// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

#pragma once

#include "exprs/vexpr.h"

namespace doris {

class VirtualSlotRef MOCK_REMOVE(final) : public VExpr {

    ENABLE_FACTORY_CREATOR(VirtualSlotRef);

public:

    VirtualSlotRef(const TExprNode& node);

    VirtualSlotRef(const SlotDescriptor* desc);

    Status prepare(RuntimeState* state, const RowDescriptor& desc, VExprContext* context) override;

    Status open(RuntimeState* state, VExprContext* context,

                FunctionContext::FunctionStateScope scope) override;

    Status execute_column(VExprContext* context, const Block* block, Selector* selector,

                          size_t count, ColumnPtr& result_column) const override;

    const std::string& expr_name() const override;

    std::string expr_label() override;

    std::string debug_string() const override;

    bool is_constant() const override { return false; }

    int column_id() const { return _column_id; }

    int slot_id() const { return _slot_id; }

    bool equals(const VExpr& other) override;

    size_t estimate_memory(const size_t rows) override { return 0; }

    void collect_slot_column_ids(std::set<int>& column_ids) const override {

        column_ids.insert(_column_id);

    }

    std::shared_ptr<VExpr> get_virtual_column_expr() const { return _virtual_column_expr; }

    Status evaluate_inverted_index(VExprContext* context, uint32_t segment_num_rows) override {

        return _virtual_column_expr->evaluate_inverted_index(context, segment_num_rows);

    }

    /*

    @brief SQL expression tree patterns for ANN range search optimization.

    Pattern 1 (should not happen):

    SELECT * FROM tbl WHERE distance_function(columnA, ArrayLiteral) > 100

    VirtualSlotRef

    |

    BINARY_PRED

    |---------------------------------------|

    |                                       |

    FUNCTION_CALL(l2_distance_approximate)  IntLiteral

    |

    |-----------------------|

    |                       |

    SlotRef                 ArrayLiteral

    Pattern 2 (optimizable case):

    SELECT distance_function(columnA, ArrayLiteral) AS dis FROM tbl WHERE dis > 100

    BINARY_PRED

    |

    |---------------------------------------|

    |                                       |

    VIRTUAL_SLOT_REF                        IntLiteral

    |

    FUNCTION_CALL(l2_distance_approximate)

    |

    |-----------------------|

    |                       |

    SlotRef                 ArrayLiteral

    */

    /**

     * @brief Evaluates ANN range search using index-based optimization.

     * 

     * This method implements the core logic for ANN range search optimization.

     * Instead of computing distances for all rows and then filtering, it uses

     * the ANN index to efficiently find only the rows within the specified range.

     * 

     * The method:

     * 1. Extracts query parameters from the range search runtime info

     * 2. Calls the ANN index to perform range search

     * 3. Updates the row bitmap with matching results

     * 4. Collects performance statistics

     * 

     * @param range_search_runtime Runtime info containing query vector, radius, and metrics

     * @param cid_to_index_iterators Vector of index iterators for each column

     * @param idx_to_cid Mapping from index position to column ID

     * @param column_iterators Vector of column iterators for data access

     * @param row_bitmap Output bitmap updated with matching row IDs

     * @param ann_index_stats Statistics collector for performance monitoring

     * @return Status indicating success or failure of the search operation

     */

    Status evaluate_ann_range_search(

            const segment_v2::AnnRangeSearchRuntime& range_search_runtime,

            const std::vector<std::unique_ptr<segment_v2::IndexIterator>>& cid_to_index_iterators,

            const std::vector<ColumnId>& idx_to_cid,

            const std::vector<std::unique_ptr<segment_v2::ColumnIterator>>& column_iterators,

            roaring::Roaring& row_bitmap, segment_v2::AnnIndexStats& ann_index_stats) override;

#ifdef BE_TEST

    // Test-only setter methods for unit testing

    void set_column_id(int column_id) { _column_id = column_id; }

    void set_column_name(const std::string* column_name) { _column_name = column_name; }

    void set_column_data_type(DataTypePtr column_data_type) {

        _column_data_type = std::move(column_data_type);

    }

    void set_virtual_column_expr(std::shared_ptr<VExpr> virtual_column_expr) {

        _virtual_column_expr = virtual_column_expr;

    }

#endif

private:

    int _column_id;                              ///< Column ID in the table schema

    int _slot_id;                                ///< Slot ID in the expression context

    const std::string* _column_name;             ///< Column name for debugging/logging

    const std::string _column_label;             ///< Column label for display purposes

    std::shared_ptr<VExpr> _virtual_column_expr; ///< Underlying virtual expression

    DataTypePtr _column_data_type;               ///< Data type of the column

};

} // namespace doris