/*
 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2.0,
 * as published by the Free Software Foundation.
 *
 * This program is also distributed with certain software (including
 * but not limited to OpenSSL) that is licensed under separate terms,
 * as designated in a particular file or component or in included license
 * documentation.  The authors of MySQL hereby grant you an additional
 * permission to link the program and your derivative works with the
 * separately licensed software that they have included with MySQL.
 *  
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License, version 2.0, for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */
syntax = "proto2";

// ifdef PROTOBUF_LITE: option optimize_for = LITE_RUNTIME;

// Expression syntax
//
// expr is the fundamental structure in various places
// of the SQL language:
//
// * ``SELECT <expr> AS ...``
// * ``WHERE <expr>``
//
// The structures can be used to:
//
// * build an Item-tree in the MySQL Server
// * generate SQL from it
// * use as filter condition in CRUD's Find(), Update() and Delete() calls.
package Polarx.Expr;
option java_package = "com.mysql.cj.x.protobuf";

import "polarx_datatypes.proto";

// Expressions
//
// the "root" of the expression tree
//
// .. productionlist::
//   expr: `operator` |
//       : `identifier` |
//       : `function_call` |
//       : variable |
//       : `literal` |
//       : placeholder
//
// If expression type is PLACEHOLDER then it refers to the value of a parameter
// specified when executing a statement (see `args` field of `StmtExecute` command).
// Field `position` (which must be present for such an expression) gives 0-based
// position of the parameter in the parameter list.
//
message Expr {
  enum Type {
    IDENT          = 1;
    LITERAL        = 2;
    VARIABLE       = 3;
    FUNC_CALL      = 4;
    OPERATOR       = 5;
    PLACEHOLDER    = 6;
    OBJECT         = 7;
    ARRAY          = 8;
    REF            = 9; // Reference output of children's input. Start from 0.
  };

  required Type type = 1;

  optional ColumnIdentifier identifier = 2;
  optional string       variable = 3;
  optional Polarx.Datatypes.Scalar literal = 4;
  optional FunctionCall function_call = 5;
  optional Operator     operator = 6;
  optional uint32       position = 7;
  optional Object       object = 8;
  optional Array        array = 9;
  optional uint32       ref_id = 10;
}

// identifier: name, schame.name
//
// .. productionlist::
//   identifier: string "." string |
//             : string
message Identifier {
  required string name = 1;
  optional string schema_name = 2;
}

// DocumentPathItem
//
// .. productionlist::
//    document_path: path_item | path_item document_path
//    path_item    : member | array_index | "**"
//    member       : "." string | "." "*"
//    array_index  : "[" number "]" | "[" "*" "]"
//
message DocumentPathItem {
  enum Type {
    MEMBER = 1;             // .member
    MEMBER_ASTERISK = 2;    // .*
    ARRAY_INDEX = 3;        // [index]
    ARRAY_INDEX_ASTERISK = 4; // [*]
    DOUBLE_ASTERISK = 5;    // **
  };
  required Type type = 1;
  optional string value = 2;
  optional uint32 index = 3;
}


// col_identifier (table): col@doc_path, tbl.col@doc_path col, tbl.col, schema.tbl.col
// col_identifier (document): doc_path
//
// .. productionlist::
//   col_identifier: string "." string "." string |
//             : string "." string |
//             : string |
//             : string "." string "." string "@" document_path |
//             : string "." string "@" document_path |
//             : string "@" document_path |
//             : document_path
//    document_path: member | arrayLocation | doubleAsterisk
//    member = "." string | "." "*"
//    arrayLocation = "[" index "]" | "[" "*" "]"
//    doubleAsterisk = "**"
//
message ColumnIdentifier {
  repeated Polarx.Expr.DocumentPathItem document_path = 1;
  optional string name = 2;
  optional string table_name = 3;
  optional string schema_name = 4;
}

// function call: ``func(a, b, "1", 3)``
//
// .. productionlist::
//   function_call: `identifier` "(" [ `expr` ["," `expr` ]* ] ")"
message FunctionCall {
  required Identifier name = 1;
  repeated Expr param = 2;
}

// operator: ``<<(a, b)``
//
// .. note::
//
//   Non-authoritative list of operators implemented (case sensitive):
//
//   Nullary
//     * ``*``
//     * ``default``
//
//   Unary
//     * ``!``
//     * ``sign_plus``
//     * ``sign_minus``
//     * ``~``
//
//   Binary
//     * ``&&``
//     * ``||``
//     * ``xor``
//     * ``==``
//     * ``!=``
//     * ``>``
//     * ``>=``
//     * ``<``
//     * ``<=``
//     * ``&``
//     * ``|``
//     * ``^``
//     * ``<<``
//     * ``>>``
//     * ``+``
//     * ``-``
//     * ``*``
//     * ``/``
//     * ``div``
//     * ``%``
//     * ``is``
//     * ``is_not``
//     * ``regexp``
//     * ``not_regexp``
//     * ``like``
//     * ``not_like``
//     * ``cast``
//     * ``cont_in``
//     * ``not_cont_in``
//
//   Using special representation, with more than 2 params
//     * ``in`` (param[0] IN (param[1], param[2], ...))
//     * ``not_in`` (param[0] NOT IN (param[1], param[2], ...))
//
//   Ternary
//     * ``between``
//     * ``between_not``
//     * ``date_add``
//     * ``date_sub``
//
//   Units for date_add/date_sub
//     * ``MICROSECOND``
//     * ``SECOND``
//     * ``MINUTE``
//     * ``HOUR``
//     * ``DAY``
//     * ``WEEK``
//     * ``MONTH``
//     * ``QUARTER``
//     * ``YEAR``
//     * ``SECOND_MICROSECOND``
//     * ``MINUTE_MICROSECOND``
//     * ``MINUTE_SECOND``
//     * ``HOUR_MICROSECOND``
//     * ``HOUR_SECOND``
//     * ``HOUR_MINUTE``
//     * ``DAY_MICROSECOND``
//     * ``DAY_SECOND``
//     * ``DAY_MINUTE``
//     * ``DAY_HOUR``
//
//   Types for cast
//     * ``BINARY[(N)]``
//     * ``CHAR[(N)]``
//     * ``DATE``
//     * ``DATETIME``
//     * ``DECIMAL[(M[,D])]``
//     * ``JSON``
//     * ``SIGNED [INTEGER]``
//     * ``TIME``
//     * ``UNSIGNED [INTEGER]``
//
// .. productionlist::
//   operator: `name` "(" [ `expr` ["," `expr` ]* ] ")"
message Operator {
  required string name = 1;
  repeated Expr param = 2;
}

// an object (with expression values)
message Object {
  message ObjectField {
    required string key = 1;
    required Expr value = 2;
  }

  repeated ObjectField fld = 1;
}

// a Array of expressions
message Array {
  repeated Expr value = 1;
}