#include "ExternalDataSourceConfiguration.h"

#include <Interpreters/Context.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTFunction.h>
#include <Parsers/ASTLiteral.h>
#include <Poco/Util/AbstractConfiguration.h>
#include <IO/WriteBufferFromString.h>


namespace DB
{

namespace ErrorCodes
{
    extern const int BAD_ARGUMENTS;
}

String ExternalDataSourceConfiguration::toString() const
{
    WriteBufferFromOwnString configuration_info;
    configuration_info << "host: " << host << "\t";
    configuration_info << "port: " << port << "\t";
    configuration_info << "username: " << username;
    return configuration_info.str();
}


std::tuple<ExternalDataSourceConfiguration, EngineArgs, bool>
tryGetConfigurationAsNamedCollection(ASTs args, ContextPtr context, bool is_database_engine)
{
    ExternalDataSourceConfiguration configuration;
    EngineArgs non_common_args;

    if (const auto * collection = typeid_cast<const ASTIdentifier *>(args[0].get()))
    {
        const auto & config = context->getConfigRef();
        const auto & config_prefix = fmt::format("named_collections.{}", collection->name());

        if (!config.has(config_prefix))
            throw Exception(ErrorCodes::BAD_ARGUMENTS, "There is no collection named `{}` in config", collection->name());

        configuration.host = config.getString(config_prefix + ".host", "");
        configuration.port = config.getInt(config_prefix + ".port", 0);
        configuration.username = config.getString(config_prefix + ".user", "");
        configuration.password = config.getString(config_prefix + ".password", "");
        configuration.database = config.getString(config_prefix + ".database", "");
        configuration.table = config.getString(config_prefix + ".table", "");
        configuration.schema = config.getString(config_prefix + ".schema", "");

        if ((args.size() == 1) && (configuration.host.empty() || configuration.port == 0
            || configuration.username.empty() || configuration.password.empty()
            || configuration.database.empty() || (configuration.table.empty() && !is_database_engine)))
        {
            throw Exception(ErrorCodes::BAD_ARGUMENTS,
                            "Named collection of connection parameters is missing some of the parameters and no key-value arguments are added");
        }

        for (size_t i = 1; i < args.size(); ++i)
        {
            if (const auto * ast_function = typeid_cast<const ASTFunction *>(args[i].get()))
            {
                const auto * args_expr = assert_cast<const ASTExpressionList *>(ast_function->arguments.get());
                auto function_args = args_expr->children;
                if (function_args.size() != 2)
                    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Expected key-value defined argument");

                auto arg_name = function_args[0]->as<ASTIdentifier>()->name();
                auto arg_value = evaluateConstantExpressionOrIdentifierAsLiteral(function_args[1], context)->as<ASTLiteral>()->value;

                if (arg_name == "host")
                    configuration.host = arg_value.safeGet<String>();
                else if (arg_name == "port")
                    configuration.port = arg_value.safeGet<UInt64>();
                else if (arg_name == "user")
                    configuration.username = arg_value.safeGet<String>();
                else if (arg_name == "password")
                    configuration.password = arg_value.safeGet<String>();
                else if (arg_name == "database")
                    configuration.database = arg_value.safeGet<String>();
                else if (arg_name == "table")
                    configuration.table = arg_value.safeGet<String>();
                else if (arg_name == "schema")
                    configuration.schema = arg_value.safeGet<String>();
                else
                    non_common_args.emplace_back(std::make_pair(arg_name, arg_value));
            }
            else
            {
                throw Exception(ErrorCodes::BAD_ARGUMENTS, "Expected key-value defined argument");
            }
        }

        return std::make_tuple(configuration, non_common_args, true);
    }
    return std::make_tuple(configuration, non_common_args, false);
}


ExternalDataSourceConfiguration tryGetConfigurationAsNamedCollection(
    const Poco::Util::AbstractConfiguration & dict_config, const String & dict_config_prefix, ContextPtr context)
{
    ExternalDataSourceConfiguration configuration;

    auto collection_name = dict_config.getString(dict_config_prefix + ".name", "");
    if (!collection_name.empty())
    {
        const auto & config = context->getConfigRef();
        const auto & config_prefix = fmt::format("named_collections.{}", collection_name);

        if (!config.has(config_prefix))
            throw Exception(ErrorCodes::BAD_ARGUMENTS, "There is no collection named `{}` in config", collection_name);

        configuration.host = dict_config.getString(dict_config_prefix + ".host", config.getString(config_prefix + ".host", ""));
        configuration.port = dict_config.getInt(dict_config_prefix + ".port", config.getUInt(config_prefix + ".port", 0));
        configuration.username = dict_config.getString(dict_config_prefix + ".user", config.getString(config_prefix + ".user", ""));
        configuration.password = dict_config.getString(dict_config_prefix + ".password", config.getString(config_prefix + ".password", ""));
        configuration.database = dict_config.getString(dict_config_prefix + ".db", config.getString(config_prefix + ".database", ""));
        configuration.table = dict_config.getString(dict_config_prefix + ".table", config.getString(config_prefix + ".table", ""));
        configuration.schema = dict_config.getString(dict_config_prefix + ".schema", config.getString(config_prefix + ".schema", ""));

        if (configuration.host.empty() || configuration.port == 0 || configuration.username.empty() || configuration.password.empty()
            || configuration.database.empty() || configuration.table.empty())
        {
            throw Exception(ErrorCodes::BAD_ARGUMENTS,
                            "Named collection of connection parameters is missing some of the parameters and dictionary parameters are added");
        }
    }
    else
    {
        configuration.host = dict_config.getString(dict_config_prefix + ".host", "");
        configuration.port = dict_config.getUInt(dict_config_prefix + ".port", 0);
        configuration.username = dict_config.getString(dict_config_prefix + ".user", "");
        configuration.password = dict_config.getString(dict_config_prefix + ".password", "");
        configuration.database = dict_config.getString(dict_config_prefix + ".db", "");
        configuration.table = dict_config.getString(fmt::format("{}.table", dict_config_prefix), "");
        configuration.schema = dict_config.getString(fmt::format("{}.schema", dict_config_prefix), "");
    }
    return configuration;
}


ExternalDataSourcesByPriority tryGetConfigurationsByPriorityAsNamedCollection(
    const Poco::Util::AbstractConfiguration & dict_config, const String & dict_config_prefix, ContextPtr context)
{
    auto common_configuration = tryGetConfigurationAsNamedCollection(dict_config, dict_config_prefix, context);
    ExternalDataSourcesByPriority configuration
    {
        .database = common_configuration.database,
        .table = common_configuration.table,
        .schema = common_configuration.schema
    };

    if (dict_config.has(dict_config_prefix + ".replica"))
    {
        Poco::Util::AbstractConfiguration::Keys config_keys;
        dict_config.keys(dict_config_prefix, config_keys);

        for (const auto & config_key : config_keys)
        {
            if (config_key.starts_with("replica"))
            {
                ExternalDataSourceConfiguration replica_configuration(common_configuration);
                String replica_name = dict_config_prefix + "." + config_key;
                size_t priority = dict_config.getInt(replica_name + ".priority", 0);

                replica_configuration.host = dict_config.getString(replica_name + ".host", common_configuration.host);
                replica_configuration.port = dict_config.getUInt(replica_name + ".port", common_configuration.port);
                replica_configuration.username = dict_config.getString(replica_name + ".user", common_configuration.username);
                replica_configuration.password = dict_config.getString(replica_name + ".password", common_configuration.password);

                if (replica_configuration.host.empty() || replica_configuration.port == 0
                    || replica_configuration.username.empty() || replica_configuration.password.empty())
                {
                    throw Exception(ErrorCodes::BAD_ARGUMENTS,
                                    "Named collection of connection parameters is missing some of the parameters and no other dictionary parameters are added");
                }

                configuration.replicas_configurations[priority].emplace_back(replica_configuration);
            }
        }
    }
    else
    {
        configuration.replicas_configurations[0].emplace_back(common_configuration);
    }

    return configuration;
}

}