// SPDX-License-Identifier: Apache-2.0

// SPDX-FileCopyrightText: Copyright The WasmEdge Authors

#pragma once

#include "ast/component/type.h"

#include "common/types.h"

#include "runtime/instance/function.h"

#include "runtime/instance/memory.h"

#include <memory>

namespace WasmEdge {

namespace Runtime {

namespace Instance {

class ComponentInstance; // forward decl for parent component pointer

namespace Component {

class FunctionInstance {

  // The component function instance currently can only be instantiated by the

  // `canon lift` operation. For the component host functions, the extension may

  // be implemented in the future.

public:

  FunctionInstance() = delete;

  /// Move constructor.

  FunctionInstance(FunctionInstance &&Inst) noexcept

      : FuncType(Inst.FuncType), LowerFunc(Inst.LowerFunc),

        MemInst(Inst.MemInst), ReallocFunc(Inst.ReallocFunc),

        PostReturnFunc(Inst.PostReturnFunc), ParentComp(Inst.ParentComp),

        Enc(Inst.Enc) {}

  /// Constructor for component native function. `PR` is the optional

  /// post-return core function (CanonicalABI.md L3367-3372); pass nullptr

  /// when the canon lift declared no post-return option.

  FunctionInstance(const AST::Component::FuncType &Type,

                   Runtime::Instance::FunctionInstance *F,

                   Runtime::Instance::MemoryInstance *M,

                   Runtime::Instance::FunctionInstance *R,

                   const Runtime::Instance::ComponentInstance *P,

                   Runtime::Instance::FunctionInstance *PR = nullptr,

                   StringEncoding E = StringEncoding::UTF8) noexcept

      : FuncType(Type), LowerFunc(F), MemInst(M), ReallocFunc(R),

        PostReturnFunc(PR), ParentComp(P), Enc(E) {}

  /// Getter for component function type.

  const AST::Component::FuncType &getFuncType() const noexcept {

    return FuncType;

  }

  /// Getter for lower core function instance.

  Runtime::Instance::FunctionInstance *getLowerFunction() const noexcept {

    return LowerFunc;

  }

  /// Getter for memory instance to value conversion.

  Runtime::Instance::MemoryInstance *getMemoryInstance() const noexcept {

    return MemInst;

  }

  /// Getter for allocation core function instance.

  Runtime::Instance::FunctionInstance *getAllocFunction() const noexcept {

    return ReallocFunc;

  }

  /// Getter for the owning component instance. Required for resolving

  /// TypeIndex-based component types through the canonical ABI.

  const Runtime::Instance::ComponentInstance *

  getComponentInstance() const noexcept {

    return ParentComp;

  }

  /// Getter for the post-return core function instance, or nullptr when the

  /// canon lift declared no post-return option (CanonicalABI.md L3367-3372).

  Runtime::Instance::FunctionInstance *getPostReturnFunction() const noexcept {

    return PostReturnFunc;

  }

  /// Getter for the guest string encoding declared by the canon lift's

  /// `string-encoding` option (defaults to UTF-8).

  StringEncoding getStringEncoding() const noexcept { return Enc; }

protected:

  const AST::Component::FuncType &FuncType;

  Runtime::Instance::FunctionInstance *LowerFunc;

  Runtime::Instance::MemoryInstance *MemInst;

  Runtime::Instance::FunctionInstance *ReallocFunc;

  Runtime::Instance::FunctionInstance *PostReturnFunc;

  const Runtime::Instance::ComponentInstance *ParentComp;

  StringEncoding Enc;

};

} // namespace Component

} // namespace Instance

} // namespace Runtime

} // namespace WasmEdge