/*
    SPDX-FileCopyrightText: 2012-2018 Daniel Vrátil <dvratil@kde.org>

    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
*/

#include "tasksservice.h"
#include "object.h"
#include "task.h"
#include "tasklist.h"
#include "utils.h"

#include <QJsonDocument>
#include <QUrlQuery>
#include <QVariant>

namespace KGAPI2
{

namespace TasksService
{

namespace
{
/* Google accepts only UTC time strictly in this format :( */
static const auto DatetimeFormat = QStringLiteral("yyyy-MM-ddThh:mm:ss.zzzZ");

static const auto TasksUrlPart = QLatin1StringView("/tasks");

static const auto PageTokenParam = QStringLiteral("pageToken");
static const auto MaxResultsParam = QStringLiteral("maxResults");
static const auto MaxResultsParamValueDefault = QStringLiteral("20");

static const auto KindAttr = QStringLiteral("kind");
static const auto IdAttr = QStringLiteral("id");
static const auto EtagAttr = QStringLiteral("etag");
static const auto TitleAttr = QStringLiteral("title");
static const auto NotesAttr = QStringLiteral("notes");
static const auto ItemsAttr = QStringLiteral("items");
static const auto NextPageTokenAttr = QStringLiteral("nextPageToken");
static const auto ParentAttr = QStringLiteral("parent");
static const auto SelfLinkAttr = QStringLiteral("selfLink");
static const auto UpdatedAttr = QStringLiteral("updated");
static const auto StatusAttr = QStringLiteral("status");
static const auto DueAttr = QStringLiteral("due");
static const auto DeletedAttr = QStringLiteral("deleted");

static const auto CompletedAttrVal = QLatin1StringView("completed");
static const auto NeedsActionAttrVal = QLatin1StringView("needsAction");
}

namespace Private
{
ObjectsList parseTaskListJSONFeed(const QVariantList &items);
ObjectsList parseTasksJSONFeed(const QVariantList &items);

ObjectPtr JSONToTaskList(const QVariantMap &jsonData);
ObjectPtr JSONToTask(const QVariantMap &jsonData);

static const QUrl GoogleApisUrl(QStringLiteral("https://www.googleapis.com"));
static const QString TasksBasePath(QStringLiteral("/tasks/v1/lists"));
static const QString TasksListsBasePath(QStringLiteral("/tasks/v1/users/@me/lists"));
}

ObjectsList parseJSONFeed(const QByteArray &jsonFeed, FeedData &feedData)
{
    QJsonDocument document = QJsonDocument::fromJson(jsonFeed);
    if (document.isNull()) {
        return ObjectsList();
    }

    ObjectsList list;
    const QVariantMap feed = document.toVariant().toMap();

    if (feed.value(KindAttr).toString() == QLatin1StringView("tasks#taskLists")) {
        list = Private::parseTaskListJSONFeed(feed.value(ItemsAttr).toList());

        if (feed.contains(NextPageTokenAttr)) {
            feedData.nextPageUrl = fetchTaskListsUrl();
            QUrlQuery query(feedData.nextPageUrl);
            query.addQueryItem(PageTokenParam, feed.value(NextPageTokenAttr).toString());
            if (query.queryItemValue(MaxResultsParam).isEmpty()) {
                query.addQueryItem(MaxResultsParam, MaxResultsParamValueDefault);
            }
            feedData.nextPageUrl.setQuery(query);
        }

    } else if (feed.value(KindAttr).toString() == QLatin1StringView("tasks#tasks")) {
        list = Private::parseTasksJSONFeed(feed.value(ItemsAttr).toList());

        if (feed.contains(NextPageTokenAttr)) {
            QString taskListId = feedData.requestUrl.toString().remove(QStringLiteral("https://www.googleapis.com/tasks/v1/lists/"));
            taskListId = taskListId.left(taskListId.indexOf(QLatin1Char('/')));

            feedData.nextPageUrl = fetchAllTasksUrl(taskListId);
            QUrlQuery query(feedData.nextPageUrl);
            query.addQueryItem(PageTokenParam, feed.value(NextPageTokenAttr).toString());
            if (query.queryItemValue(MaxResultsParam).isEmpty()) {
                query.addQueryItem(MaxResultsParam, MaxResultsParamValueDefault);
            }
            feedData.nextPageUrl.setQuery(query);
        }
    }

    return list;
}

QUrl fetchAllTasksUrl(const QString &tasklistID)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksBasePath % QLatin1Char('/') % tasklistID % TasksUrlPart);
    return url;
}

QUrl fetchTaskUrl(const QString &tasklistID, const QString &taskID)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksBasePath % QLatin1Char('/') % tasklistID % TasksUrlPart % QLatin1Char('/') % taskID);
    return url;
}

QUrl createTaskUrl(const QString &tasklistID)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksBasePath % QLatin1Char('/') % tasklistID % TasksUrlPart);
    return url;
}

QUrl updateTaskUrl(const QString &tasklistID, const QString &taskID)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksBasePath % QLatin1Char('/') % tasklistID % TasksUrlPart % QLatin1Char('/') % taskID);
    return url;
}

QUrl removeTaskUrl(const QString &tasklistID, const QString &taskID)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksBasePath % QLatin1Char('/') % tasklistID % TasksUrlPart % QLatin1Char('/') % taskID);
    return url;
}

QUrl moveTaskUrl(const QString &tasklistID, const QString &taskID, const QString &newParent)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksBasePath % QLatin1Char('/') % tasklistID % TasksUrlPart % QLatin1Char('/') % taskID % QLatin1StringView("/move"));
    if (!newParent.isEmpty()) {
        QUrlQuery query(url);
        query.addQueryItem(ParentAttr, newParent);
        url.setQuery(query);
    }

    return url;
}

QUrl fetchTaskListsUrl()
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksListsBasePath);
    return url;
}

QUrl createTaskListUrl()
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksListsBasePath);
    return url;
}

QUrl updateTaskListUrl(const QString &tasklistID)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksListsBasePath % QLatin1Char('/') % tasklistID);
    return url;
}

QUrl removeTaskListUrl(const QString &tasklistID)
{
    QUrl url(Private::GoogleApisUrl);
    url.setPath(Private::TasksListsBasePath % QLatin1Char('/') % tasklistID);
    return url;
}

/******************************* PRIVATE ******************************/

ObjectPtr Private::JSONToTaskList(const QVariantMap &jsonData)
{
    TaskListPtr taskList(new TaskList());

    taskList->setUid(jsonData.value(IdAttr).toString());
    taskList->setEtag(jsonData.value(EtagAttr).toString());
    taskList->setTitle(jsonData.value(TitleAttr).toString());
    taskList->setSelfLink(jsonData.value(SelfLinkAttr).toString());
    taskList->setUpdated(jsonData.value(UpdatedAttr).toString());

    return taskList.dynamicCast<Object>();
}

TaskListPtr JSONToTaskList(const QByteArray &jsonData)
{
    QJsonDocument document = QJsonDocument::fromJson(jsonData);
    const QVariantMap data = document.toVariant().toMap();

    if (data.value(KindAttr).toString() == QLatin1StringView("tasks#taskList")) {
        return Private::JSONToTaskList(data).staticCast<TaskList>();
    }

    return TaskListPtr();
}

ObjectPtr Private::JSONToTask(const QVariantMap &jsonData)
{
    TaskPtr task(new Task());

    task->setUid(jsonData.value(IdAttr).toString());
    task->setEtag(jsonData.value(EtagAttr).toString());
    task->setSummary(jsonData.value(TitleAttr).toString());
    task->setLastModified(Utils::rfc3339DateFromString(jsonData.value(UpdatedAttr).toString()));
    task->setDescription(jsonData.value(NotesAttr).toString());

    if (jsonData.value(StatusAttr).toString() == NeedsActionAttrVal) {
        task->setStatus(KCalendarCore::Incidence::StatusNeedsAction);
    } else if (jsonData.value(StatusAttr).toString() == CompletedAttrVal) {
        task->setStatus(KCalendarCore::Incidence::StatusCompleted);
    } else {
        task->setStatus(KCalendarCore::Incidence::StatusNone);
    }

    // "due" is date-only -- no time-of-day given.
    task->setAllDay(true);
    task->setDtDue(Utils::rfc3339DateFromString(jsonData.value(DueAttr).toString()));

    if (task->status() == KCalendarCore::Incidence::StatusCompleted) {
        task->setCompleted(Utils::rfc3339DateFromString(jsonData.value(CompletedAttrVal).toString()));
    }

    task->setDeleted(jsonData.value(DeletedAttr).toBool());

    if (jsonData.contains(ParentAttr)) {
        task->setRelatedTo(jsonData.value(ParentAttr).toString(), KCalendarCore::Incidence::RelTypeParent);
    }

    return task.dynamicCast<Object>();
}

TaskPtr JSONToTask(const QByteArray &jsonData)
{
    QJsonDocument document = QJsonDocument::fromJson(jsonData);
    const QVariantMap data = document.toVariant().toMap();

    if (data.value(KindAttr).toString() == QLatin1StringView("tasks#task")) {
        return Private::JSONToTask(data).staticCast<Task>();
    }

    return TaskPtr();
}

QByteArray taskListToJSON(const TaskListPtr &taskList)
{
    QVariantMap output;

    output.insert(KindAttr, QStringLiteral("tasks#taskList"));
    if (!taskList->uid().isEmpty()) {
        output.insert(IdAttr, taskList->uid());
    }
    output.insert(TitleAttr, taskList->title());

    QJsonDocument document = QJsonDocument::fromVariant(output);
    return document.toJson(QJsonDocument::Compact);
}

QByteArray taskToJSON(const TaskPtr &task)
{
    QVariantMap output;

    output.insert(KindAttr, QStringLiteral("tasks#task"));

    if (!task->uid().isEmpty()) {
        output.insert(IdAttr, task->uid());
    }

    output.insert(TitleAttr, task->summary());
    output.insert(NotesAttr, task->description());

    if (!task->relatedTo(KCalendarCore::Incidence::RelTypeParent).isEmpty()) {
        output.insert(ParentAttr, task->relatedTo(KCalendarCore::Incidence::RelTypeParent));
    }

    if (task->dtDue().isValid()) {
        output.insert(DueAttr, task->dtDue().toUTC().toString(DatetimeFormat));
    }

    if ((task->status() == KCalendarCore::Incidence::StatusCompleted) && task->completed().isValid()) {
        output.insert(CompletedAttrVal, task->completed().toUTC().toString(DatetimeFormat));
        output.insert(StatusAttr, CompletedAttrVal);
    } else {
        output.insert(StatusAttr, NeedsActionAttrVal);
    }

    QJsonDocument document = QJsonDocument::fromVariant(output);
    return document.toJson(QJsonDocument::Compact);
}

ObjectsList Private::parseTaskListJSONFeed(const QVariantList &items)
{
    ObjectsList list;
    list.reserve(items.size());
    for (const QVariant &item : items) {
        list.append(Private::JSONToTaskList(item.toMap()));
    }

    return list;
}

ObjectsList Private::parseTasksJSONFeed(const QVariantList &items)
{
    ObjectsList list;
    list.reserve(items.size());
    for (const QVariant &item : items) {
        list.append(Private::JSONToTask(item.toMap()));
    }

    return list;
}

} // namespace TasksService

} // namespace KGAPI2
