/*
  ==============================================================================

   This file is part of the JUCE 7 technical preview.
   Copyright (c) 2022 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For the technical preview this file cannot be licensed commercially.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

#pragma once

//==============================================================================
namespace LicenseHelpers
{
    inline LicenseState::Type licenseTypeForString (const String& licenseString)
    {
        if (licenseString == "juce-pro")       return LicenseState::Type::pro;
        if (licenseString == "juce-indie")     return LicenseState::Type::indie;
        if (licenseString == "juce-edu")       return LicenseState::Type::educational;
        if (licenseString == "juce-personal")  return LicenseState::Type::personal;

        jassertfalse; // unknown type
        return LicenseState::Type::none;
    }

    using LicenseVersionAndType = std::pair<int, LicenseState::Type>;

    inline LicenseVersionAndType findBestLicense (std::vector<LicenseVersionAndType>&& licenses)
    {
        if (licenses.size() == 1)
            return licenses[0];

        auto getValueForLicenceType = [] (LicenseState::Type type)
        {
            switch (type)
            {
                case LicenseState::Type::pro:          return 4;
                case LicenseState::Type::indie:        return 3;
                case LicenseState::Type::educational:  return 2;
                case LicenseState::Type::personal:     return 1;
                case LicenseState::Type::gpl:
                case LicenseState::Type::none:
                default:                               return -1;
            }
        };

        std::sort (licenses.begin(), licenses.end(),
                   [getValueForLicenceType] (const LicenseVersionAndType& l1, const LicenseVersionAndType& l2)
                   {
                       if (l1.first > l2.first)
                           return true;

                       if (l1.first == l2.first)
                           return getValueForLicenceType (l1.second) > getValueForLicenceType (l2.second);

                       return false;
                   });

        auto findFirstLicense = [&licenses] (bool isPaid)
        {
            auto iter = std::find_if (licenses.begin(), licenses.end(),
                                      [isPaid] (const LicenseVersionAndType& l)
                                      {
                                          auto proOrIndie = (l.second == LicenseState::Type::pro || l.second == LicenseState::Type::indie);
                                          return isPaid ? proOrIndie : ! proOrIndie;
                                      });

            return iter != licenses.end() ? *iter
                                          : LicenseVersionAndType();
        };

        auto newestPaid = findFirstLicense (true);
        auto newestFree = findFirstLicense (false);

        if (newestPaid.first >= projucerMajorVersion || newestPaid.first >= newestFree.first)
            return newestPaid;

        return newestFree;
    }
}

//==============================================================================
class LicenseQueryThread
{
public:
    enum class ErrorType
    {
        busy,
        cancelled,
        connectionError,
        webResponseError
    };

    using ErrorMessageAndType = std::pair<String, ErrorType>;
    using LicenseQueryCallback = std::function<void (ErrorMessageAndType, LicenseState)>;

    //==============================================================================
    LicenseQueryThread() = default;

    void checkLicenseValidity (const LicenseState& state, LicenseQueryCallback completionCallback)
    {
        if (jobPool.getNumJobs() > 0)
        {
            completionCallback ({ {}, ErrorType::busy }, {});
            return;
        }

        jobPool.addJob ([this, state, completionCallback]
        {
            auto updatedState = state;

            auto result = runTask (std::make_unique<UserLicenseQuery> (state.authToken), updatedState);

            WeakReference<LicenseQueryThread> weakThis (this);
            MessageManager::callAsync ([weakThis, result, updatedState, completionCallback]
            {
                if (weakThis != nullptr)
                    completionCallback (result, updatedState);
            });
        });
    }

    void doSignIn (const String& email, const String& password, LicenseQueryCallback completionCallback)
    {
        cancelRunningJobs();

        jobPool.addJob ([this, email, password, completionCallback]
        {
            LicenseState state;

            auto result = runTask (std::make_unique<UserLogin> (email, password), state);

            if (result == ErrorMessageAndType())
                result = runTask (std::make_unique<UserLicenseQuery> (state.authToken), state);

            if (result != ErrorMessageAndType())
                state = {};

            WeakReference<LicenseQueryThread> weakThis (this);
            MessageManager::callAsync ([weakThis, result, state, completionCallback]
            {
                if (weakThis != nullptr)
                    completionCallback (result, state);
            });
        });
    }

    void cancelRunningJobs()
    {
        jobPool.removeAllJobs (true, 500);
    }

private:
    //==============================================================================
    struct AccountEnquiryBase
    {
        virtual ~AccountEnquiryBase() = default;

        virtual bool isPOSTLikeRequest() const = 0;
        virtual String getEndpointURLSuffix() const = 0;
        virtual StringPairArray getParameterNamesAndValues() const = 0;
        virtual String getExtraHeaders() const = 0;
        virtual int getSuccessCode() const = 0;
        virtual String errorCodeToString (int) const = 0;
        virtual bool parseServerResponse (const String&, LicenseState&) = 0;
    };

    struct UserLogin  : public AccountEnquiryBase
    {
        UserLogin (const String& e, const String& p)
            : userEmail (e), userPassword (p)
        {
        }

        bool isPOSTLikeRequest() const override       { return true; }
        String getEndpointURLSuffix() const override  { return "/authenticate/projucer"; }
        int getSuccessCode() const override           { return 200; }

        StringPairArray getParameterNamesAndValues() const override
        {
            StringPairArray namesAndValues;
            namesAndValues.set ("email", userEmail);
            namesAndValues.set ("password", userPassword);

            return namesAndValues;
        }

        String getExtraHeaders() const override
        {
            return "Content-Type: application/json";
        }

        String errorCodeToString (int errorCode) const override
        {
            switch (errorCode)
            {
                case 400:  return "Please enter your email and password to sign in.";
                case 401:  return "Your email and password are incorrect.";
                case 451:  return "Access denied.";
                default:   return "Something went wrong, please try again.";
            }
        }

        bool parseServerResponse (const String& serverResponse, LicenseState& licenseState) override
        {
            auto json = JSON::parse (serverResponse);

            licenseState.authToken = json.getProperty ("token", {}).toString();
            licenseState.username = json.getProperty ("user", {}).getProperty ("username", {}).toString();

            return (licenseState.authToken.isNotEmpty() && licenseState.username.isNotEmpty());
        }

        String userEmail, userPassword;
    };

    struct UserLicenseQuery  : public AccountEnquiryBase
    {
        UserLicenseQuery (const String& authToken)
            : userAuthToken (authToken)
        {
        }

        bool isPOSTLikeRequest() const override       { return false; }
        String getEndpointURLSuffix() const override  { return "/user/licences/projucer"; }
        int getSuccessCode() const override           { return 200; }

        StringPairArray getParameterNamesAndValues() const override
        {
            return {};
        }

        String getExtraHeaders() const override
        {
            return "x-access-token: " + userAuthToken;
        }

        String errorCodeToString (int errorCode) const override
        {
            switch (errorCode)
            {
                case 401:  return "User not found or could not be verified.";
                default:   return "User licenses info fetch failed (unknown error).";
            }
        }

        bool parseServerResponse (const String& serverResponse, LicenseState& licenseState) override
        {
            auto json = JSON::parse (serverResponse);

            if (auto* licensesJson = json.getArray())
            {
                std::vector<LicenseHelpers::LicenseVersionAndType> licenses;

                for (auto& license : *licensesJson)
                {
                    auto version = license.getProperty ("product_version", {}).toString().trim();
                    auto type    = license.getProperty ("licence_type", {}).toString();
                    auto status  = license.getProperty ("status", {}).toString();

                    if (status == "active" && type.isNotEmpty() && version.isNotEmpty())
                        licenses.push_back ({ version.getIntValue(), LicenseHelpers::licenseTypeForString (type) });
                }

                if (! licenses.empty())
                {
                    auto bestLicense = LicenseHelpers::findBestLicense (std::move (licenses));

                    licenseState.version = bestLicense.first;
                    licenseState.type = bestLicense.second;
                }

                return true;
            }

            return false;
        }

        String userAuthToken;
    };

    //==============================================================================
    static String postDataStringAsJSON (const StringPairArray& parameters)
    {
        DynamicObject::Ptr d (new DynamicObject());

        for (auto& key : parameters.getAllKeys())
            d->setProperty (key, parameters[key]);

        return JSON::toString (var (d.get()));
    }

    static ErrorMessageAndType runTask (std::unique_ptr<AccountEnquiryBase> accountEnquiryTask, LicenseState& state)
    {
        const ErrorMessageAndType cancelledError ("Cancelled.", ErrorType::cancelled);
        const String endpointURL ("https://api.juce.com/api/v1");

        URL url (endpointURL + accountEnquiryTask->getEndpointURLSuffix());

        auto isPOST = accountEnquiryTask->isPOSTLikeRequest();

        if (isPOST)
            url = url.withPOSTData (postDataStringAsJSON (accountEnquiryTask->getParameterNamesAndValues()));

        if (ThreadPoolJob::getCurrentThreadPoolJob()->shouldExit())
            return cancelledError;

        int statusCode = 0;
        auto urlStream = url.createInputStream (URL::InputStreamOptions (isPOST ? URL::ParameterHandling::inPostData
                                                                                : URL::ParameterHandling::inAddress)
                                                  .withExtraHeaders (accountEnquiryTask->getExtraHeaders())
                                                  .withConnectionTimeoutMs (5000)
                                                  .withStatusCode (&statusCode));

        if (urlStream == nullptr)
            return { "Failed to connect to the web server.", ErrorType::connectionError };

        if (statusCode != accountEnquiryTask->getSuccessCode())
            return { accountEnquiryTask->errorCodeToString (statusCode), ErrorType::webResponseError };

        if (ThreadPoolJob::getCurrentThreadPoolJob()->shouldExit())
            return cancelledError;

        String response;

        for (;;)
        {
            char buffer [8192] = "";
            auto num = urlStream->read (buffer, sizeof (buffer));

            if (ThreadPoolJob::getCurrentThreadPoolJob()->shouldExit())
                return cancelledError;

            if (num <= 0)
                break;

            response += buffer;
        }

        if (ThreadPoolJob::getCurrentThreadPoolJob()->shouldExit())
            return cancelledError;

        if (! accountEnquiryTask->parseServerResponse (response, state))
            return { "Failed to parse server response.", ErrorType::webResponseError };

        return {};
    }

    //==============================================================================
    ThreadPool jobPool { 1 };

    //==============================================================================
    JUCE_DECLARE_WEAK_REFERENCEABLE (LicenseQueryThread)
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (LicenseQueryThread)
};