#include <memory>

#include "gtest/gtest.h"

#include "query/frontend/ast/ast.hpp"
#include "query/frontend/semantic/symbol_generator.hpp"
#include "query/frontend/semantic/symbol_table.hpp"

#include "query_common.hpp"

using namespace query;

namespace {

TEST(TestSymbolGenerator, MatchNodeReturn) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // MATCH (node_atom_1) RETURN node_atom_1
  auto query_ast = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("node_atom_1"))), RETURN("node_atom_1")));
  SymbolGenerator symbol_generator(symbol_table);
  query_ast->Accept(symbol_generator);
  // symbols for pattern, node_atom_1 and named_expr in return
  EXPECT_EQ(symbol_table.max_position(), 3);
  auto match = dynamic_cast<Match *>(query_ast->single_query_->clauses_[0]);
  auto pattern = match->patterns_[0];
  auto pattern_sym = symbol_table[*pattern->identifier_];
  EXPECT_EQ(pattern_sym.type(), Symbol::Type::Path);
  EXPECT_FALSE(pattern_sym.user_declared());
  auto node_atom = dynamic_cast<NodeAtom *>(pattern->atoms_[0]);
  auto node_sym = symbol_table[*node_atom->identifier_];
  EXPECT_EQ(node_sym.name(), "node_atom_1");
  EXPECT_EQ(node_sym.type(), Symbol::Type::Vertex);
  auto ret = dynamic_cast<Return *>(query_ast->single_query_->clauses_[1]);
  auto named_expr = ret->body_.named_expressions[0];
  auto column_sym = symbol_table[*named_expr];
  EXPECT_EQ(node_sym.name(), column_sym.name());
  EXPECT_NE(node_sym, column_sym);
  auto ret_sym = symbol_table[*named_expr->expression_];
  EXPECT_EQ(node_sym, ret_sym);
}

TEST(TestSymbolGenerator, MatchNamedPattern) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // MATCH p = (node_atom_1) RETURN node_atom_1
  auto query_ast = QUERY(SINGLE_QUERY(
      MATCH(NAMED_PATTERN("p", NODE("node_atom_1"))), RETURN("p")));
  SymbolGenerator symbol_generator(symbol_table);
  query_ast->Accept(symbol_generator);
  // symbols for p, node_atom_1 and named_expr in return
  EXPECT_EQ(symbol_table.max_position(), 3);
  auto match = dynamic_cast<Match *>(query_ast->single_query_->clauses_[0]);
  auto pattern = match->patterns_[0];
  auto pattern_sym = symbol_table[*pattern->identifier_];
  EXPECT_EQ(pattern_sym.type(), Symbol::Type::Path);
  EXPECT_EQ(pattern_sym.name(), "p");
  EXPECT_TRUE(pattern_sym.user_declared());
}

TEST(TestSymbolGenerator, MatchUnboundMultiReturn) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST using variable in return bound by naming the previous return
  // expression. This is treated as an unbound variable.
  // MATCH (node_atom_1) RETURN node_atom_1 AS n, n
  auto query_ast = QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("node_atom_1"))),
                                      RETURN("node_atom_1", AS("n"), "n")));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query_ast->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, MatchNodeUnboundReturn) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with unbound variable in return: MATCH (n) RETURN x
  auto query_ast = QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n"))), RETURN("x")));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query_ast->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, CreatePropertyUnbound) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with unbound variable in create: CREATE ({prop: x})
  auto node = NODE("anon");
  GraphDb db;
  GraphDbAccessor dba(db);
  node->properties_[PROPERTY_PAIR("prop")] = IDENT("x");
  auto query_ast = QUERY(SINGLE_QUERY(CREATE(PATTERN(node))));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query_ast->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, CreateNodeReturn) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // Simple AST returning a created node: CREATE (n) RETURN n
  auto query_ast = QUERY(SINGLE_QUERY(CREATE(PATTERN(NODE("n"))), RETURN("n")));
  SymbolGenerator symbol_generator(symbol_table);
  query_ast->Accept(symbol_generator);
  // symbols for pattern, `n` and named_expr
  EXPECT_EQ(symbol_table.max_position(), 3);
  auto create = dynamic_cast<Create *>(query_ast->single_query_->clauses_[0]);
  auto pattern = create->patterns_[0];
  auto node_atom = dynamic_cast<NodeAtom *>(pattern->atoms_[0]);
  auto node_sym = symbol_table[*node_atom->identifier_];
  EXPECT_EQ(node_sym.name(), "n");
  EXPECT_EQ(node_sym.type(), Symbol::Type::Vertex);
  auto ret = dynamic_cast<Return *>(query_ast->single_query_->clauses_[1]);
  auto named_expr = ret->body_.named_expressions[0];
  auto column_sym = symbol_table[*named_expr];
  EXPECT_EQ(node_sym.name(), column_sym.name());
  EXPECT_NE(node_sym, column_sym);
  auto ret_sym = symbol_table[*named_expr->expression_];
  EXPECT_EQ(node_sym, ret_sym);
}

TEST(TestSymbolGenerator, CreateRedeclareNode) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with redeclaring a variable when creating nodes: CREATE (n), (n)
  auto query_ast =
      QUERY(SINGLE_QUERY(CREATE(PATTERN(NODE("n")), PATTERN(NODE("n")))));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query_ast->Accept(symbol_generator), RedeclareVariableError);
}

TEST(TestSymbolGenerator, MultiCreateRedeclareNode) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with redeclaring a variable when creating nodes with multiple creates:
  // CREATE (n) CREATE (n)
  auto query_ast = QUERY(
      SINGLE_QUERY(CREATE(PATTERN(NODE("n"))), CREATE(PATTERN(NODE("n")))));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query_ast->Accept(symbol_generator), RedeclareVariableError);
}

TEST(TestSymbolGenerator, MatchCreateRedeclareNode) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with redeclaring a match node variable in create: MATCH (n) CREATE (n)
  auto query_ast = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("n"))), CREATE(PATTERN(NODE("n")))));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query_ast->Accept(symbol_generator), RedeclareVariableError);
}

TEST(TestSymbolGenerator, MatchCreateRedeclareEdge) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with redeclaring a match edge variable in create:
  // MATCH (n) -[r]- (m) CREATE (n) -[r :relationship]-> (l)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto relationship = dba.EdgeType("relationship");
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("n"), EDGE("r"), NODE("m"))),
      CREATE(PATTERN(NODE("n"),
                     EDGE("r", EdgeAtom::Direction::OUT, {relationship}),
                     NODE("l")))));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), RedeclareVariableError);
}

TEST(TestSymbolGenerator, MatchTypeMismatch) {
  AstTreeStorage storage;
  // Using an edge variable as a node causes a type mismatch.
  // MATCH (n) -[r]-> (r)
  auto query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n"), EDGE("r"), NODE("r")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), TypeMismatchError);
}

TEST(TestSymbolGenerator, MatchCreateTypeMismatch) {
  AstTreeStorage storage;
  // Using an edge variable as a node causes a type mismatch.
  // MATCH (n1) -[r1]- (n2) CREATE (r1) -[r2]-> (n2)
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("n1"), EDGE("r1"), NODE("n2"))),
      CREATE(PATTERN(NODE("r1"), EDGE("r2", EdgeAtom::Direction::OUT),
                     NODE("n2")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), TypeMismatchError);
}

TEST(TestSymbolGenerator, CreateMultipleEdgeType) {
  AstTreeStorage storage;
  // Multiple edge relationship are not allowed when creating edges.
  // CREATE (n) -[r :rel1 | :rel2]-> (m)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto rel1 = dba.EdgeType("rel1");
  auto rel2 = dba.EdgeType("rel2");
  auto edge = EDGE("r", EdgeAtom::Direction::OUT, {rel1});
  edge->edge_types_.emplace_back(rel2);
  auto query = QUERY(SINGLE_QUERY(CREATE(PATTERN(NODE("n"), edge, NODE("m")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, CreateBidirectionalEdge) {
  AstTreeStorage storage;
  // Bidirectional relationships are not allowed when creating edges.
  // CREATE (n) -[r :rel1]- (m)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto rel1 = dba.EdgeType("rel1");
  auto query = QUERY(SINGLE_QUERY(CREATE(PATTERN(
      NODE("n"), EDGE("r", EdgeAtom::Direction::BOTH, {rel1}), NODE("m")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchWhereUnbound) {
  // Test MATCH (n) WHERE missing < 42 RETURN n
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n"))),
                                  WHERE(LESS(IDENT("missing"), LITERAL(42))),
                                  RETURN("n")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, CreateDelete) {
  // Test CREATE (n) DELETE n
  AstTreeStorage storage;
  auto node = NODE("n");
  auto ident = IDENT("n");
  auto query = QUERY(SINGLE_QUERY(CREATE(PATTERN(node)), DELETE(ident)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // symbols for pattern and `n`
  EXPECT_EQ(symbol_table.max_position(), 2);
  auto node_symbol = symbol_table.at(*node->identifier_);
  auto ident_symbol = symbol_table.at(*ident);
  EXPECT_EQ(node_symbol.type(), Symbol::Type::Vertex);
  EXPECT_EQ(node_symbol, ident_symbol);
}

TEST(TestSymbolGenerator, CreateDeleteUnbound) {
  // Test CREATE (n) DELETE missing
  AstTreeStorage storage;
  auto query =
      QUERY(SINGLE_QUERY(CREATE(PATTERN(NODE("n"))), DELETE(IDENT("missing"))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, MatchWithReturn) {
  // Test MATCH (old) WITH old AS n RETURN n AS n
  AstTreeStorage storage;
  auto node = NODE("old");
  auto old_ident = IDENT("old");
  auto with_as_n = AS("n");
  auto n_ident = IDENT("n");
  auto ret_as_n = AS("n");
  auto query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(node)), WITH(old_ident, with_as_n),
                         RETURN(n_ident, ret_as_n)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // symbols for pattern, `old`, `n` and named_expr in return
  EXPECT_EQ(symbol_table.max_position(), 4);
  auto node_symbol = symbol_table.at(*node->identifier_);
  auto old = symbol_table.at(*old_ident);
  EXPECT_EQ(node_symbol, old);
  auto with_n = symbol_table.at(*with_as_n);
  EXPECT_NE(old, with_n);
  auto n = symbol_table.at(*n_ident);
  EXPECT_EQ(n, with_n);
  auto ret_n = symbol_table.at(*ret_as_n);
  EXPECT_NE(n, ret_n);
}

TEST(TestSymbolGenerator, MatchWithReturnUnbound) {
  // Test MATCH (old) WITH old AS n RETURN old
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("old"))),
                                  WITH("old", AS("n")), RETURN("old")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, MatchWithWhere) {
  // Test MATCH (old) WITH old AS n WHERE n.prop < 42
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto node = NODE("old");
  auto old_ident = IDENT("old");
  auto with_as_n = AS("n");
  auto n_prop = PROPERTY_LOOKUP("n", prop);
  auto query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(node)), WITH(old_ident, with_as_n),
                         WHERE(LESS(n_prop, LITERAL(42)))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // symbols for pattern, `old` and `n`
  EXPECT_EQ(symbol_table.max_position(), 3);
  auto node_symbol = symbol_table.at(*node->identifier_);
  auto old = symbol_table.at(*old_ident);
  EXPECT_EQ(node_symbol, old);
  auto with_n = symbol_table.at(*with_as_n);
  EXPECT_NE(old, with_n);
  auto n = symbol_table.at(*n_prop->expression_);
  EXPECT_EQ(n, with_n);
}

TEST(TestSymbolGenerator, MatchWithWhereUnbound) {
  // Test MATCH (old) WITH COUNT(old) AS c WHERE old.prop < 42
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("old"))), WITH(COUNT(IDENT("old")), AS("c")),
      WHERE(LESS(PROPERTY_LOOKUP("old", prop), LITERAL(42)))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, CreateMultiExpand) {
  // Test CREATE (n) -[r :r]-> (m), (n) - [p :p]-> (l)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto r_type = dba.EdgeType("r");
  auto p_type = dba.EdgeType("p");
  AstTreeStorage storage;
  auto node_n1 = NODE("n");
  auto edge_r = EDGE("r", EdgeAtom::Direction::OUT, {r_type});
  auto node_m = NODE("m");
  auto node_n2 = NODE("n");
  auto edge_p = EDGE("p", EdgeAtom::Direction::OUT, {p_type});
  auto node_l = NODE("l");
  auto query = QUERY(SINGLE_QUERY(CREATE(PATTERN(node_n1, edge_r, node_m),
                                         PATTERN(node_n2, edge_p, node_l))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // symbols for pattern * 2, `n`, `r`, `m`, `p`, `l`
  EXPECT_EQ(symbol_table.max_position(), 7);
  auto n1 = symbol_table.at(*node_n1->identifier_);
  auto n2 = symbol_table.at(*node_n2->identifier_);
  EXPECT_EQ(n1, n2);
  EXPECT_EQ(n1.type(), Symbol::Type::Vertex);
  auto m = symbol_table.at(*node_m->identifier_);
  EXPECT_EQ(m.type(), Symbol::Type::Vertex);
  EXPECT_NE(m, n1);
  auto l = symbol_table.at(*node_l->identifier_);
  EXPECT_EQ(l.type(), Symbol::Type::Vertex);
  EXPECT_NE(l, n1);
  EXPECT_NE(l, m);
  auto r = symbol_table.at(*edge_r->identifier_);
  auto p = symbol_table.at(*edge_p->identifier_);
  EXPECT_EQ(r.type(), Symbol::Type::Edge);
  EXPECT_EQ(p.type(), Symbol::Type::Edge);
  EXPECT_NE(r, p);
}

TEST(TestSymbolGenerator, MatchCreateExpandLabel) {
  // Test MATCH (n) CREATE (m) -[r :r]-> (n:label)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto r_type = dba.EdgeType("r");
  auto label = dba.Label("label");
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("n"))),
      CREATE(PATTERN(NODE("m"), EDGE("r", EdgeAtom::Direction::OUT, {r_type}),
                     NODE("n", label)))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, CreateExpandProperty) {
  // Test CREATE (n) -[r :r]-> (n {prop: 42})
  GraphDb db;
  GraphDbAccessor dba(db);
  auto r_type = dba.EdgeType("r");
  AstTreeStorage storage;
  auto n_prop = NODE("n");
  n_prop->properties_[PROPERTY_PAIR("prop")] = LITERAL(42);
  auto query = QUERY(SINGLE_QUERY(CREATE(PATTERN(
      NODE("n"), EDGE("r", EdgeAtom::Direction::OUT, {r_type}), n_prop))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchReturnSum) {
  // Test MATCH (n) RETURN SUM(n.prop) + 42 AS result
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto node = NODE("n");
  auto sum = SUM(PROPERTY_LOOKUP("n", prop));
  auto as_result = AS("result");
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node)),
                                  RETURN(ADD(sum, LITERAL(42)), as_result)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // 3 symbols for: pattern, 'n', 'sum' and 'result'.
  EXPECT_EQ(symbol_table.max_position(), 4);
  auto node_symbol = symbol_table.at(*node->identifier_);
  auto sum_symbol = symbol_table.at(*sum);
  EXPECT_NE(node_symbol, sum_symbol);
  auto result_symbol = symbol_table.at(*as_result);
  EXPECT_NE(result_symbol, node_symbol);
  EXPECT_NE(result_symbol, sum_symbol);
}

TEST(TestSymbolGenerator, NestedAggregation) {
  // Test MATCH (n) RETURN SUM(42 + SUM(n.prop)) AS s
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("n"))),
      RETURN(SUM(ADD(LITERAL(42), SUM(PROPERTY_LOOKUP("n", prop)))), AS("s"))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, WrongAggregationContext) {
  // Test MATCH (n) WITH n.prop AS prop WHERE SUM(prop) < 42
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("n"))), WITH(PROPERTY_LOOKUP("n", prop), AS("prop")),
      WHERE(LESS(SUM(IDENT("prop")), LITERAL(42)))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchPropCreateNodeProp) {
  // Test MATCH (n) CREATE (m {prop: n.prop})
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = PROPERTY_PAIR("prop");
  AstTreeStorage storage;
  auto node_n = NODE("n");
  auto node_m = NODE("m");
  auto n_prop = PROPERTY_LOOKUP("n", prop.second);
  node_m->properties_[prop] = n_prop;
  auto query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(node_n)), CREATE(PATTERN(node_m))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // symbols: pattern * 2, `node_n`, `node_m`
  EXPECT_EQ(symbol_table.max_position(), 4);
  auto n = symbol_table.at(*node_n->identifier_);
  EXPECT_EQ(n, symbol_table.at(*n_prop->expression_));
  auto m = symbol_table.at(*node_m->identifier_);
  EXPECT_NE(n, m);
}

TEST(TestSymbolGenerator, CreateNodeEdge) {
  // Test CREATE (n), (n) -[r :r]-> (n)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto r_type = dba.EdgeType("r");
  AstTreeStorage storage;
  auto node_1 = NODE("n");
  auto node_2 = NODE("n");
  auto edge = EDGE("r", EdgeAtom::Direction::OUT, {r_type});
  auto node_3 = NODE("n");
  auto query = QUERY(
      SINGLE_QUERY(CREATE(PATTERN(node_1), PATTERN(node_2, edge, node_3))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // symbols: pattern * 2, `n`, `r`
  EXPECT_EQ(symbol_table.max_position(), 4);
  auto n = symbol_table.at(*node_1->identifier_);
  EXPECT_EQ(n, symbol_table.at(*node_2->identifier_));
  EXPECT_EQ(n, symbol_table.at(*node_3->identifier_));
  EXPECT_NE(n, symbol_table.at(*edge->identifier_));
}

TEST(TestSymbolGenerator, MatchWithCreate) {
  // Test MATCH (n) WITH n AS m CREATE (m) -[r :r]-> (m)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto r_type = dba.EdgeType("r");
  AstTreeStorage storage;
  auto node_1 = NODE("n");
  auto node_2 = NODE("m");
  auto edge = EDGE("r", EdgeAtom::Direction::OUT, {r_type});
  auto node_3 = NODE("m");
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node_1)), WITH("n", AS("m")),
                                  CREATE(PATTERN(node_2, edge, node_3))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // symbols: pattern * 2, `n`, `m`, `r`
  EXPECT_EQ(symbol_table.max_position(), 5);
  auto n = symbol_table.at(*node_1->identifier_);
  EXPECT_EQ(n.type(), Symbol::Type::Vertex);
  auto m = symbol_table.at(*node_2->identifier_);
  EXPECT_NE(n, m);
  // Currently we don't infer expression types, so we lost true type of 'm'.
  EXPECT_EQ(m.type(), Symbol::Type::Any);
  EXPECT_EQ(m, symbol_table.at(*node_3->identifier_));
}

TEST(TestSymbolGenerator, SameResults) {
  // Test MATCH (n) WITH n AS m, n AS m
  {
    AstTreeStorage storage;
    auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n"))),
                                    WITH("n", AS("m"), "n", AS("m"))));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
  }
  // Test MATCH (n) RETURN n, n
  {
    AstTreeStorage storage;
    auto query =
        QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n"))), RETURN("n", "n")));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
  }
}

TEST(TestSymbolGenerator, SkipUsingIdentifier) {
  // Test MATCH (old) WITH old AS new SKIP old
  {
    AstTreeStorage storage;
    auto query =
        QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("old"))),
                           WITH("old", AS("new"), SKIP(IDENT("old")))));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
  }
  // Test MATCH (old) WITH old AS new SKIP new
  {
    AstTreeStorage storage;
    auto query =
        QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("old"))),
                           WITH("old", AS("new"), SKIP(IDENT("new")))));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
  }
}

TEST(TestSymbolGenerator, LimitUsingIdentifier) {
  // Test MATCH (n) RETURN n AS n LIMIT n
  AstTreeStorage storage;
  auto query = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("n"))), RETURN("n", LIMIT(IDENT("n")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, OrderByAggregation) {
  // Test MATCH (old) RETURN old AS new ORDER BY COUNT(1)
  AstTreeStorage storage;
  auto query = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("old"))),
                   RETURN("old", AS("new"), ORDER_BY(COUNT(LITERAL(1))))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, OrderByUnboundVariable) {
  // Test MATCH (old) RETURN COUNT(old) AS new ORDER BY old
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("old"))),
      RETURN(COUNT(IDENT("old")), AS("new"), ORDER_BY(IDENT("old")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, AggregationOrderBy) {
  // Test MATCH (old) RETURN COUNT(old) AS new ORDER BY new
  AstTreeStorage storage;
  auto node = NODE("old");
  auto ident_old = IDENT("old");
  auto as_new = AS("new");
  auto ident_new = IDENT("new");
  auto query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(node)), RETURN(COUNT(ident_old), as_new,
                                                      ORDER_BY(ident_new))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for pattern, `old`, `count(old)` and `new`
  EXPECT_EQ(symbol_table.max_position(), 4);
  auto old = symbol_table.at(*node->identifier_);
  EXPECT_EQ(old, symbol_table.at(*ident_old));
  auto new_sym = symbol_table.at(*as_new);
  EXPECT_NE(old, new_sym);
  EXPECT_EQ(new_sym, symbol_table.at(*ident_new));
}

TEST(TestSymbolGenerator, OrderByOldVariable) {
  // Test MATCH (old) RETURN old AS new ORDER BY old
  AstTreeStorage storage;
  auto node = NODE("old");
  auto ident_old = IDENT("old");
  auto as_new = AS("new");
  auto by_old = IDENT("old");
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node)),
                                  RETURN(ident_old, as_new, ORDER_BY(by_old))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for pattern, `old` and `new`
  EXPECT_EQ(symbol_table.max_position(), 3);
  auto old = symbol_table.at(*node->identifier_);
  EXPECT_EQ(old, symbol_table.at(*ident_old));
  EXPECT_EQ(old, symbol_table.at(*by_old));
  auto new_sym = symbol_table.at(*as_new);
  EXPECT_NE(old, new_sym);
}

TEST(TestSymbolGenerator, MergeVariableError) {
  // Test MATCH (n) MERGE (n)
  {
    AstTreeStorage storage;
    auto query = QUERY(
        SINGLE_QUERY(MATCH(PATTERN(NODE("n"))), MERGE(PATTERN(NODE("n")))));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), RedeclareVariableError);
  }
  // Test MATCH (n) -[r]- (m) MERGE (a) -[r :rel]- (b)
  {
    GraphDb db;
    GraphDbAccessor dba(db);
    auto rel = dba.EdgeType("rel");
    AstTreeStorage storage;
    auto query = QUERY(SINGLE_QUERY(
        MATCH(PATTERN(NODE("n"), EDGE("r"), NODE("m"))),
        MERGE(PATTERN(NODE("a"), EDGE("r", EdgeAtom::Direction::BOTH, {rel}),
                      NODE("b")))));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), RedeclareVariableError);
  }
}

TEST(TestSymbolGenerator, MergeEdgeWithoutType) {
  // Test MERGE (a) -[r]- (b)
  AstTreeStorage storage;
  auto query =
      QUERY(SINGLE_QUERY(MERGE(PATTERN(NODE("a"), EDGE("r"), NODE("b")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  // Edge must have a type, since it doesn't we raise.
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MergeOnMatchOnCreate) {
  // Test MATCH (n) MERGE (n) -[r :rel]- (m) ON MATCH SET n.prop = 42
  //      ON CREATE SET m.prop = 42 RETURN r AS r
  GraphDb db;
  GraphDbAccessor dba(db);
  auto rel = dba.EdgeType("rel");
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto match_n = NODE("n");
  auto merge_n = NODE("n");
  auto edge_r = EDGE("r", EdgeAtom::Direction::BOTH, {rel});
  auto node_m = NODE("m");
  auto n_prop = PROPERTY_LOOKUP("n", prop);
  auto m_prop = PROPERTY_LOOKUP("m", prop);
  auto ident_r = IDENT("r");
  auto as_r = AS("r");
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(match_n)),
                                  MERGE(PATTERN(merge_n, edge_r, node_m),
                                        ON_MATCH(SET(n_prop, LITERAL(42))),
                                        ON_CREATE(SET(m_prop, LITERAL(42)))),
                                  RETURN(ident_r, as_r)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for: pattern * 2, `n`, `r`, `m` and `AS r`.
  EXPECT_EQ(symbol_table.max_position(), 6);
  auto n = symbol_table.at(*match_n->identifier_);
  EXPECT_EQ(n, symbol_table.at(*merge_n->identifier_));
  EXPECT_EQ(n, symbol_table.at(*n_prop->expression_));
  auto r = symbol_table.at(*edge_r->identifier_);
  EXPECT_NE(r, n);
  EXPECT_EQ(r, symbol_table.at(*ident_r));
  EXPECT_NE(r, symbol_table.at(*as_r));
  auto m = symbol_table.at(*node_m->identifier_);
  EXPECT_NE(m, n);
  EXPECT_NE(m, r);
  EXPECT_NE(m, symbol_table.at(*as_r));
  EXPECT_EQ(m, symbol_table.at(*m_prop->expression_));
}

TEST(TestSymbolGenerator, WithUnwindRedeclareReturn) {
  // Test WITH [1, 2] AS list UNWIND list AS list RETURN list
  AstTreeStorage storage;
  auto query =
      QUERY(SINGLE_QUERY(WITH(LIST(LITERAL(1), LITERAL(2)), AS("list")),
                         UNWIND(IDENT("list"), AS("list")), RETURN("list")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), RedeclareVariableError);
}

TEST(TestSymbolGenerator, WithUnwindReturn) {
  // WITH [1, 2] AS list UNWIND list AS elem RETURN list AS list, elem AS elem
  AstTreeStorage storage;
  auto with_as_list = AS("list");
  auto unwind = UNWIND(IDENT("list"), AS("elem"));
  auto ret_list = IDENT("list");
  auto ret_as_list = AS("list");
  auto ret_elem = IDENT("elem");
  auto ret_as_elem = AS("elem");
  auto query = QUERY(
      SINGLE_QUERY(WITH(LIST(LITERAL(1), LITERAL(2)), with_as_list), unwind,
                   RETURN(ret_list, ret_as_list, ret_elem, ret_as_elem)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for: `list`, `elem`, `AS list`, `AS elem`
  EXPECT_EQ(symbol_table.max_position(), 4);
  const auto &list = symbol_table.at(*with_as_list);
  EXPECT_EQ(list, symbol_table.at(*unwind->named_expression_->expression_));
  const auto &elem = symbol_table.at(*unwind->named_expression_);
  EXPECT_NE(list, elem);
  EXPECT_EQ(list, symbol_table.at(*ret_list));
  EXPECT_NE(list, symbol_table.at(*ret_as_list));
  EXPECT_EQ(elem, symbol_table.at(*ret_elem));
  EXPECT_NE(elem, symbol_table.at(*ret_as_elem));
}

TEST(TestSymbolGenerator, MatchCrossReferenceVariable) {
  // MATCH (n {prop: m.prop}), (m {prop: n.prop}) RETURN n
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = PROPERTY_PAIR("prop");
  AstTreeStorage storage;
  auto node_n = NODE("n");
  auto m_prop = PROPERTY_LOOKUP("m", prop.second);
  node_n->properties_[prop] = m_prop;
  auto node_m = NODE("m");
  auto n_prop = PROPERTY_LOOKUP("n", prop.second);
  node_m->properties_[prop] = n_prop;
  auto ident_n = IDENT("n");
  auto as_n = AS("n");
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node_n), PATTERN(node_m)),
                                  RETURN(ident_n, as_n)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for pattern * 2, `n`, `m` and `AS n`
  EXPECT_EQ(symbol_table.max_position(), 5);
  auto n = symbol_table.at(*node_n->identifier_);
  EXPECT_EQ(n, symbol_table.at(*n_prop->expression_));
  EXPECT_EQ(n, symbol_table.at(*ident_n));
  EXPECT_NE(n, symbol_table.at(*as_n));
  auto m = symbol_table.at(*node_m->identifier_);
  EXPECT_EQ(m, symbol_table.at(*m_prop->expression_));
  EXPECT_NE(n, m);
  EXPECT_NE(m, symbol_table.at(*as_n));
}

TEST(TestSymbolGenerator, MatchWithAsteriskReturnAsterisk) {
  // MATCH (n) -[e]- (m) WITH * RETURN *, n.prop
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto n_prop = PROPERTY_LOOKUP("n", prop);
  auto ret = RETURN(n_prop, AS("n.prop"));
  ret->body_.all_identifiers = true;
  auto node_n = NODE("n");
  auto edge = EDGE("e");
  auto node_m = NODE("m");
  auto with = storage.Create<With>();
  with->body_.all_identifiers = true;
  auto query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(node_n, edge, node_m)), with, ret));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for pattern, `n`, `e`, `m`, `AS n.prop`.
  EXPECT_EQ(symbol_table.max_position(), 5);
  auto n = symbol_table.at(*node_n->identifier_);
  EXPECT_EQ(n, symbol_table.at(*n_prop->expression_));
}

TEST(TestSymbolGenerator, MatchReturnAsteriskSameResult) {
  // MATCH (n) RETURN *, n
  AstTreeStorage storage;
  auto ret = RETURN("n");
  ret->body_.all_identifiers = true;
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n"))), ret));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchReturnAsteriskNoUserVariables) {
  // MATCH () RETURN *
  AstTreeStorage storage;
  auto ret = storage.Create<Return>();
  ret->body_.all_identifiers = true;
  auto ident_n = storage.Create<Identifier>("anon", false);
  auto node = storage.Create<NodeAtom>(ident_n);
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node)), ret));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchMergeExpandLabel) {
  // Test MATCH (n) MERGE (m) -[r :r]-> (n:label)
  GraphDb db;
  GraphDbAccessor dba(db);
  auto r_type = dba.EdgeType("r");
  auto label = dba.Label("label");
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(
      MATCH(PATTERN(NODE("n"))),
      MERGE(PATTERN(NODE("m"), EDGE("r", EdgeAtom::Direction::OUT, {r_type}),
                    NODE("n", label)))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchEdgeWithIdentifierInProperty) {
  // Test MATCH (n) -[r {prop: n.prop}]- (m) RETURN r
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = PROPERTY_PAIR("prop");
  AstTreeStorage storage;
  auto edge = EDGE("r");
  auto n_prop = PROPERTY_LOOKUP("n", prop.second);
  edge->properties_[prop] = n_prop;
  auto node_n = NODE("n");
  auto query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(node_n, edge, NODE("m"))), RETURN("r")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for pattern, `n`, `r`, `m` and implicit in RETURN `r AS r`
  EXPECT_EQ(symbol_table.max_position(), 5);
  auto n = symbol_table.at(*node_n->identifier_);
  EXPECT_EQ(n, symbol_table.at(*n_prop->expression_));
}

TEST(TestSymbolGenerator, MatchVariablePathUsingIdentifier) {
  // Test MATCH (n) -[r *..l.prop]- (m), (l) RETURN r
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto edge = EDGE_VARIABLE("r");
  auto l_prop = PROPERTY_LOOKUP("l", prop);
  edge->upper_bound_ = l_prop;
  auto node_l = NODE("l");
  auto query = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("n"), edge, NODE("m")), PATTERN(node_l)),
                   RETURN("r")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for pattern * 2, `n`, `r`, inner_node, inner_edge, `m`, `l` and
  // implicit in RETURN `r AS r`
  EXPECT_EQ(symbol_table.max_position(), 9);
  auto l = symbol_table.at(*node_l->identifier_);
  EXPECT_EQ(l, symbol_table.at(*l_prop->expression_));
  auto r = symbol_table.at(*edge->identifier_);
  EXPECT_EQ(r.type(), Symbol::Type::EdgeList);
}

TEST(TestSymbolGenerator, MatchVariablePathUsingUnboundIdentifier) {
  // Test MATCH (n) -[r *..l.prop]- (m) MATCH (l) RETURN r
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto edge = EDGE_VARIABLE("r");
  auto l_prop = PROPERTY_LOOKUP("l", prop);
  edge->upper_bound_ = l_prop;
  auto node_l = NODE("l");
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n"), edge, NODE("m"))),
                                  MATCH(PATTERN(node_l)), RETURN("r")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, CreateVariablePath) {
  // Test CREATE (n) -[r *]-> (m) raises a SemanticException, since variable
  // paths cannot be created.
  AstTreeStorage storage;
  auto edge = EDGE_VARIABLE("r", EdgeAtom::Direction::OUT);
  auto query = QUERY(SINGLE_QUERY(CREATE(PATTERN(NODE("n"), edge, NODE("m")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MergeVariablePath) {
  // Test MERGE (n) -[r *]-> (m) raises a SemanticException, since variable
  // paths cannot be created.
  AstTreeStorage storage;
  auto edge = EDGE_VARIABLE("r", EdgeAtom::Direction::OUT);
  auto query = QUERY(SINGLE_QUERY(MERGE(PATTERN(NODE("n"), edge, NODE("m")))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, RedeclareVariablePath) {
  // Test MATCH (n) -[n*]-> (m) RETURN n raises RedeclareVariableError.
  // This is just a temporary solution, before we add the support for using
  // variable paths with already declared symbols. In the future, this test
  // should be changed to check for type errors.
  AstTreeStorage storage;
  auto edge = EDGE_VARIABLE("n", EdgeAtom::Direction::OUT);
  auto query = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("n"), edge, NODE("m"))), RETURN("n")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), RedeclareVariableError);
}

TEST(TestSymbolGenerator, VariablePathSameIdentifier) {
  // Test MATCH (n) -[r *r.prop..]-> (m) RETURN r raises UnboundVariableError.
  // `r` cannot be used inside the range expression, since it is bound by the
  // variable expansion itself.
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto edge = EDGE_VARIABLE("r", EdgeAtom::Direction::OUT);
  edge->lower_bound_ = PROPERTY_LOOKUP("r", prop);
  auto query = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("n"), edge, NODE("m"))), RETURN("r")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, MatchPropertySameIdentifier) {
  // Test MATCH (n {prop: n.prop}) RETURN n
  // Using `n.prop` needs to work, because filters are run after the value for
  // matched symbol is obtained.
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = PROPERTY_PAIR("prop");
  AstTreeStorage storage;
  auto node_n = NODE("n");
  auto n_prop = PROPERTY_LOOKUP("n", prop.second);
  node_n->properties_[prop] = n_prop;
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node_n)), RETURN("n")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  auto n = symbol_table.at(*node_n->identifier_);
  EXPECT_EQ(n, symbol_table.at(*n_prop->expression_));
}

TEST(TestSymbolGenerator, WithReturnAll) {
  // Test WITH 42 AS x RETURN all(x IN [x] WHERE x = 2) AS x, x AS y
  AstTreeStorage storage;
  auto *with_as_x = AS("x");
  auto *list_x = IDENT("x");
  auto *where_x = IDENT("x");
  auto *all = ALL("x", LIST(list_x), WHERE(EQ(where_x, LITERAL(2))));
  auto *ret_as_x = AS("x");
  auto *ret_x = IDENT("x");
  auto query = QUERY(SINGLE_QUERY(WITH(LITERAL(42), with_as_x),
                                  RETURN(all, ret_as_x, ret_x, AS("y"))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for `WITH .. AS x`, `ALL(x ...)`, `ALL(...) AS x` and `AS y`.
  EXPECT_EQ(symbol_table.max_position(), 4);
  // Check `WITH .. AS x` is the same as `[x]` and `RETURN ... x AS y`
  EXPECT_EQ(symbol_table.at(*with_as_x), symbol_table.at(*list_x));
  EXPECT_EQ(symbol_table.at(*with_as_x), symbol_table.at(*ret_x));
  EXPECT_NE(symbol_table.at(*with_as_x), symbol_table.at(*all->identifier_));
  EXPECT_NE(symbol_table.at(*with_as_x), symbol_table.at(*ret_as_x));
  // Check `ALL(x ...)` is only equal to `WHERE x = 2`
  EXPECT_EQ(symbol_table.at(*all->identifier_), symbol_table.at(*where_x));
  EXPECT_NE(symbol_table.at(*all->identifier_), symbol_table.at(*ret_as_x));
}

TEST(TestSymbolGenerator, MatchBfsReturn) {
  // Test MATCH (n) -[r *bfs..n.prop] (r, n | r.prop)]-> (m) RETURN r AS r
  GraphDb db;
  GraphDbAccessor dba(db);
  auto prop = dba.Property("prop");
  AstTreeStorage storage;
  auto *node_n = NODE("n");
  auto *r_prop = PROPERTY_LOOKUP("r", prop);
  auto *n_prop = PROPERTY_LOOKUP("n", prop);
  auto *bfs = storage.Create<EdgeAtom>(
      IDENT("r"), EdgeAtom::Type::BREADTH_FIRST, EdgeAtom::Direction::OUT,
      std::vector<GraphDbTypes::EdgeType>{});
  bfs->inner_edge_ = IDENT("r");
  bfs->inner_node_ = IDENT("n");
  bfs->filter_expression_ = r_prop;
  bfs->upper_bound_ = n_prop;
  auto *ret_r = IDENT("r");
  auto *query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node_n, bfs, NODE("m"))),
                                   RETURN(ret_r, AS("r"))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for pattern, `n`, `[r]`, `r|`, `n|`, `m` and `AS r`.
  EXPECT_EQ(symbol_table.max_position(), 7);
  EXPECT_EQ(symbol_table.at(*ret_r), symbol_table.at(*bfs->identifier_));
  EXPECT_NE(symbol_table.at(*ret_r), symbol_table.at(*bfs->inner_edge_));
  EXPECT_TRUE(symbol_table.at(*bfs->inner_edge_).user_declared());
  EXPECT_EQ(symbol_table.at(*bfs->inner_edge_),
            symbol_table.at(*r_prop->expression_));
  EXPECT_NE(symbol_table.at(*node_n->identifier_),
            symbol_table.at(*bfs->inner_node_));
  EXPECT_TRUE(symbol_table.at(*bfs->inner_node_).user_declared());
  EXPECT_EQ(symbol_table.at(*node_n->identifier_),
            symbol_table.at(*n_prop->expression_));
}

TEST(TestSymbolGenerator, MatchBfsUsesEdgeSymbolError) {
  // Test MATCH (n) -[r *bfs..10 (e, n | r)]-> (m) RETURN r
  AstTreeStorage storage;
  auto *bfs = storage.Create<EdgeAtom>(
      IDENT("r"), EdgeAtom::Type::BREADTH_FIRST, EdgeAtom::Direction::OUT);
  bfs->inner_edge_ = IDENT("e");
  bfs->inner_node_ = IDENT("n");
  bfs->filter_expression_ = IDENT("r");
  bfs->upper_bound_ = LITERAL(10);
  auto *query = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("n"), bfs, NODE("m"))), RETURN("r")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, MatchBfsUsesPreviousOuterSymbol) {
  // Test MATCH (a) -[r *bfs..10 (e, n | a)]-> (m) RETURN r
  AstTreeStorage storage;
  auto *node_a = NODE("a");
  auto *bfs = storage.Create<EdgeAtom>(
      IDENT("r"), EdgeAtom::Type::BREADTH_FIRST, EdgeAtom::Direction::OUT);
  bfs->inner_edge_ = IDENT("e");
  bfs->inner_node_ = IDENT("n");
  bfs->filter_expression_ = IDENT("a");
  bfs->upper_bound_ = LITERAL(10);
  auto *query =
      QUERY(SINGLE_QUERY(MATCH(PATTERN(node_a, bfs, NODE("m"))), RETURN("r")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.at(*node_a->identifier_),
            symbol_table.at(*bfs->filter_expression_));
}

TEST(TestSymbolGenerator, MatchBfsUsesLaterSymbolError) {
  // Test MATCH (n) -[r *bfs..10 (e, n | m)]-> (m) RETURN r
  AstTreeStorage storage;
  auto *bfs = storage.Create<EdgeAtom>(
      IDENT("r"), EdgeAtom::Type::BREADTH_FIRST, EdgeAtom::Direction::OUT);
  bfs->inner_edge_ = IDENT("e");
  bfs->inner_node_ = IDENT("n");
  bfs->filter_expression_ = IDENT("m");
  bfs->upper_bound_ = LITERAL(10);
  auto *query = QUERY(
      SINGLE_QUERY(MATCH(PATTERN(NODE("n"), bfs, NODE("m"))), RETURN("r")));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, MatchVariableLambdaSymbols) {
  // MATCH ()-[*]-() RETURN 42 AS res
  AstTreeStorage storage;
  auto ident_n = storage.Create<Identifier>("anon_n", false);
  auto node = storage.Create<NodeAtom>(ident_n);
  auto edge = storage.Create<EdgeAtom>(
      storage.Create<Identifier>("anon_r", false), EdgeAtom::Type::DEPTH_FIRST,
      EdgeAtom::Direction::BOTH);
  edge->inner_edge_ = storage.Create<Identifier>("anon_inner_e", false);
  edge->inner_node_ = storage.Create<Identifier>("anon_inner_n", false);
  auto end_node =
      storage.Create<NodeAtom>(storage.Create<Identifier>("anon_end", false));
  auto query = QUERY(SINGLE_QUERY(MATCH(PATTERN(node, edge, end_node)),
                                  RETURN(LITERAL(42), AS("res"))));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  // Symbols for `anon_n`, `anon_r`, `anon_inner_e`, `anon_inner_n`, `anon_end`
  // `AS res` and the auto-generated path name symbol.
  EXPECT_EQ(symbol_table.max_position(), 7);
  // All symbols except `AS res` are anonymously generated.
  for (const auto &id_and_symbol : symbol_table.table()) {
    const auto &symbol = id_and_symbol.second;
    if (symbol.name() == "res") {
      EXPECT_TRUE(symbol.user_declared());
    } else {
      EXPECT_FALSE(id_and_symbol.second.user_declared());
    }
  }
}

TEST(TestSymbolGenerator, MatchUnionSymbols) {
  // RETURN 5 as X UNION RETURN 6 AS x
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(RETURN(LITERAL(5), AS("X"))),
                     UNION(SINGLE_QUERY(RETURN(LITERAL(6), AS("X")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);

  EXPECT_EQ(symbol_table.max_position(), 3);
}

TEST(TestSymbolGenerator, MatchUnionMultipleSymbols) {
  // RETURN 5 as X, 6 AS Y UNION RETURN 5 AS Y, 6 AS x
  AstTreeStorage storage;
  auto query = QUERY(
      SINGLE_QUERY(RETURN(LITERAL(5), AS("X"), LITERAL(6), AS("Y"))),
      UNION(SINGLE_QUERY(RETURN(LITERAL(5), AS("Y"), LITERAL(6), AS("X")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);

  EXPECT_EQ(symbol_table.max_position(), 6);
}

TEST(TestSymbolGenerator, MatchUnionAllSymbols) {
  // RETURN 5 as X UNION ALL RETURN 6 AS x
  AstTreeStorage storage;
  auto query = QUERY(SINGLE_QUERY(RETURN(LITERAL(5), AS("X"))),
                     UNION_ALL(SINGLE_QUERY(RETURN(LITERAL(6), AS("X")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);

  EXPECT_EQ(symbol_table.max_position(), 3);
}

TEST(TestSymbolGenerator, MatchUnionAllMultipleSymbols) {
  // RETURN 5 as X, 6 AS Y UNION ALL RETURN 5 AS Y, 6 AS x
  AstTreeStorage storage;
  auto query = QUERY(
      SINGLE_QUERY(RETURN(LITERAL(5), AS("X"), LITERAL(6), AS("Y"))),
      UNION_ALL(
          SINGLE_QUERY(RETURN(LITERAL(5), AS("Y"), LITERAL(6), AS("X")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);

  EXPECT_EQ(symbol_table.max_position(), 6);
}

TEST(TestSymbolGenerator, MatchUnionReturnAllSymbols) {
  // WITH 1 as X, 2 AS Y RETURN * UNION RETURN 3 AS X, 4 AS Y
  AstTreeStorage storage;
  auto ret = storage.Create<Return>();
  ret->body_.all_identifiers = true;
  auto query = QUERY(
      SINGLE_QUERY(WITH(LITERAL(1), AS("X"), LITERAL(2), AS("Y")), ret),
      UNION(SINGLE_QUERY(RETURN(LITERAL(3), AS("X"), LITERAL(4), AS("Y")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);

  EXPECT_EQ(symbol_table.max_position(), 6);
}

TEST(TestSymbolGenerator, MatchUnionReturnSymbols) {
  // WITH 1 as X, 2 AS Y RETURN Y, X UNION RETURN 3 AS X, 4 AS Y
  AstTreeStorage storage;
  auto query = QUERY(
      SINGLE_QUERY(WITH(LITERAL(1), AS("X"), LITERAL(2), AS("Y")),
                   RETURN("Y", "X")),
      UNION(SINGLE_QUERY(RETURN(LITERAL(3), AS("X"), LITERAL(4), AS("Y")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);

  EXPECT_EQ(symbol_table.max_position(), 8);
}

TEST(TestSymbolGenerator, MatchUnionParameterNameThrowSemanticExpcetion) {
  // WITH 1 as X, 2 AS Y RETURN * UNION RETURN 3 AS Z, 4 AS Y
  AstTreeStorage storage;
  auto ret = storage.Create<Return>();
  ret->body_.all_identifiers = true;
  auto query = QUERY(
      SINGLE_QUERY(WITH(LITERAL(1), AS("X"), LITERAL(2), AS("Y")), ret),
      UNION(SINGLE_QUERY(RETURN(LITERAL(3), AS("Z"), LITERAL(4), AS("Y")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchUnionParameterNumberThrowSemanticExpcetion) {
  // WITH 1 as X, 2 AS Y RETURN * UNION RETURN 4 AS Y
  AstTreeStorage storage;
  auto ret = storage.Create<Return>();
  ret->body_.all_identifiers = true;
  auto query =
      QUERY(SINGLE_QUERY(WITH(LITERAL(1), AS("X"), LITERAL(2), AS("Y")), ret),
            UNION(SINGLE_QUERY(RETURN(LITERAL(4), AS("Y")))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
}

TEST(TestSymbolGenerator, MatchUnion) {
  // WITH 5 AS X, 3 AS Y RETURN * UNION WITH 9 AS Y, 4 AS X RETURN Y, X
  AstTreeStorage storage;
  auto ret = storage.Create<Return>();
  ret->body_.all_identifiers = true;
  auto query =
      QUERY(SINGLE_QUERY(WITH(LITERAL(5), AS("X"), LITERAL(3), AS("Y")), ret),
            UNION(SINGLE_QUERY(WITH(LITERAL(9), AS("Y"), LITERAL(4), AS("X")),
                               RETURN("Y", "X"))));

  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);

  EXPECT_EQ(symbol_table.max_position(), 8);
}

}  // namespace