// Taken from https://github.com/mapbox/vector-tile-spec/blob/master/2.1/vector_tile.proto

syntax = "proto2";

package mvt;

option optimize_for = LITE_RUNTIME;

message Tile {
  repeated Layer layers = 3;
  extensions 16 to 8191;
}

// GeomType is described in section 4.3.4 of the specification
enum GeomType {
  UNKNOWN = 0;
  POINT = 1;
  LINESTRING = 2;
  POLYGON = 3;
}

// Variant type encoding
// The use of values is described in section 4.1 of the specification
message Value {
  // Exactly one of these values must be present in a valid message
  optional string string_value = 1;
  optional float float_value = 2;
  optional double double_value = 3;
  optional int64 int_value = 4;
  optional uint64 uint_value = 5;
  optional sint64 sint_value = 6;
  optional bool bool_value = 7;

  extensions 8 to max;
}

// Features are described in section 4.2 of the specification
message Feature {
  optional uint64 id = 1 [ default = 0 ];

  // Tags of this feature are encoded as repeated pairs of
  // integers.
  // A detailed description of tags is located in sections
  // 4.2 and 4.4 of the specification
  repeated uint32 tags = 2 [ packed = true ];

  // The type of geometry stored in this feature.
  optional GeomType type = 3 [ default = UNKNOWN ];

  // Contains a stream of commands and parameters (vertices).
  // A detailed description on geometry encoding is located in
  // section 4.3 of the specification.
  repeated uint32 geometry = 4 [ packed = true ];
}

// Layers are described in section 4.1 of the specification
message Layer {
  // Any compliant implementation must first read the version
  // number encoded in this message and choose the correct
  // implementation for this version number before proceeding to
  // decode other parts of this message.
  required uint32 version = 15 [ default = 1 ];

  required string name = 1;

  // The actual features in this tile.
  repeated Feature features = 2;

  // Dictionary encoding for keys
  repeated string keys = 3;

  // Dictionary encoding for values
  repeated Value values = 4;

  // Although this is an "optional" field it is required by the specification.
  // See https://github.com/mapbox/vector-tile-spec/issues/47
  optional uint32 extent = 5 [ default = 4096 ];

  extensions 16 to max;
}