// 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 "util/jsonb_document.h"

#include <memory>
#include <string>
#include <vector>

#include "common/status.h"
#include "util/jsonb_writer.h"

namespace doris {

Status JsonbDocument::checkAndCreateDocument(const char* pb, size_t size,
                                             const JsonbDocument** doc) {
    *doc = nullptr;
    if (!pb || size == 0) {
        static const std::string buf = []() {
            JsonbWriter writer;
            (void)writer.writeNull();
            auto* out = writer.getOutput();
            return std::string(out->getBuffer(), out->getSize());
        }();
        // Treat empty input as a valid JSONB null document.
        *doc = reinterpret_cast<const JsonbDocument*>(buf.data());
        return Status::OK();
    }
    if (!pb || size < sizeof(JsonbHeader) + sizeof(JsonbValue)) {
        return Status::InvalidArgument("Invalid JSONB document: too small size({}) or null pointer",
                                       size);
    }

    const auto* doc_ptr = (const JsonbDocument*)pb;
    if (doc_ptr->header_.ver_ != JSONB_VER) {
        return Status::InvalidArgument("Invalid JSONB document: invalid version({})",
                                       doc_ptr->header_.ver_);
    }

    const auto* val = (const JsonbValue*)doc_ptr->payload_;
    // Keep this check lightweight. This API is used by JSONB scalar/table functions on every row,
    // so recursively validating object/array payloads here would add an O(document size) scan before
    // the real operation and can regress large JSONB queries. External INSERT/LOAD paths build JSONB
    // through JsonBinaryValue/JsonbWriter before storage; any untrusted raw binary boundary should
    // add explicit deep validation there instead of changing this hot-path helper.
    if (val->type < JsonbType::T_Null || val->type >= JsonbType::NUM_TYPES ||
        size != sizeof(JsonbHeader) + val->numPackedBytes()) {
        return Status::InvalidArgument("Invalid JSONB document: invalid type({}) or size({})",
                                       static_cast<JsonbTypeUnder>(val->type), size);
    }

    *doc = doc_ptr;
    return Status::OK();
}

JsonbFindResult JsonbValue::findValue(JsonbPath& path) const {
    JsonbFindResult result;
    bool is_wildcard = false;

    std::vector<const JsonbValue*> values;
    std::vector<const JsonbValue*> results;
    results.emplace_back(this);

    if (path.is_supper_wildcard()) {
        std::function<void(const JsonbValue*)> foreach_values;
        foreach_values = [&](const JsonbValue* val) {
            if (val->isObject()) {
                for (const auto& it : *val->unpack<ObjectVal>()) {
                    results.emplace_back(it.value());
                    foreach_values(it.value());
                }
            } else if (val->isArray()) {
                for (const auto& it : *val->unpack<ArrayVal>()) {
                    results.emplace_back(&it);
                    foreach_values(&it);
                }
            }
        };
        is_wildcard = true;
        foreach_values(this);
    }

    for (size_t i = 0; i < path.get_leg_vector_size(); ++i) {
        values = std::move(results);
        for (const auto* pval : values) {
            switch (path.get_leg_from_leg_vector(i)->type) {
            case MEMBER_CODE: {
                if (LIKELY(pval->type == JsonbType::T_Object)) {
                    if (path.get_leg_from_leg_vector(i)->leg_len == 1 &&
                        *path.get_leg_from_leg_vector(i)->leg_ptr == WILDCARD) {
                        is_wildcard = true;
                        for (const auto& it : *pval->unpack<ObjectVal>()) {
                            results.emplace_back(it.value());
                        }
                        continue;
                    }

                    pval = pval->unpack<ObjectVal>()->find(
                            path.get_leg_from_leg_vector(i)->leg_ptr,
                            path.get_leg_from_leg_vector(i)->leg_len);

                    if (pval) {
                        results.emplace_back(pval);
                    }
                }
                continue;
            }
            case ARRAY_CODE: {
                if (path.get_leg_from_leg_vector(i)->leg_len == 1 &&
                    *path.get_leg_from_leg_vector(i)->leg_ptr == WILDCARD) {
                    if (LIKELY(pval->type == JsonbType::T_Array)) {
                        is_wildcard = true;
                        for (const auto& it : *pval->unpack<ArrayVal>()) {
                            results.emplace_back(&it);
                        }
                    }
                    continue;
                }

                if (pval->type != JsonbType::T_Array &&
                    path.get_leg_from_leg_vector(i)->array_index == 0) {
                    // Same as mysql and postgres
                    results.emplace_back(pval);
                    continue;
                }

                if (pval->type != JsonbType::T_Array ||
                    path.get_leg_from_leg_vector(i)->leg_ptr != nullptr ||
                    path.get_leg_from_leg_vector(i)->leg_len != 0) {
                    continue;
                }

                if (path.get_leg_from_leg_vector(i)->array_index >= 0) {
                    pval = pval->unpack<ArrayVal>()->get(
                            path.get_leg_from_leg_vector(i)->array_index);
                } else {
                    pval = pval->unpack<ArrayVal>()->get(
                            pval->unpack<ArrayVal>()->numElem() +
                            path.get_leg_from_leg_vector(i)->array_index);
                }

                if (pval) {
                    results.emplace_back(pval);
                }
                continue;
            }
            }
        }
    }

    if (is_wildcard) {
        result.is_wildcard = true;
        if (results.empty()) {
            result.value = nullptr; // No values found
        } else {
            /// if supper wildcard, need distinct results
            /// because supper wildcard will traverse all nodes
            ///
            /// `select json_extract( '[1]', '$**[0]' );`
            /// +---------------------------------+
            /// | json_extract( '[1]', '$**[0]' ) |
            /// +---------------------------------+
            /// | [1,1]                           |
            /// +---------------------------------+
            if (results.size() > 1 && path.is_supper_wildcard()) [[unlikely]] {
                std::set<const JsonbValue*> distinct_results;
                for (const auto* pval : results) {
                    distinct_results.insert(pval);
                }
                results.assign(distinct_results.begin(), distinct_results.end());
            }
            result.writer = std::make_unique<JsonbWriter>();
            result.writer->writeStartArray();
            for (const auto* pval : results) {
                result.writer->writeValue(pval);
            }
            result.writer->writeEndArray();

            const JsonbDocument* doc = nullptr;
            THROW_IF_ERROR(JsonbDocument::checkAndCreateDocument(
                    result.writer->getOutput()->getBuffer(), result.writer->getOutput()->getSize(),
                    &doc));
            result.value = doc->getValue();
        }
    } else if (results.size() == 1) {
        result.value = results[0];
    }

    return result;
}

std::vector<std::pair<StringRef, const JsonbValue*>> ObjectVal::get_ordered_key_value_pairs()
        const {
    std::vector<std::pair<StringRef, const JsonbValue*>> kvs;
    const auto* obj_val = this;
    for (auto it = obj_val->begin(); it != obj_val->end(); ++it) {
        kvs.emplace_back(StringRef(it->getKeyStr(), it->klen()), it->value());
    }
    // sort by key
    std::sort(kvs.begin(), kvs.end(),
              [](const auto& left, const auto& right) { return left.first < right.first; });
    // unique by key
    kvs.erase(std::unique(kvs.begin(), kvs.end(),
                          [](const auto& left, const auto& right) {
                              return left.first == right.first;
                          }),
              kvs.end());
    return kvs;
}

} // namespace doris