#include "factory.h"

#include "array.h"
#include "date.h"
#include "decimal.h"
#include "enum.h"
#include "geo.h"
#include "ip4.h"
#include "ip6.h"
#include "lowcardinality.h"
#include "lowcardinalityadaptor.h"
#include "map.h"
#include "nothing.h"
#include "nullable.h"
#include "numeric.h"
#include "string.h"
#include "tuple.h"
#include "uuid.h"


#include "../types/type_parser.h"

#include "../exceptions.h"

#include <stdexcept>
#include <string>

namespace clickhouse {
namespace {

// Like Python's list's []:
// * 0 - first element
// * 1 - second element
// * -1 - last element
// * -2 - one before last, etc.
const auto& GetASTChildElement(const TypeAst & ast, int position) {
    if (static_cast<size_t>(abs(position)) >= ast.elements.size())
        throw ValidationError("AST child element index out of bounds: " + std::to_string(position));

    if (position < 0)
        position = static_cast<int>(ast.elements.size() + position);

    return ast.elements[static_cast<size_t>(position)];
}

static ColumnRef CreateTerminalColumn(const TypeAst& ast) {
    switch (ast.code) {
    case Type::Void:
        return std::make_shared<ColumnNothing>();

    case Type::UInt8:
        return std::make_shared<ColumnUInt8>();
    case Type::UInt16:
        return std::make_shared<ColumnUInt16>();
    case Type::UInt32:
        return std::make_shared<ColumnUInt32>();
    case Type::UInt64:
        return std::make_shared<ColumnUInt64>();

    case Type::Int8:
        return std::make_shared<ColumnInt8>();
    case Type::Int16:
        return std::make_shared<ColumnInt16>();
    case Type::Int32:
        return std::make_shared<ColumnInt32>();
    case Type::Int64:
        return std::make_shared<ColumnInt64>();
    case Type::Int128:
        return std::make_shared<ColumnInt128>();
    case Type::UInt128:
        return std::make_shared<ColumnUInt128>();

    case Type::Float32:
        return std::make_shared<ColumnFloat32>();
    case Type::Float64:
        return std::make_shared<ColumnFloat64>();

    case Type::Decimal:
        return std::make_shared<ColumnDecimal>(GetASTChildElement(ast, 0).value, GetASTChildElement(ast, -1).value);
    case Type::Decimal32:
        return std::make_shared<ColumnDecimal>(9, GetASTChildElement(ast, 0).value);
    case Type::Decimal64:
        return std::make_shared<ColumnDecimal>(18, GetASTChildElement(ast, 0).value);
    case Type::Decimal128:
        return std::make_shared<ColumnDecimal>(38, GetASTChildElement(ast, 0).value);

    case Type::String:
        return std::make_shared<ColumnString>();
    case Type::FixedString:
        return std::make_shared<ColumnFixedString>(GetASTChildElement(ast, 0).value);

    case Type::DateTime:
        if (ast.elements.empty()) {
            return std::make_shared<ColumnDateTime>();
        } else {
            return std::make_shared<ColumnDateTime>(GetASTChildElement(ast, 0).value_string);
        }
    case Type::DateTime64:
        if (ast.elements.empty()) {
            return nullptr;
        }
        if (ast.elements.size() == 1) {
            return std::make_shared<ColumnDateTime64>(ast.elements[0].value);
        } else {
            return std::make_shared<ColumnDateTime64>(ast.elements[0].value, ast.elements[1].value_string);
        }
    case Type::Date:
        return std::make_shared<ColumnDate>();
    case Type::Date32:
        return std::make_shared<ColumnDate32>();

    case Type::IPv4:
        return std::make_shared<ColumnIPv4>();
    case Type::IPv6:
        return std::make_shared<ColumnIPv6>();

    case Type::UUID:
        return std::make_shared<ColumnUUID>();

    case Type::Point:
        return std::make_shared<ColumnPoint>();

    case Type::Ring:
        return std::make_shared<ColumnRing>();

    case Type::Polygon:
        return std::make_shared<ColumnPolygon>();

    case Type::MultiPolygon:
        return std::make_shared<ColumnMultiPolygon>();

    default:
        return nullptr;
    }
}

static ColumnRef CreateColumnFromAst(const TypeAst& ast, CreateColumnByTypeSettings settings) {
    switch (ast.meta) {
        case TypeAst::Array: {
            return std::make_shared<ColumnArray>(
                CreateColumnFromAst(GetASTChildElement(ast, 0), settings)
            );
        }

        case TypeAst::Nullable: {
            return std::make_shared<ColumnNullable>(
                CreateColumnFromAst(GetASTChildElement(ast, 0), settings),
                std::make_shared<ColumnUInt8>()
            );
        }

        case TypeAst::Terminal: {
            return CreateTerminalColumn(ast);
        }

        case TypeAst::Tuple: {
            std::vector<ColumnRef> columns;

            columns.reserve(ast.elements.size());
            for (const auto& elem : ast.elements) {
                if (auto col = CreateColumnFromAst(elem, settings)) {
                    columns.push_back(col);
                } else {
                    return nullptr;
                }
            }

            return std::make_shared<ColumnTuple>(columns);
        }

        case TypeAst::Enum: {
            std::vector<Type::EnumItem> enum_items;
            //ast.elements.size() minimum is 1.
            if ((ast.elements.size() % 2) != 0) {
                throw ValidationError(ast.name + " content is not correct");
            }

            enum_items.reserve(ast.elements.size() / 2);
            for (size_t i = 0; i < ast.elements.size(); i += 2) {
                enum_items.push_back(Type::EnumItem{
                    ast.elements[i].value_string,
                    static_cast<int16_t>(ast.elements[i + 1].value)
                });
            }

            if (ast.code == Type::Enum8) {
                return std::make_shared<ColumnEnum8>(
                    Type::CreateEnum8(enum_items)
                );
            } else if (ast.code == Type::Enum16) {
                return std::make_shared<ColumnEnum16>(
                    Type::CreateEnum16(enum_items)
                );
            }
            break;
        }
        case TypeAst::LowCardinality: {
            const auto nested = GetASTChildElement(ast, 0);
            if (settings.low_cardinality_as_wrapped_column) {
                switch (nested.code) {
                    // TODO (nemkov): update this to maximize code reuse.
                    case Type::String:
                        return std::make_shared<LowCardinalitySerializationAdaptor<ColumnString>>();
                    case Type::FixedString:
                        return std::make_shared<LowCardinalitySerializationAdaptor<ColumnFixedString>>(GetASTChildElement(nested, 0).value);
                    case Type::Nullable:
                        throw UnimplementedError("LowCardinality(" + nested.name + ") is not supported with LowCardinalityAsWrappedColumn on");
                    default:
                        throw UnimplementedError("LowCardinality(" + nested.name + ") is not supported");
                }
            }
            else {
                switch (nested.code) {
                    // TODO (nemkov): update this to maximize code reuse.
                    case Type::String:
                        return std::make_shared<ColumnLowCardinalityT<ColumnString>>();
                    case Type::FixedString:
                        return std::make_shared<ColumnLowCardinalityT<ColumnFixedString>>(GetASTChildElement(nested, 0).value);
                    case Type::Nullable:
                        return std::make_shared<ColumnLowCardinality>(
                            std::make_shared<ColumnNullable>(
                                CreateColumnFromAst(GetASTChildElement(nested, 0), settings),
                                std::make_shared<ColumnUInt8>()
                            )
                        );
                    default:
                        throw UnimplementedError("LowCardinality(" + nested.name + ") is not supported");
                }
            }
        }
        case TypeAst::SimpleAggregateFunction: {
            return CreateTerminalColumn(GetASTChildElement(ast, -1));
        }

        case TypeAst::Map: {
            if (ast.elements.size() != 2) {
                throw ValidationError(ast.name + " content is not correct");
            }

            std::vector<ColumnRef> columns;

            columns.reserve(ast.elements.size());
            for (const auto& elem : ast.elements) {
                if (auto col = CreateColumnFromAst(elem, settings)) {
                    columns.push_back(col);
                } else {
                    return nullptr;
                }
            }

            return std::make_shared<ColumnMap>(
                std::make_shared<ColumnArray>(
                    std::make_shared<ColumnTuple>(columns)));
        }

        case TypeAst::Assign:
        case TypeAst::Null:
        case TypeAst::Number:
        case TypeAst::String:
            break;
    }

    return nullptr;
}

} // namespace


ColumnRef CreateColumnByType(const std::string& type_name, CreateColumnByTypeSettings settings) {
    auto ast = ParseTypeName(type_name);
    if (ast != nullptr) {
        return CreateColumnFromAst(*ast, settings);
    }

    return nullptr;
}

}
