc);
}

OUString SAL_CALL LanguageToolGrammarChecker::getImplementationName()
{
    return "org.openoffice.lingu.LanguageToolGrammarChecker";
}

sal_Bool SAL_CALL LanguageToolGrammarChecker::supportsService(const OUString& ServiceName)
{
    return cppu::supportsService(this, ServiceName);
}

Sequence<OUString> SAL_CALL LanguageToolGrammarChecker::getSupportedServiceNames()
{
    return { SN_GRAMMARCHECKER };
}

void SAL_CALL LanguageToolGrammarChecker::initialize(const Sequence<Any>& /*rArguments*/) {}

extern "C" SAL_DLLPUBLIC_EXPORT css::uno::XInterface*
lingucomponent_LanguageToolGrammarChecker_get_implementation(
    css::uno::XComponentContext*, css::uno::Sequence<css::uno::Any> const&)
{
    return cppu::acquire(static_cast<cppu::OWeakObject*>(new LanguageToolGrammarChecker()));
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */