#include "lix/libutil/config.hh"
#include "lix/libutil/args.hh"
#include "lix/libutil/file-system.hh"
#include "lix/libutil/environment-variables.hh"
#include "lix/libutil/logging.hh"
#include "tests/test-data.hh"

#include <sstream>
#include <gtest/gtest.h>
#include <nlohmann/json.hpp>

namespace nix {

    /* ----------------------------------------------------------------------------
     * Config
     * --------------------------------------------------------------------------*/

    TEST(Config, setUndefinedSetting) {
        Config config;
        ASSERT_EQ(config.set("undefined-key", "value"), false);
    }

    TEST(Config, setDefinedSetting) {
        Config config;
        std::string value;
        Setting<std::string> foo{&config, value, "name-of-the-setting", "description"};
        ASSERT_EQ(config.set("name-of-the-setting", "value"), true);
    }

    TEST(Config, getDefinedSetting) {
        Config config;
        std::string value;
        std::map<std::string, Config::SettingInfo> settings;
        Setting<std::string> foo{&config, value, "name-of-the-setting", "description"};

        config.getSettings(settings, /* overriddenOnly = */ false);
        const auto iter = settings.find("name-of-the-setting");
        ASSERT_NE(iter, settings.end());
        ASSERT_EQ(iter->second.value, "");
        ASSERT_EQ(iter->second.description, "description\n");
    }

    TEST(Config, getDefinedOverriddenSettingNotSet) {
        Config config;
        std::string value;
        std::map<std::string, Config::SettingInfo> settings;
        Setting<std::string> foo{&config, value, "name-of-the-setting", "description"};

        config.getSettings(settings, /* overriddenOnly = */ true);
        const auto e = settings.find("name-of-the-setting");
        ASSERT_EQ(e, settings.end());
    }

    TEST(Config, getDefinedSettingSet1) {
        Config config;
        std::string value;
        std::map<std::string, Config::SettingInfo> settings;
        Setting<std::string> setting{&config, value, "name-of-the-setting", "description"};

        setting.override("value");

        config.getSettings(settings, /* overriddenOnly = */ false);
        const auto iter = settings.find("name-of-the-setting");
        ASSERT_NE(iter, settings.end());
        ASSERT_EQ(iter->second.value, "value");
        ASSERT_EQ(iter->second.description, "description\n");
    }

    TEST(Config, getDefinedSettingSet2) {
        Config config;
        std::map<std::string, Config::SettingInfo> settings;
        Setting<std::string> setting{&config, "", "name-of-the-setting", "description"};

        ASSERT_TRUE(config.set("name-of-the-setting", "value"));

        config.getSettings(settings, /* overriddenOnly = */ false);
        const auto e = settings.find("name-of-the-setting");
        ASSERT_NE(e, settings.end());
        ASSERT_EQ(e->second.value, "value");
        ASSERT_EQ(e->second.description, "description\n");
    }

    TEST(Config, addSetting) {
        class TestSetting : public AbstractSetting {
            public:
            TestSetting() : AbstractSetting("test", "test", {}) {}
            void set(const std::string & value, bool append, const ApplyConfigOptions & options) override {}
            std::string to_string() const override { return {}; }
            bool isAppendable() override { return false; }
        };

        Config config;
        TestSetting setting;

        ASSERT_FALSE(config.set("test", "value"));
        config.addSetting(&setting);
        ASSERT_TRUE(config.set("test", "value"));
        ASSERT_FALSE(config.set("extra-test", "value"));
    }

    TEST(Config, withInitialValue) {
        const StringMap initials = {
            { "key", "value" },
        };
        Config config(initials);

        {
            std::map<std::string, Config::SettingInfo> settings;
            config.getSettings(settings, /* overriddenOnly = */ false);
            ASSERT_EQ(settings.find("key"), settings.end());
        }

        Setting<std::string> setting{&config, "default-value", "key", "description"};

        {
            std::map<std::string, Config::SettingInfo> settings;
            config.getSettings(settings, /* overriddenOnly = */ false);
            ASSERT_EQ(settings["key"].value, "value");
        }
    }

    TEST(Config, resetOverridden) {
        Config config;
        config.resetOverridden();
    }

    TEST(Config, resetOverriddenWithSetting) {
        Config config;
        Setting<std::string> setting{&config, "", "name-of-the-setting", "description"};

        {
            std::map<std::string, Config::SettingInfo> settings;

            setting.setDefault("foo");
            ASSERT_EQ(setting.get(), "foo");
            config.getSettings(settings, /* overriddenOnly = */ true);
            ASSERT_TRUE(settings.empty());
        }

        {
            std::map<std::string, Config::SettingInfo> settings;

            setting.override("bar");
            ASSERT_TRUE(setting.overridden);
            ASSERT_EQ(setting.get(), "bar");
            config.getSettings(settings, /* overriddenOnly = */ true);
            ASSERT_FALSE(settings.empty());
        }

        {
            std::map<std::string, Config::SettingInfo> settings;

            config.resetOverridden();
            ASSERT_FALSE(setting.overridden);
            config.getSettings(settings, /* overriddenOnly = */ true);
            ASSERT_TRUE(settings.empty());
        }
    }

    TEST(Config, toJSONOnEmptyConfig) {
        ASSERT_EQ(Config().toJSON().dump(), "{}");
    }

    TEST(Config, toJSONOnNonEmptyConfig) {
        using nlohmann::literals::operator "" _json;
        Config config;
        Setting<std::string> setting{
            &config,
            "",
            "name-of-the-setting",
            "description",
        };
        setting.override("value");

        ASSERT_EQ(config.toJSON(),
          R"#({
            "name-of-the-setting": {
              "aliases": [],
              "defaultValue": "",
              "description": "description\n",
              "documentDefault": true,
              "value": "value",
              "experimentalFeature": null
            }
          })#"_json);
    }

    TEST(Config, toJSONOnNonEmptyConfigWithExperimentalSetting) {
        using nlohmann::literals::operator "" _json;
        Config config;
        Setting<std::string> setting{
            &config,
            "",
            "name-of-the-setting",
            "description",
            {},
            true,
            Xp::Flakes,
        };
        setting.override("value");

        ASSERT_EQ(config.toJSON(),
          R"#({
            "name-of-the-setting": {
              "aliases": [],
              "defaultValue": "",
              "description": "description\n",
              "documentDefault": true,
              "value": "value",
              "experimentalFeature": "flakes"
            }
          })#"_json);
    }

    TEST(Config, setSettingAlias) {
        Config config;
        Setting<std::string> setting{&config, "", "some-int", "best number", { "another-int" }};
        ASSERT_TRUE(config.set("some-int", "1"));
        ASSERT_EQ(setting.get(), "1");
        ASSERT_TRUE(config.set("another-int", "2"));
        ASSERT_EQ(setting.get(), "2");
        ASSERT_TRUE(config.set("some-int", "3"));
        ASSERT_EQ(setting.get(), "3");
    }

    /* FIXME: The reapplyUnknownSettings method doesn't seem to do anything
     * useful (these days).  Whenever we add a new setting to Config the
     * unknown settings are always considered.  In which case is this function
     * actually useful? Is there some way to register a Setting without calling
     * addSetting? */
    TEST(Config, DISABLED_reapplyUnknownSettings) {
        Config config;
        ASSERT_FALSE(config.set("name-of-the-setting", "unknownvalue"));
        Setting<std::string> setting{&config, "default", "name-of-the-setting", "description"};
        ASSERT_EQ(setting.get(), "default");
        config.reapplyUnknownSettings();
        ASSERT_EQ(setting.get(), "unknownvalue");
    }

    TEST(Config, applyConfigEmpty) {
        Config config;
        std::map<std::string, Config::SettingInfo> settings;
        config.applyConfig("");
        config.getSettings(settings);
        ASSERT_TRUE(settings.empty());
    }

    TEST(Config, applyConfigEmptyWithComment) {
        Config config;
        std::map<std::string, Config::SettingInfo> settings;
        config.applyConfig("# just a comment");
        config.getSettings(settings);
        ASSERT_TRUE(settings.empty());
    }

    TEST(Config, applyConfigAssignment) {
        Config config;
        std::map<std::string, Config::SettingInfo> settings;
        Setting<std::string> setting{&config, "", "name-of-the-setting", "description"};
        config.applyConfig(
            "name-of-the-setting = value-from-file #useful comment\n"
            "# name-of-the-setting = foo\n"
        );
        config.getSettings(settings);
        ASSERT_FALSE(settings.empty());
        ASSERT_EQ(settings["name-of-the-setting"].value, "value-from-file");
    }

    TEST(Config, applyConfigWithReassignedSetting) {
        Config config;
        std::map<std::string, Config::SettingInfo> settings;
        Setting<std::string> setting{&config, "", "name-of-the-setting", "description"};
        config.applyConfig(
            "name-of-the-setting = first-value\n"
            "name-of-the-setting = second-value\n"
        );
        config.getSettings(settings);
        ASSERT_FALSE(settings.empty());
        ASSERT_EQ(settings["name-of-the-setting"].value, "second-value");
    }

    TEST(Config, applyConfigFailsOnMissingIncludes) {
        Config config;
        std::map<std::string, Config::SettingInfo> settings;
        Setting<std::string> setting{&config, "", "name-of-the-setting", "description"};

        ASSERT_THROW(config.applyConfig(
            "name-of-the-setting = value-from-file\n"
            "# name-of-the-setting = foo\n"
            "include /nix/store/does/not/exist.nix"
        ), Error);
    }

    TEST(Config, includeRelativePath) {
        Config config;
        Setting<std::string> setting{&config, "", "puppy", "description"};

        config.applyConfig("include puppy.conf", {
            .path = getUnitTestDataPath("nix.conf")
        });

        std::map<std::string, Config::SettingInfo> settings;
        config.getSettings(settings);
        ASSERT_FALSE(settings.empty());
        ASSERT_EQ(settings["puppy"].value, "doggy");
    }

    TEST(Config, includeTildePath) {
        Config config;
        Setting<std::string> setting{&config, "", "puppy", "description"};

        config.applyConfig("include ~/puppy.conf", {
            .path = "/doesnt-exist",
            .home = getUnitTestData()
        });

        std::map<std::string, Config::SettingInfo> settings;
        config.getSettings(settings);
        ASSERT_FALSE(settings.empty());
        ASSERT_EQ(settings["puppy"].value, "doggy");
    }

    TEST(Config, applyConfigInvalidThrows) {
        Config config;
        ASSERT_THROW(config.applyConfig("value == key"), UsageError);
        ASSERT_THROW(config.applyConfig("value "), UsageError);
    }
}