syntax="proto3";
package nu.marginalia.api.searchquery;

option java_package="nu.marginalia.api.searchquery";
option java_multiple_files=true;

service QueryApi {
  rpc query(RpcQsQuery) returns (RpcQsResponse) {}
}
service IndexApi {
  rpc query(RpcIndexQuery) returns (stream RpcDecoratedResultItem) {}
}

message Empty {}

/* Query Service query request */
message RpcQsQuery {
  string humanQuery = 1;
  string nearDomain = 2;
  repeated string tacitIncludes = 3;
  repeated string tacitExcludes = 4;
  repeated string tacitPriority = 5;
  repeated string tacitAdvice = 6;
  RpcSpecLimit quality = 7;
  RpcSpecLimit year = 8;
  RpcSpecLimit size = 9;
  RpcSpecLimit rank = 10;
  repeated int32 domainIds = 12;
  RpcQueryLimits queryLimits = 13;
  string searchSetIdentifier = 14;
  string queryStrategy = 15;      // Named query configuration
  RpcTemporalBias temporalBias = 16;
}

/* Query service query response */
message RpcQsResponse {
  RpcIndexQuery specs = 1;
  repeated RpcDecoratedResultItem results = 2;
  repeated string searchTermsHuman = 3;
  repeated string problems = 4;
  string domain = 5;
}

message RpcTemporalBias {
  enum Bias {
    NONE = 0;
    RECENT = 1;
    OLD = 2;
  }
  Bias bias = 1;
}

/* Index service query request */
message RpcIndexQuery {
  RpcQuery query = 1;
  repeated int32 domains = 2;     // (optional) A list of domain IDs to consider
  string searchSetIdentifier = 3; // (optional) A named set of domains to consider
  string humanQuery = 4;          // The search query as the user entered it
  RpcSpecLimit quality = 5;
  RpcSpecLimit year = 6;
  RpcSpecLimit size = 7;
  RpcSpecLimit rank = 8;
  RpcQueryLimits queryLimits = 10;
  string queryStrategy = 11;      // Named query configuration
  RpcResultRankingParameters parameters = 12;
}

/* A tagged union encoding some limit on a field */
message RpcSpecLimit {
  int32 value = 1;
  TYPE type = 2;

  enum TYPE {
    NONE = 0;
    EQUALS = 1;
    LESS_THAN = 2;
    GREATER_THAN = 3;
  };
}

/** A search result item decorated with title and description metadata from the link database */
message RpcDecoratedResultItem {
  RpcRawResultItem rawItem = 1;
  string url = 2;
  string title = 3;
  string description = 4;
  double urlQuality = 5;
  string format = 6;
  int32 features = 7; // bitmask encoding features of the document
  int32 pubYear = 8;
  int64 dataHash = 9;
  int32 wordsTotal = 10;
  double rankingScore = 11; // The ranking score of this search result item, lower is better
}

/** A raw index-service view of a search result */
message RpcRawResultItem {
  int64 combinedId = 1; // raw ID with bit-encoded ranking information still present
  int32 resultsFromDomain = 2; // number of other results from the same domain
  repeated RpcResultKeywordScore keywordScores = 3;
}

/* Information about how well a keyword matches a query */
message RpcResultKeywordScore {
  string keyword = 1; // the keyword
  int64 encodedWordMetadata = 2; // bit encoded word metadata
  int64 encodedDocMetadata = 3; // bit encoded document metadata
  bool hasPriorityTerms = 4; // true if this word is important to the document
  int32 htmlFeatures = 5; // bit encoded document features
}

/* Query execution parameters */
message RpcQueryLimits {
  int32 resultsByDomain = 1;
  int32 resultsTotal = 2;
  int32 timeoutMs = 3;
  int32 fetchSize = 4; // Size of the fetch buffer in the index service
}

message RpcResultRankingParameters {
  double fullK = 1; // BM25 parameter
  double fullB = 2; // BM25 parameter
  double prioK = 3; // BM25 parameter
  double prioB = 4; // BM25 parameter
  int32 shortDocumentThreshold = 5;
  double shortDocumentPenalty = 6;
  double domainRankBonus = 7;
  double qualityPenalty = 8;
  int32 shortSentenceThreshold = 9;
  double shortSentencePenalty = 10;
  double bm25FullWeight = 11;
  double bm25PrioWeight = 12;
  double tcfWeight = 13;
  RpcTemporalBias temporalBias = 14;
  double temporalBiasWeight = 15;
}

/* Defines a single subquery */
message RpcQuery {
  repeated string include = 1;  // These terms must be present
  repeated string exclude = 2;  // These terms must be absent
  repeated string advice = 3;   // These terms must be present, but do not affect ranking
  repeated string priority = 4;  // These terms are not mandatory, but affect ranking positively if they are present
  repeated RpcCoherences coherences = 5; // Groups of terms that must exist in proximity of each other
  string compiledQuery = 6;  // Compiled query in infix notation
}

/* Defines a group of search terms that must exist in close proximity within the document */
message RpcCoherences {
  repeated string coherences = 1;
}