// IACore-OSS; The Core Library for All IA Open Source Projects 
// Copyright (C) 2025 IAS (ias@iasoft.dev)
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

#include <IACore/FileOps.hpp>

#include <IACore/IATest.hpp>

using namespace IACore;

// -----------------------------------------------------------------------------
// Test Block Definition
// -----------------------------------------------------------------------------

IAT_BEGIN_BLOCK(Core, File)

    // Helper to generate a temp path for testing
    String GetTempPath(const String& filename) {
        auto path = std::filesystem::temp_directory_path() / filename;
        return path.string();
    }

    // Helper to write raw data for setup (bypassing the class we are testing)
    void CreateDummyFile(const String& path, const String& content) {
        std::ofstream out(path);
        out << content;
        out.close();
    }

    // -------------------------------------------------------------------------
    // 1. Path Utilities (Pure Logic)
    // -------------------------------------------------------------------------
    BOOL TestPathUtils() 
    {
        // We use forward slashes as std::filesystem handles them cross-platform
        String complexPath = "assets/textures/hero_diffuse.png";

        // Test ExtractDirectory
        String dir = File::ExtractDirectory(complexPath);
        // Note: On Windows this might return "assets\textures", check specific impl if strict
        // But std::filesystem usually normalizes based on the input string format.
        IAT_CHECK(dir.find("textures") != String::npos); 

        // Test ExtractFilename (With Extension)
        String nameWithExt = File::ExtractFilename<true>(complexPath);
        IAT_CHECK_EQ(nameWithExt, String("hero_diffuse.png"));

        // Test ExtractFilename (No Extension / Stem)
        String nameNoExt = File::ExtractFilename<false>(complexPath);
        IAT_CHECK_EQ(nameNoExt, String("hero_diffuse"));

        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 2. Static Read String
    // -------------------------------------------------------------------------
    BOOL TestStaticReadString() 
    {
        String path = GetTempPath("ia_test_text.txt");
        String content = "Hello IA Engine";
        
        // Arrange
        CreateDummyFile(path, content);

        // Act
        auto result = File::ReadToString(path);

        // Assert
        IAT_CHECK(result.has_value());
        IAT_CHECK_EQ(*result, content);

        // Cleanup
        std::filesystem::remove(path);
        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 3. Static Read Binary (Vector)
    // -------------------------------------------------------------------------
    BOOL TestStaticReadVector() 
    {
        String path = GetTempPath("ia_test_bin.dat");
        
        // Arrange: Create a binary file manually
        std::ofstream out(path, std::ios::binary);
        UINT8 rawBytes[] = { 0xDE, 0xAD, 0xBE, 0xEF };
        out.write((char*)rawBytes, 4);
        out.close();

        // Act
        auto result = File::ReadToVector(path);

        // Assert
        IAT_CHECK(result.has_value());
        Vector<UINT8>& vec = *result;
        
        IAT_CHECK_EQ(vec.size(), (SIZE_T)4);
        IAT_CHECK_EQ(vec[0], 0xDE);
        IAT_CHECK_EQ(vec[3], 0xEF);

        // Cleanup
        std::filesystem::remove(path);
        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 4. Instance Write & Read Loop
    // -------------------------------------------------------------------------
    BOOL TestInstanceWriteRead() 
    {
        String path = GetTempPath("ia_instance_io.bin");
        UINT32 flagsWrite = (UINT32)File::EOpenFlags::Write | 
                            (UINT32)File::EOpenFlags::Binary | 
                            (UINT32)File::EOpenFlags::Trunc;

        // 1. Write
        {
            File f;
            auto res = f.Open(path, (File::EOpenFlags)flagsWrite);
            IAT_CHECK(res.has_value());
            IAT_CHECK(f.IsOpen());

            UINT32 magic = 12345;
            f.Write(&magic, sizeof(magic));
            
            f.Close();
            IAT_CHECK_NOT(f.IsOpen());
        }

        // 2. Read Back
        {
            UINT32 flagsRead = (UINT32)File::EOpenFlags::Read | 
                               (UINT32)File::EOpenFlags::Binary;
            
            File f(path, (File::EOpenFlags)flagsRead); // Test RAII constructor
            IAT_CHECK(f.IsOpen());

            UINT32 magicRead = 0;
            SIZE_T bytesRead = f.Read(&magicRead, sizeof(magicRead));

            IAT_CHECK_EQ(bytesRead, sizeof(UINT32));
            IAT_CHECK_EQ(magicRead, (UINT32)12345);
        }

        std::filesystem::remove(path);
        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 5. Append Mode
    // -------------------------------------------------------------------------
    BOOL TestAppendMode() 
    {
        String path = GetTempPath("ia_append.txt");
        UINT32 flagsAppend = (UINT32)File::EOpenFlags::Write | (UINT32)File::EOpenFlags::Append;

        // Create initial file
        CreateDummyFile(path, "A");

        // Open in append mode
        File f;
        const auto openResult = f.Open(path, (File::EOpenFlags)flagsAppend);
        if(!openResult)
        {
            IA_PANIC(openResult.error().c_str())
            return FALSE;
        }
        char c = 'B';
        f.Write(&c, 1);
        f.Close();

        // Verify content is "AB"
        auto content = File::ReadToString(path);
        IAT_CHECK(content.has_value());
        IAT_CHECK_EQ(*content, String("AB"));

        std::filesystem::remove(path);
        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 6. Error Handling
    // -------------------------------------------------------------------------
    BOOL TestNonExistentFile() 
    {
        String ghostPath = GetTempPath("this_does_not_exist.ghost");
        
        // Ensure it really doesn't exist
        if(File::Exists(ghostPath)) std::filesystem::remove(ghostPath);

        // Test Static
        auto resStatic = File::ReadToString(ghostPath);
        IAT_CHECK_NOT(resStatic.has_value());
        // Optional: Check error message content
        // IAT_CHECK(resStatic.error().find("not found") != String::npos);

        // Test Instance
        File f;
        auto resInstance = f.Open(ghostPath, File::EOpenFlags::Read);
        IAT_CHECK_NOT(resInstance.has_value());
        IAT_CHECK_NOT(f.IsOpen());

        return TRUE;
    }

    // -------------------------------------------------------------------------
    // Registration
    // -------------------------------------------------------------------------
    IAT_BEGIN_TEST_LIST()
        IAT_ADD_TEST(TestPathUtils);
        IAT_ADD_TEST(TestStaticReadString);
        IAT_ADD_TEST(TestStaticReadVector);
        IAT_ADD_TEST(TestInstanceWriteRead);
        IAT_ADD_TEST(TestAppendMode);
        IAT_ADD_TEST(TestNonExistentFile);
    IAT_END_TEST_LIST()

IAT_END_BLOCK()


int main(int argc, char* argv[])
{
    UNUSED(argc);
    UNUSED(argv);

    // Define runner (StopOnFail=false, Verbose=true)
    ia::iatest::runner<false, true> testRunner;
    
    // Run the BinaryReader block
    testRunner.testBlock<Core_File>();

    return 0;
}