#include <gtest/gtest.h>

#include "XCUIBackend/XCUIAssetDocumentSource.h"

#include <XCEngine/Core/Asset/ResourceManager.h>
#include <XCEngine/Core/Containers/String.h>

#include <chrono>
#include <filesystem>
#include <fstream>
#include <string>

namespace {

namespace fs = std::filesystem;

using XCEngine::Containers::String;
using XCEngine::Editor::XCUIBackend::XCUIAssetDocumentSource;
using XCEngine::Resources::ResourceManager;

String ToContainersString(const std::string& value) {
    return String(value.c_str());
}

void WriteTextFile(const fs::path& path, const std::string& contents) {
    fs::create_directories(path.parent_path());
    std::ofstream output(path, std::ios::binary | std::ios::trunc);
    output << contents;
}

std::string BuildMinimalViewDocument(const std::string& themeReference) {
    return
        "<View name=\"Test\" theme=\"" + themeReference + "\">\n"
        "  <Column id=\"root\">\n"
        "    <Text text=\"hello\" />\n"
        "  </Column>\n"
        "</View>\n";
}

std::string BuildMinimalThemeDocument() {
    return
        "<Theme name=\"TestTheme\">\n"
        "  <Token name=\"color.text.primary\" type=\"color\" value=\"#FFFFFF\" />\n"
        "</Theme>\n";
}

class ScopedCurrentPath {
public:
    explicit ScopedCurrentPath(const fs::path& newPath) {
        m_originalPath = fs::current_path();
        fs::create_directories(newPath);
        fs::current_path(newPath);
    }

    ~ScopedCurrentPath() {
        if (!m_originalPath.empty()) {
            fs::current_path(m_originalPath);
        }
    }

private:
    fs::path m_originalPath = {};
};

class XCUIAssetDocumentSourceTest : public ::testing::Test {
protected:
    void SetUp() override {
        m_originalResourceRoot = ResourceManager::Get().GetResourceRoot();
        ResourceManager::Get().SetResourceRoot(String());

        m_tempRoot = fs::temp_directory_path() /
            fs::path("xcui_asset_document_source_tests");
        m_tempRoot /= fs::path(::testing::UnitTest::GetInstance()->current_test_info()->name());
        fs::remove_all(m_tempRoot);
        fs::create_directories(m_tempRoot);
    }

    void TearDown() override {
        ResourceManager::Get().UnloadAll();
        ResourceManager::Get().SetResourceRoot(m_originalResourceRoot);

        std::error_code ec;
        fs::remove_all(m_tempRoot, ec);
    }

    fs::path CreateRepositorySubdir(const std::string& relativePath) const {
        const fs::path path = m_tempRoot / fs::path(relativePath);
        fs::create_directories(path);
        return path;
    }

    void WriteProjectDocuments(const XCUIAssetDocumentSource::PathSet& paths) const {
        WriteTextFile(
            m_tempRoot / fs::path(paths.view.primaryRelativePath),
            BuildMinimalViewDocument("Theme.xctheme"));
        WriteTextFile(
            m_tempRoot / fs::path(paths.theme.primaryRelativePath),
            BuildMinimalThemeDocument());
    }

    void WriteLegacyDocuments(const XCUIAssetDocumentSource::PathSet& paths) const {
        WriteTextFile(
            m_tempRoot / fs::path(paths.view.legacyRelativePath),
            BuildMinimalViewDocument(
                fs::path(paths.theme.legacyRelativePath).filename().generic_string()));
        WriteTextFile(
            m_tempRoot / fs::path(paths.theme.legacyRelativePath),
            BuildMinimalThemeDocument());
    }

    fs::path m_tempRoot = {};

private:
    String m_originalResourceRoot = {};
};

TEST_F(XCUIAssetDocumentSourceTest, DemoAndLayoutLabPathSetsUseExpectedPaths) {
    const XCUIAssetDocumentSource::PathSet demoPaths =
        XCUIAssetDocumentSource::MakeDemoPathSet();
    EXPECT_EQ(demoPaths.setName, "Demo");
    EXPECT_EQ(demoPaths.view.primaryRelativePath, "Assets/XCUI/NewEditor/Demo/View.xcui");
    EXPECT_EQ(demoPaths.theme.primaryRelativePath, "Assets/XCUI/NewEditor/Demo/Theme.xctheme");
    EXPECT_EQ(demoPaths.view.legacyRelativePath, "new_editor/resources/xcui_demo_view.xcui");
    EXPECT_EQ(demoPaths.theme.legacyRelativePath, "new_editor/resources/xcui_demo_theme.xctheme");

    const XCUIAssetDocumentSource::PathSet layoutLabPaths =
        XCUIAssetDocumentSource::MakeLayoutLabPathSet();
    EXPECT_EQ(layoutLabPaths.setName, "LayoutLab");
    EXPECT_EQ(layoutLabPaths.view.primaryRelativePath, "Assets/XCUI/NewEditor/LayoutLab/View.xcui");
    EXPECT_EQ(layoutLabPaths.theme.primaryRelativePath, "Assets/XCUI/NewEditor/LayoutLab/Theme.xctheme");
    EXPECT_EQ(layoutLabPaths.view.legacyRelativePath, "new_editor/resources/xcui_layout_lab_view.xcui");
    EXPECT_EQ(layoutLabPaths.theme.legacyRelativePath, "new_editor/resources/xcui_layout_lab_theme.xctheme");
}

TEST_F(XCUIAssetDocumentSourceTest, MakePathSetSanitizesNamesAndBuildsLegacySnakeCase) {
    const XCUIAssetDocumentSource::PathSet paths =
        XCUIAssetDocumentSource::MakePathSet(" Layout Lab! Debug-42 ");

    EXPECT_EQ(paths.setName, "LayoutLabDebug-42");
    EXPECT_EQ(
        paths.view.primaryRelativePath,
        "Assets/XCUI/NewEditor/LayoutLabDebug-42/View.xcui");
    EXPECT_EQ(
        paths.theme.legacyRelativePath,
        "new_editor/resources/xcui_layout_lab_debug_42_theme.xctheme");
}

TEST_F(XCUIAssetDocumentSourceTest, CollectCandidatePathsPrefersProjectAssetsBeforeLegacyMirror) {
    const XCUIAssetDocumentSource::PathSet paths =
        XCUIAssetDocumentSource::MakePathSet("Worker1CandidateOrder");
    WriteProjectDocuments(paths);
    WriteLegacyDocuments(paths);

    const std::vector<XCUIAssetDocumentSource::ResolutionCandidate> candidates =
        XCUIAssetDocumentSource::CollectCandidatePaths(paths.view, m_tempRoot, fs::path());

    ASSERT_EQ(candidates.size(), 2u);
    EXPECT_EQ(candidates[0].origin, XCUIAssetDocumentSource::PathOrigin::ProjectAssets);
    EXPECT_EQ(candidates[0].resolvedPath, fs::path(m_tempRoot / paths.view.primaryRelativePath).lexically_normal());
    EXPECT_EQ(candidates[1].origin, XCUIAssetDocumentSource::PathOrigin::LegacyMirror);
    EXPECT_EQ(candidates[1].resolvedPath, fs::path(m_tempRoot / paths.view.legacyRelativePath).lexically_normal());
}

TEST_F(XCUIAssetDocumentSourceTest, DiagnoseRepositoryRootReportsProjectAssetAncestor) {
    const XCUIAssetDocumentSource::PathSet paths =
        XCUIAssetDocumentSource::MakeDemoPathSet();
    WriteProjectDocuments(paths);

    const fs::path searchRoot = CreateRepositorySubdir("tools/worker1/deep");
    const XCUIAssetDocumentSource::RepositoryDiscovery discovery =
        XCUIAssetDocumentSource::DiagnoseRepositoryRoot(paths, { searchRoot }, false);

    EXPECT_EQ(discovery.repositoryRoot, m_tempRoot.lexically_normal());
    ASSERT_EQ(discovery.probes.size(), 1u);
    EXPECT_TRUE(discovery.probes[0].matched);
    EXPECT_EQ(discovery.probes[0].searchRoot, searchRoot.lexically_normal());
    EXPECT_EQ(discovery.probes[0].matchedRelativePath, paths.view.primaryRelativePath);
    EXPECT_NE(discovery.statusMessage.find(paths.view.primaryRelativePath), std::string::npos);
}

TEST_F(XCUIAssetDocumentSourceTest, DiagnoseRepositoryRootReportsLegacyMirrorAncestor) {
    const XCUIAssetDocumentSource::PathSet paths =
        XCUIAssetDocumentSource::MakeLayoutLabPathSet();
    WriteLegacyDocuments(paths);

    const fs::path searchRoot = CreateRepositorySubdir("sandbox/runtime/session");
    const XCUIAssetDocumentSource::RepositoryDiscovery discovery =
        XCUIAssetDocumentSource::DiagnoseRepositoryRoot(paths, { searchRoot }, false);

    EXPECT_EQ(discovery.repositoryRoot, m_tempRoot.lexically_normal());
    ASSERT_EQ(discovery.probes.size(), 1u);
    EXPECT_TRUE(discovery.probes[0].matched);
    EXPECT_EQ(discovery.probes[0].matchedRelativePath, paths.view.legacyRelativePath);
    EXPECT_NE(discovery.statusMessage.find(paths.view.legacyRelativePath), std::string::npos);
}

TEST_F(XCUIAssetDocumentSourceTest, ReloadUsesLegacyFallbackAndTracksSourceChanges) {
    const XCUIAssetDocumentSource::PathSet paths =
        XCUIAssetDocumentSource::MakePathSet("Worker1HotReloadRegression");
    WriteLegacyDocuments(paths);

    const fs::path sandboxPath = CreateRepositorySubdir("runtime/worker1");
    ScopedCurrentPath scopedCurrentPath(sandboxPath);

    XCUIAssetDocumentSource source(paths);
    ASSERT_TRUE(source.Reload());

    const XCUIAssetDocumentSource::LoadState& initialState = source.GetState();
    EXPECT_TRUE(initialState.succeeded);
    EXPECT_TRUE(initialState.usedLegacyFallback);
    EXPECT_TRUE(initialState.changeTrackingReady);
    EXPECT_TRUE(initialState.missingTrackedSourcePaths.empty());
    EXPECT_EQ(initialState.repositoryRoot, m_tempRoot.lexically_normal());
    EXPECT_EQ(initialState.view.pathOrigin, XCUIAssetDocumentSource::PathOrigin::LegacyMirror);
    EXPECT_EQ(initialState.theme.pathOrigin, XCUIAssetDocumentSource::PathOrigin::LegacyMirror);
    EXPECT_FALSE(initialState.trackedSourcePaths.empty());
    EXPECT_NE(initialState.trackingStatusMessage.find("Tracking "), std::string::npos);
    EXPECT_FALSE(source.HasTrackedChanges());

    const fs::path themePath = m_tempRoot / fs::path(paths.theme.legacyRelativePath);
    fs::last_write_time(
        themePath,
        fs::last_write_time(themePath) + std::chrono::seconds(2));

    EXPECT_TRUE(source.HasTrackedChanges());
    ASSERT_TRUE(source.ReloadIfChanged());

    const XCUIAssetDocumentSource::LoadState& reloadedState = source.GetState();
    EXPECT_EQ(
        reloadedState.view.backend,
        XCUIAssetDocumentSource::LoadBackend::CompilerFallback);
    EXPECT_EQ(
        reloadedState.theme.backend,
        XCUIAssetDocumentSource::LoadBackend::CompilerFallback);
    EXPECT_TRUE(reloadedState.changeTrackingReady);
}

TEST_F(XCUIAssetDocumentSourceTest, ReloadFailureIncludesRepositoryDiscoveryDiagnostic) {
    const XCUIAssetDocumentSource::PathSet paths =
        XCUIAssetDocumentSource::MakePathSet("Worker1MissingDocuments");
    const fs::path sandboxPath = CreateRepositorySubdir("runtime/missing");
    ScopedCurrentPath scopedCurrentPath(sandboxPath);

    XCUIAssetDocumentSource source(paths);
    EXPECT_FALSE(source.Reload());

    const XCUIAssetDocumentSource::LoadState& state = source.GetState();
    EXPECT_FALSE(state.succeeded);
    EXPECT_TRUE(state.repositoryRoot.empty());
    EXPECT_NE(state.repositoryDiscovery.statusMessage.find("Repository root not found"), std::string::npos);
    EXPECT_NE(state.errorMessage.find(paths.view.primaryRelativePath), std::string::npos);
    EXPECT_NE(state.errorMessage.find("Repository root not found"), std::string::npos);
    EXPECT_TRUE(state.view.candidatePaths.empty());
    EXPECT_TRUE(state.view.attemptMessages.empty());
}

} // namespace