#include <memory>

#include "gtest/gtest.h"

#include "dbms/dbms.hpp"
#include "query/frontend/ast/ast.hpp"
#include "query/frontend/semantic/symbol_table.hpp"
#include "query/frontend/semantic/symbol_generator.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 AS node_atom_1
  auto query_ast = QUERY(MATCH(PATTERN(NODE("node_atom_1"))),
                         RETURN(IDENT("node_atom_1"), AS("node_atom_1")));
  SymbolGenerator symbol_generator(symbol_table);
  query_ast->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.max_position(), 2);
  auto match = dynamic_cast<Match *>(query_ast->clauses_[0]);
  auto pattern = match->patterns_[0];
  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->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, 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 AS n
  auto query_ast =
      QUERY(MATCH(PATTERN(NODE("node_atom_1"))),
            RETURN(IDENT("node_atom_1"), AS("n"), IDENT("n"), AS("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 AS x
  auto query_ast =
      QUERY(MATCH(PATTERN(NODE("n"))), RETURN(IDENT("x"), AS("x")));
  SymbolGenerator symbol_generator(symbol_table);
  EXPECT_THROW(query_ast->Accept(symbol_generator), UnboundVariableError);
}

TEST(TestSymbolGenerator, MatchSameEdge) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with match pattern referencing an edge multiple times:
  // MATCH (n) -[r]- (n) -[r]- (n) RETURN r AS r
  // This usually throws a redeclaration error, but we support it.
  auto query_ast = QUERY(
      MATCH(PATTERN(NODE("n"), EDGE("r"), NODE("n"), EDGE("r"), NODE("n"))),
      RETURN(IDENT("r"), AS("r")));
  SymbolGenerator symbol_generator(symbol_table);
  query_ast->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.max_position(), 3);
  auto match = dynamic_cast<Match *>(query_ast->clauses_[0]);
  auto pattern = match->patterns_[0];
  std::vector<Symbol> node_symbols;
  std::vector<Symbol> edge_symbols;
  bool is_node{true};
  for (auto &atom : pattern->atoms_) {
    auto symbol = symbol_table[*atom->identifier_];
    if (is_node) {
      node_symbols.emplace_back(symbol);
    } else {
      edge_symbols.emplace_back(symbol);
    }
    is_node = !is_node;
  }
  auto &node_symbol = node_symbols.front();
  EXPECT_EQ(node_symbol.type_, Symbol::Type::Vertex);
  for (auto &symbol : node_symbols) {
    EXPECT_EQ(node_symbol, symbol);
  }
  auto &edge_symbol = edge_symbols.front();
  EXPECT_EQ(edge_symbol.type_, Symbol::Type::Edge);
  for (auto &symbol : edge_symbols) {
    EXPECT_EQ(edge_symbol, symbol);
  }
  auto ret = dynamic_cast<Return *>(query_ast->clauses_[1]);
  auto named_expr = ret->body_.named_expressions[0];
  auto ret_symbol = symbol_table[*named_expr->expression_];
  EXPECT_EQ(edge_symbol, ret_symbol);
}

TEST(TestSymbolGenerator, CreatePropertyUnbound) {
  SymbolTable symbol_table;
  AstTreeStorage storage;
  // AST with unbound variable in create: CREATE ({prop: x})
  auto node = NODE("anon");
  Dbms dbms;
  auto dba = dbms.active();
  auto prop = dba->property("prop");
  node->properties_[prop] = IDENT("x");
  auto query_ast = 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(CREATE(PATTERN(NODE("n"))), RETURN(IDENT("n"), AS("n")));
  SymbolGenerator symbol_generator(symbol_table);
  query_ast->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.max_position(), 2);
  auto create = dynamic_cast<Create *>(query_ast->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->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(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(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(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)
  Dbms dbms;
  auto dba = dbms.active();
  auto relationship = dba->edge_type("relationship");
  auto query = QUERY(MATCH(PATTERN(NODE("n"), EDGE("r"), NODE("m"))),
                     CREATE(PATTERN(NODE("n"), EDGE("r", relationship,
                                                    EdgeAtom::Direction::RIGHT),
                                    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(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(MATCH(PATTERN(NODE("n1"), EDGE("r1"), NODE("n2"))),
            CREATE(PATTERN(NODE("r1"), EDGE("r2", EdgeAtom::Direction::RIGHT),
                           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)
  Dbms dbms;
  auto dba = dbms.active();
  auto rel1 = dba->edge_type("rel1");
  auto rel2 = dba->edge_type("rel2");
  auto edge = EDGE("r", rel1, EdgeAtom::Direction::RIGHT);
  edge->edge_types_.emplace_back(rel2);
  auto query = 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)
  Dbms dbms;
  auto dba = dbms.active();
  auto rel1 = dba->edge_type("rel1");
  auto query = QUERY(CREATE(PATTERN(NODE("n"), EDGE("r", 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 AS n
  AstTreeStorage storage;
  auto query = QUERY(MATCH(PATTERN(NODE("n"))),
                     WHERE(LESS(IDENT("missing"), LITERAL(42))),
                     RETURN(IDENT("n"), AS("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(CREATE(PATTERN(node)), DELETE(ident));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.max_position(), 1);
  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(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(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);
  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_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 AS old
  AstTreeStorage storage;
  auto query = QUERY(MATCH(PATTERN(NODE("old"))), WITH(IDENT("old"), AS("n")),
                     RETURN(IDENT("old"), AS("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
  Dbms dbms;
  auto dba = dbms.active();
  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(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);
  EXPECT_EQ(symbol_table.max_position(), 2);
  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
  Dbms dbms;
  auto dba = dbms.active();
  auto prop = dba->property("prop");
  AstTreeStorage storage;
  auto query =
      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)
  Dbms dbms;
  auto dba = dbms.active();
  auto r_type = dba->edge_type("r");
  auto p_type = dba->edge_type("p");
  AstTreeStorage storage;
  auto node_n1 = NODE("n");
  auto edge_r = EDGE("r", r_type, EdgeAtom::Direction::RIGHT);
  auto node_m = NODE("m");
  auto node_n2 = NODE("n");
  auto edge_p = EDGE("p", p_type, EdgeAtom::Direction::RIGHT);
  auto node_l = NODE("l");
  auto query = 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);
  EXPECT_EQ(symbol_table.max_position(), 5);
  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)
  Dbms dbms;
  auto dba = dbms.active();
  auto r_type = dba->edge_type("r");
  auto label = dba->label("label");
  AstTreeStorage storage;
  auto query = QUERY(
      MATCH(PATTERN(NODE("n"))),
      CREATE(PATTERN(NODE("m"), EDGE("r", r_type, EdgeAtom::Direction::RIGHT),
                     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})
  Dbms dbms;
  auto dba = dbms.active();
  auto r_type = dba->edge_type("r");
  auto prop = dba->property("prop");
  AstTreeStorage storage;
  auto n_prop = NODE("n");
  n_prop->properties_[prop] = LITERAL(42);
  auto query = QUERY(CREATE(PATTERN(
      NODE("n"), EDGE("r", r_type, EdgeAtom::Direction::RIGHT), 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
  Dbms dbms;
  auto dba = dbms.active();
  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(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: 'n', 'sum' and 'result'.
  EXPECT_EQ(symbol_table.max_position(), 3);
  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
  Dbms dbms;
  auto dba = dbms.active();
  auto prop = dba->property("prop");
  AstTreeStorage storage;
  auto query = 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
  Dbms dbms;
  auto dba = dbms.active();
  auto prop = dba->property("prop");
  AstTreeStorage storage;
  auto query = 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})
  Dbms dbms;
  auto dba = dbms.active();
  auto prop = dba->property("prop");
  AstTreeStorage storage;
  auto node_n = NODE("n");
  auto node_m = NODE("m");
  auto n_prop = PROPERTY_LOOKUP("n", prop);
  node_m->properties_[prop] = n_prop;
  auto query = QUERY(MATCH(PATTERN(node_n)), CREATE(PATTERN(node_m)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.max_position(), 2);
  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)
  Dbms dbms;
  auto dba = dbms.active();
  auto r_type = dba->edge_type("r");
  AstTreeStorage storage;
  auto node_1 = NODE("n");
  auto node_2 = NODE("n");
  auto edge = EDGE("r", r_type, EdgeAtom::Direction::RIGHT);
  auto node_3 = NODE("n");
  auto query = QUERY(CREATE(PATTERN(node_1), PATTERN(node_2, edge, node_3)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.max_position(), 2);
  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)
  Dbms dbms;
  auto dba = dbms.active();
  auto r_type = dba->edge_type("r");
  AstTreeStorage storage;
  auto node_1 = NODE("n");
  auto node_2 = NODE("m");
  auto edge = EDGE("r", r_type, EdgeAtom::Direction::RIGHT);
  auto node_3 = NODE("m");
  auto query = QUERY(MATCH(PATTERN(node_1)), WITH(IDENT("n"), AS("m")),
                     CREATE(PATTERN(node_2, edge, node_3)));
  SymbolTable symbol_table;
  SymbolGenerator symbol_generator(symbol_table);
  query->Accept(symbol_generator);
  EXPECT_EQ(symbol_table.max_position(), 3);
  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(MATCH(PATTERN(NODE("n"))),
                       WITH(IDENT("n"), AS("m"), IDENT("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(MATCH(PATTERN(NODE("n"))),
                       RETURN(IDENT("n"), AS("n"), IDENT("n"), AS("n")));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
  }
}

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

TEST(TestSymbolGenerator, OrderBy) {
  // Test MATCH (old) RETURN old AS new ORDER BY COUNT(1)
  {
    AstTreeStorage storage;
    auto query =
        QUERY(MATCH(PATTERN(NODE("old"))),
              RETURN(IDENT("old"), AS("new"), ORDER_BY(COUNT(LITERAL(1)))));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), SemanticException);
  }
  // Test MATCH (old) RETURN COUNT(old) AS new ORDER BY old
  {
    AstTreeStorage storage;
    auto query =
        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 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(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 `old`, `count(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));
    auto new_sym = symbol_table.at(*as_new);
    EXPECT_NE(old, new_sym);
    EXPECT_EQ(new_sym, symbol_table.at(*ident_new));
  }
  // 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(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 `old` and `new`
    EXPECT_EQ(symbol_table.max_position(), 2);
    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, Merge) {
  // Test MATCH (n) MERGE (n)
  {
    AstTreeStorage storage;
    auto query = 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)
  {
    Dbms dbms;
    auto dba = dbms.active();
    auto rel = dba->edge_type("rel");
    AstTreeStorage storage;
    auto query = QUERY(MATCH(PATTERN(NODE("n"), EDGE("r"), NODE("m"))),
                       MERGE(PATTERN(NODE("a"), EDGE("r", rel), NODE("b"))));
    SymbolTable symbol_table;
    SymbolGenerator symbol_generator(symbol_table);
    EXPECT_THROW(query->Accept(symbol_generator), RedeclareVariableError);
  }
  // Test MERGE (a) -[r]- (b)
  {
    AstTreeStorage storage;
    auto query = 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 MATCH (n) MERGE (n) -[r :rel]- (m) ON MATCH SET n.prop = 42
  //      ON CREATE SET m.prop = 42 RETURN r AS r
  {
    Dbms dbms;
    auto dba = dbms.active();
    auto rel = dba->edge_type("rel");
    auto prop = dba->property("prop");
    AstTreeStorage storage;
    auto match_n = NODE("n");
    auto merge_n = NODE("n");
    auto edge_r = EDGE("r", 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(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: `n`, `r`, `m` and `AS r`.
    EXPECT_EQ(symbol_table.max_position(), 4);
    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_));
  }
}

}