#include "DialogDesk.h"
#include "IO/ProjectController.h"
#include "IO/ProjectStore.h"
#include "SessionRecord.h"
#include <QFutureWatcher>
#include <QTemporaryDir>
#include <QtTest>
#include <atomic>

// Opening a project: validated first, asked second, installed last.
namespace {
const QString question = QStringLiteral("alert|2|Save changes to %1?|Your changes will be lost if you don’t save them.|Save,Cancel,Don’t Save");
const QString damaged = QStringLiteral("alert|2|Couldn’t open the project|This is not a valid OmaPhoto project, or its metadata is damaged.|OK");

// A canvas with `layers` blank layers, as unsaved work.
void paint(EditorSession &session, int layers)
{
    session.createDocument(8, 6);
    for (int index = 0; index < layers; ++index)
        session.addBlankLayer();
}

// A project of `layers` layers saved at `path`.
void store(const QString &path, int layers)
{
    EditorSession session;
    paint(session, layers);
    ProjectStore::save(session.projectSnapshot().value(), path);
}

std::optional<bool> answered(const std::function<void(std::function<void(bool)>)> &call)
{
    std::optional<bool> result;
    call([&](bool value) { result = value; });
    // An answer that never comes stays empty and fails.
    return QTest::qWaitFor([&] { return result.has_value(); }, 10'000) ? result : std::nullopt;
}

int layerCount(const EditorSession &session)
{
    return int(session.document().value().layers.size());
}

// How often the store read, and the threads it used.
std::atomic<int> loads = 0;
std::atomic<QThread *> loadingThread = nullptr, savingThread = nullptr;
QtMessageHandler forward = nullptr;
void countLoads(QtMsgType type, const QMessageLogContext &context, const QString &message)
{
    if (message.startsWith("loaded ")) {
        loads += 1;
        loadingThread = QThread::currentThread();
    }
    if (message.startsWith("saved "))
        savingThread = QThread::currentThread();
    forward(type, context, message);
}
}

class ProjectOpenTests : public QObject {
    Q_OBJECT
private slots:
    void init();
    void cleanup();
    void aSuppliedPathIsInstalledUnasked();
    void withoutAPathAFolderIsAskedFor();
    void aDamagedOrMissingProjectKeepsTheLiveDocument();
    void unsavedWorkIsAskedAboutBeforeItGoes();
    void aSaveInTheQuestionReloadsTheVeryProjectBeingOpened();
    void onlyASaveOverTheOpenedPlaceReloads();
    void theLastSignalOfAnOpenSeesItDone();
    void theStoreWorksOffTheCallersThread();
    void aTrailingSlashLeavesTheProjectItsName();
};

void ProjectOpenTests::init()
{
    loads = 0;
    forward = qInstallMessageHandler(countLoads);
}

void ProjectOpenTests::cleanup()
{
    qInstallMessageHandler(forward);
}

void ProjectOpenTests::aSuppliedPathIsInstalledUnasked()
{
    QTemporaryDir folder;
    const QString path = folder.filePath("Three.comp");
    store(path, 3);
    EditorSession session;
    ProjectController controller(session);
    DialogDesk desk;
    bool busyMeanwhile = false;
    connect(&session, &EditorSession::changed, this, [&] { busyMeanwhile = busyMeanwhile || session.isProjectBusy(); });
    QCOMPARE(answered([&](auto done) { controller.open(path, done); }), std::optional(true));
    QVERIFY(desk.seen.isEmpty() && busyMeanwhile);
    QCOMPARE(layerCount(session), 3);
    QCOMPARE(session.projectPath(), std::optional(path));
    QVERIFY(!session.isModified() && !session.isProjectBusy());
    QCOMPARE(loads, 1);
    // Saved work goes unasked as well.
    const QString other = folder.filePath("One.comp");
    store(other, 1);
    QCOMPARE(answered([&](auto done) { controller.open(other, done); }), std::optional(true));
    QVERIFY(desk.seen.isEmpty());
    QCOMPARE(layerCount(session), 1);
    QCOMPARE(session.projectPath(), std::optional(other));
    // Each read's watcher goes once it has answered.
    QTRY_VERIFY(controller.findChildren<QFutureWatcherBase *>().isEmpty());
}

void ProjectOpenTests::withoutAPathAFolderIsAskedFor()
{
    QTemporaryDir folder;
    const QString path = folder.filePath("Asked.comp");
    store(path, 2);
    EditorSession session;
    ProjectController controller(session);
    DialogDesk desk;
    desk.note = [&] { return session.isProjectBusy() ? QStringLiteral("busy") : QStringLiteral("free"); };
    // Typed with a slash at its end, as folders are.
    desk.replies = {"<cancel>", path + "/"};
    const QStringList before = described(session);
    QCOMPARE(answered([&](auto done) { controller.open(std::nullopt, done); }), std::optional(false));
    QCOMPARE(described(session), before);
    QCOMPARE(loads, 0);
    QCOMPARE(answered([&](auto done) { controller.open(std::nullopt, done); }), std::optional(true));
    QCOMPARE(desk.seen, (QStringList{"panel|Open Project|open|folder|||busy", "panel|Open Project|open|folder|||busy"}));
    QCOMPARE(layerCount(session), 2);
    QCOMPARE(session.projectPath(), std::optional(path));
    QVERIFY(!session.isProjectBusy());
}

void ProjectOpenTests::aDamagedOrMissingProjectKeepsTheLiveDocument()
{
    QTemporaryDir folder;
    const QString broken = folder.filePath("Broken.comp");
    QVERIFY(QDir().mkpath(broken));
    QFile manifest(broken + "/manifest.json");
    QVERIFY(manifest.open(QIODevice::WriteOnly));
    manifest.write("{ not a manifest");
    manifest.close();
    EditorSession session;
    paint(session, 2);
    ProjectController controller(session);
    const QStringList before = described(session);
    DialogDesk desk;
    desk.note = [&] { return session.isProjectBusy() ? QStringLiteral("busy") : QStringLiteral("free"); };
    desk.replies = {"OK", "OK"};
    QTest::ignoreMessage(QtWarningMsg, "Couldn’t open the project: This is not a valid OmaPhoto project, or its metadata is damaged.");
    QCOMPARE(answered([&](auto done) { controller.open(broken, done); }), std::optional(false));
    // Validation came first: the unsaved work was never in question.
    QCOMPARE(desk.seen, (QStringList{damaged + "|busy"}));
    QCOMPARE(described(session), before);
    QVERIFY(session.isModified() && !session.isProjectBusy());
    // A missing project is named.
    QTest::ignoreMessage(QtWarningMsg, "Couldn’t open the project: The file “Nowhere.comp” couldn’t be opened because there is no such file.");
    QCOMPARE(answered([&](auto done) { controller.open(folder.filePath("Nowhere.comp"), done); }), std::optional(false));
    QCOMPARE(desk.seen.size(), 2);
    QVERIFY2(desk.seen[1].startsWith("alert|2|Couldn’t open the project|The file “Nowhere.comp” couldn’t be opened because there is no such file.|"),
             qPrintable(desk.seen[1]));
    QCOMPARE(described(session), before);
}

void ProjectOpenTests::unsavedWorkIsAskedAboutBeforeItGoes()
{
    QTemporaryDir folder;
    const QString incoming = folder.filePath("Incoming.comp"), kept = folder.filePath("Kept.comp");
    store(incoming, 3);
    EditorSession session;
    paint(session, 1);
    ProjectController controller(session);
    DialogDesk desk;
    desk.replies = {"Cancel", "Don’t Save"};
    const QStringList before = described(session);
    QCOMPARE(answered([&](auto done) { controller.open(incoming, done); }), std::optional(false));
    QCOMPARE(described(session), before);
    QCOMPARE(answered([&](auto done) { controller.open(incoming, done); }), std::optional(true));
    QCOMPARE(desk.seen, (QStringList{question.arg("Untitled"), question.arg("Untitled")}));
    QCOMPARE(layerCount(session), 3);
    QVERIFY(!session.isModified());
    // Save first: the work reaches the disk, then goes.
    paint(session, 2);
    session.setProjectPath(kept);
    desk.replies = {"Save"};
    QCOMPARE(answered([&](auto done) { controller.open(incoming, done); }), std::optional(true));
    QCOMPARE(desk.seen.last(), question.arg("Kept.comp"));
    QCOMPARE(int(ProjectStore::load(kept).manifest.layers.size()), 2);
    QCOMPARE(layerCount(session), 3);
    QCOMPARE(session.projectPath(), std::optional(incoming));
    QVERIFY(!session.isModified() && !session.isProjectBusy());
}

void ProjectOpenTests::aSaveInTheQuestionReloadsTheVeryProjectBeingOpened()
{
    QTemporaryDir folder;
    const QString path = folder.filePath("Same.comp"), link = folder.filePath("Link.comp");
    store(path, 1);
    QVERIFY(QFile::link(path, link));
    EditorSession session;
    ProjectController controller(session);
    QCOMPARE(answered([&](auto done) { controller.open(path, done); }), std::optional(true));
    session.addBlankLayer();
    QCOMPARE(layerCount(session), 2);
    // Opened again through a link, and saved in the question.
    DialogDesk desk;
    desk.replies = {"Save"};
    loads = 0;
    QCOMPARE(answered([&](auto done) { controller.open(link, done); }), std::optional(true));
    QCOMPARE(desk.seen, (QStringList{question.arg("Same.comp")}));
    // What was read before the save is stale: read again.
    QCOMPARE(loads, 2);
    QCOMPARE(layerCount(session), 2);
    QCOMPARE(session.projectPath(), std::optional(link));
    QVERIFY(!session.isModified() && !session.isProjectBusy());
}

void ProjectOpenTests::onlyASaveOverTheOpenedPlaceReloads()
{
    QTemporaryDir folder;
    const QString first = folder.filePath("First.comp"), second = folder.filePath("Second.comp");
    store(first, 1);
    store(second, 3);
    EditorSession session;
    ProjectController controller(session);
    QCOMPARE(answered([&](auto done) { controller.open(first, done); }), std::optional(true));
    // The same place, nothing saved: one read is enough.
    session.addBlankLayer();
    DialogDesk desk;
    desk.replies = {"Don’t Save", "Save"};
    loads = 0;
    QCOMPARE(answered([&](auto done) { controller.open(first, done); }), std::optional(true));
    QCOMPARE(loads, 1);
    QCOMPARE(layerCount(session), 1);
    // Saved, but to another place than the one opened.
    session.addBlankLayer();
    loads = 0;
    QCOMPARE(answered([&](auto done) { controller.open(second, done); }), std::optional(true));
    QCOMPARE(loads, 1);
    QCOMPARE(layerCount(session), 3);
    QCOMPARE(int(ProjectStore::load(first).manifest.layers.size()), 2);
}

void ProjectOpenTests::theLastSignalOfAnOpenSeesItDone()
{
    QTemporaryDir folder;
    const QString path = folder.filePath("Seen.comp");
    store(path, 2);
    EditorSession session;
    ProjectController controller(session);
    QStringList seen;
    connect(&session, &EditorSession::changed, this, [&] { seen = described(session); });
    QCOMPARE(answered([&](auto done) { controller.open(path, done); }), std::optional(true));
    QCOMPARE(seen, described(session));
    QVERIFY(seen.contains("path " + path) && seen.contains("flags 0000"));
}

void ProjectOpenTests::theStoreWorksOffTheCallersThread()
{
    QTemporaryDir folder;
    const QString path = folder.filePath("Threads.comp");
    store(path, 1);
    EditorSession session;
    ProjectController controller(session);
    loadingThread = savingThread = nullptr;
    QCOMPARE(answered([&](auto done) { controller.open(path, done); }), std::optional(true));
    session.addBlankLayer();
    QCOMPARE(answered([&](auto done) { controller.save(false, done); }), std::optional(true));
    // The store logs from the thread that did the work.
    QVERIFY(loadingThread.load() != nullptr && savingThread.load() != nullptr);
    QVERIFY(loadingThread.load() != QThread::currentThread());
    QVERIFY(savingThread.load() != QThread::currentThread());
    QCOMPARE(controller.thread(), QThread::currentThread());
}

void ProjectOpenTests::aTrailingSlashLeavesTheProjectItsName()
{
    QTemporaryDir folder;
    const QString path = folder.filePath("Friendly.COMP");
    store(path, 1);
    EditorSession session;
    ProjectController controller(session);
    // A shell completes a folder's name with a slash.
    QCOMPARE(answered([&](auto done) { controller.open(path + "/", done); }), std::optional(true));
    QCOMPARE(session.projectPath(), std::optional(path));
    session.addBlankLayer();
    DialogDesk desk;
    desk.replies = {"Cancel", "<cancel>"};
    QCOMPARE(answered([&](auto done) { controller.confirmQuit(done); }), std::optional(false));
    QCOMPARE(answered([&](auto done) { controller.save(true, done); }), std::optional(false));
    QCOMPARE(desk.seen, (QStringList{question.arg("Friendly.COMP"), "panel|Save Project As|save|file|Friendly.COMP|comp"}));
    // Only the end is trimmed: `link/..` keeps its meaning.
    QVERIFY(QDir().mkpath(folder.filePath("remote/deep")));
    QVERIFY(QFile::link(folder.filePath("remote/deep"), folder.filePath("link")));
    store(folder.filePath("Other.comp"), 1);
    store(folder.filePath("remote/Other.comp"), 3);
    EditorSession linked;
    ProjectController opener(linked);
    const QString through = folder.filePath("link/../Other.comp");
    QCOMPARE(answered([&](auto done) { opener.open(through + "//", done); }), std::optional(true));
    QCOMPARE(layerCount(linked), 3);
    QCOMPARE(linked.projectPath(), std::optional(through));
}

QTEST_MAIN(ProjectOpenTests)
#include "ProjectOpenTests.moc"