/*-
 * #%L
 * HAPI FHIR Storage api
 * %%
 * Copyright (C) 2014 - 2025 Smile CDR, Inc.
 * %%
 * Licensed 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.
 * #L%
 */
package ca.uhn.fhir.jpa.util;

import ca.uhn.fhir.util.StopWatch;
import com.google.common.collect.Queues;
import jakarta.annotation.Nonnull;
import jakarta.annotation.Nullable;
import net.ttddyy.dsproxy.support.ProxyDataSourceBuilder;
import org.apache.commons.collections4.queue.CircularFifoQueue;
import org.hl7.fhir.r4.model.InstantType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * This is a query listener designed to be plugged into a {@link ProxyDataSourceBuilder proxy DataSource}.
 * This listener keeps the last 1000 queries across all threads in a {@link CircularFifoQueue}, dropping queries off the
 * end of the list as new ones are added.
 * <p>
 * Note that this class is really only designed for use in testing - It adds a non-trivial overhead
 * to each query.
 * </p>
 */
public class CircularQueueCaptureQueriesListener extends BaseCaptureQueriesListener {

        public static final Predicate<String> DEFAULT_SELECT_INCLUSION_CRITERIA =
                        t -> t.toLowerCase(Locale.US).startsWith("select");
        private static final int CAPACITY = 10000;
        private static final Logger ourLog = LoggerFactory.getLogger(CircularQueueCaptureQueriesListener.class);
        private Queue<SqlQuery> myQueries;
        private AtomicInteger myGetConnectionCounter;
        private AtomicInteger myCommitCounter;
        private AtomicInteger myRollbackCounter;

        @Nonnull
        private Predicate<String> mySelectQueryInclusionCriteria = DEFAULT_SELECT_INCLUSION_CRITERIA;

        /**
         * Constructor
         */
        public CircularQueueCaptureQueriesListener() {
                startCollecting();
        }

        /**
         * Sets an alternate inclusion criteria for select queries. This can be used to add
         * additional criteria beyond the default value of {@link #DEFAULT_SELECT_INCLUSION_CRITERIA}.
         */
        public CircularQueueCaptureQueriesListener setSelectQueryInclusionCriteria(
                        @Nonnull Predicate<String> theSelectQueryInclusionCriteria) {
                mySelectQueryInclusionCriteria = theSelectQueryInclusionCriteria;
                return this;
        }

        @Override
        protected Queue<SqlQuery> provideQueryList() {
                return myQueries;
        }

        @Override
        protected AtomicInteger provideCommitCounter() {
                return myCommitCounter;
        }

        @Nullable
        @Override
        protected AtomicInteger provideGetConnectionCounter() {
                return myGetConnectionCounter;
        }

        @Override
        protected AtomicInteger provideRollbackCounter() {
                return myRollbackCounter;
        }

        /**
         * Clear all stored queries
         */
        public void clear() {
                myQueries.clear();
                myGetConnectionCounter.set(0);
                myCommitCounter.set(0);
                myRollbackCounter.set(0);
        }

        /**
         * Start collecting queries (this is the default)
         */
        public void startCollecting() {
                myQueries = Queues.synchronizedQueue(new CircularFifoQueue<>(CAPACITY));
                myGetConnectionCounter = new AtomicInteger(0);
                myCommitCounter = new AtomicInteger(0);
                myRollbackCounter = new AtomicInteger(0);
        }

        /**
         * Stop collecting queries and discard any collected ones
         */
        public void stopCollecting() {
                myQueries = null;
                myCommitCounter = null;
                myRollbackCounter = null;
        }

        /**
         * Index 0 is oldest
         */
        @SuppressWarnings("UseBulkOperation")
        public List<SqlQuery> getCapturedQueries() {
                // Make a copy so that we aren't affected by changes to the list outside of the
                // synchronized block
                ArrayList<SqlQuery> retVal = new ArrayList<>(CAPACITY);
                myQueries.forEach(retVal::add);
                return Collections.unmodifiableList(retVal);
        }

        private List<SqlQuery> getQueriesForCurrentThreadStartingWith(String theStart) {
                String threadName = Thread.currentThread().getName();
                return getQueriesStartingWith(theStart, threadName);
        }

        private List<SqlQuery> getQueriesStartingWith(String theStart, String theThreadName) {
                return getCapturedQueries().stream()
                                .filter(t -> theThreadName == null || t.getThreadName().equals(theThreadName))
                                .filter(t -> t.getSql(false, false).toLowerCase().startsWith(theStart))
                                .collect(Collectors.toList());
        }

        private List<SqlQuery> getQueriesStartingWith(String theStart) {
                return getQueriesStartingWith(theStart, null);
        }

        private List<SqlQuery> getQueriesMatching(Predicate<String> thePredicate, String theThreadName) {
                return getCapturedQueries().stream()
                                .filter(t -> theThreadName == null || t.getThreadName().equals(theThreadName))
                                .filter(t -> thePredicate.test(t.getSql(false, false)))
                                .collect(Collectors.toList());
        }

        private List<SqlQuery> getQueriesMatching(Predicate<String> thePredicate) {
                return getQueriesMatching(thePredicate, null);
        }

        private List<SqlQuery> getQueriesForCurrentThreadMatching(Predicate<String> thePredicate) {
                String threadName = Thread.currentThread().getName();
                return getQueriesMatching(thePredicate, threadName);
        }

        /**
         * @deprecated Use {@link #countCommits()}
         */
        @Deprecated
        public int getCommitCount() {
                return myCommitCounter.get();
        }

        /**
         * @deprecated Use {@link #countRollbacks()}
         */
        @Deprecated
        public int getRollbackCount() {
                return myRollbackCounter.get();
        }

        /**
         * Returns all SELECT queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getSelectQueries() {
                return getQueriesMatching(mySelectQueryInclusionCriteria);
        }

        /**
         * Returns all INSERT queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getInsertQueries() {
                return getQueriesStartingWith("insert");
        }

        /**
         * Returns all INSERT queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getInsertQueries(Predicate<SqlQuery> theFilter) {
                return getQueriesStartingWith("insert").stream().filter(theFilter).collect(Collectors.toList());
        }

        /**
         * Returns all UPDATE queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getUpdateQueries() {
                return getQueriesStartingWith("update");
        }

        /**
         * Returns all UPDATE queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getUpdateQueries(Predicate<SqlQuery> theFilter) {
                return getQueriesStartingWith("update").stream().filter(theFilter).collect(Collectors.toList());
        }

        /**
         * Returns all UPDATE queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getDeleteQueries() {
                return getQueriesStartingWith("delete");
        }

        /**
         * Returns all SELECT queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getSelectQueriesForCurrentThread() {
                return getQueriesForCurrentThreadMatching(mySelectQueryInclusionCriteria);
        }

        /**
         * Returns all INSERT queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getInsertQueriesForCurrentThread() {
                return getQueriesForCurrentThreadStartingWith("insert");
        }

        /**
         * Returns all queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getAllQueriesForCurrentThread() {
                return getQueriesForCurrentThreadStartingWith("");
        }

        /**
         * Returns all UPDATE queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getUpdateQueriesForCurrentThread() {
                return getQueriesForCurrentThreadStartingWith("update");
        }

        /**
         * Returns all UPDATE queries executed on the current thread - Index 0 is oldest
         */
        public List<SqlQuery> getDeleteQueriesForCurrentThread() {
                return getQueriesForCurrentThreadStartingWith("delete");
        }

        /**
         * Log all captured UPDATE queries
         */
        public String logUpdateQueriesForCurrentThread() {
                List<SqlQuery> queries = getUpdateQueriesForCurrentThread();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);
                String joined = String.join("\n", queriesStrings);
                ourLog.info("Update Queries:\n{}", joined);
                return joined;
        }

        /**
         * Log all captured SELECT queries
         */
        public String logSelectQueriesForCurrentThread(int... theIndexes) {
                List<SqlQuery> queries = getSelectQueriesForCurrentThread();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);

                List<String> newList = new ArrayList<>();
                if (theIndexes != null && theIndexes.length > 0) {
                        for (int index : theIndexes) {
                                newList.add(queriesStrings.get(index));
                        }
                        queriesStrings = newList;
                }

                String joined = String.join("\n", queriesStrings);
                ourLog.info("Select Queries:\n{}", joined);
                return joined;
        }

        /**
         * Log all captured SELECT queries
         */
        public List<SqlQuery> logSelectQueries() {
                return logSelectQueries(true, true);
        }

        /**
         * Log all captured SELECT queries
         */
        public List<SqlQuery> logSelectQueries(boolean theInlineParams, boolean theFormatSql) {
                List<SqlQuery> queries = getSelectQueries();
                List<String> queriesStrings = renderQueriesForLogging(theInlineParams, theFormatSql, queries);
                ourLog.info("Select Queries:\n{}", String.join("\n", queriesStrings));
                return queries;
        }

        @Nonnull
        private static List<String> renderQueriesForLogging(
                        boolean theInlineParams, boolean theFormatSql, List<SqlQuery> queries) {
                List<String> queriesStrings = new ArrayList<>();
                for (int i = 0; i < queries.size(); i++) {
                        SqlQuery query = queries.get(i);
                        String remderedString = "[" + i + "] "
                                        + CircularQueueCaptureQueriesListener.formatQueryAsSql(query, theInlineParams, theFormatSql);
                        queriesStrings.add(remderedString);
                }
                return queriesStrings;
        }

        /**
         * Log first captured SELECT query
         */
        public void logFirstSelectQueryForCurrentThread() {
                boolean inlineParams = true;
                String firstSelectQuery = getSelectQueriesForCurrentThread().stream()
                                .findFirst()
                                .map(t -> CircularQueueCaptureQueriesListener.formatQueryAsSql(t, inlineParams, inlineParams))
                                .orElse("NONE FOUND");
                ourLog.info("First select SqlQuery:\n{}", firstSelectQuery);
        }

        /**
         * Log all captured INSERT queries
         */
        public String logInsertQueriesForCurrentThread() {
                List<SqlQuery> queries = getInsertQueriesForCurrentThread();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);
                String queriesAsString = String.join("\n", queriesStrings);
                ourLog.info("Insert Queries:\n{}", queriesAsString);
                return queriesAsString;
        }

        /**
         * Log all captured queries
         */
        public void logAllQueriesForCurrentThread() {
                List<SqlQuery> queries = getAllQueriesForCurrentThread();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);
                ourLog.info("Queries:\n{}", String.join("\n", queriesStrings));
        }

        /**
         * Log all captured queries
         */
        public void logAllQueries() {
                List<SqlQuery> queries = getCapturedQueries();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);
                ourLog.info("Queries:\n{}", String.join("\n", queriesStrings));
        }

        /**
         * Log all captured INSERT queries
         */
        public int logInsertQueries() {
                return logInsertQueries(null);
        }

        /**
         * Log all captured INSERT queries
         */
        public int logInsertQueries(Predicate<SqlQuery> theInclusionPredicate) {
                List<SqlQuery> insertQueries = getInsertQueries().stream()
                                .filter(t -> theInclusionPredicate == null || theInclusionPredicate.test(t))
                                .collect(Collectors.toList());
                List<String> queriesStrings = renderQueriesForLogging(true, true, insertQueries);
                ourLog.info("Insert Queries:\n{}", String.join("\n", queriesStrings));

                return countQueries(insertQueries);
        }

        /**
         * Log all captured INSERT queries
         */
        public int logUpdateQueries() {
                List<SqlQuery> queries = getUpdateQueries();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);
                ourLog.info("Update Queries:\n{}", String.join("\n", queriesStrings));

                return countQueries(queries);
        }

        /**
         * Log all captured DELETE queries
         */
        public String logDeleteQueriesForCurrentThread() {
                List<SqlQuery> queries = getDeleteQueriesForCurrentThread();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);
                String joined = String.join("\n", queriesStrings);
                ourLog.info("Delete Queries:\n{}", joined);
                return joined;
        }

        /**
         * Log all captured DELETE queries
         */
        public int logDeleteQueries() {
                List<SqlQuery> queries = getDeleteQueries();
                List<String> queriesStrings = renderQueriesForLogging(true, true, queries);
                ourLog.info("Delete Queries:\n{}", String.join("\n", queriesStrings));

                return countQueries(queries);
        }

        public int countSelectQueries() {
                return countQueries(getSelectQueries());
        }

        public int countInsertQueries() {
                return countQueries(getInsertQueries());
        }

        /**
         * This method returns a count of insert queries which were issued more than
         * once. If a query was issued twice with batched parameters, that does not
         * count as a repeated query, but if it is issued as two separate insert
         * statements with a single set of parameters this counts as a repeated
         * query.
         */
        public int countInsertQueriesRepeated() {
                return getInsertQueries(new DuplicateCheckingPredicate()).size();
        }

        public int countUpdateQueries() {
                return countQueries(getUpdateQueries());
        }

        public int countDeleteQueries() {
                return countQueries(getDeleteQueries());
        }

        public int countSelectQueriesForCurrentThread() {
                return countQueries(getSelectQueriesForCurrentThread());
        }

        public int countInsertQueriesForCurrentThread() {
                return countQueries(getInsertQueriesForCurrentThread());
        }

        public int countUpdateQueriesForCurrentThread() {
                return countQueries(getUpdateQueriesForCurrentThread());
        }

        public int countDeleteQueriesForCurrentThread() {
                return countQueries(getDeleteQueriesForCurrentThread());
        }

        @Nonnull
        private static Integer countQueries(List<SqlQuery> theQueries) {
                return theQueries.stream().map(t -> t.getSize()).reduce(0, Integer::sum);
        }

        @Nonnull
        static String formatQueryAsSql(SqlQuery theQuery) {
                boolean inlineParams = true;
                boolean formatSql = true;
                return formatQueryAsSql(theQuery, inlineParams, formatSql);
        }

        @Nonnull
        static String formatQueryAsSql(SqlQuery theQuery, boolean inlineParams, boolean formatSql) {
                String formattedSql = theQuery.getSql(inlineParams, formatSql);
                StringBuilder b = new StringBuilder();
                b.append("SqlQuery at ");
                b.append(new InstantType(new Date(theQuery.getQueryTimestamp())).getValueAsString());
                if (theQuery.getRequestPartitionId() != null
                                && theQuery.getRequestPartitionId().hasPartitionIds()) {
                        b.append(" on partition ");
                        b.append(theQuery.getRequestPartitionId().getPartitionIds());
                }
                b.append(" took ").append(StopWatch.formatMillis(theQuery.getElapsedTime()));
                b.append(" on Thread: ").append(theQuery.getThreadName());
                if (theQuery.getSize() > 1) {
                        b.append("\nExecution Count: ")
                                        .append(theQuery.getSize())
                                        .append(" (parameters shown are for first execution)");
                }
                b.append("\nSQL:\n").append(formattedSql);
                if (theQuery.getStackTrace() != null) {
                        b.append("\nStack:\n   ");
                        Stream<String> stackTraceStream = Arrays.stream(theQuery.getStackTrace())
                                        .map(StackTraceElement::toString)
                                        .filter(t -> t.startsWith("ca."));
                        b.append(stackTraceStream.collect(Collectors.joining("\n   ")));
                }
                b.append("\n");
                return b.toString();
        }

        /**
         * Create a new instance of this each time you use it
         */
        private static class DuplicateCheckingPredicate implements Predicate<SqlQuery> {
                private final Set<String> mySeenSql = new HashSet<>();

                @Override
                public boolean test(SqlQuery theSqlQuery) {
                        String sql = theSqlQuery.getSql(false, false);
                        boolean retVal = !mySeenSql.add(sql);
                        ourLog.trace("SQL duplicate[{}]: {}", retVal, sql);
                        return retVal;
                }
        }
}