//
// Cforall Version 1.0.0 Copyright (C) 2018 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Demangler.cc --
//
// Author           : Rob Schluntz
// Created On       : Thu Jul 19 12:52:41 2018
// Last Modified By : Rob Schluntz
// Last Modified On : Thu Jul 19 12:54:35 2018
// Update Count     : 2
//

#include <algorithm>
#include <sstream>

#include "CodeGen/GenType.h"
#include "Common/PassVisitor.h"
#include "Mangler.h"
#include "SynTree/Type.h"
#include "SynTree/Declaration.h"

// #define DEBUG
#ifdef DEBUG
#define PRINT(x) x
#else
#define PRINT(x) {}
#endif

namespace {
	struct GenType : public WithVisitorRef<GenType>, public WithShortCircuiting {
		std::string typeString;
		GenType( const std::string &typeString );

		void previsit( BaseSyntaxNode * );
		void postvisit( BaseSyntaxNode * );

		void postvisit( FunctionType * funcType );
		void postvisit( VoidType * voidType );
		void postvisit( BasicType * basicType );
		void postvisit( PointerType * pointerType );
		void postvisit( ArrayType * arrayType );
		void postvisit( ReferenceType * refType );
		void postvisit( StructInstType * structInst );
		void postvisit( UnionInstType * unionInst );
		void postvisit( EnumInstType * enumInst );
		void postvisit( TypeInstType * typeInst );
		void postvisit( TupleType  * tupleType );
		void postvisit( VarArgsType * varArgsType );
		void postvisit( ZeroType * zeroType );
		void postvisit( OneType * oneType );
		void postvisit( GlobalScopeType * globalType );
		void postvisit( QualifiedType * qualType );

	  private:
		void handleQualifiers( Type *type );
		std::string handleGeneric( ReferenceToType * refType );
		void genArray( const Type::Qualifiers &qualifiers, Type *base, Expression *dimension, bool isVarLen, bool isStatic );
	};

  std::string genDemangleType( Type * type, const std::string & baseString ) {
		PassVisitor<GenType> gt( baseString );
		assert( type );
		type->accept( gt );
		return gt.pass.typeString;
  }

	GenType::GenType( const std::string &typeString ) : typeString( typeString ) {}

	// *** BaseSyntaxNode
	void GenType::previsit( BaseSyntaxNode * ) {
		// turn off automatic recursion for all nodes, to allow each visitor to
		// precisely control the order in which its children are visited.
		visit_children = false;
	}

	void GenType::postvisit( BaseSyntaxNode * node ) {
		std::stringstream ss;
		node->print( ss );
		assertf( false, "Unhandled node reached in GenType: %s", ss.str().c_str() );
	}

	void GenType::postvisit( VoidType * voidType ) {
		typeString = "void " + typeString;
		handleQualifiers( voidType );
	}

	void GenType::postvisit( BasicType * basicType ) {
		BasicType::Kind kind = basicType->kind;
		assert( 0 <= kind && kind < BasicType::NUMBER_OF_BASIC_TYPES );
		typeString = std::string( BasicType::typeNames[kind] ) + " " + typeString;
		handleQualifiers( basicType );
	}

	void GenType::genArray( const Type::Qualifiers & qualifiers, Type * base, Expression *dimension, bool isVarLen, bool ) {
		std::ostringstream os;
		if ( typeString != "" ) {
			if ( typeString[ 0 ] == '*' ) {
				os << "(" << typeString << ")";
			} else {
				os << typeString;
			} // if
		} // if
		os << "[";

		if ( qualifiers.is_const ) {
			os << "const ";
		} // if
		if ( qualifiers.is_volatile ) {
			os << "volatile ";
		} // if
		if ( qualifiers.is_restrict ) {
			os << "__restrict ";
		} // if
		if ( qualifiers.is_atomic ) {
			os << "_Atomic ";
		} // if
		if ( dimension != 0 ) {
			// TODO: ???
			// PassVisitor<CodeGenerator> cg( os, pretty, genC, lineMarks );
			// dimension->accept( cg );
		} else if ( isVarLen ) {
			// no dimension expression on a VLA means it came in with the * token
			os << "*";
		} // if
		os << "]";

		typeString = os.str();

		base->accept( *visitor );
	}

	void GenType::postvisit( PointerType * pointerType ) {
		assert( pointerType->base != 0);
		if ( pointerType->get_isStatic() || pointerType->get_isVarLen() || pointerType->dimension ) {
			assert(false);
			genArray( pointerType->get_qualifiers(), pointerType->base, pointerType->dimension, pointerType->get_isVarLen(), pointerType->get_isStatic() );
		} else {
			handleQualifiers( pointerType );
			if ( typeString[ 0 ] == '?' ) {
				typeString = "* " + typeString;
			} else {
				typeString = "*" + typeString;
			} // if
			pointerType->base->accept( *visitor );
		} // if
	}

	void GenType::postvisit( ArrayType * arrayType ) {
		genArray( arrayType->get_qualifiers(), arrayType->base, arrayType->dimension, arrayType->get_isVarLen(), arrayType->get_isStatic() );
	}

	void GenType::postvisit( ReferenceType * refType ) {
		assert( false );
		assert( refType->base != 0);
		handleQualifiers( refType );
		typeString = "&" + typeString;
		refType->base->accept( *visitor );
	}

	void GenType::postvisit( FunctionType * funcType ) {
		std::ostringstream os;

		if ( typeString != "" ) {
			if ( typeString[0] == '*' ) {
				os << "(" << typeString << ")";
			} else {
				os << typeString;
			} // if
		} // if

		/************* parameters ***************/
		const std::list<DeclarationWithType *> &pars = funcType->parameters;

		if ( pars.empty() ) {
			if ( funcType->get_isVarArgs() ) {
				os << "()";
			} else {
				os << "(void)";
			} // if
		} else {
			os << "(" ;

			unsigned int i = 0;
			for (DeclarationWithType * p : pars) {
				os << genDemangleType( p->get_type(), "" );
				if (++i != pars.size()) os << ", ";
			}

			if ( funcType->get_isVarArgs() ) {
				os << ", ...";
			} // if
			os << ")";
		} // if

		typeString = os.str();

		if ( funcType->returnVals.size() == 0 ) {
			typeString += ": void";
		} else {
			typeString += ": " + genDemangleType(funcType->returnVals.front()->get_type(), "");
		} // if

		// add forall
		if( ! funcType->forall.empty() ) {
			std::ostringstream os;
			os << "forall(";
			unsigned int i = 0;
			for ( auto td : funcType->forall ) {
				os << td->typeString() << " " << td->name;
				if (! td->assertions.empty()) {
					os << " | { ";
					unsigned int j = 0;
					for (DeclarationWithType * assert : td->assertions) {
						os << genDemangleType(assert->get_type(), assert->name);
						if (++j != td->assertions.size()) os << ", ";
					}
					os << "}";
				}
				if (++i != funcType->forall.size()) os << ", ";
			}
			os << ")";
			typeString = typeString + " -> " + os.str();
		}
	}

	std::string GenType::handleGeneric( ReferenceToType * refType ) {
		if ( ! refType->parameters.empty() ) {
			std::ostringstream os;
			// TODO: ???
			// PassVisitor<CodeGenerator> cg( os, pretty, genC, lineMarks );
			os << "(";
			// cg.pass.genCommaList( refType->parameters.begin(), refType->parameters.end() );
			os << ") ";
			return os.str();
		}
		return "";
	}

	void GenType::postvisit( StructInstType * structInst )  {
		typeString = "struct " + structInst->name + handleGeneric( structInst ) + " " + typeString;
		handleQualifiers( structInst );
	}

	void GenType::postvisit( UnionInstType * unionInst ) {
		typeString = "union " + unionInst->name + handleGeneric( unionInst ) + " " + typeString;
		handleQualifiers( unionInst );
	}

	void GenType::postvisit( EnumInstType * enumInst ) {
		typeString = "enum " + enumInst->name + " " + typeString;
		handleQualifiers( enumInst );
	}

	void GenType::postvisit( TypeInstType * typeInst ) {
		typeString = typeInst->name + " " + typeString;
		handleQualifiers( typeInst );
	}

	void GenType::postvisit( TupleType * tupleType ) {
		unsigned int i = 0;
		std::ostringstream os;
		os << "[";
		for ( Type * t : *tupleType ) {
			i++;
			os << genDemangleType( t, "" ) << (i == tupleType->size() ? "" : ", ");
		}
		os << "] ";
		typeString = os.str() + typeString;
	}

	void GenType::postvisit( VarArgsType * varArgsType ) {
		typeString = "__builtin_va_list " + typeString;
		handleQualifiers( varArgsType );
	}

	void GenType::postvisit( ZeroType * zeroType ) {
		// ideally these wouldn't hit codegen at all, but should be safe to make them ints
		typeString = "zero_t " + typeString;
		handleQualifiers( zeroType );
	}

	void GenType::postvisit( OneType * oneType ) {
		// ideally these wouldn't hit codegen at all, but should be safe to make them ints
		typeString = "one_t " + typeString;
		handleQualifiers( oneType );
	}

	void GenType::postvisit( GlobalScopeType * globalType ) {
		handleQualifiers( globalType );
	}

	void GenType::postvisit( QualifiedType * qualType ) {
		std::ostringstream os;
		os << genDemangleType( qualType->parent, "" ) << "." << genDemangleType( qualType->child, "" ) << typeString;
		typeString = os.str();
		handleQualifiers( qualType );
	}

	void GenType::handleQualifiers( Type * type ) {
		if ( type->get_const() ) {
			typeString = "const " + typeString;
		} // if
		if ( type->get_volatile() ) {
			typeString = "volatile " + typeString;
		} // if
		if ( type->get_restrict() ) {
			typeString = "__restrict " + typeString;
		} // if
		if ( type->get_atomic() ) {
			typeString = "_Atomic " + typeString;
		} // if
		if ( type->get_lvalue() ) {
			// when not generating C code, print lvalue for debugging.
			typeString = "lvalue " + typeString;
		}
	}
}


namespace SymTab {
	namespace Mangler {
		namespace {
			// strips __NAME__cfa__TYPE_N, where N is [0-9]+: returns str is a match is found, returns empty string otherwise
			bool stripMangleName(const std::string & mangleName, std::string & name, std::string & type) {
				PRINT( std::cerr << "====== " << mangleName.size() << " " << mangleName << std::endl; )
				if (mangleName.size() < 4+nameSeparator.size()) return false;
				if (mangleName[0] != '_' || mangleName[1] != '_' || ! isdigit(mangleName.back())) return false;

				// find bounds for name
				size_t nameStart = 2;
				size_t nameEnd = mangleName.rfind(nameSeparator);
				PRINT( std::cerr << nameStart << " " << nameEnd << std::endl; )
				if (nameEnd == std::string::npos) return false;

				// find bounds for type
				size_t typeStart = nameEnd+nameSeparator.size();
				size_t typeEnd = mangleName.size()-1;
				PRINT( std::cerr << typeStart << " " << typeEnd << std::endl; )
				PRINT( std::cerr << "[");
				while (isdigit(mangleName[typeEnd])) {
					PRINT(std::cerr << ".");
					typeEnd--;
				}
				PRINT( std::cerr << "]" << std::endl );
				if (mangleName[typeEnd] != '_') return false;
				PRINT( std::cerr << typeEnd << std::endl; )

				// trim and return
				name = mangleName.substr(nameStart, nameEnd-nameStart);
				type = mangleName.substr(typeStart, typeEnd-typeStart);
				return true;
			}

			/// determines if `pref` is a prefix of `str`
			static inline bool isPrefix( const std::string & str, const std::string & pref, unsigned int idx ) {
				if ( pref.size() > str.size()-idx ) return false;
				auto its = std::mismatch( pref.begin(), pref.end(), std::next(str.begin(), idx) );
				return its.first == pref.end();
			}

			Type * parseType(const std::string & typeString, unsigned int & idx) {
				if (idx >= typeString.size()) return nullptr;

				// qualifiers
				Type::Qualifiers tq;
				while (true) {
					auto qual = std::find_if(qualifierLetter.begin(), qualifierLetter.end(), [&idx, &typeString](decltype(qualifierLetter)::value_type val) {
						if (isPrefix(typeString, val.second, idx)) {
							PRINT( std::cerr << "found qualifier: " << val.second << std::endl; )
							idx += std::string(val.second).size();
							return true;
						}
						return false;
					});
					if (qual == qualifierLetter.end()) break;
					tq |= qual->first;
				}

				// basic types
				const char ** letter = std::find_if(&btLetter[0], &btLetter[numBtLetter], [&idx, &typeString](const std::string & letter) {
					if (isPrefix(typeString, letter, idx)) {
						idx += letter.size();
						return true;
					}
					return false;
				});
				if (letter != &btLetter[numBtLetter]) {
					PRINT( std::cerr << "basic type: " << (letter-btLetter) << std::endl; )
					BasicType::Kind k = (BasicType::Kind)(letter-btLetter);
					return new BasicType( tq, k );
				} // BasicType?

				// everything else
				switch(typeString[idx++]) {
					case 'F': {
						PRINT( std::cerr << "function..." << std::endl; )
						if (idx >= typeString.size()) return nullptr;
						FunctionType * ftype = new FunctionType( tq, false );
						Type * retVal = parseType(typeString, idx);
						if (! retVal) return nullptr;
						PRINT( std::cerr << "with return type: " << retVal << std::endl; )
						ftype->returnVals.push_back(ObjectDecl::newObject("", retVal, nullptr));
						if (idx >= typeString.size() || typeString[idx++] != '_') return nullptr;
						while (idx < typeString.size()) {
							PRINT( std::cerr << "got ch: " << typeString[idx] << std::endl; )
							if (typeString[idx] == '_') break;
							Type * param = parseType(typeString, idx);
							if (! param) return nullptr;
							PRINT( std::cerr << "with parameter : " << param << std::endl; )
							ftype->parameters.push_back(ObjectDecl::newObject("", param, nullptr));
						}
						if (idx >= typeString.size() || typeString[idx] != '_') return nullptr;
						++idx;
						return ftype;
					}
					case 'v':
						return new VoidType( tq );
					case 'T': {
						PRINT( std::cerr << "tuple..." << std::endl; )
						std::list< Type * > types;
						while (idx < typeString.size()) {
							PRINT( std::cerr << "got ch: " << typeString[idx] << std::endl; )
							if (typeString[idx] == '_') break;
							Type * t = parseType(typeString, idx);
							if (! t) return nullptr;
							PRINT( std::cerr << "with type : " << t << std::endl; )
							types.push_back(t);
						}
						if (idx >= typeString.size() || typeString[idx] != '_') return nullptr;
						++idx;
						return new TupleType( tq, types );
					}
					case 'P': {
						PRINT( std::cerr << "pointer..." << std::endl; )
						Type * t = parseType(typeString, idx);
						if (! t) return nullptr;
						return new PointerType( tq, t );
					}

					default: assertf(false, "Unhandled type letter: %c at index: %u", typeString[idx], idx);
				}
				return nullptr;
			}

			Type * parseType(const std::string & typeString) {
				unsigned int idx = 0;
				return parseType(typeString, idx);
			}
		} // namespace
	} // namespace Mangler
} // namespace SymTab

extern "C" {
	std::string cforall_demangle(const std::string & mangleName) {
		std::string name, type;
		if (! SymTab::Mangler::stripMangleName(mangleName, name, type)) return mangleName;
		PRINT( std::cerr << name << " " << type << std::endl; )
		Type * t = SymTab::Mangler::parseType(type);
		if (! t) return mangleName;
		return genDemangleType(t, name);
	} // extern "C"
}

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //