syntax = "proto3";

enum BookCategory {
    MYSTERY = 0;
    SCIENCE_FICTION = 1;
    SELF_HELP = 2;
}

message RecommendationRequest {
    int32 user_id = 1;
    BookCategory category = 2;
    int32 max_results = 3;
}

message BookRecommendation {
    int32 id = 1;
    string title = 2;
}

message RecommendationResponse {
    repeated BookRecommendation recommendations = 1;
}

service Recommendations {
    rpc Recommend (RecommendationRequest) returns (RecommendationResponse);
}