//===-- FindSymbolsTests.cpp -------------------------*- C++ -*------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "FindTarget.h"

#include "Selection.h"
#include "TestTU.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Testing/Support/Annotations.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include <initializer_list>

namespace clang {
namespace clangd {
namespace {

// A referenced Decl together with its DeclRelationSet, for assertions.
//
// There's no great way to assert on the "content" of a Decl in the general case
// that's both expressive and unambiguous (e.g. clearly distinguishes between
// templated decls and their specializations).
//
// We use the result of pretty-printing the decl, with the {body} truncated.
struct PrintedDecl {
  PrintedDecl(const char *Name, DeclRelationSet Relations = {})
      : Name(Name), Relations(Relations) {}
  PrintedDecl(const Decl *D, DeclRelationSet Relations = {})
      : Relations(Relations) {
    std::string S;
    llvm::raw_string_ostream OS(S);
    D->print(OS);
    llvm::StringRef FirstLine =
        llvm::StringRef(OS.str()).take_until([](char C) { return C == '\n'; });
    FirstLine = FirstLine.rtrim(" {");
    Name = FirstLine.rtrim(" {");
  }

  std::string Name;
  DeclRelationSet Relations;
};
bool operator==(const PrintedDecl &L, const PrintedDecl &R) {
  return std::tie(L.Name, L.Relations) == std::tie(R.Name, R.Relations);
}
llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const PrintedDecl &D) {
  return OS << D.Name << " Rel=" << D.Relations;
}

// The test cases in for targetDecl() take the form
//  - a piece of code (Code = "...")
//  - Code should have a single AST node marked as a [[range]]
//  - an EXPECT_DECLS() assertion that verify the type of node selected, and
//    all the decls that targetDecl() considers it to reference
// Despite the name, these cases actually test allTargetDecls() for brevity.
class TargetDeclTest : public ::testing::Test {
protected:
  using Rel = DeclRelation;
  std::string Code;
  std::vector<const char *> Flags;

  // Asserts that `Code` has a marked selection of a node `NodeType`,
  // and returns allTargetDecls() as PrintedDecl structs.
  // Use via EXPECT_DECLS().
  std::vector<PrintedDecl> assertNodeAndPrintDecls(const char *NodeType) {
    llvm::Annotations A(Code);
    auto TU = TestTU::withCode(A.code());
    TU.ExtraArgs = Flags;
    auto AST = TU.build();
    EXPECT_THAT(AST.getDiagnostics(), ::testing::IsEmpty()) << Code;
    llvm::Annotations::Range R = A.range();
    SelectionTree Selection(AST.getASTContext(), AST.getTokens(), R.Begin,
                            R.End);
    const SelectionTree::Node *N = Selection.commonAncestor();
    if (!N) {
      ADD_FAILURE() << "No node selected!\n" << Code;
      return {};
    }
    EXPECT_EQ(N->kind(), NodeType) << Selection;

    std::vector<PrintedDecl> ActualDecls;
    for (const auto &Entry : allTargetDecls(N->ASTNode))
      ActualDecls.emplace_back(Entry.first, Entry.second);
    return ActualDecls;
  }
};

// This is a macro to preserve line numbers in assertion failures.
// It takes the expected decls as varargs to work around comma-in-macro issues.
#define EXPECT_DECLS(NodeType, ...)                                            \
  EXPECT_THAT(assertNodeAndPrintDecls(NodeType),                               \
              ::testing::UnorderedElementsAreArray(                            \
                  std::vector<PrintedDecl>({__VA_ARGS__})))                    \
      << Code
using ExpectedDecls = std::vector<PrintedDecl>;

TEST_F(TargetDeclTest, Exprs) {
  Code = R"cpp(
    int f();
    int x = [[f]]();
  )cpp";
  EXPECT_DECLS("DeclRefExpr", "int f()");

  Code = R"cpp(
    struct S { S operator+(S) const; };
    auto X = S() [[+]] S();
  )cpp";
  EXPECT_DECLS("DeclRefExpr", "S operator+(S) const");
}

TEST_F(TargetDeclTest, UsingDecl) {
  Code = R"cpp(
    namespace foo {
      int f(int);
      int f(char);
    }
    using foo::f;
    int x = [[f]](42);
  )cpp";
  // f(char) is not referenced!
  EXPECT_DECLS("DeclRefExpr", {"using foo::f", Rel::Alias},
               {"int f(int)", Rel::Underlying});

  Code = R"cpp(
    namespace foo {
      int f(int);
      int f(char);
    }
    [[using foo::f]];
  )cpp";
  // All overloads are referenced.
  EXPECT_DECLS("UsingDecl", {"using foo::f", Rel::Alias},
               {"int f(int)", Rel::Underlying},
               {"int f(char)", Rel::Underlying});

  Code = R"cpp(
    struct X {
      int foo();
    };
    struct Y : X {
      using X::foo;
    };
    int x = Y().[[foo]]();
  )cpp";
  EXPECT_DECLS("MemberExpr", {"using X::foo", Rel::Alias},
               {"int foo()", Rel::Underlying});
}

TEST_F(TargetDeclTest, ConstructorInitList) {
  Code = R"cpp(
    struct X {
      int a;
      X() : [[a]](42) {}
    };
  )cpp";
  EXPECT_DECLS("CXXCtorInitializer", "int a");

  Code = R"cpp(
    struct X {
      X() : [[X]](1) {}
      X(int);
    };
  )cpp";
  EXPECT_DECLS("RecordTypeLoc", "struct X");
}

TEST_F(TargetDeclTest, DesignatedInit) {
  Flags = {"-xc"}; // array designators are a C99 extension.
  Code = R"c(
    struct X { int a; };
    struct Y { int b; struct X c[2]; };
    struct Y y = { .c[0].[[a]] = 1 };
  )c";
  EXPECT_DECLS("DesignatedInitExpr", "int a");
}

TEST_F(TargetDeclTest, NestedNameSpecifier) {
  Code = R"cpp(
    namespace a { namespace b { int c; } }
    int x = a::[[b::]]c;
  )cpp";
  EXPECT_DECLS("NestedNameSpecifierLoc", "namespace b");

  Code = R"cpp(
    namespace a { struct X { enum { y }; }; }
    int x = a::[[X::]]y;
  )cpp";
  EXPECT_DECLS("NestedNameSpecifierLoc", "struct X");

  Code = R"cpp(
    template <typename T>
    int x = [[T::]]y;
  )cpp";
  // FIXME: We don't do a good job printing TemplateTypeParmDecls, apparently!
  EXPECT_DECLS("NestedNameSpecifierLoc", "");

  Code = R"cpp(
    namespace a { int x; }
    namespace b = a;
    int y = [[b]]::x;
  )cpp";
  EXPECT_DECLS("NestedNameSpecifierLoc", {"namespace b = a", Rel::Alias},
               {"namespace a", Rel::Underlying});
}

TEST_F(TargetDeclTest, Types) {
  Code = R"cpp(
    struct X{};
    [[X]] x;
  )cpp";
  EXPECT_DECLS("RecordTypeLoc", "struct X");

  Code = R"cpp(
    struct S{};
    typedef S X;
    [[X]] x;
  )cpp";
  EXPECT_DECLS("TypedefTypeLoc", {"typedef S X", Rel::Alias},
               {"struct S", Rel::Underlying});

  Code = R"cpp(
    template<class T>
    void foo() { [[T]] x; }
  )cpp";
  // FIXME: We don't do a good job printing TemplateTypeParmDecls, apparently!
  EXPECT_DECLS("TemplateTypeParmTypeLoc", "");

  Code = R"cpp(
    template<template<typename> class T>
    void foo() { [[T<int>]] x; }
  )cpp";
  EXPECT_DECLS("TemplateSpecializationTypeLoc", "template <typename> class T");

  Code = R"cpp(
    struct S{};
    S X;
    [[decltype]](X) Y;
  )cpp";
  EXPECT_DECLS("DecltypeTypeLoc", {"struct S", Rel::Underlying});

  Code = R"cpp(
    struct S{};
    [[auto]] X = S{};
  )cpp";
  // FIXME: deduced type missing in AST. https://llvm.org/PR42914
  EXPECT_DECLS("AutoTypeLoc");
}

TEST_F(TargetDeclTest, ClassTemplate) {
  Code = R"cpp(
    // Implicit specialization.
    template<int x> class Foo{};
    [[Foo<42>]] B;
  )cpp";
  EXPECT_DECLS("TemplateSpecializationTypeLoc",
               {"template<> class Foo<42>", Rel::TemplateInstantiation},
               {"class Foo", Rel::TemplatePattern});

  Code = R"cpp(
    // Explicit specialization.
    template<int x> class Foo{};
    template<> class Foo<42>{};
    [[Foo<42>]] B;
  )cpp";
  EXPECT_DECLS("TemplateSpecializationTypeLoc", "template<> class Foo<42>");

  Code = R"cpp(
    // Partial specialization.
    template<typename T> class Foo{};
    template<typename T> class Foo<T*>{};
    [[Foo<int*>]] B;
  )cpp";
  EXPECT_DECLS("TemplateSpecializationTypeLoc",
               {"template<> class Foo<int *>", Rel::TemplateInstantiation},
               {"template <typename T> class Foo<type-parameter-0-0 *>",
                Rel::TemplatePattern});
}

TEST_F(TargetDeclTest, FunctionTemplate) {
  Code = R"cpp(
    // Implicit specialization.
    template<typename T> bool foo(T) { return false; };
    bool x = [[foo]](42);
  )cpp";
  EXPECT_DECLS("DeclRefExpr",
               {"template<> bool foo<int>(int)", Rel::TemplateInstantiation},
               {"bool foo(T)", Rel::TemplatePattern});

  Code = R"cpp(
    // Explicit specialization.
    template<typename T> bool foo(T) { return false; };
    template<> bool foo<int>(int) { return false; };
    bool x = [[foo]](42);
  )cpp";
  EXPECT_DECLS("DeclRefExpr", "template<> bool foo<int>(int)");
}

TEST_F(TargetDeclTest, VariableTemplate) {
  // Pretty-printer doesn't do a very good job of variable templates :-(
  Code = R"cpp(
    // Implicit specialization.
    template<typename T> int foo;
    int x = [[foo]]<char>;
  )cpp";
  EXPECT_DECLS("DeclRefExpr", {"int foo", Rel::TemplateInstantiation},
               {"int foo", Rel::TemplatePattern});

  Code = R"cpp(
    // Explicit specialization.
    template<typename T> int foo;
    template <> bool foo<char>;
    int x = [[foo]]<char>;
  )cpp";
  EXPECT_DECLS("DeclRefExpr", "bool foo");

  Code = R"cpp(
    // Partial specialization.
    template<typename T> int foo;
    template<typename T> bool foo<T*>;
    bool x = [[foo]]<char*>;
  )cpp";
  EXPECT_DECLS("DeclRefExpr", {"bool foo", Rel::TemplateInstantiation},
               {"bool foo", Rel::TemplatePattern});
}

TEST_F(TargetDeclTest, TypeAliasTemplate) {
  Code = R"cpp(
    template<typename T, int X> class SmallVector {};
    template<typename U> using TinyVector = SmallVector<U, 1>;
    [[TinyVector<int>]] X;
  )cpp";
  EXPECT_DECLS("TemplateSpecializationTypeLoc",
               {"template<> class SmallVector<int, 1>",
                Rel::TemplateInstantiation | Rel::Underlying},
               {"class SmallVector", Rel::TemplatePattern | Rel::Underlying},
               {"using TinyVector = SmallVector<U, 1>",
                Rel::Alias | Rel::TemplatePattern});
}

TEST_F(TargetDeclTest, MemberOfTemplate) {
  Code = R"cpp(
    template <typename T> struct Foo {
      int x(T);
    };
    int y = Foo<int>().[[x]](42);
  )cpp";
  EXPECT_DECLS("MemberExpr", {"int x(int)", Rel::TemplateInstantiation},
               {"int x(T)", Rel::TemplatePattern});

  Code = R"cpp(
    template <typename T> struct Foo {
      template <typename U>
      int x(T, U);
    };
    int y = Foo<char>().[[x]]('c', 42);
  )cpp";
  EXPECT_DECLS("MemberExpr",
               {"template<> int x<int>(char, int)", Rel::TemplateInstantiation},
               {"int x(T, U)", Rel::TemplatePattern});
}

TEST_F(TargetDeclTest, Lambda) {
  Code = R"cpp(
    void foo(int x = 42) {
      auto l = [ [[x]] ]{ return x + 1; };
    };
  )cpp";
  EXPECT_DECLS("DeclRefExpr", "int x = 42");

  // It seems like this should refer to another var, with the outer param being
  // an underlying decl. But it doesn't seem to exist.
  Code = R"cpp(
    void foo(int x = 42) {
      auto l = [x]{ return [[x]] + 1; };
    };
  )cpp";
  EXPECT_DECLS("DeclRefExpr", "int x = 42");

  Code = R"cpp(
    void foo() {
      auto l = [x = 1]{ return [[x]] + 1; };
    };
  )cpp";
  // FIXME: why both auto and int?
  EXPECT_DECLS("DeclRefExpr", "auto int x = 1");
}

TEST_F(TargetDeclTest, OverloadExpr) {
  Code = R"cpp(
    void func(int*);
    void func(char*);

    template <class T>
    void foo(T t) {
      [[func]](t);
    };
  )cpp";
  EXPECT_DECLS("UnresolvedLookupExpr", "void func(int *)", "void func(char *)");

  Code = R"cpp(
    struct X {
      void func(int*);
      void func(char*);
    };

    template <class T>
    void foo(X x, T t) {
      x.[[func]](t);
    };
  )cpp";
  EXPECT_DECLS("UnresolvedMemberExpr", "void func(int *)", "void func(char *)");
}

TEST_F(TargetDeclTest, ObjC) {
  Flags = {"-xobjective-c"};
  Code = R"cpp(
    @interface Foo {}
    -(void)bar;
    @end
    void test(Foo *f) {
      [f [[bar]] ];
    }
  )cpp";
  EXPECT_DECLS("ObjCMessageExpr", "- (void)bar");

  Code = R"cpp(
    @interface Foo { @public int bar; }
    @end
    int test(Foo *f) {
      return [[f->bar]];
    }
  )cpp";
  EXPECT_DECLS("ObjCIvarRefExpr", "int bar");

  Code = R"cpp(
    @interface Foo {}
    -(int) x;
    -(void) setX:(int)x;
    @end
    void test(Foo *f) {
      [[f.x]] = 42;
    }
  )cpp";
  EXPECT_DECLS("ObjCPropertyRefExpr", "- (void)setX:(int)x");

  Code = R"cpp(
    @interface Foo {}
    @property int x;
    @end
    void test(Foo *f) {
      [[f.x]] = 42;
    }
  )cpp";
  EXPECT_DECLS("ObjCPropertyRefExpr",
               "@property(atomic, assign, unsafe_unretained, readwrite) int x");

  Code = R"cpp(
    @protocol Foo
    @end
    id test() {
      return [[@protocol(Foo)]];
    }
  )cpp";
  EXPECT_DECLS("ObjCProtocolExpr", "@protocol Foo");

  Code = R"cpp(
    @interface Foo
    @end
    void test([[Foo]] *p);
  )cpp";
  EXPECT_DECLS("ObjCInterfaceTypeLoc", "@interface Foo");

  Code = R"cpp(
    @protocol Foo
    @end
    void test([[id<Foo>]] p);
  )cpp";
  EXPECT_DECLS("ObjCObjectTypeLoc", "@protocol Foo");

  Code = R"cpp(
    @class C;
    @protocol Foo
    @end
    void test(C<[[Foo]]> *p);
  )cpp";
  // FIXME: there's no AST node corresponding to 'Foo', so we're stuck.
  EXPECT_DECLS("ObjCObjectTypeLoc");
}

class FindExplicitReferencesTest : public ::testing::Test {
protected:
  struct AllRefs {
    std::string AnnotatedCode;
    std::string DumpedReferences;
  };

  /// Parses \p Code, finds function '::foo' and annotates its body with results
  /// of findExplicitReferecnces.
  /// See actual tests for examples of annotation format.
  AllRefs annotateReferencesInFoo(llvm::StringRef Code) {
    TestTU TU;
    TU.Code = Code;

    auto AST = TU.build();

    auto *TestDecl = &findDecl(AST, "foo");
    if (auto *T = llvm::dyn_cast<FunctionTemplateDecl>(TestDecl))
      TestDecl = T->getTemplatedDecl();
    auto &Func = llvm::cast<FunctionDecl>(*TestDecl);

    std::vector<ReferenceLoc> Refs;
    findExplicitReferences(Func.getBody(), [&Refs](ReferenceLoc R) {
      Refs.push_back(std::move(R));
    });

    auto &SM = AST.getSourceManager();
    llvm::sort(Refs, [&](const ReferenceLoc &L, const ReferenceLoc &R) {
      return SM.isBeforeInTranslationUnit(L.NameLoc, R.NameLoc);
    });

    std::string AnnotatedCode;
    unsigned NextCodeChar = 0;
    for (unsigned I = 0; I < Refs.size(); ++I) {
      auto &R = Refs[I];

      SourceLocation Pos = R.NameLoc;
      assert(Pos.isValid());
      if (Pos.isMacroID()) // FIXME: figure out how to show macro locations.
        Pos = SM.getExpansionLoc(Pos);
      assert(Pos.isFileID());

      FileID File;
      unsigned Offset;
      std::tie(File, Offset) = SM.getDecomposedLoc(Pos);
      if (File == SM.getMainFileID()) {
        // Print the reference in a source code.
        assert(NextCodeChar <= Offset);
        AnnotatedCode += Code.substr(NextCodeChar, Offset - NextCodeChar);
        AnnotatedCode += "$" + std::to_string(I) + "^";

        NextCodeChar = Offset;
      }
    }
    AnnotatedCode += Code.substr(NextCodeChar);

    std::string DumpedReferences;
    for (unsigned I = 0; I < Refs.size(); ++I)
      DumpedReferences += llvm::formatv("{0}: {1}\n", I, Refs[I]);

    return AllRefs{std::move(AnnotatedCode), std::move(DumpedReferences)};
  }
};

TEST_F(FindExplicitReferencesTest, All) {
  std::pair</*Code*/ llvm::StringRef, /*References*/ llvm::StringRef> Cases[] =
      {
          // Simple expressions.
          {R"cpp(
        int global;
        int func();
        void foo(int param) {
          $0^global = $1^param + $2^func();
        }
        )cpp",
           "0: targets = {global}\n"
           "1: targets = {param}\n"
           "2: targets = {func}\n"},
          {R"cpp(
        struct X { int a; };
        void foo(X x) {
          $0^x.$1^a = 10;
        }
        )cpp",
           "0: targets = {x}\n"
           "1: targets = {X::a}\n"},
          // Namespaces and aliases.
          {R"cpp(
          namespace ns {}
          namespace alias = ns;
          void foo() {
            using namespace $0^ns;
            using namespace $1^alias;
          }
        )cpp",
           "0: targets = {ns}\n"
           "1: targets = {alias}\n"},
          // Using declarations.
          {R"cpp(
          namespace ns { int global; }
          void foo() {
            using $0^ns::$1^global;
          }
        )cpp",
           "0: targets = {ns}\n"
           "1: targets = {ns::global}, qualifier = 'ns::'\n"},
          // Simple types.
          {R"cpp(
         struct Struct { int a; };
         using Typedef = int;
         void foo() {
           $0^Struct x;
           $1^Typedef y;
           static_cast<$2^Struct*>(0);
         }
       )cpp",
           "0: targets = {Struct}\n"
           "1: targets = {Typedef}\n"
           "2: targets = {Struct}\n"},
          // Name qualifiers.
          {R"cpp(
         namespace a { namespace b { struct S { typedef int type; }; } }
         void foo() {
           $0^a::$1^b::$2^S x;
           using namespace $3^a::$4^b;
           $5^S::$6^type y;
         }
        )cpp",
           "0: targets = {a}\n"
           "1: targets = {a::b}, qualifier = 'a::'\n"
           "2: targets = {a::b::S}, qualifier = 'a::b::'\n"
           "3: targets = {a}\n"
           "4: targets = {a::b}, qualifier = 'a::'\n"
           "5: targets = {a::b::S}\n"
           "6: targets = {a::b::S::type}, qualifier = 'struct S::'\n"},
          // Simple templates.
          {R"cpp(
          template <class T> struct vector { using value_type = T; };
          template <> struct vector<bool> { using value_type = bool; };
          void foo() {
            $0^vector<int> vi;
            $1^vector<bool> vb;
          }
        )cpp",
           "0: targets = {vector<int>}\n"
           "1: targets = {vector<bool>}\n"},
          // Template type aliases.
          {R"cpp(
            template <class T> struct vector { using value_type = T; };
            template <> struct vector<bool> { using value_type = bool; };
            template <class T> using valias = vector<T>;
            void foo() {
              $0^valias<int> vi;
              $1^valias<bool> vb;
            }
          )cpp",
           "0: targets = {valias}\n"
           "1: targets = {valias}\n"},
          // MemberExpr should know their using declaration.
          {R"cpp(
            struct X { void func(int); }
            struct Y : X {
              using X::func;
            };
            void foo(Y y) {
              $0^y.$1^func(1);
            }
        )cpp",
           "0: targets = {y}\n"
           "1: targets = {Y::func}\n"},
          // DeclRefExpr should know their using declaration.
          {R"cpp(
            namespace ns { void bar(int); }
            using ns::bar;

            void foo() {
              $0^bar(10);
            }
        )cpp",
           "0: targets = {bar}\n"},
          // References from a macro.
          {R"cpp(
            #define FOO a
            #define BAR b

            void foo(int a, int b) {
              $0^FOO+$1^BAR;
            }
        )cpp",
           "0: targets = {a}\n"
           "1: targets = {b}\n"},
          // No references from implicit nodes.
          {R"cpp(
            struct vector {
              int *begin();
              int *end();
            };

            void foo() {
              for (int x : $0^vector()) {
                $1^x = 10;
              }
            }
        )cpp",
           "0: targets = {vector}\n"
           "1: targets = {x}\n"},
          // Handle UnresolvedLookupExpr.
          {R"cpp(
            namespace ns1 { void func(char*); }
            namespace ns2 { void func(int*); }
            using namespace ns1;
            using namespace ns2;

            template <class T>
            void foo(T t) {
              $0^func($1^t);
            }
        )cpp",
           "0: targets = {ns1::func, ns2::func}\n"
           "1: targets = {t}\n"},
          // Handle UnresolvedMemberExpr.
          {R"cpp(
            struct X {
              void func(char*);
              void func(int*);
            };

            template <class T>
            void foo(X x, T t) {
              $0^x.$1^func($2^t);
            }
        )cpp",
           "0: targets = {x}\n"
           "1: targets = {X::func, X::func}\n"
           "2: targets = {t}\n"},
          // Type template parameters.
          {R"cpp(
            template <class T>
            void foo() {
              static_cast<$0^T>(0);
              $1^T();
              $2^T t;
            }
        )cpp",
           "0: targets = {T}\n"
           "1: targets = {T}\n"
           "2: targets = {T}\n"},
          // Non-type template parameters.
          {R"cpp(
            template <int I>
            void foo() {
              int x = $0^I;
            }
        )cpp",
           "0: targets = {I}\n"},
      };

  for (const auto &C : Cases) {
    llvm::StringRef ExpectedCode = C.first;
    llvm::StringRef ExpectedRefs = C.second;

    auto Actual =
        annotateReferencesInFoo(llvm::Annotations(ExpectedCode).code());
    EXPECT_EQ(ExpectedCode, Actual.AnnotatedCode);
    EXPECT_EQ(ExpectedRefs, Actual.DumpedReferences) << ExpectedCode;
  }
}

} // namespace
} // namespace clangd
} // namespace clang