/*
 * Copyright 2021 The Android Open Source Project
 *
 * 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.
 */
package com.android.server.appsearch.external.localstorage.stats;

import android.annotation.IntDef;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.app.appsearch.AppSearchResult;
import android.app.appsearch.SearchSpec;

import com.android.internal.util.Preconditions;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Objects;

/**
 * Class holds detailed stats for {@link android.app.appsearch.AppSearchSession#search(String,
 * SearchSpec)}
 *
 * @hide
 */
public final class SearchStats {
    @IntDef(
            value = {
                // Searches apps' own documents.
                VISIBILITY_SCOPE_LOCAL,
                // Searches the global documents. Including platform surfaceable and 3p-access.
                VISIBILITY_SCOPE_GLOBAL,
                // TODO(b/173532925) Add THIRD_PARTY_ACCESS once we can distinguish platform
                //  surfaceable from 3p access(right both of them are categorized as
                //  VISIBILITY_SCOPE_GLOBAL)
            })
    @Retention(RetentionPolicy.SOURCE)
    public @interface VisibilityScope {}

    // Searches apps' own documents.
    public static final int VISIBILITY_SCOPE_LOCAL = 1;
    // Searches the global documents. Including platform surfaceable and 3p-access.
    public static final int VISIBILITY_SCOPE_GLOBAL = 2;

    // TODO(b/173532925): Add a field searchType to indicate where the search is used(normal
    //  query vs in removeByQuery vs during migration)

    @NonNull private final String mPackageName;
    @Nullable private final String mDatabase;
    /**
     * The status code returned by {@link AppSearchResult#getResultCode()} for the call or internal
     * state.
     */
    @AppSearchResult.ResultCode private final int mStatusCode;

    private final int mTotalLatencyMillis;
    /** Time used to rewrite the search spec. */
    private final int mRewriteSearchSpecLatencyMillis;
    /** Time used to rewrite the search results. */
    private final int mRewriteSearchResultLatencyMillis;
    /** Defines the scope the query is searching over */
    @VisibilityScope private final int mVisibilityScope;
    /** Overall time used for the native function call. */
    private final int mNativeLatencyMillis;
    /** Number of terms in the query string. */
    private final int mNativeNumTerms;
    /** Length of the query string. */
    private final int mNativeQueryLength;
    /** Number of namespaces filtered. */
    private final int mNativeNumNamespacesFiltered;
    /** Number of schema types filtered. */
    private final int mNativeNumSchemaTypesFiltered;
    /** The requested number of results in one page. */
    private final int mNativeRequestedPageSize;
    /** The actual number of results returned in the current page. */
    private final int mNativeNumResultsReturnedCurrentPage;
    /**
     * Whether the function call is querying the first page. If it's not, Icing will fetch the
     * results from cache so that some steps may be skipped.
     */
    private final boolean mNativeIsFirstPage;
    /**
     * Time used to parse the query, including 2 parts: tokenizing and transforming tokens into an
     * iterator tree.
     */
    private final int mNativeParseQueryLatencyMillis;
    /** Strategy of scoring and ranking. */
    @SearchSpec.RankingStrategy private final int mNativeRankingStrategy;
    /** Number of documents scored. */
    private final int mNativeNumDocumentsScored;
    /** Time used to score the raw results. */
    private final int mNativeScoringLatencyMillis;
    /** Time used to rank the scored results. */
    private final int mNativeRankingLatencyMillis;
    /**
     * Time used to fetch the document protos. Note that it includes the time to snippet if {@link
     * SearchStats#mNativeNumResultsWithSnippets} is greater than 0.
     */
    private final int mNativeDocumentRetrievingLatencyMillis;
    /** How many snippets are calculated. */
    private final int mNativeNumResultsWithSnippets;

    SearchStats(@NonNull Builder builder) {
        Objects.requireNonNull(builder);
        mPackageName = builder.mPackageName;
        mDatabase = builder.mDatabase;
        mStatusCode = builder.mStatusCode;
        mTotalLatencyMillis = builder.mTotalLatencyMillis;
        mRewriteSearchSpecLatencyMillis = builder.mRewriteSearchSpecLatencyMillis;
        mRewriteSearchResultLatencyMillis = builder.mRewriteSearchResultLatencyMillis;
        mVisibilityScope = builder.mVisibilityScope;
        mNativeLatencyMillis = builder.mNativeLatencyMillis;
        mNativeNumTerms = builder.mNativeNumTerms;
        mNativeQueryLength = builder.mNativeQueryLength;
        mNativeNumNamespacesFiltered = builder.mNativeNumNamespacesFiltered;
        mNativeNumSchemaTypesFiltered = builder.mNativeNumSchemaTypesFiltered;
        mNativeRequestedPageSize = builder.mNativeRequestedPageSize;
        mNativeNumResultsReturnedCurrentPage = builder.mNativeNumResultsReturnedCurrentPage;
        mNativeIsFirstPage = builder.mNativeIsFirstPage;
        mNativeParseQueryLatencyMillis = builder.mNativeParseQueryLatencyMillis;
        mNativeRankingStrategy = builder.mNativeRankingStrategy;
        mNativeNumDocumentsScored = builder.mNativeNumDocumentsScored;
        mNativeScoringLatencyMillis = builder.mNativeScoringLatencyMillis;
        mNativeRankingLatencyMillis = builder.mNativeRankingLatencyMillis;
        mNativeNumResultsWithSnippets = builder.mNativeNumResultsWithSnippets;
        mNativeDocumentRetrievingLatencyMillis = builder.mNativeDocumentRetrievingLatencyMillis;
    }

    /** Returns the package name of the session. */
    @NonNull
    public String getPackageName() {
        return mPackageName;
    }

    /**
     * Returns the database name of the session.
     *
     * @return database name used by the session. {@code null} if and only if it is a global
     *     search(visibilityScope is {@link SearchStats#VISIBILITY_SCOPE_GLOBAL}).
     */
    @Nullable
    public String getDatabase() {
        return mDatabase;
    }

    /** Returns status of the search. */
    @AppSearchResult.ResultCode
    public int getStatusCode() {
        return mStatusCode;
    }

    /** Returns the total latency of the search. */
    public int getTotalLatencyMillis() {
        return mTotalLatencyMillis;
    }

    /** Returns how much time spent on rewriting the {@link SearchSpec}. */
    public int getRewriteSearchSpecLatencyMillis() {
        return mRewriteSearchSpecLatencyMillis;
    }

    /** Returns how much time spent on rewriting the {@link android.app.appsearch.SearchResult}. */
    public int getRewriteSearchResultLatencyMillis() {
        return mRewriteSearchResultLatencyMillis;
    }

    /** Returns the visibility scope of the search. */
    @VisibilityScope
    public int getVisibilityScope() {
        return mVisibilityScope;
    }

    /** Returns how much time spent on the native calls. */
    public int getNativeLatencyMillis() {
        return mNativeLatencyMillis;
    }

    /** Returns number of terms in the search string. */
    public int getTermCount() {
        return mNativeNumTerms;
    }

    /** Returns the length of the search string. */
    public int getQueryLength() {
        return mNativeQueryLength;
    }

    /** Returns number of namespaces filtered. */
    public int getFilteredNamespaceCount() {
        return mNativeNumNamespacesFiltered;
    }

    /** Returns number of schema types filtered. */
    public int getFilteredSchemaTypeCount() {
        return mNativeNumSchemaTypesFiltered;
    }

    /** Returns the requested number of results in one page. */
    public int getRequestedPageSize() {
        return mNativeRequestedPageSize;
    }

    /** Returns the actual number of results returned in the current page. */
    public int getCurrentPageReturnedResultCount() {
        return mNativeNumResultsReturnedCurrentPage;
    }

    // TODO(b/185184738) Make it an integer to show how many pages having been returned.
    /** Returns whether the function call is querying the first page. */
    public boolean isFirstPage() {
        return mNativeIsFirstPage;
    }

    /**
     * Returns time used to parse the query, including 2 parts: tokenizing and transforming tokens
     * into an iterator tree.
     */
    public int getParseQueryLatencyMillis() {
        return mNativeParseQueryLatencyMillis;
    }

    /** Returns strategy of scoring and ranking. */
    @SearchSpec.RankingStrategy
    public int getRankingStrategy() {
        return mNativeRankingStrategy;
    }

    /** Returns number of documents scored. */
    public int getScoredDocumentCount() {
        return mNativeNumDocumentsScored;
    }

    /** Returns time used to score the raw results. */
    public int getScoringLatencyMillis() {
        return mNativeScoringLatencyMillis;
    }

    /** Returns time used to rank the scored results. */
    public int getRankingLatencyMillis() {
        return mNativeRankingLatencyMillis;
    }

    /**
     * Returns time used to fetch the document protos. Note that it includes the time to snippet if
     * {@link SearchStats#mNativeNumResultsWithSnippets} is not zero.
     */
    public int getDocumentRetrievingLatencyMillis() {
        return mNativeDocumentRetrievingLatencyMillis;
    }

    /** Returns the number of the results in the page returned were snippeted. */
    public int getResultWithSnippetsCount() {
        return mNativeNumResultsWithSnippets;
    }

    /** Builder for {@link SearchStats} */
    public static class Builder {
        @NonNull final String mPackageName;
        @Nullable String mDatabase;
        @AppSearchResult.ResultCode int mStatusCode;
        int mTotalLatencyMillis;
        int mRewriteSearchSpecLatencyMillis;
        int mRewriteSearchResultLatencyMillis;
        int mVisibilityScope;
        int mNativeLatencyMillis;
        int mNativeNumTerms;
        int mNativeQueryLength;
        int mNativeNumNamespacesFiltered;
        int mNativeNumSchemaTypesFiltered;
        int mNativeRequestedPageSize;
        int mNativeNumResultsReturnedCurrentPage;
        boolean mNativeIsFirstPage;
        int mNativeParseQueryLatencyMillis;
        int mNativeRankingStrategy;
        int mNativeNumDocumentsScored;
        int mNativeScoringLatencyMillis;
        int mNativeRankingLatencyMillis;
        int mNativeNumResultsWithSnippets;
        int mNativeDocumentRetrievingLatencyMillis;

        /**
         * Constructor
         *
         * @param visibilityScope scope for the corresponding search.
         * @param packageName name of the calling package.
         */
        public Builder(@VisibilityScope int visibilityScope, @NonNull String packageName) {
            mVisibilityScope = visibilityScope;
            mPackageName = Objects.requireNonNull(packageName);
        }

        /** Sets the database used by the session. */
        @NonNull
        public Builder setDatabase(@NonNull String database) {
            mDatabase = Objects.requireNonNull(database);
            return this;
        }

        /** Sets the status of the search. */
        @NonNull
        public Builder setStatusCode(@AppSearchResult.ResultCode int statusCode) {
            mStatusCode = statusCode;
            return this;
        }

        /** Sets total latency for the search. */
        @NonNull
        public Builder setTotalLatencyMillis(int totalLatencyMillis) {
            mTotalLatencyMillis = totalLatencyMillis;
            return this;
        }

        /** Sets time used to rewrite the search spec. */
        @NonNull
        public Builder setRewriteSearchSpecLatencyMillis(int rewriteSearchSpecLatencyMillis) {
            mRewriteSearchSpecLatencyMillis = rewriteSearchSpecLatencyMillis;
            return this;
        }

        /** Sets time used to rewrite the search results. */
        @NonNull
        public Builder setRewriteSearchResultLatencyMillis(int rewriteSearchResultLatencyMillis) {
            mRewriteSearchResultLatencyMillis = rewriteSearchResultLatencyMillis;
            return this;
        }

        /** Sets overall time used for the native function calls. */
        @NonNull
        public Builder setNativeLatencyMillis(int nativeLatencyMillis) {
            mNativeLatencyMillis = nativeLatencyMillis;
            return this;
        }

        /** Sets number of terms in the search string. */
        @NonNull
        public Builder setTermCount(int termCount) {
            mNativeNumTerms = termCount;
            return this;
        }

        /** Sets length of the search string. */
        @NonNull
        public Builder setQueryLength(int queryLength) {
            mNativeQueryLength = queryLength;
            return this;
        }

        /** Sets number of namespaces filtered. */
        @NonNull
        public Builder setFilteredNamespaceCount(int filteredNamespaceCount) {
            mNativeNumNamespacesFiltered = filteredNamespaceCount;
            return this;
        }

        /** Sets number of schema types filtered. */
        @NonNull
        public Builder setFilteredSchemaTypeCount(int filteredSchemaTypeCount) {
            mNativeNumSchemaTypesFiltered = filteredSchemaTypeCount;
            return this;
        }

        /** Sets the requested number of results in one page. */
        @NonNull
        public Builder setRequestedPageSize(int requestedPageSize) {
            mNativeRequestedPageSize = requestedPageSize;
            return this;
        }

        /** Sets the actual number of results returned in the current page. */
        @NonNull
        public Builder setCurrentPageReturnedResultCount(int currentPageReturnedResultCount) {
            mNativeNumResultsReturnedCurrentPage = currentPageReturnedResultCount;
            return this;
        }

        /**
         * Sets whether the function call is querying the first page. If it's not, Icing will fetch
         * the results from cache so that some steps may be skipped.
         */
        @NonNull
        public Builder setIsFirstPage(boolean nativeIsFirstPage) {
            mNativeIsFirstPage = nativeIsFirstPage;
            return this;
        }

        /**
         * Sets time used to parse the query, including 2 parts: tokenizing and transforming tokens
         * into an iterator tree.
         */
        @NonNull
        public Builder setParseQueryLatencyMillis(int parseQueryLatencyMillis) {
            mNativeParseQueryLatencyMillis = parseQueryLatencyMillis;
            return this;
        }

        /** Sets strategy of scoring and ranking. */
        @NonNull
        public Builder setRankingStrategy(@SearchSpec.RankingStrategy int rankingStrategy) {
            mNativeRankingStrategy = rankingStrategy;
            return this;
        }

        /** Sets number of documents scored. */
        @NonNull
        public Builder setScoredDocumentCount(int scoredDocumentCount) {
            mNativeNumDocumentsScored = scoredDocumentCount;
            return this;
        }

        /** Sets time used to score the raw results. */
        @NonNull
        public Builder setScoringLatencyMillis(int scoringLatencyMillis) {
            mNativeScoringLatencyMillis = scoringLatencyMillis;
            return this;
        }

        /** Sets time used to rank the scored results. */
        @NonNull
        public Builder setRankingLatencyMillis(int rankingLatencyMillis) {
            mNativeRankingLatencyMillis = rankingLatencyMillis;
            return this;
        }

        /** Sets time used to fetch the document protos. */
        @NonNull
        public Builder setDocumentRetrievingLatencyMillis(int documentRetrievingLatencyMillis) {
            mNativeDocumentRetrievingLatencyMillis = documentRetrievingLatencyMillis;
            return this;
        }

        /** Sets how many snippets are calculated. */
        @NonNull
        public Builder setResultWithSnippetsCount(int resultWithSnippetsCount) {
            mNativeNumResultsWithSnippets = resultWithSnippetsCount;
            return this;
        }

        /**
         * Constructs a new {@link SearchStats} from the contents of this {@link
         * SearchStats.Builder}.
         */
        @NonNull
        public SearchStats build() {
            if (mDatabase == null) {
                Preconditions.checkState(
                        mVisibilityScope != SearchStats.VISIBILITY_SCOPE_LOCAL,
                        "database can not be null if visibilityScope is local.");
            }

            return new SearchStats(/* builder= */ this);
        }
    }
}