// Copyright 2020 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SRC_WRITER_WGSL_GENERATOR_IMPL_H_
#define SRC_WRITER_WGSL_GENERATOR_IMPL_H_

#include <string>

#include "src/ast/assignment_statement.h"
#include "src/ast/binary_expression.h"
#include "src/ast/bitcast_expression.h"
#include "src/ast/break_statement.h"
#include "src/ast/continue_statement.h"
#include "src/ast/discard_statement.h"
#include "src/ast/fallthrough_statement.h"
#include "src/ast/for_loop_statement.h"
#include "src/ast/if_statement.h"
#include "src/ast/index_accessor_expression.h"
#include "src/ast/loop_statement.h"
#include "src/ast/member_accessor_expression.h"
#include "src/ast/return_statement.h"
#include "src/ast/switch_statement.h"
#include "src/ast/unary_op_expression.h"
#include "src/program.h"
#include "src/sem/storage_texture_type.h"
#include "src/sem/struct.h"
#include "src/writer/text_generator.h"

namespace tint {
namespace writer {
namespace wgsl {

/// Implementation class for WGSL generator
class GeneratorImpl : public TextGenerator {
 public:
  /// Constructor
  /// @param program the program
  explicit GeneratorImpl(const Program* program);
  ~GeneratorImpl();

  /// Generates the result data
  /// @returns true on successful generation; false otherwise
  bool Generate();

  /// Handles generating a declared type
  /// @param ty the declared type to generate
  /// @returns true if the declared type was emitted
  bool EmitTypeDecl(const ast::TypeDecl* ty);
  /// Handles an index accessor expression
  /// @param out the output of the expression stream
  /// @param expr the expression to emit
  /// @returns true if the index accessor was emitted
  bool EmitIndexAccessor(std::ostream& out,
                         const ast::IndexAccessorExpression* expr);
  /// Handles an assignment statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emitted successfully
  bool EmitAssign(const ast::AssignmentStatement* stmt);
  /// Handles generating a binary expression
  /// @param out the output of the expression stream
  /// @param expr the binary expression
  /// @returns true if the expression was emitted, false otherwise
  bool EmitBinary(std::ostream& out, const ast::BinaryExpression* expr);
  /// Handles generating a bitcast expression
  /// @param out the output of the expression stream
  /// @param expr the bitcast expression
  /// @returns true if the bitcast was emitted
  bool EmitBitcast(std::ostream& out, const ast::BitcastExpression* expr);
  /// Handles a block statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emitted successfully
  bool EmitBlock(const ast::BlockStatement* stmt);
  /// Handles a break statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emitted successfully
  bool EmitBreak(const ast::BreakStatement* stmt);
  /// Handles generating a call expression
  /// @param out the output of the expression stream
  /// @param expr the call expression
  /// @returns true if the call expression is emitted
  bool EmitCall(std::ostream& out, const ast::CallExpression* expr);
  /// Handles a case statement
  /// @param stmt the statement
  /// @returns true if the statment was emitted successfully
  bool EmitCase(const ast::CaseStatement* stmt);
  /// Handles generating a literal expression
  /// @param out the output of the expression stream
  /// @param expr the literal expression expression
  /// @returns true if the literal expression is emitted
  bool EmitLiteral(std::ostream& out, const ast::LiteralExpression* expr);
  /// Handles a continue statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emitted successfully
  bool EmitContinue(const ast::ContinueStatement* stmt);
  /// Handles generate an Expression
  /// @param out the output of the expression stream
  /// @param expr the expression
  /// @returns true if the expression was emitted
  bool EmitExpression(std::ostream& out, const ast::Expression* expr);
  /// Handles generating a fallthrough statement
  /// @param stmt the fallthrough statement
  /// @returns true if the statement was successfully emitted
  bool EmitFallthrough(const ast::FallthroughStatement* stmt);
  /// Handles generating a function
  /// @param func the function to generate
  /// @returns true if the function was emitted
  bool EmitFunction(const ast::Function* func);
  /// Handles generating an identifier expression
  /// @param out the output of the expression stream
  /// @param expr the identifier expression
  /// @returns true if the identifier was emitted
  bool EmitIdentifier(std::ostream& out, const ast::IdentifierExpression* expr);
  /// Handles an if statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was successfully emitted
  bool EmitIf(const ast::IfStatement* stmt);
  /// Handles generating a discard statement
  /// @param stmt the discard statement
  /// @returns true if the statement was successfully emitted
  bool EmitDiscard(const ast::DiscardStatement* stmt);
  /// Handles a loop statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emtited
  bool EmitLoop(const ast::LoopStatement* stmt);
  /// Handles a for-loop statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emtited
  bool EmitForLoop(const ast::ForLoopStatement* stmt);
  /// Handles a member accessor expression
  /// @param out the output of the expression stream
  /// @param expr the member accessor expression
  /// @returns true if the member accessor was emitted
  bool EmitMemberAccessor(std::ostream& out,
                          const ast::MemberAccessorExpression* expr);
  /// Handles return statements
  /// @param stmt the statement to emit
  /// @returns true if the statement was successfully emitted
  bool EmitReturn(const ast::ReturnStatement* stmt);
  /// Handles statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emitted
  bool EmitStatement(const ast::Statement* stmt);
  /// Handles a statement list
  /// @param stmts the statements to emit
  /// @returns true if the statements were emitted
  bool EmitStatements(const ast::StatementList& stmts);
  /// Handles a statement list with an increased indentation
  /// @param stmts the statements to emit
  /// @returns true if the statements were emitted
  bool EmitStatementsWithIndent(const ast::StatementList& stmts);
  /// Handles generating a switch statement
  /// @param stmt the statement to emit
  /// @returns true if the statement was emitted
  bool EmitSwitch(const ast::SwitchStatement* stmt);
  /// Handles generating type
  /// @param out the output of the expression stream
  /// @param type the type to generate
  /// @returns true if the type is emitted
  bool EmitType(std::ostream& out, const ast::Type* type);
  /// Handles generating a struct declaration
  /// @param str the struct
  /// @returns true if the struct is emitted
  bool EmitStructType(const ast::Struct* str);
  /// Handles emitting an image format
  /// @param out the output of the expression stream
  /// @param fmt the format to generate
  /// @returns true if the format is emitted
  bool EmitImageFormat(std::ostream& out, const ast::TexelFormat fmt);
  /// Handles emitting an access control
  /// @param out the output of the expression stream
  /// @param access the access to generate
  /// @returns true if the access is emitted
  bool EmitAccess(std::ostream& out, const ast::Access access);
  /// Handles a unary op expression
  /// @param out the output of the expression stream
  /// @param expr the expression to emit
  /// @returns true if the expression was emitted
  bool EmitUnaryOp(std::ostream& out, const ast::UnaryOpExpression* expr);
  /// Handles generating a variable
  /// @param out the output of the expression stream
  /// @param var the variable to generate
  /// @returns true if the variable was emitted
  bool EmitVariable(std::ostream& out, const ast::Variable* var);
  /// Handles generating a attribute list
  /// @param out the output of the expression stream
  /// @param attrs the attribute list
  /// @returns true if the attributes were emitted
  bool EmitAttributes(std::ostream& out, const ast::AttributeList& attrs);
};

}  // namespace wgsl
}  // namespace writer
}  // namespace tint

#endif  // SRC_WRITER_WGSL_GENERATOR_IMPL_H_