/*
 * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
 * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
 * Copyright (c) 2021, Gunnar Beutner <gbeutner@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <LibCrypto/BigInt/SignedBigInteger.h>
#include <LibJS/Bytecode/Instruction.h>
#include <LibJS/Bytecode/Label.h>
#include <LibJS/Bytecode/Register.h>
#include <LibJS/Bytecode/StringTable.h>
#include <LibJS/Heap/Cell.h>
#include <LibJS/Runtime/ScopeObject.h>
#include <LibJS/Runtime/Value.h>

namespace JS::Bytecode::Op {

class Load final : public Instruction {
public:
    explicit Load(Register src)
        : Instruction(Type::Load)
        , m_src(src)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Register m_src;
};

class LoadImmediate final : public Instruction {
public:
    explicit LoadImmediate(Value value)
        : Instruction(Type::LoadImmediate)
        , m_value(value)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Value m_value;
};

class Store final : public Instruction {
public:
    explicit Store(Register dst)
        : Instruction(Type::Store)
        , m_dst(dst)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Register m_dst;
};

#define JS_ENUMERATE_COMMON_BINARY_OPS(O)     \
    O(Add, add)                               \
    O(Sub, sub)                               \
    O(Mul, mul)                               \
    O(Div, div)                               \
    O(Exp, exp)                               \
    O(Mod, mod)                               \
    O(In, in)                                 \
    O(InstanceOf, instance_of)                \
    O(GreaterThan, greater_than)              \
    O(GreaterThanEquals, greater_than_equals) \
    O(LessThan, less_than)                    \
    O(LessThanEquals, less_than_equals)       \
    O(AbstractInequals, abstract_inequals)    \
    O(AbstractEquals, abstract_equals)        \
    O(TypedInequals, typed_inequals)          \
    O(TypedEquals, typed_equals)              \
    O(BitwiseAnd, bitwise_and)                \
    O(BitwiseOr, bitwise_or)                  \
    O(BitwiseXor, bitwise_xor)                \
    O(LeftShift, left_shift)                  \
    O(RightShift, right_shift)                \
    O(UnsignedRightShift, unsigned_right_shift)

#define JS_DECLARE_COMMON_BINARY_OP(OpTitleCase, op_snake_case)   \
    class OpTitleCase final : public Instruction {                \
    public:                                                       \
        explicit OpTitleCase(Register lhs_reg)                    \
            : Instruction(Type::OpTitleCase)                      \
            , m_lhs_reg(lhs_reg)                                  \
        {                                                         \
        }                                                         \
                                                                  \
        void execute_impl(Bytecode::Interpreter&) const;          \
        String to_string_impl(Bytecode::Executable const&) const; \
                                                                  \
    private:                                                      \
        Register m_lhs_reg;                                       \
    };

JS_ENUMERATE_COMMON_BINARY_OPS(JS_DECLARE_COMMON_BINARY_OP)
#undef JS_DECLARE_COMMON_BINARY_OP

#define JS_ENUMERATE_COMMON_UNARY_OPS(O) \
    O(BitwiseNot, bitwise_not)           \
    O(Not, not_)                         \
    O(UnaryPlus, unary_plus)             \
    O(UnaryMinus, unary_minus)           \
    O(Typeof, typeof_)

#define JS_DECLARE_COMMON_UNARY_OP(OpTitleCase, op_snake_case)    \
    class OpTitleCase final : public Instruction {                \
    public:                                                       \
        OpTitleCase()                                             \
            : Instruction(Type::OpTitleCase)                      \
        {                                                         \
        }                                                         \
                                                                  \
        void execute_impl(Bytecode::Interpreter&) const;          \
        String to_string_impl(Bytecode::Executable const&) const; \
    };

JS_ENUMERATE_COMMON_UNARY_OPS(JS_DECLARE_COMMON_UNARY_OP)
#undef JS_DECLARE_COMMON_UNARY_OP

class NewString final : public Instruction {
public:
    explicit NewString(StringTableIndex string)
        : Instruction(Type::NewString)
        , m_string(string)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    StringTableIndex m_string;
};

class NewObject final : public Instruction {
public:
    NewObject()
        : Instruction(Type::NewObject)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

class NewBigInt final : public Instruction {
public:
    explicit NewBigInt(Crypto::SignedBigInteger bigint)
        : Instruction(Type::NewBigInt)
        , m_bigint(move(bigint))
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Crypto::SignedBigInteger m_bigint;
};

// NOTE: This instruction is variable-width depending on the number of elements!
class NewArray final : public Instruction {
public:
    explicit NewArray(Vector<Register> const& elements)
        : Instruction(Type::NewArray)
        , m_element_count(elements.size())
    {
        for (size_t i = 0; i < m_element_count; ++i)
            m_elements[i] = elements[i];
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

    size_t length_impl() const { return sizeof(*this) + sizeof(Register) * m_element_count; }

private:
    size_t m_element_count { 0 };
    Register m_elements[];
};

class ConcatString final : public Instruction {
public:
    explicit ConcatString(Register lhs)
        : Instruction(Type::ConcatString)
        , m_lhs(lhs)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Register m_lhs;
};

class SetVariable final : public Instruction {
public:
    explicit SetVariable(StringTableIndex identifier)
        : Instruction(Type::SetVariable)
        , m_identifier(identifier)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    StringTableIndex m_identifier;
};

class GetVariable final : public Instruction {
public:
    explicit GetVariable(StringTableIndex identifier)
        : Instruction(Type::GetVariable)
        , m_identifier(identifier)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    StringTableIndex m_identifier;
};

class GetById final : public Instruction {
public:
    explicit GetById(StringTableIndex property)
        : Instruction(Type::GetById)
        , m_property(property)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    StringTableIndex m_property;
};

class PutById final : public Instruction {
public:
    explicit PutById(Register base, StringTableIndex property)
        : Instruction(Type::PutById)
        , m_base(base)
        , m_property(property)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Register m_base;
    StringTableIndex m_property;
};

class GetByValue final : public Instruction {
public:
    explicit GetByValue(Register base)
        : Instruction(Type::GetByValue)
        , m_base(base)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Register m_base;
};

class PutByValue final : public Instruction {
public:
    PutByValue(Register base, Register property)
        : Instruction(Type::PutByValue)
        , m_base(base)
        , m_property(property)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Register m_base;
    Register m_property;
};

class Jump : public Instruction {
public:
    constexpr static bool IsTerminator = true;

    explicit Jump(Type type, Optional<Label> taken_target = {}, Optional<Label> nontaken_target = {})
        : Instruction(type)
        , m_true_target(move(taken_target))
        , m_false_target(move(nontaken_target))
    {
    }

    explicit Jump(Optional<Label> taken_target = {}, Optional<Label> nontaken_target = {})
        : Instruction(Type::Jump)
        , m_true_target(move(taken_target))
        , m_false_target(move(nontaken_target))
    {
    }

    void set_targets(Optional<Label> true_target, Optional<Label> false_target)
    {
        m_true_target = move(true_target);
        m_false_target = move(false_target);
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

protected:
    Optional<Label> m_true_target;
    Optional<Label> m_false_target;
};

class JumpConditional final : public Jump {
public:
    explicit JumpConditional(Optional<Label> true_target = {}, Optional<Label> false_target = {})
        : Jump(Type::JumpConditional, move(true_target), move(false_target))
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

class JumpNullish final : public Jump {
public:
    explicit JumpNullish(Optional<Label> true_target = {}, Optional<Label> false_target = {})
        : Jump(Type::JumpNullish, move(true_target), move(false_target))
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

// NOTE: This instruction is variable-width depending on the number of arguments!
class Call final : public Instruction {
public:
    enum class CallType {
        Call,
        Construct,
    };

    Call(CallType type, Register callee, Register this_value, Vector<Register> const& arguments)
        : Instruction(Type::Call)
        , m_callee(callee)
        , m_this_value(this_value)
        , m_type(type)
        , m_argument_count(arguments.size())
    {
        for (size_t i = 0; i < m_argument_count; ++i)
            m_arguments[i] = arguments[i];
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

    size_t length_impl() const { return sizeof(*this) + sizeof(Register) * m_argument_count; }

private:
    Register m_callee;
    Register m_this_value;
    CallType m_type;
    size_t m_argument_count { 0 };
    Register m_arguments[];
};

class NewFunction final : public Instruction {
public:
    explicit NewFunction(FunctionNode const& function_node)
        : Instruction(Type::NewFunction)
        , m_function_node(function_node)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    FunctionNode const& m_function_node;
};

class Return final : public Instruction {
public:
    constexpr static bool IsTerminator = true;

    Return()
        : Instruction(Type::Return)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

class Increment final : public Instruction {
public:
    Increment()
        : Instruction(Type::Increment)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

class Decrement final : public Instruction {
public:
    Decrement()
        : Instruction(Type::Decrement)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

class Throw final : public Instruction {
public:
    constexpr static bool IsTerminator = true;

    Throw()
        : Instruction(Type::Throw)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

class EnterUnwindContext final : public Instruction {
public:
    constexpr static bool IsTerminator = true;

    EnterUnwindContext(Label entry_point, Optional<Label> handler_target, Optional<Label> finalizer_target)
        : Instruction(Type::EnterUnwindContext)
        , m_entry_point(move(entry_point))
        , m_handler_target(move(handler_target))
        , m_finalizer_target(move(finalizer_target))
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Label m_entry_point;
    Optional<Label> m_handler_target;
    Optional<Label> m_finalizer_target;
};

class LeaveUnwindContext final : public Instruction {
public:
    LeaveUnwindContext()
        : Instruction(Type::LeaveUnwindContext)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;
};

class ContinuePendingUnwind final : public Instruction {
public:
    constexpr static bool IsTerminator = true;

    explicit ContinuePendingUnwind(Label resume_target)
        : Instruction(Type::ContinuePendingUnwind)
        , m_resume_target(resume_target)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Label m_resume_target;
};

class Yield final : public Instruction {
public:
    constexpr static bool IsTerminator = true;

    explicit Yield(Label continuation_label)
        : Instruction(Type::Yield)
        , m_continuation_label(continuation_label)
    {
    }

    explicit Yield(std::nullptr_t)
        : Instruction(Type::Yield)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    Optional<Label> m_continuation_label;
};

class PushLexicalEnvironment final : public Instruction {
public:
    explicit PushLexicalEnvironment(HashMap<u32, Variable> variables)
        : Instruction(Type::PushLexicalEnvironment)
        , m_variables(move(variables))
    {
    }
    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    HashMap<u32, Variable> m_variables;
};

class LoadArgument final : public Instruction {
public:
    explicit LoadArgument(size_t index)
        : Instruction(Type::LoadArgument)
        , m_index(index)
    {
    }

    void execute_impl(Bytecode::Interpreter&) const;
    String to_string_impl(Bytecode::Executable const&) const;

private:
    size_t m_index { 0 };
};

}

namespace JS::Bytecode {

ALWAYS_INLINE void Instruction::execute(Bytecode::Interpreter& interpreter) const
{
#define __BYTECODE_OP(op)       \
    case Instruction::Type::op: \
        return static_cast<Bytecode::Op::op const&>(*this).execute_impl(interpreter);

    switch (type()) {
        ENUMERATE_BYTECODE_OPS(__BYTECODE_OP)
    default:
        VERIFY_NOT_REACHED();
    }

#undef __BYTECODE_OP
}

ALWAYS_INLINE size_t Instruction::length() const
{
    if (type() == Type::Call)
        return static_cast<Op::Call const&>(*this).length_impl();
    else if (type() == Type::NewArray)
        return static_cast<Op::NewArray const&>(*this).length_impl();

#define __BYTECODE_OP(op) \
    case Type::op:        \
        return sizeof(Op::op);

    switch (type()) {
        ENUMERATE_BYTECODE_OPS(__BYTECODE_OP)
    default:
        VERIFY_NOT_REACHED();
    }
#undef __BYTECODE_OP
}

}