// 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/Environment.hpp>

#include <IACore/IATest.hpp>

using namespace IACore;

// -----------------------------------------------------------------------------
// Constants
// -----------------------------------------------------------------------------
// We use a unique prefix to ensure we don't accidentally mess with real
// system variables like PATH or HOME.
static const char* TEST_KEY = "IA_TEST_ENV_VAR_12345";
static const char* TEST_VAL = "Hello World";

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

IAT_BEGIN_BLOCK(Core, Environment)

    // -------------------------------------------------------------------------
    // 1. Basic Set and Get (The Happy Path)
    // -------------------------------------------------------------------------
    BOOL TestBasicCycle() 
    {
        // 1. Ensure clean slate
        Environment::Unset(TEST_KEY);
        IAT_CHECK_NOT(Environment::Exists(TEST_KEY));

        // 2. Set
        BOOL setRes = Environment::Set(TEST_KEY, TEST_VAL);
        IAT_CHECK(setRes);
        IAT_CHECK(Environment::Exists(TEST_KEY));

        // 3. Find (Optional)
        auto opt = Environment::Find(TEST_KEY);
        IAT_CHECK(opt.has_value());
        IAT_CHECK_EQ(*opt, String(TEST_VAL));

        // 4. Get (Direct)
        String val = Environment::Get(TEST_KEY);
        IAT_CHECK_EQ(val, String(TEST_VAL));

        // Cleanup
        Environment::Unset(TEST_KEY);
        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 2. Overwriting Values
    // -------------------------------------------------------------------------
    BOOL TestOverwrite() 
    {
        Environment::Set(TEST_KEY, "ValueA");
        IAT_CHECK_EQ(Environment::Get(TEST_KEY), String("ValueA"));

        // Overwrite
        Environment::Set(TEST_KEY, "ValueB");
        IAT_CHECK_EQ(Environment::Get(TEST_KEY), String("ValueB"));

        Environment::Unset(TEST_KEY);
        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 3. Unset Logic
    // -------------------------------------------------------------------------
    BOOL TestUnset() 
    {
        Environment::Set(TEST_KEY, "To Be Deleted");
        IAT_CHECK(Environment::Exists(TEST_KEY));

        BOOL unsetRes = Environment::Unset(TEST_KEY);
        IAT_CHECK(unsetRes);

        // Verify it is actually gone
        IAT_CHECK_NOT(Environment::Exists(TEST_KEY));
        
        // Find should return nullopt
        auto opt = Environment::Find(TEST_KEY);
        IAT_CHECK_NOT(opt.has_value());

        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 4. Default Value Fallbacks
    // -------------------------------------------------------------------------
    BOOL TestDefaults() 
    {
        const char* ghostKey = "IA_THIS_KEY_DOES_NOT_EXIST";
        
        // Ensure it really doesn't exist
        Environment::Unset(ghostKey);

        // Test Get with implicit default ("")
        String empty = Environment::Get(ghostKey);
        IAT_CHECK(empty.empty());

        // Test Get with explicit default
        String fallback = Environment::Get(ghostKey, "MyDefault");
        IAT_CHECK_EQ(fallback, String("MyDefault"));

        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 5. Empty Strings vs Null/Unset
    // -------------------------------------------------------------------------
    // This is a critical edge case. 
    // Does Set(Key, "") create an existing empty variable, or unset it?
    // Standard POSIX/Windows API behavior is that it EXISTS, but is empty.
    BOOL TestEmptyValue() 
    {
        Environment::Set(TEST_KEY, "");

        // It should exist
        IAT_CHECK(Environment::Exists(TEST_KEY));

        // It should be retrievable as empty string
        auto opt = Environment::Find(TEST_KEY);
        IAT_CHECK(opt.has_value());
        IAT_CHECK(opt->empty());

        // Cleanup
        Environment::Unset(TEST_KEY);
        IAT_CHECK_NOT(Environment::Exists(TEST_KEY));

        return TRUE;
    }

    // -------------------------------------------------------------------------
    // 6. Validation / Bad Input
    // -------------------------------------------------------------------------
    BOOL TestBadInput() 
    {
        // Setting an empty key should fail gracefully
        BOOL res = Environment::Set("", "Value");
        IAT_CHECK_NOT(res);

        // Unsetting an empty key should fail
        BOOL resUnset = Environment::Unset("");
        IAT_CHECK_NOT(resUnset);

        return TRUE;
    }

    // -------------------------------------------------------------------------
    // Registration
    // -------------------------------------------------------------------------
    IAT_BEGIN_TEST_LIST()
        IAT_ADD_TEST(TestBasicCycle);
        IAT_ADD_TEST(TestOverwrite);
        IAT_ADD_TEST(TestUnset);
        IAT_ADD_TEST(TestDefaults);
        IAT_ADD_TEST(TestEmptyValue);
        IAT_ADD_TEST(TestBadInput);
    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_Environment>();

    return 0;
}