// 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 <gen_cpp/Exprs_types.h>

#include <cstddef>

#include <cstdint>

#include <map>

#include <memory>

#include <roaring/roaring.hh>

#include <set>

#include <string>

#include <unordered_map>

#include <utility>

#include <vector>

#include "common/status.h"

#include "core/block/adaptive_block_size_predictor.h"

#include "core/block/block.h"

#include "core/block/column_with_type_and_name.h"

#include "core/block/columns_with_type_and_name.h"

#include "core/column/column.h"

#include "core/data_type/data_type.h"

#include "core/data_type/primitive_type.h"

#include "core/field.h"

#include "exec/common/variant_util.h"

#include "exprs/score_runtime.h"

#include "exprs/vexpr_fwd.h"

#include "io/fs/file_reader_writer_fwd.h"

#include "runtime/runtime_profile.h"

#include "storage/index/ann/ann_topn_runtime.h"

#include "storage/index/index_iterator.h"

#include "storage/iterators.h"

#include "storage/olap_common.h"

#include "storage/predicate/block_column_predicate.h"

#include "storage/predicate/column_predicate.h"

#include "storage/row_cursor.h"

#include "storage/schema.h"

#include "storage/segment/common.h"

#include "storage/segment/segment.h"

#include "util/json/path_in_data.h"

#include "util/slice.h"

namespace doris {

class VExpr;

class VExprContext;

struct RowLocation;

namespace segment_v2 {

class ColumnIterator;

class RowRanges;

class IndexIterator;

class SegmentIterator : public RowwiseIterator {

public:

    // Within SegmentIterator, ColumnId means an ordinal in the read schema.

    // Storage UIDs and caller-visible Block positions are named explicitly.

    SegmentIterator(std::shared_ptr<Segment> segment, ReadSchemaSPtr schema);

    ~SegmentIterator() override;

    [[nodiscard]] Status init_iterators();

    [[nodiscard]] Status init(const StorageReadOptions& opts) override;

    [[nodiscard]] Status next_batch(Block* block) override;

    // Get current block row locations. This function should be called

    // after the `next_batch` function.

    // Only vectorized version is supported.

    [[nodiscard]] Status current_block_row_locations(

            std::vector<RowLocation>* block_row_locations) override;

    const ReadSchema& schema() const override { return *_schema; }

    uint64_t data_id() const override { return _segment->id(); }

    void update_profile(RuntimeProfile* profile) override {

        _update_profile(profile, _short_cir_eval_predicate, "ShortCircuitPredicates");

        _update_profile(profile, _pre_eval_block_predicate, "PreEvaluatePredicates");

        if (_opts.delete_condition_predicates != nullptr) {

            std::set<std::shared_ptr<const ColumnPredicate>> delete_predicate_set;

            _opts.delete_condition_predicates->get_all_column_predicate(delete_predicate_set);

            _update_profile(profile, delete_predicate_set, "DeleteConditionPredicates");

        }

    }

    bool has_index_in_iterators() const {

        return std::any_of(_index_iterators.begin(), _index_iterators.end(),

                           [](const auto& iterator) { return iterator != nullptr; });

    }

private:

    Status _next_batch_internal(Block* block);

    Status _check_output_block(Block* block);

    template <typename Container>

    void _update_profile(RuntimeProfile* profile, const Container& predicates,

                         const std::string& title) {

        if (predicates.empty()) {

            return;

        }

        std::string info;

        for (auto pred : predicates) {

            info += "\n" + pred->debug_string();

        }

        profile->add_info_string(title, info);

    }

Unexecuted instantiation: _ZN5doris10segment_v215SegmentIterator15_update_profileISt6vectorISt10shared_ptrINS_15ColumnPredicateEESaIS6_EEEEvPNS_14RuntimeProfileERKT_RKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE

Unexecuted instantiation: _ZN5doris10segment_v215SegmentIterator15_update_profileISt3setISt10shared_ptrIKNS_15ColumnPredicateEESt4lessIS7_ESaIS7_EEEEvPNS_14RuntimeProfileERKT_RKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE

    [[nodiscard]] Status _lazy_init(Block* block);

    [[nodiscard]] Status _init_impl(const StorageReadOptions& opts);

    [[nodiscard]] Status _init_column_iterators();

    [[nodiscard]] Status _init_index_iterators();

    // calculate row ranges that fall into requested key ranges using short key index

    [[nodiscard]] Status _get_row_ranges_by_keys();

    [[nodiscard]] Status _prepare_seek(const StorageReadOptions::KeyRange& key_range);

    [[nodiscard]] Status _lookup_ordinal(const RowCursor& key, bool is_include, rowid_t upper_bound,

                                         rowid_t* rowid);

    // lookup the ordinal of given key from short key index

    // the returned rowid is rowid in primary index, not the rowid encoded in primary key

    [[nodiscard]] Status _lookup_ordinal_from_sk_index(const RowCursor& key, bool is_include,

                                                       rowid_t upper_bound, rowid_t* rowid);

    // lookup the ordinal of given key from primary key index

    [[nodiscard]] Status _lookup_ordinal_from_pk_index(const RowCursor& key, bool is_include,

                                                       rowid_t* rowid);

    [[nodiscard]] Status _seek_and_peek(rowid_t rowid);

    // calculate row ranges that satisfy requested column conditions using various column index

    [[nodiscard]] Status _get_row_ranges_by_column_conditions();

    [[nodiscard]] Status _get_row_ranges_from_conditions(RowRanges* condition_row_ranges);

    [[nodiscard]] Status _apply_expr_zonemap_to_row_ranges(const VExprContextSPtrs& conjuncts,

                                                           rowid_t min_rowid,

                                                           RowRanges* row_ranges);

    [[nodiscard]] Status _apply_inverted_index();

    [[nodiscard]] Status _apply_inverted_index_on_column_predicate(

            std::shared_ptr<ColumnPredicate> pred,

            std::vector<std::shared_ptr<ColumnPredicate>>& remaining_predicates,

            bool* continue_apply);

    [[nodiscard]] Status _apply_ann_topn_predicate();

    [[nodiscard]] Status _apply_index_expr();

    // G02: true iff answering the single pushed-down MATCH predicate by its

    // match COUNT alone is indistinguishable from the row-accurate bitmap for

    // this COUNT_ON_INDEX scan (no deletes, no other filters, full row bitmap,

    // no row-id consumers). Gates IndexQueryContext::count_on_index_fastpath;

    // the decision predicate itself lives in count_on_index_fastpath.h.

    bool _count_on_index_fastpath_safe() const;

    // G03: teardown of the G02 handshake. Captures whether the reader answered

    // with a fabricated count bitmap into _count_fastpath_hit and clears both

    // context flags so no later read_from_index call can observe or forge

    // them. Runs on every exit of the index-apply scope.

    void _capture_count_fastpath_hit();

    // G03: true iff the per-batch defaults fill of _read_columns_by_index

    // would apply to `cid` (the _no_need_read_key_data or _prune_column

    // branch) AND the block column needs no storage->schema cast, i.e. the

    // emission shortcut can reproduce the column's batch content exactly.

    bool _column_emits_defaults_for_count(ColumnId cid);

    // G03: fills CountEmitShortcutFacts from live iterator state at the end of

    // _lazy_init and returns the pure-guard verdict; the decision predicate

    // itself lives in count_on_index_fastpath.h.

    bool _should_engage_count_emit_shortcut(const Block* block);

    // G03: one emission-shortcut batch: min(remaining, kCountEmitBatchRows)

    // default rows filled straight into the block (NOT-NULL defaults for

    // nullable columns, mirroring _prune_column), then EOF once the countdown

    // reaches zero. Replaces the whole per-rowid _next_batch_internal body for

    // engaged scans.

    Status _emit_count_shortcut_batch(Block* block);

    bool _column_has_fulltext_index(int32_t cid);

    bool _column_has_ann_index(int32_t cid);

    bool _downgrade_without_index(Status res, bool need_remaining = false);

    inline bool _inverted_index_not_support_pred_type(const PredicateType& type);

    void _init_column_states();

    void _rebuild_scan_predicate_states();

    void _mark_common_expr_states(const VExprSPtr& expr);

    Status _vec_init_lazy_materialization();

    uint32_t segment_id() const { return _segment->id(); }

    uint32_t num_rows() const { return _segment->num_rows(); }

    [[nodiscard]] Status _read_columns_by_index(const std::vector<ColumnId>& read_ordinals,

                                                uint32_t nrows_read_limit, uint16_t& nrows_read);

    void _replace_version_col_if_needed(const std::vector<ColumnId>& ordinals, size_t num_rows);

    void _update_tso_col_if_needed(const std::vector<ColumnId>& ordinals, size_t num_rows);

    Status _init_current_block(Block* block, std::vector<MutableColumnPtr>& non_pred_vector,

                               uint32_t nrows_read_limit);

    uint16_t _evaluate_vectorization_predicate(uint16_t* sel_rowid_idx, uint16_t selected_size);

    uint16_t _evaluate_short_circuit_predicate(uint16_t* sel_rowid_idx, uint16_t selected_size);

    Status _apply_read_limit_to_selected_rows(Block* block, uint16_t& selected_size);

    Status _output_columns_to_block(Block* block);

    [[nodiscard]] Status _read_columns_by_rowids(const std::vector<ColumnId>& read_ordinals,

                                                 std::vector<rowid_t>& rowid_vector,

                                                 uint16_t* sel_rowid_idx, size_t select_size,

                                                 MutableColumns* mutable_columns,

                                                 bool init_condition_cache = false,

                                                 bool read_for_predicate = false);

    [[nodiscard]] Status _read_lazy_pruned_columns(Block* block);

    Status copy_column_data_by_selector(IColumn* input_col_ptr, MutableColumnPtr& output_col,

                                        uint16_t* sel_rowid_idx, uint16_t select_size,

                                        size_t batch_size);

    template <class Container>

    [[nodiscard]] Status _output_column_by_sel_idx(Block* block, const Container& ordinals,

                                                   uint16_t* sel_rowid_idx, uint16_t select_size) {

        SCOPED_RAW_TIMER(&_opts.stats->output_col_ns);

        for (auto ordinal : ordinals) {

            if (ordinal >= _schema->num_block_columns()) {

                continue;

            }

            const auto& file_column_type = _storage_name_and_type[ordinal].second;

            if (!file_column_type->equals(*block->get_by_position(ordinal).type)) {

                // Do additional cast

                MutableColumnPtr tmp = file_column_type->create_column();

                RETURN_IF_ERROR(copy_column_data_by_selector(_current_columns[ordinal].get(), tmp,

                                                             sel_rowid_idx, select_size,

                                                             _opts.block_row_max));

                RETURN_IF_ERROR(variant_util::cast_column({tmp->get_ptr(), file_column_type, ""},

                                                          block->get_by_position(ordinal).type,

                                                          &block->get_by_position(ordinal).column));

            } else {

                MutableColumnPtr output_column =

                        block->get_by_position(ordinal).column->assert_mutable();

                RETURN_IF_ERROR(copy_column_data_by_selector(_current_columns[ordinal].get(),

                                                             output_column, sel_rowid_idx,

                                                             select_size, _opts.block_row_max));

            }

        }

        return Status::OK();

    }

    bool _can_evaluated_by_vectorized(std::shared_ptr<ColumnPredicate> predicate);

    [[nodiscard]] Status _execute_common_expr(uint16_t* sel_rowid_idx, uint16_t& selected_size,

                                              Block* block);

    Status _process_common_expr(uint16_t* sel_rowid_idx, uint16_t& selected_size, Block* block);

    uint16_t _evaluate_common_expr_filter(uint16_t* sel_rowid_idx, uint16_t selected_size,

                                          const IColumn::Filter& filter);

    // Dictionary column should do something to initial.

    void _convert_dict_code_for_predicate_if_necessary();

    void _convert_dict_code_for_predicate_if_necessary_impl(const ColumnPredicate& predicate);

    bool _check_apply_by_inverted_index(std::shared_ptr<ColumnPredicate> pred);

    void _output_index_result_column(const VExprContextSPtrs& expr_ctxs, uint16_t* sel_rowid_idx,

                                     uint16_t select_size);

    bool _need_read_data(ColumnId cid);

    bool _prune_column(ColumnId cid, MutableColumnPtr& column, size_t num_of_defaults);

    Status _construct_compound_expr_context();

    // Both the key cursor and _seek_block lay out the leading tablet key

    // columns densely, so position i addresses the same column in both.

    int _compare_short_key_with_seek_block(const RowCursor& key, size_t num_key_cols) {

        for (uint32_t i = 0; i < num_key_cols; ++i) {

            auto ord = key.field(i) <=> (*_seek_block[i])[0];

            if (ord != std::strong_ordering::equal) {

                return ord == std::strong_ordering::less ? -1 : 1;

            }

        }

        return 0;

    }

    Status _convert_column_to_expected_type(ColumnId column_id);

    Status _convert_to_expected_type(const std::vector<ColumnId>& ordinals);

    bool _no_need_read_key_data(ColumnId cid, MutableColumnPtr& column, size_t nrows_read);

    // Side-effect-free eligibility half of _no_need_read_key_data (no column

    // fill); shared by the per-batch fill and the G03 engage-time per-column

    // proof so the two can never drift.

    bool _no_need_read_key_data_eligible(ColumnId cid);

    bool _has_delete_pred(ColumnId cid) const;

    bool _has_lazy_pruned_children(ColumnId cid) const;

    bool _can_skip_reading_extra_column(ColumnId cid);

    bool _can_opt_limit_reads();

    void _initialize_predicate_results();

    bool _check_all_conditions_passed_inverted_index_for_column(ColumnId cid,

                                                                bool default_return = false);

    void _calculate_common_expr_index_exec_status();

    Status _process_eof(Block* block);

    void _fill_column_nothing();

    Status _process_columns(const std::vector<ColumnId>& ordinals, Block* block);

    // Initialize virtual columns in the block, set all virtual columns in the block to ColumnNothing

    void _init_virtual_columns(Block* block);

    // Fallback logic for virtual column materialization, materializing all unmaterialized virtual columns through expressions

    Status _materialization_of_virtual_column(Block* block);

    void _prepare_score_column_materialization();

    void _init_row_bitmap_by_condition_cache();

    void _init_segment_prefetchers();

    class BitmapRangeIterator;

    class BackwardBitmapRangeIterator;

    // Example:

    //   SELECT k, s.b, o FROM t

    //   WHERE k > 1 AND abs(k) < 10 AND abs(s.a) < 5;

    //   ReadSchema ordinals: [0:k, 1:s STRUCT<a,b>, 2:o]

    // When no filter is fully evaluated by an index:

    //   state[0:k] = {has_delete_pred=false, has_scan_pred=true,

    //                 has_common_expr=true, need_read_data=true}

    //   state[1:s] = {has_delete_pred=false, has_scan_pred=false,

    //                 has_common_expr=true, need_read_data=true}

    //   state[2:o] = {has_delete_pred=false, has_scan_pred=false,

    //                 has_common_expr=false, need_read_data=true}

    // A storage-only column appended for a delete condition would have

    // has_delete_pred=true.

    struct ColumnReadState {

        bool has_delete_pred = false;

        // Mirrors the mutable _col_predicates list: initially all safe scan

        // predicates, then only residual predicates after index evaluation.

        bool has_scan_pred = false;

        bool has_common_expr = false;

        // Index evaluation sets this to false when it fully supplies the column result.

        // _need_read_data() applies the remaining read constraints.

        bool need_read_data = true;

        bool has_predicate() const { return has_delete_pred || has_scan_pred; }

    };

    std::shared_ptr<Segment> _segment;

    // read schema from scanner

    ReadSchemaSPtr _schema;

    // Inverted-index field name and storage/materialization type for each ReadSchema column.

    std::vector<IndexFieldNameAndTypePair> _storage_name_and_type;

    // vector idx -> column iterarator

    std::vector<std::unique_ptr<ColumnIterator>> _column_iterators;

    std::vector<std::unique_ptr<IndexIterator>> _index_iterators;

    // after init(), `_row_bitmap` contains all rowid to scan

    roaring::Roaring _row_bitmap;

    // an iterator for `_row_bitmap` that can be used to extract row range to scan

    std::unique_ptr<BitmapRangeIterator> _range_iter;

    // the next rowid to read

    rowid_t _cur_rowid;

    // members related to lazy materialization read

    // --------------------------------------------

    // remember the rowids we've read for the current row block.

    // could be a local variable of next_batch(), kept here to reuse vector memory

    std::vector<rowid_t> _block_rowids;

    bool _is_need_vec_eval = false;

    bool _is_need_short_eval = false;

    bool _is_need_expr_eval = false;

    bool _enable_prune_nested_column = false;

    // Per-column state indexed by read schema ordinal. Ordered column lists

    // below are execution plans rather than additional column membership sets.

    std::vector<ColumnReadState> _column_states;

    // Columns of the current batch, indexed by read schema ordinal.

    MutableColumns _current_columns;

    std::vector<std::shared_ptr<ColumnPredicate>> _pre_eval_block_predicate;

    std::vector<std::shared_ptr<ColumnPredicate>> _short_cir_eval_predicate;

    // Example:

    //   SELECT k, s.b, o FROM t

    //   WHERE k > 1 AND abs(k) < 10 AND abs(s.a) < 5;

    //   ReadSchema ordinals: [0:k, 1:s STRUCT<a,b>, 2:o]

    //

    // The first three lists assign each active column to its earliest materialization stage:

    //   _predicate_ordinals   = [0] // k is used by both k > 1 and abs(k) < 10; predicate wins.

    //   _common_expr_ordinals = [1] // s is read for the abs(s.a) < 5 expression.

    //   _output_ordinals      = [2] // o is needed only by output.

    std::vector<ColumnId> _predicate_ordinals;

    std::vector<ColumnId> _common_expr_ordinals;

    std::vector<ColumnId> _output_ordinals;

    //   _lazy_pruned_ordinals = [1] // After filtering on s.a, read s.b for surviving rows.

    // Unlike the first three disjoint lists, this recovery list may contain the same ordinal.

    std::vector<ColumnId> _lazy_pruned_ordinals;

    // the actual init process is delayed to the first call to next_batch()

    bool _lazy_inited;

    bool _inited;

    StorageReadOptions _opts;

    // Adaptive batch size predictor; null when the feature is disabled.

    std::unique_ptr<AdaptiveBlockSizePredictor> _block_size_predictor;

    // Build the AdaptiveBlockSizePredictor for this segment based on segment footer

    // metadata for the projected output columns. Returns nullptr if the feature is

    // disabled or the byte budget is non-positive.

    std::unique_ptr<AdaptiveBlockSizePredictor> _make_block_size_predictor() const;

    // Snapshot of _opts.block_row_max at init time; used as the hard upper bound so that

    // dynamic adjustments never exceed the capacity of pre-allocated buffers.

    uint32_t _initial_block_row_max = 0;

    // make a copy of `_opts.column_predicates` in order to make local changes

    std::vector<std::shared_ptr<ColumnPredicate>> _col_predicates;

    VExprContextSPtrs _common_expr_ctxs_push_down;

    // row schema of the key to seek

    // only used in `_get_row_ranges_by_keys`

    std::unique_ptr<ReadSchema> _seek_schema;

    // used to binary search the rowid for a given key

    // only used in `_get_row_ranges_by_keys`

    MutableColumns _seek_block;

    // Per-seek-schema-ordinal column iterators for the short-key seek path.

    // Points into _column_iterators when the key column is also read, otherwise

    // into _owned_seek_column_iterators (a seek key column may not be part of

    // the read schema at all).

    std::vector<ColumnIterator*> _seek_column_iterators;

    std::vector<std::unique_ptr<ColumnIterator>> _owned_seek_column_iterators;

    io::FileReaderSPtr _file_reader;

    // used for compaction, record selectd rowids of current batch

    uint16_t _selected_size;

    std::vector<uint16_t> _sel_rowid_idx;

    // Rows already produced by this iterator. Used together with

    // _opts.read_limit to compute the remaining per-batch budget.

    size_t _rows_returned = 0;

    int64_t _tablet_id = 0;

    // Column UIDs requested by the caller. A -1 entry means light schema change is disabled and

    // the column has no UID, so the _need_read_data() optimization is disabled.

    std::set<int32_t> _output_column_uids;

    std::vector<uint8_t> _ret_flags;

    /*

    * column and column_predicates on it.

    * a boolean value to indicate whether the column has been read by the index.

    */

    std::unordered_map<ColumnId, std::unordered_map<std::shared_ptr<ColumnPredicate>, bool>>

            _column_predicate_index_exec_status;

    /*

    * column and common expr on it.

    * a boolean value to indicate whether the column has been read by the index.

    */

    std::unordered_map<ColumnId, std::unordered_map<const VExpr*, bool>>

            _common_expr_index_exec_status;

    /*

    * common expr context to slotref map

    * slot ref map is used to get slot ref expr by using column id.

    */

    std::unordered_map<VExprContext*, std::unordered_map<ColumnId, VExpr*>>

            _common_expr_to_slotref_map;

    ScoreRuntimeSPtr _score_runtime;

    std::shared_ptr<segment_v2::AnnTopNRuntime> _ann_topn_runtime;

    // cid to virtual column expr

    std::map<ColumnId, VExprContextSPtr> _virtual_column_exprs;

    IndexQueryContextPtr _index_query_context;

    // G03 count-emission shortcut state (see count_on_index_fastpath.h).

    // _count_fastpath_hit: the reader answered the single MATCH predicate with

    // a fabricated count bitmap (captured from the G02 handshake reply).

    // _count_emit_shortcut: engaged at the end of _lazy_init when

    // count_emit_shortcut_safe holds; every subsequent batch is emitted by

    // _emit_count_shortcut_batch from _count_emit_rows_remaining (initialized

    // to the post-apply _row_bitmap cardinality) without touching the row

    // bitmap iterator.

    bool _count_fastpath_hit = false;

    bool _count_emit_shortcut = false;

    uint64_t _count_emit_rows_remaining = 0;

    // Batch size for shortcut emission: VStatisticsIterator's

    // MAX_ROW_SIZE_IN_COUNT, the largest default-rows block shape already

    // proven through every consumer above the segment iterator by the plain

    // COUNT pushdown (rowset reader, collect iterator, block reader, scanner).

    static constexpr uint64_t kCountEmitBatchRows = 65535;

    // key is column uid, value is the sparse column cache

    std::unordered_map<int32_t, PathToBinaryColumnCacheUPtr> _variant_sparse_column_cache;

    bool _find_condition_cache = false;

    std::shared_ptr<std::vector<bool>> _condition_cache;

    static constexpr int CONDITION_CACHE_OFFSET = 2048;

};

} // namespace segment_v2

} // namespace doris