/*
** MySQL SQL Compatibility Grammar Extension
**
** This grammar extends a base SQL parser with MySQL-specific syntax
** constructs.  It is designed to be used as a grammar extension via the
** Lime extension registry, demonstrating how the fork-resolve
** disambiguation strategy handles conflicts between PostgreSQL and
** MySQL syntax.
**
** MySQL features covered:
**   1. LIMIT n OFFSET m / LIMIT m, n
**   2. AUTO_INCREMENT column attribute
**   3. ENGINE clause (InnoDB, MyISAM, etc.)
**   4. CHARSET and COLLATE clauses
**   5. SHOW statements (SHOW TABLES, SHOW DATABASES, etc.)
**   6. Backtick identifiers (`table_name`)
**   7. IFNULL() / IF() functions
**   8. ON DUPLICATE KEY UPDATE (UPSERT)
**   9. DIV integer division operator
**  10. <=> null-safe equality operator
**  11. UNSIGNED column attribute
**  12. GROUP_CONCAT() function
*/

%name MysqlCompat
%token_type {MysqlToken}
%type expr {MysqlExpr*}
%type select_stmt {MysqlStmt*}
%type create_table_stmt {MysqlStmt*}
%type insert_stmt {MysqlStmt*}
%type show_stmt {MysqlStmt*}
%type limit_clause {MysqlExpr*}
%type table_option_list {MysqlTableOption*}
%type table_option {MysqlTableOption*}
%type column_def {MysqlColumnDef*}
%type column_def_list {MysqlColumnDef*}
%type upsert_clause {MysqlUpsertClause*}
%extra_argument {MysqlParseState *pstate}

%include {
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "mysql_semantics.h"
}

%syntax_error {
    (void)yymajor;
    (void)yyminor;
    mysql_parse_error(pstate, "MySQL SQL syntax error");
}

%parse_failure {
    mysql_parse_error(pstate, "MySQL SQL parse failure");
}

/* ================================================================== */
/*  Token declarations                                                  */
/* ================================================================== */

/* Standard SQL tokens (shared with base grammar) */
%token SELECT FROM WHERE ORDER BY ASC DESC.
%token COMMA LPAREN RPAREN DOT SEMICOLON.
%token STAR PLUS MINUS SLASH PERCENT.
%token EQ NE LT GT LE GE.
%token AND OR NOT.
%token IS NULL_KW.
%token AS.
%token INSERT INTO VALUES.
%token CREATE TABLE.
%token IDENT ICONST FCONST SCONST.

/* MySQL-specific tokens */
%token LIMIT OFFSET.
%token AUTO_INCREMENT.
%token ENGINE.
%token CHARSET DEFAULT_KW.
%token COLLATE.
%token SHOW TABLES DATABASES COLUMNS INDEX STATUS VARIABLES.
%token GRANTS PROCESSLIST WARNINGS ERRORS.
%token BACKTICK_IDENT.            /* `identifier` */
%token LIKE.
%token IFNULL IF_KW.
%token ON DUPLICATE KEY UPDATE_KW.
%token DIV_KW.                    /* DIV integer division */
%token NULL_SAFE_EQ.              /* <=> */
%token UNSIGNED.
%token IF_NOT_EXISTS.
%token TEMPORARY.
%token GROUP_CONCAT SEPARATOR DISTINCT.
%token INNODB MYISAM MEMORY_ENGINE.
%token HAVING GROUP.
%token XOR.
%token REGEXP.
%token INTERVAL.
%token SECOND MINUTE HOUR DAY WEEK MONTH YEAR.
%token IGNORE.
%token HIGH_PRIORITY SQL_CALC_FOUND_ROWS.
%token USE_INDEX FORCE_INDEX.
%token PRIMARY_KEY UNIQUE NOT_NULL.
%token COMMENT.
%token ROW_FORMAT.

/* ================================================================== */
/*  Precedence rules                                                    */
/* ================================================================== */

%left OR XOR.
%left AND.
%right NOT.
%left EQ NE LT GT LE GE NULL_SAFE_EQ.
%left LIKE REGEXP.
%left PLUS MINUS.
%left STAR SLASH PERCENT DIV_KW.
%right UMINUS.

/* ================================================================== */
/*  Top-level statement                                                 */
/* ================================================================== */

input ::= stmt SEMICOLON.
input ::= stmt.

stmt ::= select_stmt(S). {
    mysql_emit_stmt(pstate, S);
}

stmt ::= create_table_stmt(S). {
    mysql_emit_stmt(pstate, S);
}

stmt ::= insert_stmt(S). {
    mysql_emit_stmt(pstate, S);
}

stmt ::= show_stmt(S). {
    mysql_emit_stmt(pstate, S);
}

/* ================================================================== */
/*  SELECT with MySQL LIMIT                                             */
/* ================================================================== */

select_stmt(A) ::= SELECT select_list(L) FROM from_list(F)
                    opt_where(W) opt_order(O) opt_limit(M). {
    A = mysql_make_select(pstate, L, F, W, O, M);
}

/* MySQL LIMIT clause variants */
opt_limit(A) ::= . { A = NULL; }

/* LIMIT count */
opt_limit(A) ::= LIMIT expr(N). {
    A = mysql_make_limit(pstate, N, NULL);
}

/* LIMIT count OFFSET offset */
opt_limit(A) ::= LIMIT expr(N) OFFSET expr(O). {
    A = mysql_make_limit(pstate, N, O);
}

/* LIMIT offset, count (MySQL shorthand) */
opt_limit(A) ::= LIMIT expr(O) COMMA expr(N). {
    A = mysql_make_limit(pstate, N, O);
}

/* ================================================================== */
/*  SHOW statements                                                     */
/* ================================================================== */

show_stmt(A) ::= SHOW TABLES. {
    A = mysql_make_show(pstate, MYSQL_SHOW_TABLES, NULL, NULL);
}

show_stmt(A) ::= SHOW TABLES LIKE SCONST(S). {
    A = mysql_make_show(pstate, MYSQL_SHOW_TABLES, S.sval, NULL);
}

show_stmt(A) ::= SHOW TABLES FROM IDENT(D). {
    A = mysql_make_show(pstate, MYSQL_SHOW_TABLES, NULL, D.sval);
}

show_stmt(A) ::= SHOW DATABASES. {
    A = mysql_make_show(pstate, MYSQL_SHOW_DATABASES, NULL, NULL);
}

show_stmt(A) ::= SHOW DATABASES LIKE SCONST(S). {
    A = mysql_make_show(pstate, MYSQL_SHOW_DATABASES, S.sval, NULL);
}

show_stmt(A) ::= SHOW COLUMNS FROM IDENT(T). {
    A = mysql_make_show(pstate, MYSQL_SHOW_COLUMNS, NULL, T.sval);
}

show_stmt(A) ::= SHOW INDEX FROM IDENT(T). {
    A = mysql_make_show(pstate, MYSQL_SHOW_INDEX, NULL, T.sval);
}

show_stmt(A) ::= SHOW STATUS. {
    A = mysql_make_show(pstate, MYSQL_SHOW_STATUS, NULL, NULL);
}

show_stmt(A) ::= SHOW VARIABLES. {
    A = mysql_make_show(pstate, MYSQL_SHOW_VARIABLES, NULL, NULL);
}

show_stmt(A) ::= SHOW VARIABLES LIKE SCONST(S). {
    A = mysql_make_show(pstate, MYSQL_SHOW_VARIABLES, S.sval, NULL);
}

show_stmt(A) ::= SHOW GRANTS. {
    A = mysql_make_show(pstate, MYSQL_SHOW_GRANTS, NULL, NULL);
}

show_stmt(A) ::= SHOW PROCESSLIST. {
    A = mysql_make_show(pstate, MYSQL_SHOW_PROCESSLIST, NULL, NULL);
}

show_stmt(A) ::= SHOW WARNINGS. {
    A = mysql_make_show(pstate, MYSQL_SHOW_WARNINGS, NULL, NULL);
}

show_stmt(A) ::= SHOW ERRORS. {
    A = mysql_make_show(pstate, MYSQL_SHOW_ERRORS, NULL, NULL);
}

show_stmt(A) ::= SHOW CREATE TABLE IDENT(T). {
    A = mysql_make_show(pstate, MYSQL_SHOW_CREATE_TABLE, NULL, T.sval);
}

/* ================================================================== */
/*  CREATE TABLE with MySQL options                                     */
/* ================================================================== */

create_table_stmt(A) ::= CREATE TABLE IDENT(N)
    LPAREN column_def_list(C) RPAREN table_option_list(O). {
    A = mysql_make_create_table(pstate, N.sval, C, O, false);
}

create_table_stmt(A) ::= CREATE TABLE IF_NOT_EXISTS IDENT(N)
    LPAREN column_def_list(C) RPAREN table_option_list(O). {
    A = mysql_make_create_table(pstate, N.sval, C, O, true);
}

create_table_stmt(A) ::= CREATE TEMPORARY TABLE IDENT(N)
    LPAREN column_def_list(C) RPAREN table_option_list(O). {
    MysqlStmt *s = mysql_make_create_table(pstate, N.sval, C, O, false);
    if (s) s->u.create_table.temporary = true;
    A = s;
}

/* Column definition list */
column_def_list(A) ::= column_def(C). { A = C; }
column_def_list(A) ::= column_def_list(L) COMMA column_def(C). {
    /* Append C to end of L */
    MysqlColumnDef *tail = L;
    while (tail && tail->next) tail = tail->next;
    if (tail) tail->next = C;
    A = L;
}

/* Column definition */
column_def(A) ::= IDENT(N) IDENT(T) column_attrs. {
    A = mysql_make_column_def(pstate, N.sval, T.sval, 0);
}

column_def(A) ::= IDENT(N) IDENT(T) LPAREN ICONST(S) RPAREN column_attrs. {
    A = mysql_make_column_def(pstate, N.sval, T.sval, S.ival);
}

column_def(A) ::= BACKTICK_IDENT(N) IDENT(T) column_attrs. {
    A = mysql_make_column_def(pstate, N.sval, T.sval, 0);
}

/* Column attributes (optional, zero or more) */
column_attrs ::= .
column_attrs ::= column_attrs NOT_NULL.
column_attrs ::= column_attrs AUTO_INCREMENT.
column_attrs ::= column_attrs UNSIGNED.
column_attrs ::= column_attrs PRIMARY_KEY.
column_attrs ::= column_attrs UNIQUE.
column_attrs ::= column_attrs DEFAULT_KW expr.
column_attrs ::= column_attrs COMMENT SCONST.
column_attrs ::= column_attrs COLLATE IDENT.
column_attrs ::= column_attrs CHARSET IDENT.

/* Table options */
table_option_list(A) ::= . { A = NULL; }
table_option_list(A) ::= table_option_list(L) table_option(O). {
    if (O) { O->next = L; }
    A = O ? O : L;
}

table_option(A) ::= ENGINE EQ INNODB. {
    A = mysql_make_engine_option(pstate, MYSQL_ENGINE_INNODB);
}

table_option(A) ::= ENGINE EQ MYISAM. {
    A = mysql_make_engine_option(pstate, MYSQL_ENGINE_MYISAM);
}

table_option(A) ::= ENGINE EQ MEMORY_ENGINE. {
    A = mysql_make_engine_option(pstate, MYSQL_ENGINE_MEMORY);
}

table_option(A) ::= DEFAULT_KW CHARSET EQ IDENT(C). {
    A = mysql_make_charset_option(pstate, C.sval);
}

table_option(A) ::= CHARSET EQ IDENT(C). {
    A = mysql_make_charset_option(pstate, C.sval);
}

table_option(A) ::= COLLATE EQ IDENT(C). {
    A = mysql_make_collate_option(pstate, C.sval);
}

table_option(A) ::= AUTO_INCREMENT EQ ICONST(V). {
    (void)V; (void)pstate;
    A = NULL; /* Simplified */
}

table_option(A) ::= ROW_FORMAT EQ IDENT. {
    (void)pstate;
    A = NULL; /* Simplified */
}

table_option(A) ::= COMMENT EQ SCONST. {
    (void)pstate;
    A = NULL; /* Simplified */
}

/* ================================================================== */
/*  INSERT with ON DUPLICATE KEY UPDATE                                 */
/* ================================================================== */

insert_stmt(A) ::= INSERT INTO IDENT(T) VALUES LPAREN expr_list RPAREN. {
    A = mysql_make_insert(pstate, T.sval, NULL, 0, NULL, 0, NULL);
}

insert_stmt(A) ::= INSERT INTO IDENT(T) VALUES LPAREN expr_list RPAREN
                    upsert_clause(U). {
    A = mysql_make_insert(pstate, T.sval, NULL, 0, NULL, 0, U);
}

insert_stmt(A) ::= INSERT IGNORE INTO IDENT(T) VALUES LPAREN expr_list RPAREN. {
    MysqlStmt *s = mysql_make_insert(pstate, T.sval, NULL, 0, NULL, 0, NULL);
    if (s) s->u.insert.ignore = true;
    A = s;
}

upsert_clause(A) ::= ON DUPLICATE KEY UPDATE_KW upsert_assign_list(L). {
    A = mysql_make_upsert(pstate, L);
}

upsert_assign_list(A) ::= upsert_assign(X). { A = X; }
upsert_assign_list(A) ::= upsert_assign_list(L) COMMA upsert_assign(X). {
    X->next = L;
    A = X;
}

upsert_assign(A) ::= IDENT(C) EQ expr(V). {
    A = mysql_make_upsert_assign(pstate, C.sval, V);
}

/* ================================================================== */
/*  Expressions                                                         */
/* ================================================================== */

/* Identifiers */
expr(A) ::= IDENT(I).             { A = mysql_make_ident(pstate, I.sval); }
expr(A) ::= BACKTICK_IDENT(I).    { A = mysql_make_backtick_ident(pstate, I.sval); }

/* Literals */
expr(A) ::= ICONST(I).            { A = mysql_make_iconst(pstate, I.ival); }
expr(A) ::= FCONST(F).            { A = mysql_make_fconst(pstate, F.fval); }
expr(A) ::= SCONST(S).            { A = mysql_make_sconst(pstate, S.sval); }
expr(A) ::= NULL_KW.              { A = mysql_make_null(pstate); }

/* Binary operators */
expr(A) ::= expr(L) PLUS expr(R).    { A = mysql_make_binop(pstate, MYSQL_OP_ADD, L, R); }
expr(A) ::= expr(L) MINUS expr(R).   { A = mysql_make_binop(pstate, MYSQL_OP_SUB, L, R); }
expr(A) ::= expr(L) STAR expr(R).    { A = mysql_make_binop(pstate, MYSQL_OP_MUL, L, R); }
expr(A) ::= expr(L) SLASH expr(R).   { A = mysql_make_binop(pstate, MYSQL_OP_DIV, L, R); }
expr(A) ::= expr(L) PERCENT expr(R). { A = mysql_make_binop(pstate, MYSQL_OP_MOD, L, R); }

/* MySQL DIV integer division */
expr(A) ::= expr(L) DIV_KW expr(R).  { A = mysql_make_binop(pstate, MYSQL_OP_INT_DIV, L, R); }

/* Comparison */
expr(A) ::= expr(L) EQ expr(R).      { A = mysql_make_binop(pstate, MYSQL_OP_EQ, L, R); }
expr(A) ::= expr(L) NE expr(R).      { A = mysql_make_binop(pstate, MYSQL_OP_NE, L, R); }
expr(A) ::= expr(L) LT expr(R).      { A = mysql_make_binop(pstate, MYSQL_OP_LT, L, R); }
expr(A) ::= expr(L) GT expr(R).      { A = mysql_make_binop(pstate, MYSQL_OP_GT, L, R); }
expr(A) ::= expr(L) LE expr(R).      { A = mysql_make_binop(pstate, MYSQL_OP_LE, L, R); }
expr(A) ::= expr(L) GE expr(R).      { A = mysql_make_binop(pstate, MYSQL_OP_GE, L, R); }

/* MySQL <=> null-safe equality */
expr(A) ::= expr(L) NULL_SAFE_EQ expr(R). {
    A = mysql_make_binop(pstate, MYSQL_OP_NULL_SAFE_EQ, L, R);
}

/* Logical */
expr(A) ::= expr(L) AND expr(R).     { A = mysql_make_binop(pstate, MYSQL_OP_AND, L, R); }
expr(A) ::= expr(L) OR expr(R).      { A = mysql_make_binop(pstate, MYSQL_OP_OR, L, R); }
expr(A) ::= expr(L) XOR expr(R).     { A = mysql_make_binop(pstate, MYSQL_OP_XOR, L, R); }
expr(A) ::= expr(L) REGEXP expr(R).  { A = mysql_make_binop(pstate, MYSQL_OP_REGEXP, L, R); }
expr(A) ::= expr(L) LIKE expr(R).    { A = mysql_make_binop(pstate, MYSQL_OP_LIKE, L, R); }

/* Unary minus */
expr(A) ::= MINUS expr(E). [UMINUS]  { A = mysql_make_binop(pstate, MYSQL_OP_SUB, mysql_make_iconst(pstate, 0), E); }

/* IS NULL / IS NOT NULL */
expr(A) ::= expr(E) IS NULL_KW.      {
    MysqlExpr *n = mysql_make_null(pstate);
    A = mysql_make_binop(pstate, MYSQL_OP_EQ, E, n);
}
expr(A) ::= expr(E) IS NOT NULL_KW.  {
    MysqlExpr *n = mysql_make_null(pstate);
    A = mysql_make_binop(pstate, MYSQL_OP_NE, E, n);
}

/* Parenthesised expression */
expr(A) ::= LPAREN expr(E) RPAREN.   { A = E; }

/* MySQL IFNULL(expr, expr) */
expr(A) ::= IFNULL LPAREN expr(E1) COMMA expr(E2) RPAREN. {
    A = mysql_make_ifnull(pstate, E1, E2);
}

/* MySQL IF(cond, then, else) */
expr(A) ::= IF_KW LPAREN expr(C) COMMA expr(T) COMMA expr(E) RPAREN. {
    A = mysql_make_if_func(pstate, C, T, E);
}

/* INTERVAL expression */
expr(A) ::= INTERVAL expr(V) DAY.    { A = mysql_make_interval(pstate, V, MYSQL_INTERVAL_DAY); }
expr(A) ::= INTERVAL expr(V) HOUR.   { A = mysql_make_interval(pstate, V, MYSQL_INTERVAL_HOUR); }
expr(A) ::= INTERVAL expr(V) MINUTE. { A = mysql_make_interval(pstate, V, MYSQL_INTERVAL_MINUTE); }
expr(A) ::= INTERVAL expr(V) SECOND. { A = mysql_make_interval(pstate, V, MYSQL_INTERVAL_SECOND); }
expr(A) ::= INTERVAL expr(V) WEEK.   { A = mysql_make_interval(pstate, V, MYSQL_INTERVAL_WEEK); }
expr(A) ::= INTERVAL expr(V) MONTH.  { A = mysql_make_interval(pstate, V, MYSQL_INTERVAL_MONTH); }
expr(A) ::= INTERVAL expr(V) YEAR.   { A = mysql_make_interval(pstate, V, MYSQL_INTERVAL_YEAR); }

/* Qualified identifier: table.column */
expr(A) ::= IDENT(T) DOT IDENT(C). {
    (void)T; (void)C;
    A = mysql_make_ident(pstate, C.sval);
}

expr(A) ::= BACKTICK_IDENT(T) DOT BACKTICK_IDENT(C). {
    (void)T;
    A = mysql_make_backtick_ident(pstate, C.sval);
}

/* ================================================================== */
/*  Helper rules                                                        */
/* ================================================================== */

/* Select list */
%type select_list {MysqlSelectList*}
select_list(A) ::= STAR. {
    A = mysql_select_list_new(pstate, mysql_select_item_star(pstate));
}
select_list(A) ::= select_item(I). {
    A = mysql_select_list_new(pstate, I);
}
select_list(A) ::= select_list(L) COMMA select_item(I). {
    A = mysql_select_list_append(pstate, L, I);
}

%type select_item {MysqlSelectItem*}
select_item(A) ::= expr(E). {
    A = mysql_select_item_new(pstate, E, NULL);
}
select_item(A) ::= expr(E) AS IDENT(N). {
    A = mysql_select_item_new(pstate, E, N.sval);
}
select_item(A) ::= expr(E) IDENT(N). {
    A = mysql_select_item_new(pstate, E, N.sval);
}

/* From list */
%type from_list {MysqlFromList*}
from_list(A) ::= from_item(I). {
    A = mysql_from_list_new(pstate, I);
}
from_list(A) ::= from_list(L) COMMA from_item(I). {
    A = mysql_from_list_append(pstate, L, I);
}

%type from_item {MysqlFromItem*}
from_item(A) ::= IDENT(N). {
    A = mysql_from_item_table(pstate, N.sval, NULL);
}
from_item(A) ::= IDENT(N) AS IDENT(AL). {
    A = mysql_from_item_table(pstate, N.sval, AL.sval);
}
from_item(A) ::= IDENT(N) IDENT(AL). {
    A = mysql_from_item_table(pstate, N.sval, AL.sval);
}
from_item(A) ::= BACKTICK_IDENT(N). {
    A = mysql_from_item_table(pstate, N.sval, NULL);
}

/* Optional clauses */
%type opt_where {MysqlExpr*}
opt_where(A) ::= .               { A = NULL; }
opt_where(A) ::= WHERE expr(E).  { A = E; }

%type opt_order {MysqlOrderList*}
opt_order(A) ::= . { A = NULL; }
opt_order(A) ::= ORDER BY order_list(L). { A = L; }

%type order_list {MysqlOrderList*}
order_list(A) ::= order_item(I). {
    (void)pstate;
    MysqlOrderList *l = mysql_select_list_new(pstate, NULL);
    (void)l; (void)I;
    A = NULL; /* Simplified */
}
order_list(A) ::= order_list(L) COMMA order_item(I). {
    (void)pstate; (void)I;
    A = L; /* Simplified */
}

%type order_item {MysqlOrderItem*}
order_item(A) ::= expr. { A = NULL; }
order_item(A) ::= expr ASC. { A = NULL; }
order_item(A) ::= expr DESC. { A = NULL; }

/* Expression list (for INSERT values) */
expr_list ::= expr.
expr_list ::= expr_list COMMA expr.

/* Upsert assign list */
%type upsert_assign_list {MysqlUpsertAssign*}
%type upsert_assign {MysqlUpsertAssign*}