// 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.

#include "exprs/vsearch.h"

#include <memory>

#include <roaring/roaring.hh>

#include "common/logging.h"

#include "common/status.h"

#include "core/column/column_const.h"

#include "exprs/function/function_search.h"

#include "exprs/vexpr_context.h"

#include "exprs/vliteral.h"

#include "exprs/vslot_ref.h"

#include "glog/logging.h"

#include "runtime/runtime_state.h"

#include "storage/index/inverted/inverted_index_reader.h"

#include "storage/segment/segment.h"

namespace doris {

using namespace segment_v2;

namespace {

struct SearchInputBundle {

    std::unordered_map<std::string, IndexIterator*> iterators;

    std::unordered_map<std::string, IndexFieldNameAndTypePair> field_types;

    std::unordered_map<std::string, int> field_name_to_column_id;

    std::vector<int> column_ids;

    ColumnsWithTypeAndName literal_args;

};

Status collect_search_inputs(const VSearchExpr& expr, VExprContext* context,

                             SearchInputBundle* bundle) {

    DCHECK(bundle != nullptr);

    auto index_context = context->get_index_context();

    if (index_context == nullptr) {

        LOG(WARNING) << "collect_search_inputs: No inverted index context available";

        return Status::InternalError("No inverted index context available");

    }

    // Get field bindings for variant subcolumn support

    const auto& search_param = expr.get_search_param();

    const auto& field_bindings = search_param.field_bindings;

    std::unordered_map<std::string, ColumnId> parent_to_base_column_id;

    std::unordered_map<std::string, std::string> parent_to_storage_field_prefix;

    // Resolve and cache the base (parent) column id for a variant field binding.

    // This avoids repeated schema lookups when multiple subcolumns share the same parent column.

    auto resolve_parent_column_id = [&](const std::string& parent_field, ColumnId* column_id) {

        // Guard against invalid inputs: variant bindings may miss parent_field, and callers must

        // provide a valid output pointer to receive the resolved id.

        if (parent_field.empty() || column_id == nullptr) {

            return false;

        }

        auto it = parent_to_base_column_id.find(parent_field);

        if (it != parent_to_base_column_id.end()) {

            *column_id = it->second;

            return true;

        }

        if (index_context == nullptr || index_context->segment() == nullptr) {

            return false;

        }

        const int32_t ordinal =

                index_context->segment()->tablet_schema()->field_index(parent_field);

        if (ordinal < 0) {

            return false;

        }

        ColumnId resolved_id = static_cast<ColumnId>(ordinal);

        parent_to_base_column_id.emplace(parent_field, resolved_id);

        if (auto* storage_name_type = index_context->get_storage_name_and_type_by_id(resolved_id);

            storage_name_type != nullptr) {

            parent_to_storage_field_prefix[parent_field] = storage_name_type->first;

        }

        *column_id = resolved_id;

        return true;

    };

    int child_index = 0; // Index for iterating through children

    for (const auto& child : expr.children()) {

        if (child->is_slot_ref()) {

            auto* column_slot_ref = assert_cast<VSlotRef*>(child.get());

            int column_id = column_slot_ref->column_id();

            // Determine the field_name from field_bindings (for variant subcolumns)

            // field_bindings and children should have the same order

            std::string field_name;

            const TSearchFieldBinding* binding = nullptr;

            if (child_index < field_bindings.size()) {

                // Use field_name from binding (may include "parent.subcolumn" for variant)

                binding = &field_bindings[child_index];

                field_name = binding->field_name;

            } else {

                // Fallback to column_name if binding not found

                field_name = column_slot_ref->column_name();

            }

            bundle->field_name_to_column_id[field_name] = column_id;

            auto* iterator = index_context->get_inverted_index_iterator_by_column_id(column_id);

            const auto* storage_name_type =

                    index_context->get_storage_name_and_type_by_column_id(column_id);

            bool field_added = false;

            // For variant subcolumns, slot_ref might not map to a real indexed column in the scan schema.

            // Fall back to the parent variant column's iterator and synthesize lucene field name.

            if (iterator == nullptr && binding != nullptr &&

                binding->__isset.is_variant_subcolumn && binding->is_variant_subcolumn &&

                binding->__isset.parent_field_name && !binding->parent_field_name.empty()) {

                ColumnId base_column_id = 0;

                if (resolve_parent_column_id(binding->parent_field_name, &base_column_id)) {

                    iterator = index_context->get_inverted_index_iterator_by_id(base_column_id);

                    const auto* base_storage_name_type =

                            index_context->get_storage_name_and_type_by_id(base_column_id);

                    if (iterator != nullptr && base_storage_name_type != nullptr) {

                        std::string prefix = base_storage_name_type->first;

                        if (auto pit =

                                    parent_to_storage_field_prefix.find(binding->parent_field_name);

                            pit != parent_to_storage_field_prefix.end() && !pit->second.empty()) {

                            prefix = pit->second;

                        } else {

                            parent_to_storage_field_prefix[binding->parent_field_name] = prefix;

                        }

                        std::string sub_path;

                        if (binding->__isset.subcolumn_path) {

                            sub_path = binding->subcolumn_path;

                        }

                        if (sub_path.empty()) {

                            // Fallback: strip "parent." prefix from logical field name

                            std::string pfx = binding->parent_field_name + ".";

                            if (field_name.starts_with(pfx)) {

                                sub_path = field_name.substr(pfx.size());

                            }

                        }

                        if (!sub_path.empty()) {

                            bundle->iterators[field_name] = iterator;

                            bundle->field_types[field_name] =

                                    std::make_pair(prefix + "." + sub_path, nullptr);

                            int base_column_index =

                                    index_context->column_index_by_id(base_column_id);

                            if (base_column_index >= 0) {

                                bundle->column_ids.emplace_back(base_column_index);

                            }

                            field_added = true;

                        }

                    }

                }

            }

            // Only collect fields that have iterators (materialized columns with indexes)

            if (!field_added && iterator != nullptr) {

                if (storage_name_type == nullptr) {

                    return Status::InternalError("storage_name_type not found for column {} in {}",

                                                 column_id, expr.expr_name());

                }

                bundle->iterators.emplace(field_name, iterator);

                bundle->field_types.emplace(field_name, *storage_name_type);

                bundle->column_ids.emplace_back(column_id);

            }

            child_index++;

        } else if (child->is_literal()) {

            auto* literal = assert_cast<VLiteral*>(child.get());

            bundle->literal_args.emplace_back(literal->get_column_ptr(), literal->get_data_type(),

                                              literal->expr_name());

        } else {

            // Check if this is ElementAt expression (for variant subcolumn access)

            if (child->expr_name() == "element_at" && child_index < field_bindings.size() &&

                field_bindings[child_index].__isset.is_variant_subcolumn &&

                field_bindings[child_index].is_variant_subcolumn) {

                // Variant subcolumn not materialized - skip, will create empty BitSetQuery in function_search

                child_index++;

                continue;

            }

            // Not a supported child type

            return Status::InvalidArgument("Unsupported child node type: {}", child->expr_name());

        }

    }

    return Status::OK();

}

} // namespace

VSearchExpr::VSearchExpr(const TExprNode& node) : VExpr(node) {

    if (node.__isset.search_param) {

        _search_param = node.search_param;

        _original_dsl = _search_param.original_dsl;

    }

}

Status VSearchExpr::prepare(RuntimeState* state, const RowDescriptor& row_desc,

                            VExprContext* context) {

    RETURN_IF_ERROR(VExpr::prepare(state, row_desc, context));

    const auto& query_options = state->query_options();

    if (query_options.__isset.enable_inverted_index_query_cache) {

        _enable_cache = query_options.enable_inverted_index_query_cache;

    }

    return Status::OK();

}

const std::string& VSearchExpr::expr_name() const {

    static const std::string name = "VSearchExpr";

    return name;

}

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

                                   size_t count, ColumnPtr& result_column) const {

    if (fast_execute(context, selector, count, result_column)) {

        return Status::OK();

    }

    return Status::InternalError("SearchExpr should not be executed without inverted index");

}

Status VSearchExpr::evaluate_inverted_index(VExprContext* context, uint32_t segment_num_rows) {

    if (_search_param.original_dsl.empty()) {

        return Status::InvalidArgument("search DSL is empty");

    }

    auto index_context = context->get_index_context();

    if (!index_context) {

        LOG(WARNING) << "VSearchExpr: No inverted index context available";

        return Status::OK();

    }

    SearchInputBundle bundle;

    RETURN_IF_ERROR(collect_search_inputs(*this, context, &bundle));

    VLOG_DEBUG << "VSearchExpr: bundle.iterators.size()=" << bundle.iterators.size();

    const bool is_nested_query = _search_param.root.clause_type == "NESTED";

    if (bundle.iterators.empty() && !is_nested_query) {

        LOG(WARNING) << "VSearchExpr: No indexed columns available for evaluation, DSL: "

                     << _original_dsl;

        auto empty_bitmap = InvertedIndexResultBitmap(std::make_shared<roaring::Roaring>(),

                                                      std::make_shared<roaring::Roaring>());

        index_context->set_index_result_for_expr(this, std::move(empty_bitmap));

        return Status::OK();

    }

    auto function = std::make_shared<FunctionSearch>();

    auto result_bitmap = InvertedIndexResultBitmap();

    auto status = function->evaluate_inverted_index_with_search_param(

            _search_param, bundle.field_types, bundle.iterators, segment_num_rows, result_bitmap,

            _enable_cache, index_context.get(), bundle.field_name_to_column_id);

    if (!status.ok()) {

        LOG(WARNING) << "VSearchExpr: Function evaluation failed: " << status.to_string();

        return status;

    }

    index_context->set_index_result_for_expr(this, result_bitmap);

    for (int column_id : bundle.column_ids) {

        index_context->set_true_for_index_status(this, column_id);

    }

    return Status::OK();

}

} // namespace doris